A Genome-wide Human ORF Gain-of-function Screen to Identify Genes that can Bypass p16INK4a-mediated Cellular Senescence
Le résumé fourni par la source
Cellular senescence is a genuine tumour suppressor mechanism. It can be induced by ionising radiation, activated oncogenes and by the p16INK4a tumour suppressor gene, commonly known as p16, which is frequently mutated, deleted or silenced in melanoma and other cancers. Human naevi or moles represent a unique system to study senescence and early stage tumour initiation in a non-epithelial cell type. The expression of high p16 levels is commonly observed in naevi along with other features of senescence, such as proliferative arrest. However, early stage primary melanomas can also express high p16 levels while being proliferative; indicating that bypass of p16-mediated senescence is a critical event in melanoma initiation. The identification of novel early stage melanoma genes that can bypass p16-mediated senescence is of potential biological significance not only because the details of how p16 suppresses melanoma is not clearly understood but this mechanism may also be dysregulated in other tumours with features of pre-malignancy. In order to better characterise the mechanism of p16-mediated senescence and identify potential genes that can bypass its initiation, we have screened a human ORF lentiviral expression library, representing approximately 17000 unique full-length ORFs. High-content imaging of a melanoma cell line with inducible p16 was used to identify genes, which bypassed p16-induced senescence. This is the first time a genome scale gain-of-function screen has been performed in a human cell line using lentiviruses. We aim to validate hits in BRaf-induced and replicative senescence in primary melanocytes and examine the expression of these candidates in patient samples of naevi and primary melanomas. The identification of over-expressed genes and pathways that can bypass senescence induced by p16 will provide an improved understanding of the unique mechanism of p16-mediated senescence and may lead to the discovery of novel drug targets that selectively target a sub-type of primary melanoma.
Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.