Poster presentation, P135

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

Genome-wide shRNA screen for tumor suppressors mediating oncogene-induced senescence

Oncogene-induced senescence (OIS) is a tumor-suppressive mechanism that restrains the outgrowth of neoplastic cells in vivo. We have shown previously that OIS occurs in oncogene-expressing melanocytic nevi in humans, confining the progression of these benign lesions to melanoma. Such malignant transformation events are relatively rare, however, suggesting that additional (epi)genetic alterations are required. Animal models with melanocyte-specific oncogene expression support these findings. To date, only few mediators of OIS have been identified. We therefore performed a genome-wide shRNA OIS bypass screen to identify mediators of RAS-induced senescence. We made use of a genome-wide shRNA (TRC) library, that was transduced into a cell system that allows for conditional induction of RAS-induced senescence. We screened for shRNAs that were enriched in cells bypassing OIS, by quantitative high throughput sequencing (Illumina). The analysis of technical replicates, used to determine the quality of PCR amplification and sequencing, revealed that we could reproducibly detect shRNAs with a high abundance. Gratifyingly, shRNAs targeting genes that are known to play a role in OIS (Cdkn2a, p53) were among the top outliers. We are currently validating our top 25 hits. By identifying critical mediators of OIS we aim to gain further insight into the molecular mechanism of this tumor suppressive mechanism and to identify signaling pathways that contribute to malignant transformation.

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