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Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Symposium: New Drugs on the Horizon Part 3 12:30-1:25 PM

Reporter: Stephen J. Williams, PhD

New Drugs on the Horizon: Part 3
Introduction

Andrew J. Phillips, C4 Therapeutics

  • symposium brought by AACR CICR and had about 30 proposals for talks and chose three talks
  • unfortunately the networking event is not possible but hope to see you soon in good health

ABBV-184: A novel survivin specific T cell receptor/CD3 bispecific therapeutic that targets both solid tumor and hematological malignancies

Edward B Reilly
AbbVie Inc. @abbvie

  • T-cell receptors (TCR) can recognize the intracellular targets whereas antibodies only recognize the 25% of potential extracellular targets
  • survivin is expressed in multiple cancers and correlates with poor survival and prognosis
  • CD3 bispecific TCR to survivn (Ab to CD3 on T- cells and TCR to survivin on cancer cells presented in MHC Class A3)
  • ABBV184  effective in vivo in lung cancer models as single agent;
  • in humanized mouse tumor models CD3/survivin bispecific can recruit T cells into solid tumors; multiple immune cells CD4 and CD8 positive T cells were found to infiltrate into tumor
  • therapeutic window as measured by cytokine release assays in tumor vs. normal cells very wide (>25 fold)
  • ABBV184 does not bind platelets and has good in vivo safety profile
  • First- in human dose determination trial: used in vitro cancer cell assays to determine 1st human dose
  • looking at AML and lung cancer indications
  • phase 1 trial is underway for safety and efficacy and determine phase 2 dose
  • survivin has very few mutations so they are not worried about a changing epitope of their target TCR peptide of choice

The discovery of TNO155: A first in class SHP2 inhibitor

Matthew J. LaMarche
Novartis @Novartis

  • SHP2 is an intracellular phosphatase that is upstream of MEK ERK pathway; has an SH2 domain and PTP domain
  • knockdown of SHP2 inhibits tumor growth and colony formation in soft agar
  • 55 TKIs there are very little phosphatase inhibitors; difficult to target the active catalytic site; inhibitors can be oxidized at the active site; so they tried to target the two domains and developed an allosteric inhibitor at binding site where three domains come together and stabilize it
  • they produced a number of chemical scaffolds that would bind and stabilize this allosteric site
  • block the redox reaction by blocking the cysteine in the binding site
  • lead compound had phototoxicity; used SAR analysis to improve affinity and reduce phototox effects
  • was very difficult to balance efficacy, binding properties, and tox by adjusting stuctures
  • TNO155 is their lead into trials
  • SHP2 expressed in T cells and they find good combo with I/O with uptick of CD8 cells
  • TNO155 is very selective no SHP1 inhibition; SHP2 can autoinhibit itself when three domains come together and stabilize; no cross reactivity with other phosphatases
  • they screened 1.5 million compounds and got low hit rate so that is why they needed to chemically engineer and improve on the classes they found as near hits

Closing Remarks

 

Xiaojing Wang
Genentech, Inc. @genentech

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Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 27, 2020 Minisymposium on Signaling in Cancer 11:45am-1:30 pm

Reporter: Stephen J. Williams, PhD.

SESSION VMS.MCB01.01 – Emerging Signaling Vulnerabilities in Cancer
April 27, 2020, 11:45 AM – 1:30 PM
Virtual Meeting: All Session Times Are U.S. EDT
DESCRIPTION

All session times are U.S. Eastern Daylight Time (EDT). Access to AACR Virtual Annual Meeting I sessions are free with registration. Register now at http://www.aacr.org/virtualam2020

Session Type

Virtual Minisymposium

Track(s)

Molecular and Cellular Biology/Genetics

16 Presentations
11:45 AM – 1:30 PM
– Chairperson

J. Silvio Gutkind. UCSD Moores Cancer Center, La Jolla, CA

11:45 AM – 1:30 PM
– Chairperson

  • in 80’s and 90’s signaling focused on defects and also oncogene addiction.  Now the field is switching to finding vulnerabilities in signaling cascades in cancer

Adrienne D. Cox. University of North Carolina at Chapel Hill, Chapel Hill, NC

11:45 AM – 11:55 AM
– Introduction

J. Silvio Gutkind. UCSD Moores Cancer Center, La Jolla, CA

11:55 AM – 12:05 PM
1085 – Interrogating the RAS interactome identifies EFR3A as a novel enhancer of RAS oncogenesis

Hema Adhikari, Walaa Kattan, John F. Hancock, Christopher M. Counter. Duke University, Durham, NC, University of Texas MD Anderson Cancer Center, Houston, TX

Abstract: Activating mutations in one of the three RAS genes (HRAS, NRAS, and KRAS) are detected in as much as a third of all human cancers. As oncogenic RAS mediates it tumorigenic signaling through protein-protein interactions primarily at the plasma membrane, we sought to document the protein networks engaged by each RAS isoform to identify new vulnerabilities for future therapeutic development. To this end, we determined interactomes of oncogenic HRAS, NRAS, and KRAS by BirA-mediated proximity labeling. This analysis identified roughly ** proteins shared among multiple interactomes, as well as a smaller subset unique to a single RAS oncoprotein. To identify those interactome components promoting RAS oncogenesis, we created and screened sgRNA library targeting the interactomes for genes modifying oncogenic HRAS-, NRAS-, or KRAS-mediated transformation. This analysis identified the protein EFR3A as not only a common component of all three RAS interactomes, but when inactivated, uniformly reduced the growth of cells transformed by any of the three RAS isoforms. EFR3A recruits a complex containing the druggable phosphatidylinositol (Ptdlns) 4 kinase alpha (PI4KA) to the plasma membrane to generate the Ptdlns species PI4P. We show that EFR3A sgRNA reduced multiple RAS effector signaling pathways, suggesting that EFR3A acts at the level of the oncoprotein itself. As lipids play a critical role in the membrane localization of RAS, we tested and found that EFR3A sgRNA reduced not only the occupancy of RAS at the plasma membrane, but also the nanoclustering necessary for signaling. Furthermore, the loss of oncogenic RAS signaling induced by EFR3A sgRNA was rescued by targeting PI4K to the plasma membrane. Taken together, these data support a model whereby EFR3A recruits PI4K to oncogenic RAS to promote plasma membrane localization and nonclustering, and in turn, signaling and transformation. To investigate the therapeutic potential of this new RAS enhancer, we show that EFR3A sgRNA reduced oncogenic KRAS signaling and transformed growth in a panel of pancreatic ductal adenocarcinoma (PDAC) cell lines. Encouraged by these results we are exploring whether genetically inactivating the kinase activity of PI4KA inhibits oncogenic signaling and transformation in PDAC cell lines. If true, pharmacologically targeting PI4K may hold promise as a way to enhance the anti-neoplastic activity of drugs targeting oncogenic RAS or its effectors.

@DukeU

@DukeMedSchool

@MDAndersonNews

  • different isoforms of ras mutations exist differentially in various tumor types e.g. nras vs kras
  • the C terminal end serve as hotspots of mutations and probably isoform specific functions
  • they determined the interactomes of nras and kras and determined how many candidates are ras specific
  • they overlayed results from proteomic and CRSPR screen; EFR3a was a potential target that stuck out
  • using TCGA patients with higher EFR3a had poorer prognosis
  • EFR3a promotes Ras signaling; and required for RAS driven tumor growth (in RAS addicted tumors?)
  • EGFR3a promotes clustering of oncogenic RAS at plasma membrane

 

12:05 PM – 12:10 PM
– Discussion

12:10 PM – 12:20 PM
1086 – Downstream kinase signaling is dictated by specific KRAS mutations; Konstantin Budagyan, Jonathan Chernoff. Drexel University College of Medicine, Philadelphia, PA, Fox Chase Cancer Center, Philadelphia, PA @FoxChaseCancer

Abstract: Oncogenic KRAS mutations are common in colorectal cancer (CRC), found in ~50% of tumors, and are associated with poor prognosis and resistance to therapy. There is substantial diversity of KRAS alleles observed in CRC. Importantly, emerging clinical and experimental analysis of relatively common KRAS mutations at amino acids G12, G13, A146, and Q61 suggest that each mutation differently influences the clinical properties of a disease and response to therapy. For example, KRAS G12 mutations confer resistance to EGFR-targeted therapy, while G13D mutations do not. Although there is clinical evidence to suggest biological differences between mutant KRAS alleles, it is not yet known what drives these differences and whether they can be exploited for allele-specific therapy. We hypothesized that different KRAS mutants elicit variable alterations in downstream signaling pathways. To investigate this hypothesis, we created a novel system by which we can model KRAS mutants in isogenic mouse colon epithelial cell lines. To generate the cell lines, we developed an assay using fluorescent co-selection for CRISPR-driven genome editing. This assay involves simultaneous introduction of single-guide RNAs (sgRNAs) to two different endogenous loci resulting in double-editing events. We first introduced Cas9 and blue fluorescent protein (BFP) into mouse colon epithelial cell line containing heterozygous KRAS G12D mutation. We then used sgRNAs targeting BFP and the mutant G12D KRAS allele along with homology-directed repair (HDR) templates for a GFP gene and a KRAS mutant allele of our choice. Cells that successfully undergo HDR are GFP-positive and contain the desired KRAS mutation. Therefore, selection for GFP-positive cells allows us to identify those with phenotypically silent KRAS edits. Ultimately, this method allows us to toggle between different mutant alleles while preserving the wild-type allele, all in an isogenic background. Using this method, we have generated cell lines with endogenous heterozygous KRAS mutations commonly seen in CRC (G12D, G12V, G12C, G12R, G13D). In order to elucidate cellular signaling pathway differences between the KRAS mutants, we screened the mutated cell lines using a small-molecule library of ~160 protein kinase inhibitors. We found that there are mutation-specific differences in drug sensitivity profiles. These observations suggest that KRAS mutants drive specific cellular signaling pathways, and that further exploration of these pathways may prove to be valuable for identification of novel therapeutic opportunities in CRC.

  • Flourescent coselection of KRAS edits by CRSPR screen in a colorectal cancer line; a cell that is competent to undergo HR can undergo combination multiple KRAS
  • target only mutant allele while leaving wild type intact;
  • it was KRAS editing event in APC  +/- mouse cell line
  • this enabled a screen for kinase inhibitors that decreased tumor growth in isogenic cell lines; PKC alpha and beta 1 inhibitors, also CDK4 inhibitors inhibited cell growth
  • questions about heterogeneity in KRAS clones; they looked at off target guides and looked at effects in screens; then they used top two clones that did not have off target;  questions about 3D culture- they have not done that; Question ? dependency on AKT activity? perhaps the G12E has different downstream effectors

 

12:20 PM – 12:25 PM
– Discussion

12:25 PM – 12:35 PM
1087 – NF1 regulates the RAS-related GTPases, RRAS and RRAS2, independent of RAS activity; Jillian M. Silva, Lizzeth Canche, Frank McCormick. University of California, San Francisco, San Francisco, CA @UCSFMedicine

Abstract: Neurofibromin, which is encoded by the neurofibromatosis type 1 (NF1) gene, is a tumor suppressor that acts as a RAS-GTPase activating protein (RAS-GAP) to stimulate the intrinsic GTPase activity of RAS as well as the closely related RAS subfamily members, RRAS, RRAS2, and MRAS. This results in the conversion of the active GTP-bound form of RAS into the inactive GDP-bound state leading to the downregulation of several RAS downstream effector pathways, most notably MAPK signaling. While the region of NF1 that regulates RAS activity represents only a small fraction of the entire protein, a large extent of the NF1 structural domains and their corresponding mechanistic functions remain uncharacterized despite the fact there is a high frequency of NF1 mutations in several different types of cancer. Thus, we wanted to elucidate the underlying biochemical and signaling functions of NF1 that are unrelated to the regulation of RAS and how loss of these functions contributes to the pathogenesis of cancer. To accomplish this objective, we used CRISPR-Cas9 methods to knockout NF1 in an isogenic “RASless” MEF model system, which is devoid of the major oncogenic RAS isoforms (HRAS, KRAS, and NRAS) and reconstituted with the KRAS4b wild-type or mutant KRASG12C or KRASG12D isoform. Loss of NF1 led to elevated RAS-GTP levels, however, this increase was not as profound as the levels in KRAS-mutated cells or provided a proliferative advantage. Although ablation of NF1 resulted in sustained activation of MAPK signaling, it also unexpectedly, resulted in a robust increase in AKT phosphorylation compared to KRAS-mutated cells. Surprisingly, loss of NF1 in KRAS4b wild-type and KRAS-mutated cells potently suppressed the RAS-related GTPases, RRAS and RRAS2, with modest effects on MRAS, at both the transcript and protein levels. A Clariom™D transcriptome microarray analysis revealed a significant downregulation in the NF-κB target genes, insulin-like growth factor binding protein 2 (IGFBP2), argininosuccinate synthetase 1 (ASS1), and DUSP1, in both the NF1 knockout KRAS4b wild-type and KRAS-mutated cells. Moreover, NF1Null melanoma cells also displayed a potent suppression of RRAS and RRAS2 as well as these NF-κB transcription factors. Since RRAS and RRAS2 both contain the same NF-κB transcription factor binding sites, we hypothesize that IGFBP2, ASS1, and/or DUSP1 may contribute to the NF1-mediated regulation of these RAS-related GTPases. More importantly, this study provides the first evidence of at least one novel RAS-independent function of NF1 to regulate the RAS-related subfamily members, RRAS and RRAS2, in a manner exclusive of its RAS-GTPase activity and this may provide insight into new potential biomarkers and molecular targets for treating patients with mutations in NF1.
  • NF1 and SPRED work together to signal from RTK cKIT through RAS
  • NF1 knockout cells had higher KRAS and had increased cell proliferation
  • NF1 -/-  or SPRED loss had increased ERK phosphorylation and some increase in AKT activity compared to parental cells
  • they used isogenic cell lines devoid of all RAS isoforms and then reconstituted with specific RAS WT or mutants
  • NF1 and SPRED KO both reduce RRAS expression; in an AKT independent mannner
  • NF1 SPRED KO cells have almost no IGFBP2 protein expression and SNAIL so maybe affecting EMT?
  • this effect is independent of its RAS GTPAse activity (noncanonical)

12:35 PM – 12:40 PM
– Discussion

12:40 PM – 12:50 PM
1088 – Elucidating the regulation of delayed-early gene targets of sustained MAPK signaling; Kali J. Dale, Martin McMahon. University of Utah, Salt Lake City, UT, Huntsman Cancer Institute, Salt Lake City, UT

Abstract: RAS and its downstream effector, BRAF, are commonly mutated proto-oncogenes in many types of human cancer. Mutationally activated RAS or BRAF signal through the MEK→ERK MAP kinase (MAPK) pathway to regulate key cancer cell hallmarks such as cell division cycle progression, reduced programmed cell death, and enhanced cell motility. Amongst the list of RAS/RAF-regulated genes are those encoding integrins, alpha-beta heterodimeric transmembrane proteins that regulate cell adhesion to the extracellular matrix. Altered integrin expression has been linked to the acquisition of more aggressive behavior by melanoma, lung, and breast cancer cells leading to diminished survival of cancer patients. We have previously documented the ability of the RAS-activated MAPK pathway to induce the expression of ITGB3 encoding integrin β3 in several different cell types. RAS/RAF-mediated induction of ITGB3 mRNA requires sustained, high-level activation of RAF→MEK→ERK signaling mediated by oncogene activation and is classified as “delayed-early”, in that it is sensitive to the protein synthesis inhibitor cycloheximide. However, to date, the regulatory mechanisms that allow for induced ITGB3 downstream of sustained, high-level activation of MAPK signaling remains obscure. We have identified over 300 DEGs, including those expressing additional cell surface proteins, that display similar regulatory characteristics as ITGB3. We use integrin β3 as a model to test our hypothesis that there is a different mechanism of regulation for delayed-early genes (DEG) compared to the canonical regulation of Immediate-Early genes. There are three regions in the chromatin upstream of the ITGB3 that become more accessible during RAF activation. We are relating the chromatin changes seen during RAF activation to active enhancer histone marks. To elucidate the essential genes of this regulation process, we are employing the use of a genome-wide CRISPR knockout screen. The work presented from this abstract will help elucidate the regulatory properties of oncogenic progression in BRAF mutated cancers that could lead to the identification of biomarkers.

12:50 PM – 12:55 PM
– Discussion

12:55 PM – 1:05 PM
1090 – Regulation of PTEN translation by PI3K signaling maintains pathway homeostasis

Radha Mukherjee, Kiran Gireesan Vanaja, Jacob A. Boyer, Juan Qiu, Xiaoping Chen, Elisa De Stanchina, Sarat Chandarlapaty, Andre Levchenko, Neal Rosen. Memorial Sloan Kettering Cancer Center, New York, NY, Yale University, West Haven, CT, Memorial Sloan Kettering Cancer Center, New York, NY, Memorial Sloan Kettering Cancer Center, New York, NY @sloan_kettering

Abstract: The PI3K pathway is a key regulator of metabolism, cell proliferation and migration and some of its components (e.g. PIK3CA and PTEN) are frequently altered in cancer by genetic events that deregulate its output. However, PI3K signaling is not usually the primary driver of these tumors and inhibitors of components of the pathway have only modest antitumor effects. We now show that both physiologic and oncogenic activation of the PI3K signaling by growth factors and an activating hotspot PIK3CA mutation respectively, cause an increase in the expression of the lipid phosphatase PTEN, thus limiting the duration of the signal and the output of the pathway in tumors. Pharmacologic and physiologic inhibition of the pathway by HER2/PI3K/AKT/mTOR inhibitors and nutrient starvation respectively reduce PTEN, thus buffering the effects of inhibition and contributing to the rebound in pathway activity that occurs in tumors. This regulation is found to be a feature of multiple types of cancer, non-cancer cell line and PDX models thereby highlighting its role as a key conserved feedback loop within the PI3K signaling network, both in vitro and in vivo. Regulation of expression is due to mTOR/4EBP1 dependent control of PTEN translation and is lost when 4EBP1 is knocked out. Translational regulation of PTEN is therefore a major homeostatic regulator of physiologic PI3K signaling and plays a role in reducing the output of oncogenic mutants that deregulate the pathway and the antitumor activity of PI3K pathway inhibitors.

  • mTOR can be a potent regulator of PTEN and therefore a major issue when developing PI3K inhibitors

1:05 PM – 1:10 PM
– Discussion

1:10 PM – 1:20 PM
1091 – BI-3406 and BI 1701963: Potent and selective SOS1::KRAS inhibitors induce regressions in combination with MEK inhibitors or irinotecan

Daniel Gerlach, Michael Gmachl, Juergen Ramharter, Jessica Teh, Szu-Chin Fu, Francesca Trapani, Dirk Kessler, Klaus Rumpel, Dana-Adriana Botesteanu, Peter Ettmayer, Heribert Arnhof, Thomas Gerstberger, Christiane Kofink, Tobias Wunberg, Christopher P. Vellano, Timothy P. Heffernan, Joseph R. Marszalek, Mark Pearson, Darryl B. McConnell, Norbert Kraut, Marco H. Hofmann. Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria, The University of Texas MD Anderson Cancer Center, Houston, TX, The University of Texas MD Anderson Cancer Center, Houston, TX, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria

  • there is rational for developing an SOS1 inhibitor (GEF); BI3406 shows better PK and PD as a candidate
  • most sensitive cell lines to inhibitor carry KRAS mutation; NRAS or BRAF mutations are not sensititve
  • KRAS mutation defines sensitivity so they created KRAS mut isogenic cell lines
  • found best to co inhibit SOS and MEK as observed plasticity with only SOS
  • dual combination in lung NSCLC pancreatic showed enhanced efficacy compared to monotherapy
  • SOS1 inhibition plus irinotecan enhances DNA double strand breaks; no increased DNA damage in normal stroma but preferentially in tumor cells
  • these SOS1 had broad activity against KRAS mutant models;
  • phase 1 started in 2019;

@Boehringer

1:20 PM – 1:25 PM
– Discussion

1:25 PM – 1:30 PM
– Closing Remarks

Adrienne D. Cox. University of North Carolina at Chapel Hill, Chapel Hill, NC

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An Intelligent DNA Nanorobot to Fight Cancer by Targeting HER2 Expression

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

HER2 is an important prognostic biomarker for 20–30% of breast cancers, which is the most common cancer in women. Overexpression of the HER2 receptor stimulates breast cells to proliferate and differentiate uncontrollably, thereby enhancing the malignancy of breast cancer and resulting in a poor prognosis for affected individuals. Current therapies to suppress the overexpression of HER2 in breast cancer mainly involve treatment with HER2-specific monoclonal antibodies. However, these monoclonal anti-HER2 antibodies have severe side effects in clinical trials, such as diarrhea, abnormal liver function, and drug resistance. Removing HER2 from the plasma membrane or inhibiting the gene expression of HER2 is a promising alternative that could limit the malignancy of HER2-positive cancer cells.

 

DNA origami is an emerging field of DNA-based nanotechnology and intelligent DNA nanorobots show great promise in working as a drug delivery system in healthcare. Different DNA-based nanorobots have been developed as affordable and facile therapeutic drugs. In particular, many studies reported that a tetrahedral framework nucleic acid (tFNA) could serve as a promising DNA nanocarrier for many antitumor drugs, owing to its high biocompatibility and biosecurity. For example, tFNA was reported to effectively deliver paclitaxel or doxorubicin to cancer cells for reversing drug resistance, small interfering RNAs (siRNAs) have been modified into tFNA for targeted drug delivery. Moreover, the production and storage of tFNA are not complicated, and they can be quickly degraded in lysosomes by cells. Since both free HApt and tFNA can be diverted into lysosomes, so,  combining the HApt and tFNA as a novel DNA nanorobot (namely, HApt-tFNA) can be an effective strategy to improve its delivery and therapeutic efficacy in treating HER2-positive breast cancer.

 

Researchers reported that a DNA framework-based intelligent DNA nanorobot for selective lysosomal degradation of tumor-specific proteins on cancer cells. An anti-HER2 aptamer (HApt) was site-specifically anchored on a tetrahedral framework nucleic acid (tFNA). This DNA nanorobot (HApt-tFNA) could target HER2-positive breast cancer cells and specifically induce the lysosomal degradation of the membrane protein HER2. An injection of the DNA nanorobot into a mouse model revealed that the presence of tFNA enhanced the stability and prolonged the blood circulation time of HApt, and HApt-tFNA could therefore drive HER2 into lysosomal degradation with a higher efficiency. The formation of the HER2-HApt-tFNA complexes resulted in the HER2-mediated endocytosis and digestion in lysosomes, which effectively reduced the amount of HER2 on the cell surfaces. An increased HER2 digestion through HApt-tFNA further induced cell apoptosis and arrested cell growth. Hence, this novel DNA nanorobot sheds new light on targeted protein degradation for precision breast cancer therapy.

 

It was previously reported that tFNA was degraded by lysosomes and could enhance cell autophagy. Results indicated that free Cy5-HApt and Cy5-HApt-tFNA could enter the lysosomes; thus, tFNA can be regarded as an efficient nanocarrier to transmit HApt into the target organelle. The DNA nanorobot composed of HApt and tFNA showed a higher stability and a more effective performance than free HApt against HER2-positive breast cancer cells. The PI3K/AKT pathway was inhibited when membrane-bound HER2 decreased in SK-BR-3 cells under the action of HApt-tFNA. The research findings suggest that tFNA can enhance the anticancer effects of HApt on SK-BR-3 cells; while HApt-tFNA can bind to HER2 specifically, the compounded HER2-HApt-tFNA complexes can then be transferred and degraded in lysosomes. After these processes, the accumulation of HER2 in the plasma membrane would decrease, which could also influence the downstream PI3K/AKT signaling pathway that is associated with cell growth and death.

 

However, some limitations need to be noted when interpreting the findings: (i) the cytotoxicity of the nanorobot on HER2-positive cancer cells was weak, and the anticancer effects between conventional monoclonal antibodies and HApt-tFNA was not compared; (ii) the differences in delivery efficiency between tFNA and other nanocarriers need to be confirmed; and (iii) the confirmation of anticancer effects of HApt-tFNA on tumors within animals remains challenging. Despite these limitations, the present study provided novel evidence of the biological effects of tFNA when combined with HApt. Although the stability and the anticancer effects of HApt-tFNA may require further improvement before clinical application, this study initiates a promising step toward the development of nanomedicines with novel and intelligent DNA nanorobots for tumor treatment.

 

References:

 

https://pubs.acs.org/doi/10.1021/acs.nanolett.9b01320

 

https://www.ncbi.nlm.nih.gov/pubmed/27939064

 

https://www.ncbi.nlm.nih.gov/pubmed/11694782

 

https://www.ncbi.nlm.nih.gov/pubmed/27082923

 

https://www.ncbi.nlm.nih.gov/pubmed/25365825

 

https://www.ncbi.nlm.nih.gov/pubmed/26840503

 

https://www.ncbi.nlm.nih.gov/pubmed/29802035

 

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Single-cell RNA-seq helps in finding intra-tumoral heterogeneity in pancreatic cancer

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Pancreatic cancer is a significant cause of cancer mortality; therefore, the development of early diagnostic strategies and effective treatment is essential. Improvements in imaging technology, as well as use of biomarkers are changing the way that pancreas cancer is diagnosed and staged. Although progress in treatment for pancreas cancer has been incremental, development of combination therapies involving both chemotherapeutic and biologic agents is ongoing.

 

Cancer is an evolutionary disease, containing the hallmarks of an asexually reproducing unicellular organism subject to evolutionary paradigms. Pancreatic ductal adenocarcinoma (PDAC) is a particularly robust example of this phenomenon. Genomic features indicate that pancreatic cancer cells are selected for fitness advantages when encountering the geographic and resource-depleted constraints of the microenvironment. Phenotypic adaptations to these pressures help disseminated cells to survive in secondary sites, a major clinical problem for patients with this disease.

 

The immune system varies in cell types, states, and locations. The complex networks, interactions, and responses of immune cells produce diverse cellular ecosystems composed of multiple cell types, accompanied by genetic diversity in antigen receptors. Within this ecosystem, innate and adaptive immune cells maintain and protect tissue function, integrity, and homeostasis upon changes in functional demands and diverse insults. Characterizing this inherent complexity requires studies at single-cell resolution. Recent advances such as massively parallel single-cell RNA sequencing and sophisticated computational methods are catalyzing a revolution in our understanding of immunology.

 

PDAC is the most common type of pancreatic cancer featured with high intra-tumoral heterogeneity and poor prognosis. In the present study to comprehensively delineate the PDAC intra-tumoral heterogeneity and the underlying mechanism for PDAC progression, single-cell RNA-seq (scRNA-seq) was employed to acquire the transcriptomic atlas of 57,530 individual pancreatic cells from primary PDAC tumors and control pancreases. The diverse malignant and stromal cell types, including two ductal subtypes with abnormal and malignant gene expression profiles respectively, were identified in PDAC.

 

The researchers found that the heterogenous malignant subtype was composed of several subpopulations with differential proliferative and migratory potentials. Cell trajectory analysis revealed that components of multiple tumor-related pathways and transcription factors (TFs) were differentially expressed along PDAC progression. Furthermore, it was found a subset of ductal cells with unique proliferative features were associated with an inactivation state in tumor-infiltrating T cells, providing novel markers for the prediction of antitumor immune response. Together, the findings provided a valuable resource for deciphering the intra-tumoral heterogeneity in PDAC and uncover a connection between tumor intrinsic transcriptional state and T cell activation, suggesting potential biomarkers for anticancer treatment such as targeted therapy and immunotherapy.

 

References:

 

https://www.ncbi.nlm.nih.gov/pubmed/31273297

 

https://www.ncbi.nlm.nih.gov/pubmed/21491194

 

https://www.ncbi.nlm.nih.gov/pubmed/27444064

 

https://www.ncbi.nlm.nih.gov/pubmed/28983043

 

https://www.ncbi.nlm.nih.gov/pubmed/24976721

 

https://www.ncbi.nlm.nih.gov/pubmed/27693023

 

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Gender of a person can affect the kinds of cancer-causing mutations they develop, according to a genomic analysis spanning nearly 2,000 tumours and 28 types of cancer. The results show striking differences in the cancer-causing mutations found in people who are biologically male versus those who are biologically female — not only in the number of mutations lurking in their tumours, but also in the kinds of mutations found there.

 

Liver tumours from women were more likely to carry mutations caused by a faulty system of DNA mending called mismatch repair, for instance. And men with any type of cancer were more likely to exhibit DNA changes thought to be linked to a process that the body uses to repair DNA with two broken strands. These biases could point researchers to key biological differences in how tumours develop and evolve across sexes.

 

The data add to a growing realization that sex is important in cancer, and not only because of lifestyle differences. Lung and liver cancer, for example, are more common in men than in women — even after researchers control for disparities in smoking or alcohol consumption. The source of that bias, however, has remained unclear.

In 2014, the US National Institutes of Health began encouraging researchers to consider sex differences in preclinical research by, for example, including female animals and cell lines from women in their studies. And some studies have since found sex-linked biases in the frequency of mutations in protein-coding genes in certain cancer types, including some brain cancers and advanced melanoma.

 

But the present study is the most comprehensive study of sex differences in tumour genomes so far. It looks at mutations not only in genes that code for proteins, but also in the vast expanses of DNA that have other functions, such as controlling when genes are turned on or off. The study also compares male and female genomes across many different cancers, which can allow researchers to pick up on additional patterns of DNA mutations, in part by increasing the sample sizes.

 

Researchers analysed full genome sequences gathered by the International Cancer Genome Consortium. They looked at differences in the frequency of 174 mutations known to drive cancer, and found that some of these mutations occurred more frequently in men than in women, and vice versa. When they looked more broadly at the loss or duplication of DNA segments in the genome, they found 4,285 sex-biased genes spread across 15 chromosomes.

 

There were also differences found when some mutations seemed to arise during tumour development, suggesting that some cancers follow different evolutionary paths in men and women. Researchers also looked at particular patterns of DNA changes. Such patterns can, in some cases, reflect the source of the mutation. Tobacco smoke, for example, leaves behind a particular signature in the DNA.

 

Taken together, the results highlight the importance of accounting for sex, not only in clinical trials but also in preclinical studies. This could eventually allow researchers to pin down the sources of many of the differences found in this study. Liver cancer is roughly three times as common in men as in women in some populations, and its incidence is increasing in some countries. A better understanding of its aetiology may turn out to be really important for prevention strategies and treatments.

 

References:

 

https://www.nature.com/articles/d41586-019-00562-7?utm_source=Nature+Briefing

 

https://www.nature.com/news/policy-nih-to-balance-sex-in-cell-and-animal-studies-1.15195

 

https://www.ncbi.nlm.nih.gov/pubmed/26296643

 

https://www.biorxiv.org/content/10.1101/507939v1

 

https://www.ncbi.nlm.nih.gov/pubmed/25985759

 

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Protein kinase C (PKC) isozymes function as tumor suppressors in increasing contexts. These enzymes are crucial for a number of cellular activities, including cell survival, proliferation and migration — functions that must be carefully controlled if cells get out of control and form a tumor. In contrast to oncogenic kinases, whose function is acutely regulated by transient phosphorylation, PKC is constitutively phosphorylated following biosynthesis to yield a stable, autoinhibited enzyme that is reversibly activated by second messengers. Researchers at University of California San Diego School of Medicine found that another enzyme, called PHLPP1, acts as a “proofreader” to keep careful tabs on PKC.

 

The researchers discovered that in pancreatic cancer high PHLPP1 levels lead to low PKC levels, which is associated with poor patient survival. They reported that the phosphatase PHLPP1 opposes PKC phosphorylation during maturation, leading to the degradation of aberrantly active species that do not become autoinhibited. They discovered that any time an over-active PKC is inadvertently produced, the PHLPP1 “proofreader” tags it for destruction. That means the amount of PHLPP1 in patient’s cells determines his amount of PKC and it turns out those enzyme levels are especially important in pancreatic cancer.

 

This team of researchers reversed a 30-year paradigm when they reported evidence that PKC actually suppresses, rather than promotes, tumors. For decades before this revelation, many researchers had attempted to develop drugs that inhibit PKC as a means to treat cancer. Their study implied that anti-cancer drugs would actually need to do the opposite — boost PKC activity. This study sets the stage for clinicians to one day use a pancreatic cancer patient’s PHLPP1/PKC levels as a predictor for prognosis, and for researchers to develop new therapeutic drugs that inhibit PHLPP1 and boost PKC as a means to treat the disease.

 

The ratio — high PHLPP1/low PKC — correlated with poor prognoses: no pancreatic patient with low PKC in the database survived longer than five-and-a-half years. On the flip side, 50 percent of the patients with low PHLPP1/high PKC survived longer than that. While still in the earliest stages, the researchers hope that this information might one day aid pancreatic diagnostics and treatment. The researchers are next planning to screen chemical compounds to find those that inhibit PHLPP1 and restore PKC levels in low-PKC-pancreatic cancer cells in the lab. These might form the basis of a new therapeutic drug for pancreatic cancer.

 

References:

 

https://health.ucsd.edu/news/releases/Pages/2019-03-20-two-enzymes-linked-to-pancreatic-cancer-survival.aspx?elqTrackId=b6864b278958402787f61dd7b7624666

 

https://www.ncbi.nlm.nih.gov/pubmed/30904392

 

https://www.ncbi.nlm.nih.gov/pubmed/29513138

 

https://www.ncbi.nlm.nih.gov/pubmed/18511290

 

https://www.ncbi.nlm.nih.gov/pubmed/28476658

 

https://www.ncbi.nlm.nih.gov/pubmed/28283201

 

https://www.ncbi.nlm.nih.gov/pubmed/24231509

 

https://www.ncbi.nlm.nih.gov/pubmed/28112438

 

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Immunoediting can be a constant defense in the cancer landscape


Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

There are many considerations in the cancer immunoediting landscape of defense and regulation in the cancer hallmark biology. The cancer hallmark biology in concert with key controls of the HLA compatibility affinity mechanisms are pivotal in architecting a unique patient-centric therapeutic application. Selection of random immune products including neoantigens, antigens, antibodies and other vital immune elements creates a high level of uncertainty and risk of undesirable immune reactions. Immunoediting is a constant process. The human innate and adaptive forces can either trigger favorable or unfavorable immunoediting features. Cancer is a multi-disease entity. There are multi-factorial initiators in a certain disease process. Namely, environmental exposures, viral and / or microbiome exposure disequilibrium, direct harm to DNA, poor immune adaptability, inherent risk and an individual’s own vibration rhythm in life.

 

When a human single cell is crippled (Deranged DNA) with mixed up molecular behavior that is the initiator of the problem. A once normal cell now transitioned into full threatening molecular time bomb. In the modeling and creation of a tumor it all begins with the singular molecular crisis and crippling of a normal human cell. At this point it is either chop suey (mixed bit responses) or a productive defensive and regulation response and posture of the immune system. Mixed bits of normal DNA, cancer-laden DNA, circulating tumor DNA, circulating normal cells, circulating tumor cells, circulating immune defense cells, circulating immune inflammatory cells forming a moiety of normal and a moiety of mess. The challenge is to scavenge the mess and amplify the normal.

 

Immunoediting is a primary push-button feature that is definitely required to be hit when it comes to initiating immune defenses against cancer and an adaptation in favor of regression. As mentioned before that the tumor microenvironment is a “mixed bit” moiety, which includes elements of the immune system that can defend against circulating cancer cells and tumor growth. Personalized (Precision-Based) cancer vaccines must become the primary form of treatment in this case. Current treatment regimens in conventional therapy destroy immune defenses and regulation and create more serious complications observed in tumor progression, metastasis and survival. Commonly resistance to chemotherapeutic agents is observed. These personalized treatments will be developed in concert with cancer hallmark analytics and immunocentrics affinity and selection mapping. This mapping will demonstrate molecular pathway interface and HLA compatibility and adaptation with patientcentricity.

References:

 

https://www.linkedin.com/pulse/immunoediting-cancer-landscape-john-catanzaro/

 

https://www.cell.com/cell/fulltext/S0092-8674(16)31609-9

 

https://www.researchgate.net/publication/309432057_Circulating_tumor_cell_clusters_What_we_know_and_what_we_expect_Review

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4190561/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840207/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593672/

 

https://www.frontiersin.org/articles/10.3389/fimmu.2018.00414/full

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593672/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4190561/

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388310/

 

https://www.linkedin.com/pulse/cancer-hallmark-analytics-omics-data-pathway-studio-review-catanzaro/

 

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