1551P - Epithelial to mesenchymal transition induces autophagy in renal cell carcinoma: Implications in cancer therapy

Date 10 October 2016
Event ESMO 2016 Congress
Session Poster display
Topics Translational Research
Basic Principles in the Management and Treatment (of cancer)
Presenter Shalmoli Bhattacharyya
Citation Annals of Oncology (2016) 27 (6): 526-544. 10.1093/annonc/mdw392
Authors S. Bhattacharyya1, M. Singla2, A. Bal3, S.K. Singh4, A.K. Mandal4
  • 1Department Of Biophysics, Post Graduate Institute of Medical Education and Research (PGIMER), 160012 - Chandigarh/IN
  • 2Department Of Biophysics, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh/IN
  • 3Department Of Histopathology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh/IN
  • 4Department Of Urology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh/IN

Abstract

Background

Epithelial to mesenchymal transition (EMT) contributes to the metastatic and invasive potential of tumors including renal-cell carcinoma (RCC). Various preclinical and clinical results have indicated that dysregulated elements leading to EMT can be a potential target in RCC. We assessed the expression profile of EMT associated genes in surgically resected tumor tissue and targeted the survival mechanism of EMT-induced cells.

Methods

We studied the expression of epithelial marker (E-cadherin), mesenchymal markers (Snail, Slug, Vimentin, Twist) and cancer stem cell marker (ALDH1) in 71 patients of histologically proven RCC. These were analysed in both tumor section and the adjoining normal looking parenchyma by real time PCR and Western immunoblot. In vitro studies were carried out in primary cultures and RCC cell line (A498) where EMT was induced pharmacologically using tumor growth factor-beta (TGF-ß, 10ng/ml). Autophagy was assessed in EMT induced cells by acridine orange staining. Tetrazolium dye, (MTT) 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and propidium iodide (PI)-Annexin staining were done to evaluate post-treatment cell survival in EMT cells with temsirolimus and autophagy inhibitor, choloroquine.

Results

Epithelial marker, E-cadherin was significantly down-regulated in tumor tissue while expression of mesenchymal and cancer stem cell markers increased in tumor tissue as compared to adjoining normal tissue. EMT signature proteins showed an increase in in vitro culture of primary cells from tumor tissue as well as in EMT- induced A498 cells. We also observed increased invasiveness and autophagy in EMT induced A498 cells and primary tumor cells as compared to the normal cells. It was observed that addition of autophagy inhibitor (chloroquine) with temsirolimus to EMT-induced cells decrease their viability. Annexin-PI assay showed a significant cell death in combination of chloroquine and temsirolomus on EMT induced cells.

Conclusions

Our study shows that the process of EMT is involved in the metastatic spread of RCC and autophagy helps in survival of the EMT-induced cells. Thus, inhibition of autophagy might represent a future therapeutic option.

Clinical trial identification

None

Legal entity responsible for the study

Postgraduate institute of Medical Education and Research, Chandigarh, India

Funding

Postgraduate institute of Medical Education and Research, Chandigarh, India

Disclosure

All authors have declared no conflicts of interest.