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Use of Systems Biology for Design of inhibitor of Galectins as Cancer Therapeutic – Strategy and Software

Curator: Stephen J. Williams, Ph.D.

Below is a slide representation of the overall mission 4 to produce a PROTAC to inhibit Galectins 1, 3, and 9.

 

Using A Priori Knowledge of Galectin Receptor Interaction to Create a BioModel of Galectin 3 Binding

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Now after collecting literature from PubMed on “galectin-3” AND “binding” to determine literature containing kinetic data we generate a WordCloud on the articles.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This following file contains the articles needed for BioModels generation.

https://pharmaceuticalintelligence.com/wp-content/uploads/2022/12/Curating-Galectin-articles-for-Biomodels.docx

 

From the WordCloud we can see that these corpus of articles describe galectin binding to the CRD (carbohydrate recognition domain).  Interestingly there are many articles which describe van Der Waals interactions as well as electrostatic interactions.  Certain carbohydrate modifictions like Lac NAc and Gal 1,4 may be important.  Many articles describe the bonding as well as surface  interactions.  Many studies have been performed with galectin inhibitors like TDGs (thio-digalactosides) like TAZ TDG (3-deoxy-3-(4-[m-fluorophenyl]-1H-1,2,3-triazol-1-yl)-thio-digalactoside).  This led to an interesting article

Dual thio-digalactoside-binding modes of human galectins as the structural basis for the design of potent and selective inhibitors

Affiliations 2016 Jul 15;6:29457.
 doi: 10.1038/srep29457. Free PMC article

Abstract

Human galectins are promising targets for cancer immunotherapeutic and fibrotic disease-related drugs. We report herein the binding interactions of three thio-digalactosides (TDGs) including TDG itself, TD139 (3,3′-deoxy-3,3′-bis-(4-[m-fluorophenyl]-1H-1,2,3-triazol-1-yl)-thio-digalactoside, recently approved for the treatment of idiopathic pulmonary fibrosis), and TAZTDG (3-deoxy-3-(4-[m-fluorophenyl]-1H-1,2,3-triazol-1-yl)-thio-digalactoside) with human galectins-1, -3 and -7 as assessed by X-ray crystallography, isothermal titration calorimetry and NMR spectroscopy. Five binding subsites (A-E) make up the carbohydrate-recognition domains of these galectins. We identified novel interactions between an arginine within subsite E of the galectins and an arene group in the ligands. In addition to the interactions contributed by the galactosyl sugar residues bound at subsites C and D, the fluorophenyl group of TAZTDG preferentially bound to subsite B in galectin-3, whereas the same group favored binding at subsite E in galectins-1 and -7. The characterised dual binding modes demonstrate how binding potency, reported as decreased Kd values of the TDG inhibitors from μM to nM, is improved and also offer insights to development of selective inhibitors for individual galectins.

Figures

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Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners

Curator: Stephen J. Williams, Ph.D.

First please see the summary of LPBI efforts into development of inhibitors of Galectin-3 for cancer therapeutics

Mission 4: Use of Systems Biology for Design of inhibitor of Galectins as Cancer Therapeutic – Strategy and Software

The following paper in Cells describes the discovery of protein interactors of endoglin, which is recruited to membranes at the TGF-β receptor complex upon TGF-β signaling. Interesting a carbohydrate binding protein, galectin-3, and an E3-ligase, TRIM21, were found to be unique interactors within this complex.

Gallardo-Vara E, Ruiz-Llorente L, Casado-Vela J, Ruiz-Rodríguez MJ, López-Andrés N, Pattnaik AK, Quintanilla M, Bernabeu C. Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners. Cells. 2019 Sep 13;8(9):1082. doi: 10.3390/cells8091082. PMID: 31540324; PMCID: PMC6769930.

Abstract

Endoglin is a 180-kDa glycoprotein receptor primarily expressed by the vascular endothelium and involved in cardiovascular disease and cancer. Heterozygous mutations in the endoglin gene (ENG) cause hereditary hemorrhagic telangiectasia type 1, a vascular disease that presents with nasal and gastrointestinal bleeding, skin and mucosa telangiectases, and arteriovenous malformations in internal organs. A circulating form of endoglin (alias soluble endoglin, sEng), proteolytically released from the membrane-bound protein, has been observed in several inflammation-related pathological conditions and appears to contribute to endothelial dysfunction and cancer development through unknown mechanisms. Membrane-bound endoglin is an auxiliary component of the TGF-β receptor complex and the extracellular region of endoglin has been shown to interact with types I and II TGF-β receptors, as well as with BMP9 and BMP10 ligands, both members of the TGF-β family. To search for novel protein interactors, we screened a microarray containing over 9000 unique human proteins using recombinant sEng as bait. We find that sEng binds with high affinity, at least, to 22 new proteins. Among these, we validated the interaction of endoglin with galectin-3, a secreted member of the lectin family with capacity to bind membrane glycoproteins, and with tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin-protein ligase. Using human endothelial cells and Chinese hamster ovary cells, we showed that endoglin co-immunoprecipitates and co-localizes with galectin-3 or TRIM21. These results open new research avenues on endoglin function and regulation.

Source: https://www.mdpi.com/2073-4409/8/9/1082/htm

Endoglin is an auxiliary TGF-β co-receptor predominantly expressed in endothelial cells, which is involved in vascular development, repair, homeostasis, and disease [1,2,3,4]. Heterozygous mutations in the human ENDOGLIN gene (ENG) cause hereditary hemorrhagic telangiectasia (HHT) type 1, a vascular disease associated with nasal and gastrointestinal bleeds, telangiectases on skin and mucosa and arteriovenous malformations in the lung, liver, and brain [4,5,6]. The key role of endoglin in the vasculature is also illustrated by the fact that endoglin-KO mice die in utero due to defects in the vascular system [7]. Endoglin expression is markedly upregulated in proliferating endothelial cells involved in active angiogenesis, including the solid tumor neovasculature [8,9]. For this reason, endoglin has become a promising target for the antiangiogenic treatment of cancer [10,11,12]. Endoglin is also expressed in cancer cells where it can behave as both a tumor suppressor in prostate, breast, esophageal, and skin carcinomas [13,14,15,16] and a promoter of malignancy in melanoma and Ewing’s sarcoma [17]. Ectodomain shedding of membrane-bound endoglin may lead to a circulating form of the protein, also known as soluble endoglin (sEng) [18,19,20]. Increased levels of sEng have been found in several vascular-related pathologies, including preeclampsia, a disease of high prevalence in pregnant women which, if left untreated, can lead to serious and even fatal complications for both mother and baby [2,18,19,21]. Interestingly, several lines of evidence support a pathogenic role of sEng in the vascular system, including endothelial dysfunction, antiangiogenic activity, increased vascular permeability, inflammation-associated leukocyte adhesion and transmigration, and hypertension [18,22,23,24,25,26,27]. Because of its key role in vascular pathology, a large number of studies have addressed the structure and function of endoglin at the molecular level, in order to better understand its mechanism of action.

 Galectin-3 Interacts with Endoglin in Cells

Galectin-3 is a secreted member of the lectin family with the capacity to bind membrane glycoproteins like endoglin and is involved in the pathogenesis of many human diseases [52]. We confirmed the protein screen data for galectin-3, as evidenced by two-way co-immunoprecipitation of endoglin and galectin-3 upon co-transfection in CHO-K1 cells. As shown in Figure 1A, galectin-3 and endoglin were efficiently transfected, as demonstrated by Western blot analysis in total cell extracts. No background levels of endoglin were observed in control cells transfected with the empty vector (Ø). By contrast, galectin-3 could be detected in all samples but, as expected, showed an increased signal in cells transfected with the galectin-3 expression vector. Co-immunoprecipitation studies of these cell lysates showed that galectin-3 was present in endoglin immunoprecipitates (Figure 1B). Conversely, endoglin was also detected in galectin-3 immunoprecipitates (Figure 1C).

Cells 08 01082 g001 550

Figure 1. Protein–protein association between galectin-3 and endoglin. (AC). Co-immunoprecipitation of galectin-3 and endoglin. CHO-K1 cells were transiently transfected with pcEXV-Ø (Ø), pcEXV–HA–EngFL (Eng) and pcDNA3.1–Gal-3 (Gal3) expression vectors. (A) Total cell lysates (TCL) were analyzed by SDS-PAGE under reducing conditions, followed by Western blot (WB) analysis using specific antibodies to endoglin, galectin-3 and β-actin (loading control). Cell lysates were subjected to immunoprecipitation (IP) with anti-endoglin (B) or anti-galectin-3 (C) antibodies, followed by SDS-PAGE under reducing conditions and WB analysis with anti-endoglin or anti-galectin-3 antibodies, as indicated. Negative controls with an IgG2b (B) and IgG1 (C) were included. (D) Protein-protein interactions between galectin-3 and endoglin using Bio-layer interferometry (BLItz). The Ni–NTA biosensors tips were loaded with 7.3 µM recombinant human galectin-3/6xHis at the C-terminus (LGALS3), and protein binding was measured against 0.1% BSA in PBS (negative control) or 4.1 µM soluble endoglin (sEng). Kinetic sensorgrams were obtained using a single channel ForteBioBLItzTM instrument.

Cells 08 01082 g002 550

Figure 2.Galectin-3 and endoglin co-localize in human endothelial cells. Human umbilical vein-derived endothelial cell (HUVEC) monolayers were fixed with paraformaldehyde, permeabilized with Triton X-100, incubated with the mouse mAb P4A4 anti-endoglin, washed, and incubated with a rabbit polyclonal anti-galectin-3 antibody (PA5-34819). Galectin-3 and endoglin were detected by immunofluorescence upon incubation with Alexa 647 goat anti-rabbit IgG (red staining) and Alexa 488 goat anti-mouse IgG (green staining) secondary antibodies, respectively. (A) Single staining of galectin-3 (red) and endoglin (green) at the indicated magnifications. (B) Merge images plus DAPI (nuclear staining in blue) show co-localization of galectin-3 and endoglin (yellow color). Representative images of five different experiments are shown.

Endoglin associates with the cullin-type E3 ligase TRIM21
Cells 08 01082 g003 550

Figure 3.Protein–protein association between TRIM21 and endoglin. (AE) Co-immunoprecipitation of TRIM21 and endoglin. A,B. HUVEC monolayers were lysed and total cell lysates (TCL) were subjected to SDS-PAGE under reducing (for TRIM21 detection) or nonreducing (for endoglin detection) conditions, followed by Western blot (WB) analysis using antibodies to endoglin, TRIM21 or β-actin (A). HUVECs lysates were subjected to immunoprecipitation (IP) with anti-TRIM21 or negative control antibodies, followed by WB analysis with anti-endoglin (B). C,D. CHO-K1 cells were transiently transfected with pDisplay–HA–Mock (Ø), pDisplay–HA–EngFL (E) or pcDNA3.1–HA–hTRIM21 (T) expression vectors, as indicated. Total cell lysates (TCL) were subjected to SDS-PAGE under nonreducing conditions and WB analysis using specific antibodies to endoglin, TRIM21, and β-actin (C). Cell lysates were subjected to immunoprecipitation (IP) with anti-TRIM21 or anti-endoglin antibodies, followed by SDS-PAGE under reducing (upper panel) or nonreducing (lower panel) conditions and WB analysis with anti-TRIM21 or anti-endoglin antibodies. Negative controls of appropriate IgG were included (D). E. CHO-K1 cells were transiently transfected with pcDNA3.1–HA–hTRIM21 and pDisplay–HA–Mock (Ø), pDisplay–HA–EngFL (FL; full-length), pDisplay–HA–EngEC (EC; cytoplasmic-less) or pDisplay–HA–EngTMEC (TMEC; cytoplasmic-less) expression vectors, as indicated. Cell lysates were subjected to immunoprecipitation with anti-TRIM21, followed by SDS-PAGE under reducing conditions and WB analysis with anti-endoglin antibodies, as indicated. The asterisk indicates the presence of a nonspecific band. Mr, molecular reference; Eng, endoglin; TRIM, TRIM21. (F) Protein–protein interactions between TRIM21 and endoglin using Bio-layer interferometry (BLItz). The Ni–NTA biosensors tips were loaded with 5.4 µM recombinant human TRIM21/6xHis at the N-terminus (R052), and protein binding was measured against 0.1% BSA in PBS (negative control) or 4.1 µM soluble endoglin (sEng). Kinetic sensorgrams were obtained using a single channel ForteBioBLItzTM instrument.

Table 1. Human protein-array analysis of endoglin interactors1.

Accession #Protein NameCellular Compartment
NM_172160.1Potassium voltage-gated channel, shaker-related subfamily, beta member 1 (KCNAB1), transcript variant 1Plasma membrane
Q14722
NM_138565.1Cortactin (CTTN), transcript variant 2Plasma membrane
Q14247
BC036123.1Stromal membrane-associated protein 1 (SMAP1)Plasma membrane
Q8IYB5
NM_173822.1Family with sequence similarity 126, member B (FAM126B)Plasma membrane, cytosol
Q8IXS8
BC047536.1Sciellin (SCEL)Plasma membrane, extracellular or secreted
O95171
BC068068.1Galectin-3Plasma membrane, mitochondrion, nucleus, extracellular or secreted
P17931
BC001247.1Actin-binding LIM protein 1 (ABLIM1)Cytoskeleton
O14639
NM_198943.1Family with sequence similarity 39, member B (FAM39B)Endosome, cytoskeleton
Q6VEQ5
NM_005898.4Cell cycle associated protein 1 (CAPRIN1), transcript variant 1Cytosol
Q14444
BC002559.1YTH domain family, member 2 (YTHDF2)Nucleus, cytosol
Q9Y5A9
NM_003141.2Tripartite motif-containing 21 (TRIM21)Nucleus, cytosol
P19474
BC025279.1Scaffold attachment factor B2 (SAFB2)Nucleus
Q14151
BC031650.1Putative E3 ubiquitin-protein ligase SH3RF2Nucleus
Q8TEC5
BC034488.2ATP-binding cassette, sub-family F (GCN20), member 1 (ABCF1)Nucleus
Q8NE71
BC040946.1Spliceosome-associated protein CWC15 homolog (HSPC148)Nucleus
Q9P013
NM_003609.2HIRA interacting protein 3 (HIRIP3)Nucleus
Q9BW71
NM_005572.1Lamin A/C (LMNA), transcript variant 2Nucleus
P02545
NM_006479.2RAD51 associated protein 1 (RAD51AP1)Nucleus
Q96B01
NM_014321.2Origin recognition complex, subunit 6 like (yeast) (ORC6L)Nucleus
Q9Y5N6
NM_015138.2RNA polymerase-associated protein RTF1 homolog (RTF1)Nucleus
Q92541
NM_032141.1Coiled-coil domain containing 55 (CCDC55), transcript variant 1Nucleus
Q9H0G5
BC012289.1Protein PRRC2B, KIAA0515Data not available
Q5JSZ5

1 Microarrays containing over 9000 unique human proteins were screened using recombinant sEng as a probe. Protein interactors showing the highest scores (Z-score ≥2.0) are listed. GeneBank (https://www.ncbi.nlm.nih.gov/genbank/) and UniProtKB (https://www.uniprot.org/help/uniprotkb) accession numbers are indicated with a yellow or green background, respectively. The cellular compartment of each protein was obtained from the UniProtKB webpage. Proteins selected for further studies (TRIM21 and galectin-3) are indicated in bold type with blue background.

Note: the following are from NCBI Genbank and Genecards on TRIM21

 From Genbank: https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=DetailsSearch&Term=6737

TRIM21 tripartite motif containing 21 [ Homo sapiens (human) ]

Gene ID: 6737, updated on 6-Sep-2022

Summary

Official Symbol TRIM21provided by HGNC Official Full Name tripartite motif containing 21provided by HGNC Primary source HGNC:HGNC:11312 See related Ensembl:ENSG00000132109MIM:109092;AllianceGenome:HGNC:11312 Gene type protein coding RefSeq status REVIEWED Organism Homo sapiens Lineage Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo Also known as SSA; RO52; SSA1; RNF81; Ro/SSA Summary This gene encodes a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The encoded protein is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus. RoSSA interacts with autoantigens in patients with Sjogren syndrome and systemic lupus erythematosus. Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined. [provided by RefSeq, Jul 2008] Expression Ubiquitous expression in spleen (RPKM 15.5), appendix (RPKM 13.2) and 24 other tissues See more Orthologs mouseall NEW Try the new Gene table
Try the new Transcript table

Genomic context

See TRIM21 in Genome Data Viewer Location:   11p15.4 Exon count:   7

Annotation releaseStatusAssemblyChrLocation
110currentGRCh38.p14 (GCF_000001405.40)11NC_000011.10 (4384897..4393702, complement)
110currentT2T-CHM13v2.0 (GCF_009914755.1)11NC_060935.1 (4449988..4458819, complement)
105.20220307previous assemblyGRCh37.p13 (GCF_000001405.25)11NC_000011.9 (4406127..4414932, complement)

Chromosome 11 – NC_000011.10Genomic Context describing neighboring genes

Bibliography

Related articles in PubMed

  1. TRIM21 inhibits the osteogenic differentiation of mesenchymal stem cells by facilitating K48 ubiquitination-mediated degradation of Akt.Xian J, et al. Exp Cell Res, 2022 Mar 15. PMID 35051432
  2. A Promising Intracellular Protein-Degradation Strategy: TRIMbody-Away Technique Based on Nanobody Fragment.Chen G, et al. Biomolecules, 2021 Oct 14. PMID 34680146, Free PMC Article
  3. Induced TRIM21 ISGylation by IFN-β enhances p62 ubiquitination to prevent its autophagosome targeting.Jin J, et al. Cell Death Dis, 2021 Jul 13. PMID 34257278, Free PMC Article
  4. TRIM21 Polymorphisms are associated with Susceptibility and Clinical Status of Oral Squamous Cell Carcinoma patients.Chuang CY, et al. Int J Med Sci, 2021. PMID 34220328, Free PMC Article
  5. TRIM21 inhibits porcine epidemic diarrhea virus proliferation by proteasomal degradation of the nucleocapsid protein.Wang H, et al. Arch Virol, 2021 Jul. PMID 33900472, Free PMC Article

From GeneCard:https://www.genecards.org/cgi-bin/carddisp.pl?gene=TRIM21

Entrez Gene Summary for TRIM21 Gene

  • This gene encodes a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The encoded protein is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus. RoSSA interacts with autoantigens in patients with Sjogren syndrome and systemic lupus erythematosus. Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined. [provided by RefSeq, Jul 2008]

GeneCards Summary for TRIM21 Gene

TRIM21 (Tripartite Motif Containing 21) is a Protein Coding gene. Diseases associated with TRIM21 include Heart Block, Congenital and Sjogren Syndrome. Among its related pathways are Cytosolic sensors of pathogen-associated DNA and KEAP1-NFE2L2 pathway. Gene Ontology (GO) annotations related to this gene include identical protein binding and ligase activity. An important paralog of this gene is TRIM6.

UniProtKB/Swiss-Prot Summary for TRIM21 Gene

E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2. Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination. Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes. A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B (‘Thr-187’ phosphorylated-form), thereby promoting its degradation by the proteasome. Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling. Negatively regulates IFN-beta production post-pathogen recognition by polyubiquitin-mediated degradation of IRF3. Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway. Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages. Plays a role in the regulation of the cell cycle progression. Enhances the decapping activity of DCP2. Exists as a ribonucleoprotein particle present in all mammalian cells studied and composed of a single polypeptide and one of four small RNA molecules. At least two isoforms are present in nucleated and red blood cells, and tissue specific differences in RO/SSA proteins have been identified. The common feature of these proteins is their ability to bind HY RNAs.2. Involved in the regulation of innate immunity and the inflammatory response in response to IFNG/IFN-gamma. Organizes autophagic machinery by serving as a platform for the assembly of ULK1, Beclin 1/BECN1 and ATG8 family members and recognizes specific autophagy targets, thus coordinating target recognition with assembly of the autophagic apparatus and initiation of autophagy. Acts as an autophagy receptor for the degradation of IRF3, hence attenuating type I interferon (IFN)-dependent immune responses (PubMed:26347139162978621631662716472766168805111802269418361920186413151884514219675099). Represses the innate antiviral response by facilitating the formation of the NMI-IFI35 complex through ‘Lys-63’-linked ubiquitination of NMI (PubMed:26342464). ( RO52_HUMAN,P19474 )

Molecular function for TRIM21 Gene according to UniProtKB/Swiss-Prot

Function:

  • E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2.
    Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination.
    Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes.
    A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B (‘Thr-187’ phosphorylated-form), thereby promoting its degradation by the proteasome.
    Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling.
    Negatively regulates IFN-beta production post-pathogen recognition by polyubiquitin-mediated degradation of IRF3.
    Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway.
    Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages.
    Plays a role in the regulation of the cell cycle progression.

Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners

Gallardo-Vara E, Ruiz-Llorente L, Casado-Vela J, Ruiz-Rodríguez MJ, López-Andrés N, Pattnaik AK, Quintanilla M, Bernabeu C. Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners. Cells. 2019 Sep 13;8(9):1082. doi: 10.3390/cells8091082. PMID: 31540324; PMCID: PMC6769930.

Abstract

Endoglin is a 180-kDa glycoprotein receptor primarily expressed by the vascular endothelium and involved in cardiovascular disease and cancer. Heterozygous mutations in the endoglin gene (ENG) cause hereditary hemorrhagic telangiectasia type 1, a vascular disease that presents with nasal and gastrointestinal bleeding, skin and mucosa telangiectases, and arteriovenous malformations in internal organs. A circulating form of endoglin (alias soluble endoglin, sEng), proteolytically released from the membrane-bound protein, has been observed in several inflammation-related pathological conditions and appears to contribute to endothelial dysfunction and cancer development through unknown mechanisms. Membrane-bound endoglin is an auxiliary component of the TGF-β receptor complex and the extracellular region of endoglin has been shown to interact with types I and II TGF-β receptors, as well as with BMP9 and BMP10 ligands, both members of the TGF-β family. To search for novel protein interactors, we screened a microarray containing over 9000 unique human proteins using recombinant sEng as bait. We find that sEng binds with high affinity, at least, to 22 new proteins. Among these, we validated the interaction of endoglin with galectin-3, a secreted member of the lectin family with capacity to bind membrane glycoproteins, and with tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin-protein ligase. Using human endothelial cells and Chinese hamster ovary cells, we showed that endoglin co-immunoprecipitates and co-localizes with galectin-3 or TRIM21. These results open new research avenues on endoglin function and regulation.
 
 
Endoglin is an auxiliary TGF-β co-receptor predominantly expressed in endothelial cells, which is involved in vascular development, repair, homeostasis, and disease [1,2,3,4]. Heterozygous mutations in the human ENDOGLIN gene (ENG) cause hereditary hemorrhagic telangiectasia (HHT) type 1, a vascular disease associated with nasal and gastrointestinal bleeds, telangiectases on skin and mucosa and arteriovenous malformations in the lung, liver, and brain [4,5,6]. The key role of endoglin in the vasculature is also illustrated by the fact that endoglin-KO mice die in utero due to defects in the vascular system [7]. Endoglin expression is markedly upregulated in proliferating endothelial cells involved in active angiogenesis, including the solid tumor neovasculature [8,9]. For this reason, endoglin has become a promising target for the antiangiogenic treatment of cancer [10,11,12]. Endoglin is also expressed in cancer cells where it can behave as both a tumor suppressor in prostate, breast, esophageal, and skin carcinomas [13,14,15,16] and a promoter of malignancy in melanoma and Ewing’s sarcoma [17]. Ectodomain shedding of membrane-bound endoglin may lead to a circulating form of the protein, also known as soluble endoglin (sEng) [18,19,20]. Increased levels of sEng have been found in several vascular-related pathologies, including preeclampsia, a disease of high prevalence in pregnant women which, if left untreated, can lead to serious and even fatal complications for both mother and baby [2,18,19,21]. Interestingly, several lines of evidence support a pathogenic role of sEng in the vascular system, including endothelial dysfunction, antiangiogenic activity, increased vascular permeability, inflammation-associated leukocyte adhesion and transmigration, and hypertension [18,22,23,24,25,26,27]. Because of its key role in vascular pathology, a large number of studies have addressed the structure and function of endoglin at the molecular level, in order to better understand its mechanism of action.
 

 Galectin-3 Interacts with Endoglin in Cells

Galectin-3 is a secreted member of the lectin family with the capacity to bind membrane glycoproteins like endoglin and is involved in the pathogenesis of many human diseases [52]. We confirmed the protein screen data for galectin-3, as evidenced by two-way co-immunoprecipitation of endoglin and galectin-3 upon co-transfection in CHO-K1 cells. As shown in Figure 1A, galectin-3 and endoglin were efficiently transfected, as demonstrated by Western blot analysis in total cell extracts. No background levels of endoglin were observed in control cells transfected with the empty vector (Ø). By contrast, galectin-3 could be detected in all samples but, as expected, showed an increased signal in cells transfected with the galectin-3 expression vector. Co-immunoprecipitation studies of these cell lysates showed that galectin-3 was present in endoglin immunoprecipitates (Figure 1B). Conversely, endoglin was also detected in galectin-3 immunoprecipitates (Figure 1C).
Figure 1. Protein–protein association between galectin-3 and endoglin. (AC). Co-immunoprecipitation of galectin-3 and endoglin. CHO-K1 cells were transiently transfected with pcEXV-Ø (Ø), pcEXV–HA–EngFL (Eng) and pcDNA3.1–Gal-3 (Gal3) expression vectors. (A) Total cell lysates (TCL) were analyzed by SDS-PAGE under reducing conditions, followed by Western blot (WB) analysis using specific antibodies to endoglin, galectin-3 and β-actin (loading control). Cell lysates were subjected to immunoprecipitation (IP) with anti-endoglin (B) or anti-galectin-3 (C) antibodies, followed by SDS-PAGE under reducing conditions and WB analysis with anti-endoglin or anti-galectin-3 antibodies, as indicated. Negative controls with an IgG2b (B) and IgG1 (C) were included. (D) Protein-protein interactions between galectin-3 and endoglin using Bio-layer interferometry (BLItz). The Ni–NTA biosensors tips were loaded with 7.3 µM recombinant human galectin-3/6xHis at the C-terminus (LGALS3), and protein binding was measured against 0.1% BSA in PBS (negative control) or 4.1 µM soluble endoglin (sEng). Kinetic sensorgrams were obtained using a single channel ForteBioBLItzTM instrument.
Figure 2. Galectin-3 and endoglin co-localize in human endothelial cells. Human umbilical vein-derived endothelial cell (HUVEC) monolayers were fixed with paraformaldehyde, permeabilized with Triton X-100, incubated with the mouse mAb P4A4 anti-endoglin, washed, and incubated with a rabbit polyclonal anti-galectin-3 antibody (PA5-34819). Galectin-3 and endoglin were detected by immunofluorescence upon incubation with Alexa 647 goat anti-rabbit IgG (red staining) and Alexa 488 goat anti-mouse IgG (green staining) secondary antibodies, respectively. (A) Single staining of galectin-3 (red) and endoglin (green) at the indicated magnifications. (B) Merge images plus DAPI (nuclear staining in blue) show co-localization of galectin-3 and endoglin (yellow color). Representative images of five different experiments are shown.
  
Endoglin associates with the cullin-type E3 ligase TRIM21
 
Figure 3. Protein–protein association between TRIM21 and endoglin. (AE) Co-immunoprecipitation of TRIM21 and endoglin. A,B. HUVEC monolayers were lysed and total cell lysates (TCL) were subjected to SDS-PAGE under reducing (for TRIM21 detection) or nonreducing (for endoglin detection) conditions, followed by Western blot (WB) analysis using antibodies to endoglin, TRIM21 or β-actin (A). HUVECs lysates were subjected to immunoprecipitation (IP) with anti-TRIM21 or negative control antibodies, followed by WB analysis with anti-endoglin (B). C,D. CHO-K1 cells were transiently transfected with pDisplay–HA–Mock (Ø), pDisplay–HA–EngFL (E) or pcDNA3.1–HA–hTRIM21 (T) expression vectors, as indicated. Total cell lysates (TCL) were subjected to SDS-PAGE under nonreducing conditions and WB analysis using specific antibodies to endoglin, TRIM21, and β-actin (C). Cell lysates were subjected to immunoprecipitation (IP) with anti-TRIM21 or anti-endoglin antibodies, followed by SDS-PAGE under reducing (upper panel) or nonreducing (lower panel) conditions and WB analysis with anti-TRIM21 or anti-endoglin antibodies. Negative controls of appropriate IgG were included (D). E. CHO-K1 cells were transiently transfected with pcDNA3.1–HA–hTRIM21 and pDisplay–HA–Mock (Ø), pDisplay–HA–EngFL (FL; full-length), pDisplay–HA–EngEC (EC; cytoplasmic-less) or pDisplay–HA–EngTMEC (TMEC; cytoplasmic-less) expression vectors, as indicated. Cell lysates were subjected to immunoprecipitation with anti-TRIM21, followed by SDS-PAGE under reducing conditions and WB analysis with anti-endoglin antibodies, as indicated. The asterisk indicates the presence of a nonspecific band. Mr, molecular reference; Eng, endoglin; TRIM, TRIM21. (F) Protein–protein interactions between TRIM21 and endoglin using Bio-layer interferometry (BLItz). The Ni–NTA biosensors tips were loaded with 5.4 µM recombinant human TRIM21/6xHis at the N-terminus (R052), and protein binding was measured against 0.1% BSA in PBS (negative control) or 4.1 µM soluble endoglin (sEng). Kinetic sensorgrams were obtained using a single channel ForteBioBLItzTM instrument.
 
Table 1. Human protein-array analysis of endoglin interactors1.
Accession # Protein Name Cellular Compartment
NM_172160.1 Potassium voltage-gated channel, shaker-related subfamily, beta member 1 (KCNAB1), transcript variant 1 Plasma membrane
Q14722
NM_138565.1 Cortactin (CTTN), transcript variant 2 Plasma membrane
Q14247
BC036123.1 Stromal membrane-associated protein 1 (SMAP1) Plasma membrane
Q8IYB5
NM_173822.1 Family with sequence similarity 126, member B (FAM126B) Plasma membrane, cytosol
Q8IXS8
BC047536.1 Sciellin (SCEL) Plasma membrane, extracellular or secreted
O95171
BC068068.1 Galectin-3 Plasma membrane, mitochondrion, nucleus, extracellular or secreted
P17931
BC001247.1 Actin-binding LIM protein 1 (ABLIM1) Cytoskeleton
O14639
NM_198943.1 Family with sequence similarity 39, member B (FAM39B) Endosome, cytoskeleton
Q6VEQ5
NM_005898.4 Cell cycle associated protein 1 (CAPRIN1), transcript variant 1 Cytosol
Q14444
BC002559.1 YTH domain family, member 2 (YTHDF2) Nucleus, cytosol
Q9Y5A9
NM_003141.2 Tripartite motif-containing 21 (TRIM21) Nucleus, cytosol
P19474
BC025279.1 Scaffold attachment factor B2 (SAFB2) Nucleus
Q14151
BC031650.1 Putative E3 ubiquitin-protein ligase SH3RF2 Nucleus
Q8TEC5
BC034488.2 ATP-binding cassette, sub-family F (GCN20), member 1 (ABCF1) Nucleus
Q8NE71
BC040946.1 Spliceosome-associated protein CWC15 homolog (HSPC148) Nucleus
Q9P013
NM_003609.2 HIRA interacting protein 3 (HIRIP3) Nucleus
Q9BW71
NM_005572.1 Lamin A/C (LMNA), transcript variant 2 Nucleus
P02545
NM_006479.2 RAD51 associated protein 1 (RAD51AP1) Nucleus
Q96B01
NM_014321.2 Origin recognition complex, subunit 6 like (yeast) (ORC6L) Nucleus
Q9Y5N6
NM_015138.2 RNA polymerase-associated protein RTF1 homolog (RTF1) Nucleus
Q92541
NM_032141.1 Coiled-coil domain containing 55 (CCDC55), transcript variant 1 Nucleus
Q9H0G5
BC012289.1 Protein PRRC2B, KIAA0515 Data not available
Q5JSZ5
1 Microarrays containing over 9000 unique human proteins were screened using recombinant sEng as a probe. Protein interactors showing the highest scores (Z-score ≥2.0) are listed. GeneBank (https://www.ncbi.nlm.nih.gov/genbank/) and UniProtKB (https://www.uniprot.org/help/uniprotkb) accession numbers are indicated with a yellow or green background, respectively. The cellular compartment of each protein was obtained from the UniProtKB webpage. Proteins selected for further studies (TRIM21 and galectin-3) are indicated in bold type with blue background.
  

Note: the following are from NCBI Genbank and Genecards on TRIM21

TRIM21 tripartite motif containing 21 [ Homo sapiens (human) ]

Gene ID: 6737, updated on 6-Sep-2022

Summary
Official Symbol
TRIM21provided by HGNC
Official Full Name
tripartite motif containing 21provided by HGNC
Primary source
HGNC:HGNC:11312
See related
Ensembl:ENSG00000132109 MIM:109092; AllianceGenome:HGNC:11312
Gene type
protein coding
RefSeq status
REVIEWED
Organism
Homo sapiens
Lineage
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
Also known as
SSA; RO52; SSA1; RNF81; Ro/SSA
Summary
This gene encodes a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The encoded protein is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus. RoSSA interacts with autoantigens in patients with Sjogren syndrome and systemic lupus erythematosus. Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined. [provided by RefSeq, Jul 2008]
Expression
Ubiquitous expression in spleen (RPKM 15.5), appendix (RPKM 13.2) and 24 other tissues See more
Orthologs
NEW
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Try the new Transcript table
Genomic context
 
See TRIM21 in Genome Data Viewer
Location:
11p15.4
Exon count:
7
Annotation release Status Assembly Chr Location
110 current GRCh38.p14 (GCF_000001405.40) 11 NC_000011.10 (4384897..4393702, complement)
110 current T2T-CHM13v2.0 (GCF_009914755.1) 11 NC_060935.1 (4449988..4458819, complement)
105.20220307 previous assembly GRCh37.p13 (GCF_000001405.25) 11 NC_000011.9 (4406127..4414932, complement)

Chromosome 11 – NC_000011.10Genomic Context describing neighboring genes

Neighboring gene olfactory receptor family 52 subfamily B member 4 Neighboring gene olfactory receptor family 52 subfamily B member 3 pseudogene Neighboring gene olfactory receptor family 51 subfamily R member 1 pseudogene Neighboring gene olfactory receptor family 52 subfamily P member 2 pseudogene

 

Entrez Gene Summary for TRIM21 Gene

  • This gene encodes a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The encoded protein is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus. RoSSA interacts with autoantigens in patients with Sjogren syndrome and systemic lupus erythematosus. Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined. [provided by RefSeq, Jul 2008]

GeneCards Summary for TRIM21 Gene

TRIM21 (Tripartite Motif Containing 21) is a Protein Coding gene. Diseases associated with TRIM21 include Heart Block, Congenital and Sjogren Syndrome. Among its related pathways are Cytosolic sensors of pathogen-associated DNA and KEAP1-NFE2L2 pathway. Gene Ontology (GO) annotations related to this gene include identical protein binding and ligase activity. An important paralog of this gene is TRIM6.

UniProtKB/Swiss-Prot Summary for TRIM21 Gene

E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2. Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination. Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes. A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B (‘Thr-187’ phosphorylated-form), thereby promoting its degradation by the proteasome. Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling. Negatively regulates IFN-beta production post-pathogen recognition by polyubiquitin-mediated degradation of IRF3. Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway. Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages. Plays a role in the regulation of the cell cycle progression. Enhances the decapping activity of DCP2. Exists as a ribonucleoprotein particle present in all mammalian cells studied and composed of a single polypeptide and one of four small RNA molecules. At least two isoforms are present in nucleated and red blood cells, and tissue specific differences in RO/SSA proteins have been identified. The common feature of these proteins is their ability to bind HY RNAs.2. Involved in the regulation of innate immunity and the inflammatory response in response to IFNG/IFN-gamma. Organizes autophagic machinery by serving as a platform for the assembly of ULK1, Beclin 1/BECN1 and ATG8 family members and recognizes specific autophagy targets, thus coordinating target recognition with assembly of the autophagic apparatus and initiation of autophagy. Acts as an autophagy receptor for the degradation of IRF3, hence attenuating type I interferon (IFN)-dependent immune responses (PubMed:26347139162978621631662716472766168805111802269418361920186413151884514219675099). Represses the innate antiviral response by facilitating the formation of the NMI-IFI35 complex through ‘Lys-63’-linked ubiquitination of NMI (PubMed:26342464). ( RO52_HUMAN,P19474 )

Molecular function for TRIM21 Gene according to UniProtKB/Swiss-Prot

Function:
  • E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2.
    Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination.
    Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes.
    A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B (‘Thr-187’ phosphorylated-form), thereby promoting its degradation by the proteasome.
    Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling.
    Negatively regulates IFN-beta production post-pathogen recognition by polyubiquitin-mediated degradation of IRF3.
    Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway.
    Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages.
    Plays a role in the regulation of the cell cycle progression.

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Accelerating PROTAC drug discovery: Establishing a relationship between ubiquitination and target protein degradation

Curator: Stephen J. Williams, Ph.D.

PROTACs have been explored in multiple disease fields with focus on only few ligases like cereblon (CRBN), Von Hippel-Lindau (VHL), IAP and MDM2. Cancer targets like androgen receptor, estrogen receptor, BTK, BCL2, CDK8 and c-MET [[6], [7], [8], [9], [10], [11]] have been successfully targeted using PROTACs. A variety of BET family (BRD2, BRD3, and BRD4)- PROTACs were designed using multiple ligases; MDM2-based BRD4 PROTAC [12], CRBN based dBET1 [13] and BETd-24-6 [14] for triple-negative breast cancer, enhanced membrane permeable dBET6 [15], and dBET57 PROTAC [16]. PROTACs for Hepatitis c virus (HCV) protease, IRAK4 and Tau [[17], [18], [19]] have been explored for viral, immune and neurodegenerative diseases, respectively. Currently, the PROTAC field expansion to vast undruggable proteome is hindered due to narrow focus on select E3 ligases. Lack of reliable tools to rapidly evaluate PROTACs based on new ligases is hindering the progress. Screening platforms designed must be physiologically relevant and represent true PROTAC cellular function, i.e., PROTAC-mediated target ubiquitination and degradation.

In the current study, we employ TUBEs as affinity capture reagents to monitor PROTAC-induced poly-ubiquitination and degradation as a measure of potency. We established and validated proof-of-concept cell-based assays in a 96-well format using PROTACS for three therapeutic targets BET family proteins, kinases, and KRAS. To our knowledge, the proposed PROTAC assays are first of its kind that can simultaneously 1) detect ubiquitination of endogenous, native protein targets, 2) evaluate the potency of PROTACs, and 3) establish a link between the UPS and protein degradation. Using these TUBE assays, we established rank order potencies between four BET family PROTACs dBET1, dBET6, BETd246 and dBET57 based on peak ubiquitination signals (“UbMax”) of the target protein. TUBE assay was successful in demonstrating promiscuous kinase PROTACs efficiency to degrade Aurora Kinase A at sub-nanomolar concentrations within 1 h. A comparative study to identify changes in the ubiquitination and degradation profile of KRAS G12C PROTACs recruiting two E3 ligases (CRBN and VHL). All of the ubiquitination and degradation profiles obtained from TUBE based assays correlate well with traditional low throughput immunoblotting. Significant correlation between DC50 obtained from protein degradation in western blotting and UbMax values demonstrates our proposed assays can aid in high-throughput screening and drastically eliminate artifacts to overcome bottlenecks in PROTAC drug discovery.

To successfully set up HTS screening with novel PROTACs without pre-existing knowledge, we recommend the following steps. 1. Identify a model PROTAC that can potentially demonstrate activity based on knowledge in PROTAC design or in vitro binding studies. 2. Perform a time course study with 2–3 doses of the model PROTAC based on affinities of the ligands selected. 3. Monitor ubiquitination and degradation profiles using plate-based assay and identify time point that demonstrates UbMax. 4. Perform a dose response at selected time point with a library of PROTACs to establish rank order potency.

INTRODUCTION

Ubiquitination is a major regulatory mechanism to maintain cellular protein homeostasis by marking proteins for proteasomal-mediated degradation [1]. Given ubiquitin’s role in a variety of pathologies, the idea of targeting the Ubiquitin Proteasome System (UPS) is at the forefront of drug discovery [2]. “Event-driven” protein degradation using the cell’s own UPS is a promising technology for addressing the “undruggable” proteome [3]. Targeted protein degradation (TPD) has emerged as a new paradigm and promising therapeutic option to selectively attack previously intractable drug targets using PROteolytic TArgeting Chimeras (PROTACs) [4]. PROTACs are heterobifunctional molecules with a distinct ligand that targets a specific E3 ligase which is tethered to another ligand specific for the target protein using an optimized chemical linker. A functional PROTAC induces a ternary E3-PROTAC-target complex, resulting in poly-ubiquitination and subsequent controlled protein degradation [5]. Ability to function at sub-stoichiometric levels for efficient degradation, a significant advantage over traditional small molecules.

PROTACs have been explored in multiple disease fields with focus on only few ligases like cereblon (CRBN), Von Hippel-Lindau (VHL), IAP and MDM2. Cancer targets like androgen receptorestrogen receptor, BTK, BCL2, CDK8 and c-MET [[6][7][8][9][10][11]] have been successfully targeted using PROTACs. A variety of BET family (BRD2, BRD3, and BRD4)- PROTACs were designed using multiple ligases; MDM2-based BRD4 PROTAC [12], CRBN based dBET1 [13] and BETd-24-6 [14] for triple-negative breast cancer, enhanced membrane permeable dBET6 [15], and dBET57 PROTAC [16]. PROTACs for Hepatitis c virus (HCV) proteaseIRAK4 and Tau [[17][18][19]] have been explored for viral, immune and neurodegenerative diseases, respectively. Currently, the PROTAC field expansion to vast undruggable proteome is hindered due to narrow focus on select E3 ligases. Lack of reliable tools to rapidly evaluate PROTACs based on new ligases is hindering the progress. Screening platforms designed must be physiologically relevant and represent true PROTAC cellular function, i.e., PROTAC-mediated target ubiquitination and degradation.

Cellular PROTAC screening is traditionally performed using cell lines harboring reporter genes and/or Western blotting. While Western blotting is easy to perform, they are low throughput, semi-quantitative and lack sensitivity. While reporter gene assays address some of the issues, they are challenged by reporter tags having internal lysines leading to artifacts. Currently, no approaches are available that can identify true PROTAC effects such as target ubiquitination and proteasome-mediated degradation simultaneously. High affinity ubiquitin capture reagents like TUBEs [20] (tandem ubiquitin binding entities), are engineered ubiquitin binding domains (UBDs) that allow for detection of ultralow levels of polyubiquitinated proteins under native conditions with affinities as low as 1 nM. The versatility and selectivity of TUBEs makes them superior to antibodies, and they also offer chain-selectivity (-K48, -K63, or linear) [21]. High throughput assays that can report the efficacy of multiple PROTACs simultaneously by monitoring PROTAC mediated ubiquitination can help establish rank order potency and guide chemists in developing meaningful structure activity relationships (SAR) rapidly.

In the current study, we employ TUBEs as affinity capture reagents to monitor PROTAC-induced poly-ubiquitination and degradation as a measure of potency. We established and validated proof-of-concept cell-based assays in a 96-well format using PROTACS for three therapeutic targets BET family proteins, kinases, and KRAS. To our knowledge, the proposed PROTAC assays are first of its kind that can simultaneously 1) detect ubiquitination of endogenous, native protein targets, 2) evaluate the potency of PROTACs, and 3) establish a link between the UPS and protein degradation. Using these TUBE assays, we established rank order potencies between four BET family PROTACs dBET1, dBET6, BETd246 and dBET57 based on peak ubiquitination signals (“UbMax”) of the target protein. TUBE assay was successful in demonstrating promiscuous kinase PROTACs efficiency to degrade Aurora Kinase A at sub-nanomolar concentrations within 1 h. A comparative study to identify changes in the ubiquitination and degradation profile of KRAS G12C PROTACs recruiting two E3 ligases (CRBN and VHL). All of the ubiquitination and degradation profiles obtained from TUBE based assays correlate well with traditional low throughput immunoblotting. Significant correlation between DC50 obtained from protein degradation in western blotting and UbMax values demonstrates our proposed assays can aid in high-throughput screening and drastically eliminate artifacts to overcome bottlenecks in PROTAC drug discovery.

Fig. 1. Schematic representation of TUBE assay to monitor PROTAC mediated cellular ubiquitination of target proteins.
Fig. 2. TUBE based assay screening of PROTACs: Jurkat cell lysates were treated with BRD3-specific PROTACs A) dBET1, B) dBET6, C) BETd24-6, and D) dBET57. Polyubiquitination profiles and Ubmax of BRD3 for each PROTAC were represented as relative CL intensity. Relative CL intensities were calculated by dividing raw CL signals from a given PROTAC dose over DMSO treated samples. Error bars represent standard deviations, n = 3.
Fig. 3. PROTAC mediated degradation of bromodomain proteins analyzed by anti-BRD3 western blotting. Dose response of PROTACs dBET1, dBET6, Betd-24-6 and dBET57 at 45 min in Jurkat cells demonstrates degradation of BRD3, Acting as loading control.

 

 

 

 

 

 

 

 

 

Fig. 4. PROTAC mediated ubiquitination and degradation of AURKA in K562 cells. (A) Time course study to evaluate intracellular ubiquitination and degradation. (B) Western blot analysis of time course study: degradation kinetics (C) A dose response study to evaluate DC50 of the promiscuous kinase PROTAC in K562 cells. (D) Western blot analysis of dose response study to monitor degradation, GAPDH as loading control. Error bars represent standard deviation, n = 3.

SOURCE

https://www.sciencedirect.com/science/article/abs/pii/S0006291X22011792

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The Vibrant Philly Biotech Scene: Proteovant Therapeutics Using Artificial Intelligence and Machine Learning to Develop PROTACs

The Map of human proteins drawn by artificial intelligence and PROTAC (proteolysis targeting chimeras) Technology for Drug Discovery

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The Vibrant Philly Biotech Scene: Proteovant Therapeutics Using Artificial Intelligence and Machine Learning to Develop PROTACs

Reporter: Stephen J. Williams, Ph.D.

It has been a while since I have added to this series but there have been a plethora of exciting biotech startups in the Philadelphia area, and many new startups combining technology, biotech, and machine learning. One such exciting biotech is Proteovant Therapeutics, which is combining the new PROTAC (Proteolysis-Targeting Chimera) technology with their in house ability to utilize machine learning and artificial intelligence to design these types of compounds to multiple intracellular targets.

PROTACs (which actually is under a trademark name of Arvinus Operations, but is also refered to as Protein Degraders. These PROTACs take advantage of the cell protein homeostatic mechanism of ubiquitin-mediated protein degradation, which is a very specific targeted process which regulates protein levels of various transcription factors, protooncogenes, and receptors. In essence this regulated proteolyic process is needed for normal cellular function, and alterations in this process may lead to oncogenesis, or a proteotoxic crisis leading to mitophagy, autophagy and cellular death. The key to this technology is using chemical linkers to associate an E3 ligase with a protein target of interest. E3 ligases are the rate limiting step in marking the proteins bound for degradation by the proteosome with ubiquitin chains.

Model of PROTAC Ternarary Complex

A review of this process as well as PROTACs can be found elsewhere in articles (and future articles) on this Open Access Journal.

Protevant have made two important collaborations:

  1. Oncopia Therapeutics: came out of University of Michigan Innovation Hub and lab of Shaomeng Wang, who developed a library of BET and MDM2 based protein degraders. In 2020 was aquired by Riovant Sciences.
  2. Riovant Sciences: uses computer aided design of protein degraders

Proteovant Company Description:

Proteovant is a newly launched development-stage biotech company focusing on discovery and development of disease-modifying therapies by harnessing natural protein homeostasis processes. We have recently acquired numerous assets at discovery and development stages from Oncopia, a protein degradation company. Our lead program is on track to enter IND in 2021. Proteovant is building a strong drug discovery engine by combining deep drugging expertise with innovative platforms including Roivant’s AI capabilities to accelerate discovery and development of protein degraders to address unmet needs across all therapeutic areas. The company has recently secured $200M funding from SK Holdings in addition to investment from Roivant Sciences. Our current therapeutic focus includes but is not limited to oncology, immunology and neurology. We remain agnostic to therapeutic area and will expand therapeutic focus based on opportunity. Proteovant is expanding its discovery and development teams and has multiple positions in biology, chemistry, biochemistry, DMPK, bioinformatics and CMC at many levels. Our R&D organization is located close to major pharmaceutical companies in Eastern Pennsylvania with a second site close to biotech companies in Boston area.

Protein degradation

Source: Protevant

The ubiquitin proteasome system (UPS) is responsible for maintaining protein homeostasis. Targeted protein degradation by the UPS is a cellular process that involves marking proteins and guiding them to the proteasome for destruction. We leverage this physiological cellular machinery to target and destroy disease-causing proteins.

Unlike traditional small molecule inhibitors, our approach is not limited by the classic “active site” requirements. For example, we can target transcription factors and scaffold proteins that lack a catalytic pocket. These classes of proteins, historically, have been very difficult to drug. Further, we selectively degrade target proteins, rather than isozymes or paralogous proteins with high homology. Because of the catalytic nature of the interactions,  it is possible to achieve efficacy at lower doses with prolonged duration while decreasing dose-limiting toxicities.

Biological targets once deemed “undruggable” are now within reach.

About Riovant Sciences: from PRNewsWire https://www.prnewswire.com/news-releases/roivant-unveils-targeted-protein-degradation-platform-301186928.html

Roivant develops transformative medicines faster by building technologies and developing talent in creative ways, leveraging the Roivant platform to launch “Vants” – nimble and focused biopharmaceutical and health technology companies. These Vants include Proteovant but also Dermovant, ImmunoVant,as well as others.

Roivant’s drug discovery capabilities include the leading computational physics-based platform for in silico drug design and optimization as well as machine learning-based models for protein degradation.

The integration of our computational and experimental engines enables the rapid design of molecules with high precision and fidelity to address challenging targets for diseases with high unmet need.

Our current modalities include small molecules, heterobifunctionals and molecular glues.

Roivant Unveils Targeted Protein Degradation Platform

– First therapeutic candidate on track to enter clinical studies in 2021

– Computationally-designed degraders for six targets currently in preclinical development

– Acquisition of Oncopia Therapeutics and research collaboration with lab of Dr. Shaomeng Wang at the University of Michigan to add diverse pipeline of current and future compounds

Clinical-stage degraders will provide foundation for multiple new Vants in distinct disease areas

– Platform supported by $200 million strategic investment from SK Holdings

Other articles in this Vibrant Philly Biotech Scene on this Online Open Access Journal include:

The Vibrant Philly Biotech Scene: PCCI Meeting Announcement, BioDetego Presents Colon Cancer Diagnostic Tool

The Vibrant Philly Biotech Scene: Focus on KannaLife Sciences and the Discipline and Potential of Pharmacognosy

The Vibrant Philly Biotech Scene: Focus on Vaccines and Philimmune, LLC

The Vibrant Philly Biotech Scene: Focus on Computer-Aided Drug Design and Gfree Bio, LLC

Philly Biotech Scene: Biobots and 3D BioPrinting (Now called Allevi)

Philly Biotech Scene: November 2015 PCCI Meeting Showcasing ViFant (Penn Center For Innovation)

Spark Therapeutics’ $4.8Billion deal Confirmed as Biggest VC-backed Exit in Philadelphia

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Live Conference Coverage AACR 2020 in Real Time: Monday June 22, 2020 Late Day Sessions

 

Reporter: Stephen J. Williams, PhD

 

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AACR VIRTUAL ANNUAL MEETING II

 

June 22-24: Free Registration for AACR Members, the Cancer Community, and the Public
This virtual meeting will feature more than 120 sessions and 4,000 e-posters, including sessions on cancer health disparities and the impact of COVID-19 on clinical trials

 

This Virtual Meeting is Part II of the AACR Annual Meeting.  Part I was held online in April and was centered only on clinical findings.  This Part II of the virtual meeting will contain all the Sessions and Abstracts pertaining to basic and translational cancer research as well as clinical trial findings.

 

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Virtual Educational Session

Prevention Research, Science Policy, Epidemiology, Survivorship

Carcinogens at Home: Science and Pathways to Prevention

Chemicals known to cause cancer are used and released to the environment in large volumes, exposing people where they live, work, play, and go to school. The science establishing an important role for such exposures in the development of cancers continues to strengthen, yet cancer prevention researchers are largely unfamiliar with the data drawn upon in identifying carcinogens and making decisions about their use. Characterizing and reducing harmful exposures and accelerating the devel

Julia Brody, Kathryn Z. Guyton, Polly J. Hoppin, Bill Walsh, Mary H. Ward

DETAILS

Monday, June 22

1:30 PM – 3:30 PM EDT

Virtual Educational Session

Tumor Biology, Molecular and Cellular Biology/Genetics, Clinical Research Excluding Trials

EMT Still Matters: Let’s Explore! – Dedicated to the Memory of Isaiah J. Fidler

During carcinoma progression, initially benign epithelial cells acquire the ability to invade locally and disseminate to distant tissues by activating epithelial-mesenchymal transition (EMT). EMT is a cellular process during which epithelial cells lose their epithelial features and acquire mesenchymal phenotypes and behavior. Growing evidence supports the notion that EMT programs during tumor progression are usually activated to various extents and often partial and reversible, thus pr

Jean-Paul Thiery, Heide L Ford, Jing Yang, Geert Berx

DETAILS

Monday, June 22

1:30 PM – 3:00 PM EDT

Virtual Educational Session

Tumor Biology, Experimental and Molecular Therapeutics, Molecular and Cellular Biology/Genetics

One of These Things Is Not Like the Other: The Many Faces of Senescence in Cancer

Cellular senescence is a stable cell growth arrest that is broadly recognized to act as a barrier against tumorigenesis. Senescent cells acquire a senescence-associated secretory phenotype (SASP), a transcriptional response involving the secretion of inflammatory cytokines, immune modulators, and proteases that can shape the tumor microenvironment. The SASP can initially stimulate tumor immune surveillance and reinforce growth arrest. However, if senescent cells are not removed by the

Clemens A Schmitt, Andrea Alimonti, René Bernards

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Monday, June 22

1:30 PM – 3:00 PM EDT

Virtual Educational Session

Clinical Research Excluding Trials, Molecular and Cellular Biology/Genetics

Recent Advances in Applications of Cell-Free DNA

The focus of this educational session will be on recent developments in cell-free DNA (cfDNA) analysis that have the potential to impact the care of cancer patients. Tumors continually shed DNA into the circulation, where it can be detected as circulating tumor DNA (ctDNA). Analysis of ctDNA has become a routine part of care for a subset of patients with advanced malignancies. However, there are a number of exciting potential applications that have promising preliminary data but that h

Michael R Speicher, Maximilian Diehn, Aparna Parikh

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Monday, June 22

1:30 PM – 3:30 PM EDT

Virtual Methods Workshop

Clinical Research Excluding Trials, Clinical Trials, Experimental and Molecular Therapeutics, Molecular and Cellular Biology/Genetics

Translating Genetics and Genomics to the Clinic and Population

This session will describe how advances in understanding cancer genomes and in genetic testing technologies are being translated to the clinic. The speakers will illustrate the clinical impact of genomic discoveries for diagnostics and treatment of common tumor types in adults and in children. Cutting-edge technologies for characterization of patient and tumor genomes will be described. New insights into the importance of patient factors for cancer risk and outcome, including predispos

Heather L. Hampel, Gordana Raca, Jaclyn Biegel, Jeffrey M Trent

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Monday, June 22

1:30 PM – 3:22 PM EDT

Virtual Educational Session

Regulatory Science and Policy, Drug Development, Epidemiology

Under-representation in Clinical Trials and the Implications for Drug Development

The U.S. Food and Drug Administration relies on data from clinical trials to determine whether medical products are safe and effective. Ideally, patients enrolled in those trials are representative of the population in which the product will be used if approved, including people of different ages, races, ethnic groups, and genders. Unfortunately, with few patients enrolling in clinical trials, many groups are not well-represented in clinical trials. This session will explore challenges

Ajay K. Nooka, Nicole J. Gormley, Kenneth C Anderson, Ruben A. Mesa, Daniel J. George, Yelak Biru, RADM Richardae Araojo, Lola A. Fashoyin-Aje

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Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Cancer Chemistry

Targeted Protein Degradation: Target Validation Tools and Therapeutic Opportunity

This educational session will cover the exciting emerging field of targeted protein degradation. Key learning topics will include: 1. an introduction to the technology and its relevance to oncology; 2. PROTACS, degraders, and CELMoDs; 3. enzymology and protein-protein interactions in targeted protein degraders; 4. examples of differentiated biology due to degradation vs. inhibition; 5. how to address questions of specificity; and 6. how the field is approaching challenges in optimizing therapies

George Burslem, Mary Matyskiela, Lyn H. Jones, Stewart L Fisher, Andrew J Phillips

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Bioinformatics and Systems Biology, Experimental and Molecular Therapeutics, Drug Development, Molecular and Cellular Biology/Genetics

Obstacles and opportunities for protein degradation drug discovery

Lyn H. Jones
  • PROTACs ubiquitin mediated by E3 ligases;  first discovered by DeShaies and targeted to specific proteins
  • PROTACs used in drug discovery against a host of types of targets including kinases and membrane receptors
  • PROTACs can be modular but lack molecular structural activity relationships
  • can use chemical probes for target validation
  • four requirements: candidate exposure at site of action (for example lipophilicity for candidates needed to cross membranes and accumulate in lysosomes), target engagement (ternary occupancy as measured by FRET), functional pharmacology, relevant phenotype
  • PROTACs hijack the proteosomal degradation system

Proteolysis-targeting chimeras as therapeutics and tools for biological discovery

George Burslem
  • first PROTAC developed to coopt the VHL ubiquitin ligase system which degrades HIF1alpha but now modified for EREalpha
  • in screen for potential PROTACS there were compounds which bound high affinity but no degradation so phenotypic screening very important
  • when look at molecular dynamics can see where PROTAC can add additional protein protein interaction, verifed by site directed mutagenesis
  • able to target bcr-Abl
  • he says this is a rapidly expanding field because of all the new E3 ligase targets being discovered

Expanding the horizons of cereblon modulators

Mary Matyskiela

Translating cellular targeted protein degradation to in vivo models using an enzymology framework

Stewart L Fisher
  • new targeting compounds have an E3 ligase binding domain, a target binding domain and a linker domain
  • in vivo these compounds are very effective; BRD4 degraders good invitro and in vivo with little effect on body weight
  • degraders are essential activators of E3 ligases as these degraders bring targets in close proximity so activates a catalytic cycle of a multistep process (has now high turnover number)
  • in enzymatic pathway the degraders make a productive complex so instead of a kcat think of measuring a kprod or productivity of degraders linked up an E3 ligase
  • the degraders are also affecting the rebound protein synthesis; so Emax never to zero and see a small rebound of protein synthesis

 

Data-Driven Approaches for Choosing Combinatorial Therapies

Drug combinations remain the gold standard for treating cancer, as they significantly outperform single agents. However, due to the enormous size of drug combination space, it is virtually impossible to interrogate all possible combinations. This session will discuss approaches to identify novel combinations using both experimental and computational approaches. Speakers will discuss i) approaches to drug screening in cell lines, the impact of the microenvironment, and attempts to more

Bence Szalai, James E Korkola, Lisa Tucker-Kellogg, Jeffrey W Tyner

DETAILS

Monday, June 22

3:45 PM – 5:21 PM EDT

Virtual Educational Session

Tumor Biology

Cancer Stem Cells and Therapeutic Resistance

Cancer stem cells are a subpopulation of cells with a high capacity for self-renewal, differentiation and resistance to therapy. In this session, we will define cancer stem cells, discuss cellular plasticity, interactions between cancer stem cells and the tumor microenvironment, and mechanisms that contribute to therapeutic resistance.

Robert S Kerbel, Dolores Hambardzumyan, Jennifer S. Yu

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Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Drug Development, Experimental and Molecular Therapeutics

Molecular Imaging in Cancer Research

This session will cover the fundamentals as well as the major advances made in the field of molecular imaging. Topics covered will include the basics for optical, nuclear, and ultrasound imaging; the pros and cons of each modality; and the recent translational advancements. Learning objectives include the fundamentals of each imaging modality, recent advances in the technology, the processes involved to translate an imaging agent from bench to bedside, and how molecular imaging can gui

Julie Sutcliffe, Summer L Gibbs, Mark D Pagel, Katherine W Ferrara

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Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Tumor Biology, Immunology, Experimental and Molecular Therapeutics, Drug Development

Tumor Endothelium: The Gatekeepers of Tumor Immune Surveillance

Tumor-associated endothelium is a gatekeeper that coordinates the entry and egress of innate and adaptive immune cells within the tumor microenvironment. This is achieved, in part, via the coordinated expression of chemokines and cell adhesion molecules on the endothelial cell surface that attract and retain circulating leukocytes. Crosstalk between adaptive immune cells and the tumor endothelium is therefore essential for tumor immune surveillance and the success of immune-based thera

Dai Fukumura, Maria M Steele, Wen Jiang, Andrew C Dudley

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Immunology, Experimental and Molecular Therapeutics

Novel Strategies in Cancer Immunotherapy: The Next Generation of Targets for Anticancer Immunotherapy

T-cell immunotherapy in the form of immune checkpoint blockade or cellular T-cell therapies has been tremendously successful in some types of cancer. This success has opened the door to consider what other modalities or types of immune cells can be harnessed for exert antitumor functions. In this session, experts in their respective fields will discuss topics including novel approaches in immunotherapy, including NK cells, macrophage, and viral oncotherapies.

Evanthia Galanis, Kerry S Campbell, Milan G Chheda, Jennifer L Guerriero

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Tumor Biology, Drug Development, Immunology, Clinical Research Excluding Trials

Benign Cells as Drivers of Cancer Progression: Fat and Beyond

Carcinomas develop metastases and resistance to therapy as a result of interaction with tumor microenvironment, composed of various nonmalignant cell types. Understanding the complexity and origins of tumor stromal cells is a prerequisite for development of effective treatments. The link between obesity and cancer progression has revealed the engagement of adipose stromal cells (ASC) and adipocytes from adjacent fat tissue. However, the molecular mechanisms through which they stimulate

Guojun Wu, Matteo Ligorio, Mikhail Kolonin, Maria T Diaz-Meco

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Educational Session

Clinical Research Excluding Trials, Experimental and Molecular Therapeutics, Tumor Biology

Dharma Master Jiantai Symposium on Lung Cancer: Know Thy Organ – Lessons Learned from Lung and Pancreatic Cancer Research

The term “cancer” encompasses hundreds of distinct disease entities involving almost every possible site in the human body. Effectively interrogating cancer, either in animals models or human specimens, requires a deep understanding of the involved organ. This includes both the normal cellular constituents of the affected tissue as well as unique aspects of tissue-specific tumorigenesis. It is critical to “Know Thy Organ” when studying cancer. This session will focus on two of the most

Trudy G Oliver, Hossein Borghaei, Laura Delong Wood, Howard C Crawford

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Methods Workshop

Clinical Trials

Clinical Trial Design: Part 1: Novel Approaches and Methods in Clinical Trial Design

Good clinical trial design has always had to balance the competing interests of effectively and convincingly answering the question with the limitations imposed by scarce resources, complex logistics, and risks and potential benefits to participants. New targeted therapies, immuno-oncology, and novel combination treatments add new challenges on top of the old ones. This session will introduce these concerns and 1) suggest ways to consider what outcomes are relevant, 2) how we can best

Mary W. Redman, Nolan A. Wages, Susan G Hilsenbeck, Karyn A. Goodman

DETAILS

Monday, June 22

3:45 PM – 5:45 PM EDT

Virtual Methods Workshop

Tumor Biology, Drug Development

High-Throughput Screens for Drivers of Progression and Resistance

The sequencing of human cancers now provides a landscape of the genetic alterations that occur in human cancer, and increasingly knowledge of somatic genetic alterations is becoming part of the evaluation of cancer patients. In some cases, this information leads directly to the selection of particular therapeutic approaches; however, we still lack the ability to decipher the significance of genetic alterations in many cancers. This session will focus on recent developments that permit the identification of molecular targets in specific cancers. This information, coupled with genomic characterization of cancer, will facilitate the development of new therapeutic agents and provide a path to implement precision cancer medicine to all patients.

William C Hahn, Mark A Dawson, Mariella Filbin, Michael Bassik

DETAILS

Monday, June 22

3:45 PM – 5:15 PM EDT

Defining a cancer dependency map

William C Hahn

Introduction

William C Hahn

Genome-scale CRISPR screens in 3D spheroids identify cancer vulnerabilities

Michael Bassik

Utilizing single-cell RNAseq and CRISPR screens to target cancer stem cells in pediatric brain tumors

Mariella Filbin
  • many gliomas are defined by discreet mutational spectra that also discriminates based on age and site as well (for example many cortical tumors have mainly V600E Braf mutations while thalamus will be FGFR1
  • they did single cell RNAseq on needle biopsy from 7 gliomas which gave about 3500 high quality single cells; obtained full length RNA
  • tumors clustered mainly where the patient it came from but had stromal cell contamination probably so did a deconvolution?  Copy number variation showed which were tumor cells and did principle component analysis
  • it seems they used a human glioma model as training set
  • identified a stem cell like glioma cell so concentrated on the genes altered in these for translational studies
  • developed multiple PDX models from patients
  • PDX transcriptome closest to patient transcriptome but organoid grown in serum free very close while organoids grown in serum very distinct transcriptome
  • developed a CRISPR barcoded library to determine genes for survival genes
  • pulled out BMI1  and EZH2 (polycomb complex proteins) as good targets

Virtual Methods Workshop

Prevention Research, Survivorship, Clinical Research Excluding Trials, Epidemiology

Implementation Science Methods for Cancer Prevention and Control in Diverse Populations: Integration of Implementation Science Methods in Care Settings

Through this Education Session we will use examples from ongoing research to provide an overview of implementation science approaches to cancer prevention and control research. We draw on examples to highlight study design approaches, research methods, and real-world solutions when applying implementation science to achieve health equity. Approaches to defining change in the care setting and measuring sustained changes are also emphasized. Using real examples of patient navigation prog

Graham A Colditz, Sanja Percac-Lima, Nathalie Huguet

DETAILS

Monday, June 22

3:45 PM – 5:30 PM EDT

Virtual Educational Session

Regulatory Science and Policy, Epidemiology

COVID-19 and Cancer: Guidance for Clinical Trial Conduct and Considerations for RWE

This session will consider the use of real-world evidence in the context of oncology clinical trials affected by the COVID-19 pandemic. Key aspects of the FDA’s recent “Guidance on Conduct of Clinical Trials of Medical Products of Medical Products during COVID-19 Public Health Emergency” will be discussed, including telemedicine, accounting for missing data, obtaining laboratory tests and images locally, using remote informed consent procedures, and additional considerations for contin

Wendy Rubinstein, Paul G. Kluetz, Amy P. Abernethy, Jonathan Hirsch, C.K. Wang

 

 

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Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Session on Novel Targets and Therapies 2:35 PM

Reporter: Stephen J. Williams, PhD

Updated on 07/08/2021  

https://cancerdiscovery.aacrjournals.org/content/early/2021/07/01/2159-8290.CD-20-1741

Session VMS.ET04.01 – Novel Targets and Therapies

Targeting chromatin remodeling-associated genetic vulnerabilities in cancer: PBRM1 defects are synthetic lethal with PARP and ATR inhibitors

Presenter/AuthorsRoman Merial Chabanon, Daphné Morel, Léo Colmet-Daage, Thomas Eychenne, Nicolas Dorvault, Ilirjana Bajrami, Marlène Garrido, Suzanna Hopkins, Cornelia Meisenberg, Andrew Lamb, Theo Roumeliotis, Samuel Jouny, Clémence Astier, Asha Konde, Geneviève Almouzni, Jyoti Choudhary, Jean-Charles Soria, Jessica Downs, Christopher J. Lord, Sophie Postel-Vinay. Gustave Roussy, Villejuif, France, The Francis Crick Institute, London, United Kingdom, Institute of Cancer Research, London, United Kingdom, Sage Bionetworks, Seattle, WA, Institute of Cancer Research, London, United Kingdom, Institute of Cancer Research, London, United Kingdom, Institut Curie, Paris, France, Université Paris-Sud/Université Paris-Saclay, Le Kremlin-Bicêtre, France, Gustave Roussy Cancer Campus and U981 INSERM, ATIP-Avenir group, Villejuif, FranceDisclosures R.M. Chabanon: None. D. Morel: None. L. Colmet-Daage: None. T. Eychenne: None. N. Dorvault: None. I. Bajrami: None. M. Garrido: None. S. Hopkins: ; Fishawack Group of Companies. C. Meisenberg: None. A. Lamb: None. T. Roumeliotis: None. S. Jouny: None. C. Astier: None. A. Konde: None. G. Almouzni: None. J. Choudhary: None. J. Soria: ; Medimmune/AstraZeneca. ; Astex. ; Gritstone. ; Clovis. ; GSK. ; GamaMabs. ; Lilly. ; MSD. ; Mission Therapeutics. ; Merus. ; Pfizer. ; PharmaMar. ; Pierre Fabre. ; Roche/Genentech. ; Sanofi. ; Servier. ; Symphogen. ; Takeda. J. Downs: None. C.J. Lord: ; AstraZeneca. ; Merck KGaA. ; Artios. ; Tango. ; Sun Pharma. ; GLG. ; Vertex. ; Ono Pharma. ; Third Rock Ventures. S. Postel-Vinay: ; Merck KGaA. ; Principal investigator of clinical trials for Gustave Roussy.; Boehringer Ingelheim. ; Principal investigator of clinical trials for Gustave Roussy.; Roche. ; Principal investigator of clinical trials for Gustave Roussy. Benefited from reimbursement for attending symposia.; AstraZeneca. ; Principal investigator of clinical trials for Gustave Roussy.; Clovis. ; Principal investigator of clinical trials for Gustave Roussy.; Bristol-Myers Squibb. ; Principal investigator of clinical trials for Gustave Roussy.; Agios. ; Principal investigator of clinical trials for Gustave Roussy.; GSK.AbstractAim: Polybromo-1 (PBRM1), a specific subunit of the pBAF chromatin remodeling complex, is frequently inactivated in cancer. For example, 40% of clear cell Renal Cell Carcinoma (ccRCC) and 15% of cholangiocarcinoma present deleterious PBRM1 mutations. There is currently no precision medicine-based therapeutic approach that targets PBRM1 defects. To identify novel, targeted therapeutic strategies for PBRM1-defective cancers, we carried out high-throughput functional genomics and drug screenings followed by in vitro and in vivo validation studies.
Methods: High-throughput siRNA-drug sensitization and drug sensitivity screens evaluating > 150 cancer-relevant small molecules in dose-response were performed in Pbrm1 siRNA-transfected mouse embryonic stem cells (mES) and isogenic PBRM1-KO or -WT HAP1 cells, respectively. After identification of PBRM1-selective small molecules, revalidation was carried out in a series of in-house-generated isogenic models of PBRM1 deficiency – including 786-O (ccRCC), A498 (ccRCC), U2OS (osteosarcoma) and H1299 (non-small cell lung cancer) human cancer cell lines – and non-isogenic ccRCC models, using multiple clinical compounds. Mechanistic dissection was performed using immunofluorescence, RT-qPCR, western blotting, DNA fiber assay, transcriptomics, proteomics and DRIP-sequencing to evaluate markers of DNA damage response (DDR), replication stress and cell-autonomous innate immune signaling. Preclinical data were integrated with TCGA tumor data.
Results: Parallel high-throughput drug screens independently identified PARP inhibitors (PARPi) as being synthetic lethal with PBRM1 defects – a cell type-independent effect which was exacerbated by ATR inhibitors (ATRi) and which we revalidated in vitro in isogenic and non-isogenic systems and in vivo in a xenograft model. PBRM1 defects were associated with increased replication fork stress (higher γH2AX and RPA foci levels, decreased replication fork speed and increased ATM checkpoint activation), R-loop accumulation and enhanced genomic instability in vitro; these effects were exacerbated upon PARPi exposure. In patient tumor samples, we also found that PBRM1-mutant cancers possessed a higher mutational load. Finally, we found that ATRi selectively activated the cGAS/STING cytosolic DNA sensing pathway in PBRM1-deficient cells, resulting in increased expression of type I interferon genes.
Conclusion: PBRM1-defective cancer cells present increased replication fork stress, R-loop formation, genome instability and are selectively sensitive to PARPi and ATRi through a synthetic lethal mechanism that is cell type-independent. Our data provide the pre-clinical rationale for assessing PARPi as a monotherapy or in combination with ATRi or immune-modulating agents in molecularly-selected patients with PBRM1-defective cancers.

1057 – Targeting MTHFD2 using first-in-class inhibitors kills haematological and solid cancer through thymineless-induced replication stress

Presenter/AuthorsThomas Helleday. University of Sheffield, Sheffield, United KingdomDisclosures T. Helleday: None.AbstractSummary
Thymidine synthesis pathways are upregulated pathways in cancer. Since the 1940s, targeting nucleotide and folate metabolism to induce thymineless death has remained first-line anti-cancer treatment. Recent discoveries that showing cancer cells have rewired networks and exploit unique enzymes for proliferation, have renewed interest in metabolic pathways. The cancer-specific expression of MTHFD2 has gained wide-spread attention and here we describe an emerging role for MTHFD2 in the DNA damage response (DDR). The folate metabolism enzyme MTHFD2 is one of the most consistently overexpressed metabolic enzymes in cancer and an emerging anticancer target. We show a novel role for MTHFD2 being essential for DNA replication and genomic stability in cancer cells. We describe first-in-class nanomolar MTHFD2 inhibitors (MTHFD2i), with protein co-crystal structures demonstrating binding in the active site of MTHFD2 and engaging with the target in cells and tumours. We show MTHFD2i reduce replication fork speed and induce replication stress, followed by S phase arrest, apoptosis and killing of a range of haematological and solid cancer cells in vitro and in vivo, with a therapeutic window spanning up to four orders of magnitude compared to non-transformed cells. Mechanistically, MTHFD2i prevent thymidine production leading to mis-incorporation of uracil into DNA and replication stress. As MTHFD2 expression is cancer specific there is a potential of MTHFD2i to synergize with other treatments. Here, we show MTHFD2i synergize with dUTPase inhibitors as well as other DDR inhibitors and demonstrate the mechanism of action. These results demonstrate a new link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically.
Keywords
MTHFD2, one-carbon metabolism, folate metabolism, DNA replication, replication stress, synthetic lethal, thymineless death, small-molecule inhibitor, DNA damage response

1060 – Genetic and pharmacologic inhibition of Skp2, an E3 ubiquitin ligase and RB1-target, has antitumor activity in RB1-deficient human and mouse small cell lung cancer (SCLC)

Presenter/Authors
Hongling ZhaoVineeth SukrithanNiloy IqbalCari NicholasYingjiao XueJoseph LockerJuntao ZouLiang ZhuEdward L. Schwartz. Albert Einstein College of Medicine, Bronx, NY, Albert Einstein College of Medicine, Bronx, NY, Albert Einstein College of Medicine, Bronx, NY, University of Pittsburgh Medical Center, Pittsburgh, PA, Albert Einstein College of Medicine, Bronx, NY
Disclosures
 H. Zhao: None. V. Sukrithan: None. N. Iqbal: None. C. Nicholas: None. Y. Xue: None. J. Locker: None. J. Zou: None. L. Zhu: None. E.L. Schwartz: None.
Abstract
The identification of driver mutations and their corresponding targeted drugs has led to significant improvements in the treatment of non-small cell lung cancer (NSCLC) and other solid tumors; however, similar advances have not been made in the treatment of small cell lung cancer (SCLC). Due to their aggressive growth, frequent metastases, and resistance to chemotherapy, the five-year overall survival of SCLC is less than 5%. While SCLC tumors can be sensitive to first-line therapy of cisplatin and etoposide, most patients relapse, often in less than 3 months after initial therapy. Dozens of drugs have been tested clinically in SCLC, including more than 40 agents that have failed in phase III trials.
The near uniform bi-allelic inactivation of the tumor suppressor gene RB1 is a defining feature of SCLC. RB1 is mutated in highly aggressive tumors, including SCLC, where its functional loss, along with that of TP53, is both required and sufficient for tumorigenesis. While it is known that RB1 mutant cells fail to arrest at G1/S in response to checkpoint signals, this information has not led to effective strategies to treat RB1-deficient tumors, and it has been challenging to develop targeted drugs for tumors that are driven by the loss of gene function.
Our group previously identified Skp2, a substrate recruiting subunit of the SCF-Skp2 E3 ubiquitin ligase, as an early repression target of pRb whose knockout blocked tumorigenesis in Rb1-deficient prostate and pituitary tumors. Here we used genetic mouse models to demonstrate that deletion of Skp2 completely blocked the formation of SCLC in Rb1/p53-knockout mice (RP mice). Skp2 KO caused an increased accumulation of the Skp2-degradation target p27, a cyclin-dependent kinase inhibitor, and we confirmed this was the mechanism of protection in the RP-Skp2 KO mice by using the knock-in of a mutant p27 that was unable to bind to Skp2. Building on the observed synthetic lethality between Rb1 and Skp2, we found that small molecules that bind to and/or inhibit Skp2 induced apoptosis and inhibited SCLC cell growth. In a panel of SCLC cell lines, growth inhibition by a Skp2 inhibitor was not correlated with sensitivity/resistance to etoposide. Targeting Skp2 also had in vivo antitumor activity in mouse tumors and human patient-derived xenograft models of SCLC. Using the genetic and pharmacologic approaches, antitumor activity was seen in vivo in established SCLC primary lung tumors, in liver metastases, and in chemotherapy-resistant tumors. The identification and validation of an actionable target downstream of RB1 could have a broad impact on treatment of SCLC and other advanced tumors with mutant RB1, for which there are currently no targeted therapies available.

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Lesson 4 Cell Signaling And Motility: G Proteins, Signal Transduction: Curations and Articles of reference as supplemental information: #TUBiol3373

Curator: Stephen J. Williams, Ph.D.

Updated 7/15/2019

Below please find the link to the Powerpoint presentation for lesson #4 for #TUBiol3373.  The lesson first competes the discussion on G Protein Coupled Receptors, including how cells terminate cell signals.  Included are mechanisms of receptor desensitization.  Please NOTE that desensitization mechanisms like B arrestin decoupling of G proteins and receptor endocytosis occur after REPEATED and HIGH exposures to agonist.  Hydrolysis of GTP of the alpha subunit of G proteins, removal of agonist, and the action of phosphodiesterase on the second messenger (cAMP or cGMP) is what results in the downslope of the effect curve, the termination of the signal after agonist-receptor interaction.

 

Click below for PowerPoint of lesson 4

Powerpoint for lesson 4

 

Please Click below for the papers for your Group presentations

paper 1: Membrane interactions of G proteins and other related proteins

paper 2: Macaluso_et_al-2002-Journal_of_Cellular_Physiology

paper 3: Interactions of Ras proteins with the plasma membrane

paper 4: Futosi_et_al-2016-Immunological_Reviews

 

Please find related article on G proteins and Receptor Tyrosine Kinases on this Open Access Online Journal

G Protein–Coupled Receptor and S-Nitrosylation in Cardiac Ischemia and Acute Coronary Syndrome

Action of Hormones on the Circulation

Newer Treatments for Depression: Monoamine, Neurotrophic Factor & Pharmacokinetic Hypotheses

VEGF activation and signaling, lysine methylation, and activation of receptor tyrosine kinase

 

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Biological Pathways

Reporter: Aviva Lev-Ari, PhD, RN

 

Biological Pathways

View larger

SOURCE

https://www.genome.gov/27530687/biological-pathways-fact-sheet/

Figure 3: Examples of biological pathways that are regulated by selective mRNA export.

FromControl of mammalian gene expression by selective mRNA export

Nature Reviews Molecular Cell Biology
16,
431–442
(2015)
doi:10.1038/nrm4010

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Understanding Autophagy to Enhance Clinical Discovery: The 2016 Dr. Paul Janssen Award Symposium, September 22, 2016 | 8:00 AM – 2:15 PM, The New York Academy of Medicine, 1216 Fifth Avenue New York, NY 10029

Reporter: Aviva Lev-Ari, PhD, RN

 

Understanding Autophagy to Enhance Clinical Discovery: The 2016 Dr. Paul Janssen Award Symposium

Thursday, September 22, 2016 | 8:00 AM – 2:15 PM
The New York Academy of Medicine

Presented by the Dr. Paul Janssen Award for Biomedical Research and the New York Academy of Sciences

This symposium will honor Dr. Yoshinori Ohsumi, who will reflect on his initial work on the key players in autophagy, and share his vision for future advancements in the field. Following his award lecture, fellow prominent scientists at the forefront of autophagy research will discuss emerging concepts and technologies.

AGENDA

 

Preliminary Symposium Agenda

* Presentation times are subject to change.


Thursday, September 22, 2016

8:00 AM Registration and Breakfast
9:00 AM Welcome and Introductory Remarks
Anthony Shih, MD, MPH, The New York Academy of Medicine
Representative, Johnson & Johnson
Brooke Grindlinger, PhD, The New York Academy of Sciences

Session I: Elucidating the Underlying Cellular Processes of Autophagy

9:15 AM 2016 Dr. Paul Janssen Award for Biomedical Research Announcement
Representative, Janssen Research & Development
9:30 AM Dr. Paul Janssen Award for Biomedical Research Lecture
Uncovering the Key Molecular and Cellular Components in Autophagy
Yoshinori Ohsumi, PhD, Tokyo Institute of Technology
10:20 AM Coffee and Networking Break

Session II: Understanding the Molecular Landscape of Autophagy: From Basic Mechanisms to Human Health

Session Chair: Representative, The New York Academy of Sciences

10:50 AM Potential Therapeutic Targets in Autophagy
Beth Levine, MD, University of Texas Southwestern Medical Center, Howard Hughes Medical Institute (HHMI)
11:20 AM Autophagy in Cell Survival and Cell Death
Eric H. Baehrecke, PhD, University of Massachusetts Medical School
11:50 AM The Role of Chaperone-mediated Autophagy in Human Pathogenesis
Ana Maria Cuervo, MD, PhD, Albert Einstein College of Medicine
12:20 PM Title to Be Announced
Matthias Versele, PhD, Janssen Research & Development
12:50 PM Panel Discussion: The Future of Autophagy Research

Panelists:
Yoshinori Ohsumi, PhD, Tokyo Institute of Technology
Eric H. Baehrecke, PhD, University of Massachusetts Medical School
Ana Maria Cuervo, MD, PhD, Albert Einstein College of Medicine
Beth Levine, MD, University of Texas Southwestern Medical Center, Howard Hughes Medical Institute (HHMI)

* Additional Panelists to Be Announced

1:15 PM Luncheon
2:15 PM Adjourn

SOURCE

http://www.nyas.org/Events/Detail.aspx?cid=f5480228-c7ed-4f29-80bf-cc42b503e703

 

Other articles On and related to AUTOPHAGY published on this Open Access Online Scientific Journal include the following:

Autophagy

Writer and Curator: Larry H Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2015/04/03/autophagy/

 

Autophagy-Modulating Proteins and Small Molecules Candidate Targets for Cancer Therapy: Commentary of Bioinformatics Approaches

Author and Curator: Larry H Bernstein, MD, FCAP and Article Architect: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2014/09/18/autophagy-modulating-proteins-and-small-molecules-candidate-targets-for-cancer-therapy-commentary-of-bioinformatics-approaches/

 

A Curated Census of Autophagy-Modulating Proteins and Small Molecules Candidate Targets for Cancer Therapy 

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2014/09/14/a-curated-census-of-autophagy-modulating-proteins-and-small-molecules-candidate-targets-for-cancer-therapy/

 

Autophagy: Selective articles by Larry H. Bernstein, MD, FCAP

Curator: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2014/05/01/autophagy-selective-articles-by-larry-h-bernstein-md-fcap/

 

 

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