Near‐genomewide RNAi screening for regulators of BRAFV600E‐induced senescence identifies RASEF, a gene epigenetically silenced in melanoma. (14th May 2014)

• Record Type: Journal Article
• Authors: Kaplon, Joanna; Hömig‐Hölzel, Cornelia; Gao, Linda; Meissl, Katrin; Verdegaal, Els M. E.; van der Burg, Sjoerd H.; van Doorn, Remco; Peeper, Daniel S.
• Is Part Of: Pigment cell & melanoma research. Volume 27:Number 4(2014:Jul.)
• Page Start: 640
• Page End: 652
• Publication Date: 2014-05-14
• Subjects: Melanoma -- Periodicals; Chromatophores -- Periodicals; Animal pigments -- Periodicals; 616.99477
• DOI: 10.1111/pcmr.12248
• Languages: English
• ISSNs: 1755-1471

Abstract

<abstract abstract-type="main" id="pcmr12248-abs-0001"> <title>Summary</title> <p>The activation of oncogenes in primary cells blocks proliferation by inducing oncogene‐induced senescence (OIS), a highly potent in vivo tumor‐suppressing program. A prime example is mutant BRAF, which drives OIS in melanocytic nevi. Progression to melanoma occurs only in the context of additional alteration(s) like the suppression of <italic>PTEN</italic>, which abrogates OIS. Here, we performed a near‐genomewide short hairpin (sh)RNA screen for novel OIS regulators and identified by next generation sequencing and functional validation seven genes. While all but one were upregulated in OIS, depletion of each of them abrogated BRAF^V^600E‐induced arrest. With genome‐wide DNA methylation analysis, we found one of these genes, <italic>RASEF</italic>, to be hypermethylated in primary cutaneous melanomas but not nevi. Bypass of OIS by depletion of <italic>RASEF</italic> was associated with suppression of several senescence biomarkers including senescence‐associated (SA)‐<italic>β</italic>‐galactosidase activity, interleukins, and tumor suppressor p15^INK^4B. Restoration of <italic>RASEF</italic> expression inhibited proliferation. These results illustrate the power of shRNA OIS bypass screens and identify a potential novel melanoma suppressor gene.</p> </abstract>