Poster Presentation 25th Lorne Cancer Conference 2013

GENOME-WIDE GAIN-OF-FUNCTION SCREEN FOR GENES THAT INDUCE EPITHELIAL TO MESENCHYMAL TRANSITION IN BREAST CANCER (#357)

Dubravka Skalamera 1 , Mareike Dahmer 1 , Cletus Pinto 2 , Nur Akmarina B. M. Said 3 , Brian Gabrielli 1 , Elizabeth D. Williams 3 , Thomas J. Gonda 4 , Erik W. Thompson 2
  1. UQ Diamantina Institute, University of Queensland, Brisbane, Queensland, Australia
  2. St Vincent’s Institute of Medical Research, and University of Melbourne Dept. Surgery, SVH,, Melbourne, Victoria, Australia
  3. Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
  4. UQ Diamantina Institute and School of Pharmacy, University of Queensland, Brisbane, Queensland, Australia

                Epithelial to mesenchymal transition (EMT) is a complex process required for normal development of many organs. Epithelial mesenchymal plasticity (EMP) has also been implicated in progression, metastasis and therapeutic resistance of some carcinomas so that identifying genes that can drive EMT has potential therapeutic benefits. EMT is accompanied by extensive changes in gene expression profiles that underlie well-defined changes in cell shape, motility and molecular content. One of the hallmarks of EMT is expression of vimentin, a cytoskeletal protein normally absent from the cytoplasm of epithelial cells. To identify genes that are capable of inducing EMT, we screened a 17,000 clone lentiviral expression vector library of EF1alpha promoter-driven human open reading frames (ORFs). Library supernatants were used to express each IRES-GFP-tagged ORF in an MDA-MB-468 cell line containing a vimentin promoter-reporter construct. This cell line was derived from a mammary carcinoma and can be induced to undergo EMT with EGF or hypoxia. We used high-content imaging to identify genes whose overexpression induced EMT as evidenced by an increased proportion of transduced cells expressing vimentin. We measured vimentin promoter activity using the reporter construct as well as cytoplasmic vimentin protein using fluorescence immunocytochemistry. More than 200 genes that caused an increase in vimentin promoter activity and/or cytoplasmic vimentin protein were identified. They included well-characterised EMT inducers such as SNAIL1 and SNAIL2, as well as genes that could represent novel targets for anti-cancer therapy. The relationship between vimentin promoter activity and vimentin protein is also under study. These genes will be characterized in future experiments and through data integration with related studies on EMT within the EMPathy National Collaborative Research Program sponsored by the National Breast Cancer Foundation.