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Targeting Epithelial To Mesenchymal Transition (EMT) As A Therapy Strategy For Pancreatic Cancer

Posted in Cancer and Current Therapeutics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cell Biology, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, tagged Clinical trial, EMT, hedgehog, Pancreatic cancer, Wnt on April 19, 2016| Leave a Comment »

Targeting Epithelial To Mesenchymal Transition (EMT) As A Therapy Strategy For Pancreatic Cancer

Curator: David Orchard-Webb, PhD

Epithelial to mesenchymal transition (EMT) is a mechanism by which cells of an epithelial phenotype dedifferentiate to a plastic mesenchymal phenotype. The epithelial cell rearranges its actin cytoskeleton from a cortical tight junction associated ring to form elongated stress fibres, redistributes and down regulates its cell-cell contacts, loses its polarity, and upregulates mesenchymal markers including α-smooth muscle actin (α-SMA) and vimentin [1]. The cell changes the composition of its extracellular matrix (ECM) contacts and secretes matrix metalloproteinases [2]. EMT has a role during development [3], chronic fibrotic disorders [4], and a postulated role in epithelial cancer metastasis [5].

Mouse mammary cell line induced to EMT with TGFβ1. Image Source: David Orchard-Webb.

Inflammatory signalling associated with pancreatitis is a driver of both pancreatic cancer and EMT [4,8]. Pancreatic cancer has a large stromal component that has therapeutic implications such as reduced drug tumour penetrance [9]. EMT is a mechanism of pancreatic stroma generation and may generate cancer stem-like cells [10]. This suggests a strategy for success in pancreatic cancer therapy. Cancer stem cells and stroma are major impediments to current therapeutics therefore targeting EMT is strategically viable to enhance their effectiveness.

A number of drug candidates have entered clinical trial which target EMT pathways. Curcumin which can reverse the EMT phenotype in vitro, has been shown to enhance the effectiveness of gemcitabine, the first FDA approved chemotherapeutic for pancreatic cancer [11]. Prism Pharma Co., Ltd. has developed a Wnt pathway inhibitor that may be effective in pancreatic cancer, however the associated phase I trial had to be terminated in 2015 due to low enrolment [14]. There are ongoing clinical trials targeting the hedgehog pathway which plays a role in EMT, in combination with gemcitabine and nab-paclitaxel (Abraxane) [12, 13].

STATs are transcription factors which are normally present in the cytoplasm and activated by inflammatory signalling associated with EMT which leads to their nuclear import [15]. STAT3 expression is maintained and constitutive activation has been reported in at least 30% of pancreatic cancers [6]. STAT3 is not active in normal pancreatic tissue but its activation is required in the early stages of pancreatic cancer progression. A means to eliminate STAT3 has been developed by Astrazeneca – stable systemically delivered siRNA which has completed phase I clinical trials [7]. This may prove beneficial in combination with standard chemotherapeutics.

In summary a number of EMT pathway targeting therapeutics are in development which have the potential to target pancreatic cancer stem cells, which could reduce cancer recurrence, and deplete the cancer associated stroma which should improve the penetrance of existing therapeutics and may help relieve suppression of the immune system by pancreatic tumours.

REFERENCES

Savagner, P. 2001. Leaving the neighborhood: molecular mechanisms involved during Epithelial-Mesenchymal Transition. BioEssays. 23: 912-923.
LaGamba, D. Nawshad, A. and Hay, E.D. 2005. Microarray analysis of gene expression during Epithelial-Mesenchymal Transformation. Dev Dyn. 234: 132-42
Hay, E.D. 1995. An overview of Epithelio-Mesenchymal Transformation. Acta Anat (Basel). 154: 8-20.
Kalluri, R. and Neilson, E.G. 2003. Epithelial-Mesenchymal Transition and its implications for fibrosis. J Clin Invest. 112: 1776-84.
Thiery, J.P. 2002. Epithelial-Mesenchymal Transitions in tumour progression. Nat Rev Cancer. 2: 442–454.
Corcoran, R. B., G. Contino, V. Deshpande, A. Tzatsos, C. Conrad, C. H. Benes, D. E. Levy, J. Settleman, J. A. Engelman, and N. Bardeesy. ‘STAT3 Plays a Critical Role in KRAS-Induced Pancreatic Tumorigenesis’. Cancer Research 71, no. 14 (15 July 2011): 5020–29. doi:10.1158/0008-5472.CAN-11-0908.
Hong, David, Razelle Kurzrock, Youngsoo Kim, Richard Woessner, Anas Younes, John Nemunaitis, Nathan Fowler, et al. ‘AZD9150, a next-Generation Antisense Oligonucleotide Inhibitor of STAT3 with Early Evidence of Clinical Activity in Lymphoma and Lung Cancer’. Science Translational Medicine 7, no. 314 (18 November 2015): 314ra185. doi:10.1126/scitranslmed.aac5272.
Guerra, Carmen, Alberto J. Schuhmacher, Marta Cañamero, Paul J. Grippo, Lena Verdaguer, Lucía Pérez-Gallego, Pierre Dubus, Eric P. Sandgren, and Mariano Barbacid. ‘Chronic Pancreatitis Is Essential for Induction of Pancreatic Ductal Adenocarcinoma by K-Ras Oncogenes in Adult Mice’. Cancer Cell 11, no. 3 (March 2007): 291–302. doi:10.1016/j.ccr.2007.01.012.
Xie, Dacheng, and Keping Xie. ‘Pancreatic Cancer Stromal Biology and Therapy’. Genes & Diseases 2, no. 2 (June 2015): 133–43. doi:10.1016/j.gendis.2015.01.002.
Dangi-Garimella, Surabhi, Seth B. Krantz, Mario A. Shields, Paul J. Grippo, and Hidayatullah G. Munshi. ‘Epithelial-Mesenchymal Transition and Pancreatic Cancer Progression’. In Pancreatic Cancer and Tumor Microenvironment, edited by Paul J. Grippo and Hidayatullah G. Munshi. Trivandrum (India): Transworld Research Network, 2012. http://www.ncbi.nlm.nih.gov/books/NBK98932/.
Osterman, Carlos J. Díaz, and Nathan R. Wall. ‘Curcumin and Pancreatic Cancer: A Research and Clinical Update’. Journal of Nature and Science 1, no. 6 (2015): 124. http://www.jnsci.org/files/html/e124.htm.
‘Hedgehog Inhibitors for Metastatic Adenocarcinoma of the Pancreas – Full Text View – ClinicalTrials.gov’. Accessed 18 April 2016. https://clinicaltrials.gov/ct2/show/NCT01088815.
Singh, Brahma N., Junsheng Fu, Rakesh K. Srivastava, and Sharmila Shankar. ‘Hedgehog Signaling Antagonist GDC-0449 (Vismodegib) Inhibits Pancreatic Cancer Stem Cell Characteristics: Molecular Mechanisms’. PLOS ONE 6, no. 11 (8 November 2011): e27306. doi:10.1371/journal.pone.0027306.
‘Safety and Efficacy Study of PRI-724 in Subjects With Advanced Solid Tumors – Full Text View – ClinicalTrials.gov’. Accessed 18 April 2016. https://clinicaltrials.gov/ct2/show/NCT01302405.
Kaplan, Mark H. ‘STAT Signaling in Inflammation’. JAK-STAT 2, no. 1 (January 2013): e24198. doi:10.4161/jkst.24198.

In Focus: Identity of Cancer Stem Cells

Posted in Biomarkers & Medical Diagnostics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cell Biology, Signaling & Cell Circuits, Genome Biology, Stem Cells for Regenerative Medicine, tagged ALDH, anti-cancer therapy, biomarkers, breast cancer, Cancer - General, cancer stem cells, CD34, CD38, CD44, CD96, CML, CSC, CSCs, EMT, Epithelial-mesenchymal transition, genetic heterogeneity, Glioma, Hematopoietic stem cells, hierarchy, HSCs, IL-6, Imatinib, Interleukin 6, LSCs, polarized epithelial cells, self-renewal, stem cells, tumors, tyrosin kinase inhibitor on March 22, 2013| 9 Comments »

Author and Curator: Ritu Saxena, PhD

Word Cloud By Danielle Smolyar

What are cancer stem cells?

Cancer is a debilitating disease estimated to be responsible for about 7.6 million deaths in 2008 (Jemal A, et al, CA Cancer J Clin, Mar-Apr 2011;61(2):69-90). Thus, extensive research is underway to deal with the various types of cancer. The concept of cancer stem cells (CSC) has surfaced in in the past decade after identification and characterization of CSC-enriched populations in several different types of cancer (Lapidot T, et al, Nature, 17 Feb 1994;367(6464):645-8; Reya T, et al, Nature, 1 Nov 2001;414(6859):105-11; Trumpp A and Wiestler OD, et al, Nat Clin Pract Oncol, Jun 2008;5(6):337-47). Although there has been lot of debate on the cell of origin of CSC, according to the classical concept CSC are defined by their functional properties.

Functional properties of CSC

CSCs are at the top of tumor hierarchy. Regenerative tissues follow a hierarchical organization with adult stem cells at the top maintaining tissues and normal adult cells during homeostasis and regeneration during cell loss from injury. Similarly, several tumors follow the hierarchy with CSC at the top. Hierarchical organization has been reported in several cancer types including but not limited to breast cancer, brain cancer, colon cancer, leukemia and pancreatic cancer (Lapidot T, et al, Nature, 17 Feb 1994;367(6464):645-8; Al-Hajj M, et al, PNAS USA, 1 Apr 200;100(7):3983-8; Singh SK, et al, Nature, 18 Nov 2004;432(7015):396-401; Dalerba P, et al, PNAS USA, 12 Jun 2007;104(24):10158-63; Hermann PC, et al, Cell Stem Cell, 13 Sep 2007;1(3):313-23).
CSCs possess unlimited self-renewal capacity similar to that of physiological stem cells and unlike other differentiated cell types within the tumor. Cancer stem cells can also generate non-CSC progeny that is comprised of differentiated cells and forms tumor bulk.
Some CSs exhibit quiescent or dormant stage. Although not observed in all CSC types, some CSCs have been found to shuttle between quiescent, slow-cycling, and active states. The CSCs in their dormant and slow-cycling stage are less likely to be affected by conventional anti-tumor therapies which generally target rapidly dividing cells. Dormant stage is exhibited even in adult stem cells and the dormant normal stem cells can regain cell division potential during tissue injury (Wilson A, et al, Cell, 12 Dec 2008;135(6):1118-29). Thus, it has been speculated that dormant CSC might be a reason for tumor relapse even after pathologic complete response is observed post therapy.
Some CSCs are resistant to conventional anti-cancer therapies. This leads to accumulation of CSC that might result in relapse after anti-cancer therapy. For instance, Li et al (2008) reported that CSC accumulated in the breast of women with locally advanced tumors after cytotoxic chemotherapy had eliminated the bulk of the tumor cells (Li X,et al, J Natl Cancer Inst, 7 May 2008;100(9):672-9). A similar observation was made by Oravecz-Wilson et al (2009) stating that despite remarkable responses to the tyrosine kinase inhibitor imatinib, CML patients show imatinib refractoriness because leukemia stem cells in CML are resistant tyrosine kinase (Oravecz-Wilson KI, et al, Cancer Cell, 4 Aug 2009;16(2):137-48).
The CSC niche. CSC functional traits might be sustained by this microenvironment, termed “niche”. The niche is the environment in which stem cells reside and is responsible for the maintenance of unique stem cell properties such as self-renewal and an undifferentiated state. The heterogeneous populations which constitute a niche include both stem cells and surrounding differentiated cells. The necessary intrinsic pathways that are utilized by this cancer stem cell population to maintain both self-renewal and the ability to differentiate are believed to be a result of the environment where cancer stem cells reside. (Cabarcas SM, et al, Int J Cancer, 15 Nov 2011;129(10):2315-27). For instance, properties of CSC in glioma in a mouse xenograft model were maintained by vascular endothelial cells (Calabrese C, et al, Cancer Cell, Jan 2007;11(1):69-82). Several molecules including interleukin 6 have been observed to play a role in tumor proliferation and hence, participate in maintaining tumorigenic and self-renewal potential of CSC. Moreover, the CSC niche might not only regulate CSCs traits but might also directly provide CSC features to non-CSC population.

What is the origin of CSC?

According to current thinking, CSC result from epithelial-mesenchymal transition (EMT) when cells switch from a polarized epithelial to a non-polarized mesenchymal cell type with stem cell properties, including migratory behavior, self-renewal and generation of differentiated progeny, and reduced responsiveness to conventional cancer therapies (Scheel C and Weinberg RA, Semin Cancer Biol, Oct 2012;22(5-6):396-403; Crews LA and Jamieson CH, Cancer Lett, 17 Aug 2012). Evidence is accumulating that cancers of distinct subtypes within an organ may derive from different ‘cells of origin’. The tumor cell of origin is the cell type from which the disease is derived after it undergoes oncogenic mutation. It might take a series of mutations to achieve the CSC phenotype (Visvader JE, Nature, 20 Jan 2011;469(7330):314-22). Also, CSCs have been reported to originate from stem cells in some cases.

Biomarkers for CSC

CSC targeting therapy could either eliminate CSCs by either killing them after differentiating them from other tumor population, and/or by disrupting their niche. Efficient eradication of CSCs may require the combined ablation of CSCs themselves and their niches. Identifying appropriate biomarkers of CSC is a very important aim for CSCs to be useful as targets of anti-cancer therapies in order to possibly prevent relapse. Using cell surface markers, CSCs have been isolated and purified from cancers of breast, brain, thyroid, cervix, lung, blood (leukemia), skin (melanoma), organs of the gastrointestinal and reproductive tracts, and the retina. The challenge, however, is that CSCs share similar markers with normal cells which makes CSCs targeting difficult as it would harm normal cells in the process. More recently, advanced techniques such as signal sequence trap (SST) PCR screening methods have been developed to identify a leukemia-specific stem cell marker (CD96). After a small subset of human AML cells displayed tumorigenic properties, Leukemia Stem Cells (LSCs) were identified as leukemia cells with CD23+/CD38+ markers. These cells closely resemble hematopeotic stem cells (HSCs) (Bonnet D and Dick JR, Nat Med, Jul 1997;3(7):730-7). In solid tumors, a significant discovery was made when CSCs in breast cancer were identified within the ESA+/CD44+/CD24low-neg population of mammary pleural effusion and tumor samples (Al-Hajj M, et al, PNAS USA, 1 Apr 200;100(7):3983-8).

After these two landmark publications, CSCs were identified in many more solid and hematopoietic human tumors as well. In addition, within a tumor type, CSC-enriched populations display heterogeneity in markers. For example, only 1% of breast cancer cells simultaneously express both reported CSC phenotypes ESA+/CD44+/

CD24low-neg and ALDH-1+ (Ginestier C, et al, Cell Stem Cell, 1 Nov 2007;1(5):555-67). The discrepancy might be due to different techniques used to identify the markers and also a reflection of the molecular heterogeneity within the tumors. Recent advances in genome wide expression profiling studies have led to the identification of different subtypes in a particular type of cancer. Breast cancer was recently classified into different subtypes and this genetic heterogeneity is likely paralleled by a heterogeneous CSC complexity.

Conclusion

A lot of research is currently underway on various aspects of CSCs including biomarker identification, cell of origin, and clinical trials targeting CSC population in cancer. The concept of CSCs has evolved quite a bit since their discovery. Recently, identification of high genetic heterogeneity within a tumor has been in focus and subsequently it has been observed that several CSC clones can coexist and compete with each other within a tumor. Adding complexity to their identity is the fact that CSCs may have unstable phenotypes and genotypes. Taken together, the dynamics associated with CSCs makes it difficult to identify reliable and robust biomarkers and develop efficient targeted therapies. Thus, a major thrust of research should be to focus on the unfolding of the dynamic identity of CSCs in tumor types and at different that might lead to the identification and targeting of highly specific CSCs biomarkers.

Reference

Jemal A, et al, CA Cancer J Clin, Mar-Apr 2011;61(2):69-90

Reya T, et al, Nature, 1 Nov 2001;414(6859):105-11

Trumpp A and Wiestler OD, et al, Nat Clin Pract Oncol, Jun 2008;5(6):337-47

Lapidot T, et al, Nature, 17 Feb 1994;367(6464):645-8

Singh SK, et al, Nature, 18 Nov 2004;432(7015):396-401

Dalerba P, et al, PNAS USA, 12 Jun 2007;104(24):10158-63

Hermann PC, et al, Cell Stem Cell, 13 Sep 2007;1(3):313-23

Wilson A, et al, Cell, 12 Dec 2008;135(6):1118-29

Li X,et al, J Natl Cancer Inst, 7 May 2008;100(9):672-9

Oravecz-Wilson KI, et al, Cancer Cell, 4 Aug 2009;16(2):137-48

Cabarcas SM, et al, Int J Cancer, 15 Nov 2011;129(10):2315-27

Calabrese C, et al, Cancer Cell, Jan 2007;11(1):69-82

Scheel C and Weinberg RA, Semin Cancer Biol, Oct 2012;22(5-6):396-403

Crews LA and Jamieson CH, Cancer Lett, 17 Aug 2012

Visvader JE, Nature, 20 Jan 2011;469(7330):314-22

Bonnet D and Dick JR, Nat Med, Jul 1997;3(7):730-7

Al-Hajj M, et al, PNAS USA, 1 Apr 200;100(7):3983-8

Ginestier C, et al, Cell Stem Cell, 1 Nov 2007;1(5):555-67

Baccelli I and Trumpp AJ, Cell Biol, 6 Aug 2012;198(3):281-93

Zhao L, et al, Eur Surg Res, 2012;49(1):8-15

Pharmaceutical Intelligence posts:

http://pharmaceuticalintelligence.com/2012/08/15/to-die-or-not-to-die-time-and-order-of-combination-drugs-for-triple-negative-breast-cancer-cells-a-systems-level-analysis/

Authors: Anamika Sarkar, PhD and Ritu Saxena, PhD

http://pharmaceuticalintelligence.com/2013/03/07/the-importance-of-cancer-prevention-programs-new-perceptions-for-fighting-cancer/ Author: Ziv Raviv, PhD

http://pharmaceuticalintelligence.com/2013/03/03/treatment-for-metastatic-her2-breast-cancer/ Reporter: Larry H Bernstein, MD

http://pharmaceuticalintelligence.com/2013/03/02/recurrence-risk-for-breast-cancer/

Larry H Bernstein, MD

http://pharmaceuticalintelligence.com/2013/02/14/prostate-cancer-androgen-driven-pathomechanism-in-early-onset-forms-of-the-disease/ Curator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/01/15/exploring-the-role-of-vitamin-c-in-cancer-therapy/ Curator: Ritu Saxena, PhD

http://pharmaceuticalintelligence.com/2013/01/12/harnessing-personalized-medicine-for-cancer-management-prospects-of-prevention-and-cure-opinions-of-cancer-scientific-leaders-httppharmaceuticalintelligence-com/ Curator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/01/10/the-molecular-pathology-of-breast-cancer-progression/ Author and reporter: Tilda Barliya PhD

http://pharmaceuticalintelligence.com/2012/11/30/histone-deacetylase-inhibitors-induce-epithelial-to-mesenchymal-transition-in-prostate-cancer-cells/ Reporter and Curator: Stephen J. Williams, PhD

http://pharmaceuticalintelligence.com/2012/10/22/blood-vessel-generating-stem-cells-discovered/ Reporter: Ritu Saxena, PhD

http://pharmaceuticalintelligence.com/2012/10/17/stomach-cancer-subtypes-methylation-based-identified-by-singapore-led-team/ Reporter: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/09/17/natural-agents-for-prostate-cancer-bone-metastasis-treatment/ Reporter: Ritu Saxena, PhD

http://pharmaceuticalintelligence.com/2012/08/28/cardiovascular-outcomes-function-of-circulating-endothelial-progenitor-cells-cepcs-exploring-pharmaco-therapy-targeted-at-endogenous-augmentation-of-cepcs/ Aviva Lev-Ari, PhD, RN

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Prostate Cancer Cells: Histone Deacetylase Inhibitors Induce Epithelial-to-Mesenchymal Transition

Posted in Bio Instrumentation in Experimental Life Sciences Research, Biological Networks, Gene Regulation and Evolution, BioSimilars, CANCER BIOLOGY & Innovations in Cancer Therapy, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Health Economics and Outcomes Research, Pharmaceutical Analytics, Stem Cells for Regenerative Medicine, tagged Aviva Lev-Ari, Biology, breast cancer, Cancer - General, cancer drug resistance, Cancer research, cancer stem cells, Cell Biology, Chemotherapy, Clinical trial, Conditions and Diseases, DNA, EMT, epithelial-mesenchymal, Epithelial-mesenchymal transition, gene, HDAC, health, Histone, Histone deacetylase, Histone deacetylase inhibitor, histone modification, medicine, metastasis, Prostate cancer, research, Squamous epithelial cell on November 30, 2012| 21 Comments »

Histone Deacetylase Inhibitors Induce Epithelial-to-Mesenchymal Transition in Prostate Cancer Cells(1)

Word Cloud By Danielle Smolyar

Authors: Dejuan Kong, Aamir Ahmad, Bin Bao, Yiwei Li, Sanjeev Banarjee, Fazlul H. Sarkar, Wayne State University School of Medicine

Reporter-Curator: Stephen J. Williams, Ph.D.

Clinically, there has not been much success in treating solid tumors with histone deacetylase inhibitors (HDACi). Histone acetylation and deacetylation play an important role in transcriptional regulation of genes and increased activity is associated with many cancers, therefore it was thought that HDAC inhibition might be fruitful as a therapy. There have been several phase I and II clinical trials using HDACi for treatment of various malignancies, including hematological and solid malignancies(2), with most success seen in hematologic malignancies such as cutaneous T-cell lymphoma and peripheral T-cell lymphoma and little or no positive outcome with solid tumors. Many mechanisms of resistance to HDACi in solid tumors have been described, most of which are seen with other chemotherapeutics such as increased multidrug resistance gene MDR1, increased anti-apoptotic proteins and activation of cell survival pathways(3).

A report in PLOS One by Dr. Dejuan Kong, Dr. Fazlul Sarkar, and colleagues from Wayne State University School of Medicine, demonstrate another possible mechanism of resistance to HDACi in prostate cancer, by induction of the epithelial-to-mesenchymal transition (EMT), which has been associated with the development of resistance to chemotherapies in other malignancies of epithelial origin(4,5).

EMT is an important differentiation process in embryogenesis and felt to be important in progression of cancer. Epithelial cells will acquire a mesenchymal morphology (on plastic this looks like a cuboidal epithelial cell gaining a more flattened, elongated, tri-corner morphology; see paper Figure 1) and down-regulate epithelial markers such as cytokeratin, up-regulation of mesenchymal markers, increased migration and invasiveness in standard assays, and increased resistance to chemotherapeutics, and similarity to cancer stem cells(6-10).

Figure 1. HDACis led to the induction of EMT phemotype. (A and B) PC3 cells treated with TSA and SAHA for 24 h at indicated doses. The photomicrographs of PC3 cells treated with TSA and SAHA exhibited a fibroblastic-type phenotype, while cells treated with DMAO control displayed rounded epithelial cell morphology (original magnification, x 100). (C) Treated PC3 cells show increased mesenchymal markers vimentin and ZEB1 and F-actin reorganization. Figure taken from Kong, D., Ahmad, A., Bao, B., Li, Y., Banerjee, S., and Sarkar, F. H. (2012) PloS one 7, e45045

In this study the authors found that treatment of prostate carcinoma cells with two different HDACis (trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA)) induced EMT phenotype mediated through up-regulation of transcription factors ZEB1, ZEB2 and Slug, increased expression of mesenchymal markers vimentin, N-cadherin and fibronectin by promoting histone 3 acetylation on gene promoters. In addition TSA increased the stem cell markers Sox2 and Nanog with concomitant EMT morphology and increased cell motility.

Below is the abstract of this paper(1):

ABSTRACT

Clinical experience of histone deacetylase inhibitors (HDACIs) in patients with solid tumors has been disappointing; however, the molecular mechanism of treatment failure is not known. Therefore, we sought to investigate the molecular mechanism of treatment failure of HDACIs in the present study. We found that HDACIs Trichostatin A (TSA) and Suberoylanilide hydroxamic acid (SAHA) could induce epithelial-to-mesenchymal transition (EMT) phenotype in prostate cancer (PCa) cells, which was associated with changes in cellular morphology consistent with increased expression of transcription factors ZEB1, ZEB2 and Slug, and mesenchymal markers such as vimentin, N-cadherin and Fibronectin. CHIP assay showed acetylation of histone 3 on proximal promoters of selected genes, which was in part responsible for increased expression of EMT markers. Moreover, TSA treatment led to further increase in the expression of Sox2 and Nanog in PCa cells with EMT phenotype, which was associated with cancer stem-like cell (CSLC) characteristics consistent with increased cell motility. Our results suggest that HDACIs alone would lead to tumor aggressiveness, and thus strategies for reverting EMT-phenotype to mesenchymal-to-epithelial transition (MET) phenotype or the reversal of CSLC characteristics prior to the use of HDACIs would be beneficial to realize the value of HDACIs for the treatment of solid tumors especially PCa.

Highlights of the research include:

TSA and SAHA induce morphologic changes in prostate carcinoma LNCaP and PC3 cells related to EMT by microscopy as well as accumulation of mesenchymal markers ZEB1, vimentin, and F-actin reorganization shown by immunofluorescence microscopy and increased expression of these markers shown by real-time PCR
Western blotting showed TSA treatment resulted in hyperacetyulation of histone 3 whi8le CHIP analysis revealed increased histone 3 acetylation on the promoters of vimentin, ZEB2, Slug, and MMP2
Western analysis revealed that HDACi not only induced EMT but increased the expression of cancer stem cell markers associated with increased motility such as Sox2 and Nanog. Increased cell migration was measured by Transwell migration assays and increased cell motility was measured via cell detachment assays

1. Kong, D., Ahmad, A., Bao, B., Li, Y., Banerjee, S., and Sarkar, F. H. (2012) PloS one 7, e45045

2. Bertino, E. M., and Otterson, G. A. (2011) Expert opinion on investigational drugs 20, 1151-1158

3. Robey, R. W., Chakraborty, A. R., Basseville, A., Luchenko, V., Bahr, J., Zhan, Z., and Bates, S. E. (2011) Molecular pharmaceutics 8, 2021-2031

4. Wang, Z., Li, Y., Kong, D., Banerjee, S., Ahmad, A., Azmi, A. S., Ali, S., Abbruzzese, J. L., Gallick, G. E., and Sarkar, F. H. (2009) Cancer research 69, 2400-2407

5. Wang, Z., Li, Y., Ahmad, A., Azmi, A. S., Kong, D., Banerjee, S., and Sarkar, F. H. (2010) Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy 13, 109-118

6. Hugo, H., Ackland, M. L., Blick, T., Lawrence, M. G., Clements, J. A., Williams, E. D., and Thompson, E. W. (2007) Journal of cellular physiology 213, 374-383

7. Thiery, J. P. (2002) Nature reviews. Cancer 2, 442-454

8. Kong, D., Banerjee, S., Ahmad, A., Li, Y., Wang, Z., Sethi, S., and Sarkar, F. H. (2010) PloS one 5, e12445

9. Kong, D., Li, Y., Wang, Z., and Sarkar, F. H. (2011) Cancers 3, 716-729

10. Bao, B., Wang, Z., Ali, S., Kong, D., Li, Y., Ahmad, A., Banerjee, S., Azmi, A. S., Miele, L., and Sarkar, F. H. (2011) Cancer letters 307, 26-36