SWI/SNF regulates a transcriptional program that induces senescence to prevent liver cancer.
Genes Dev 2016;
30:2187-2198. [PMID:
27737960 PMCID:
PMC5088567 DOI:
10.1101/gad.286112.116]
[Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/14/2016] [Indexed: 01/01/2023]
Abstract
Here, Tordella et. al identified senescence regulators relevant to cancer by screening an shRNA library targeting genes deleted in hepatocellular carcinoma (HCC). They show that knockdown of the SWI/SNF component ARID1B prevents oncogene-induced senescence and cooperates with RAS to induce liver tumors, and their results provide new insights into the mechanisms by which epigenetic regulators can affect tumor progression.
Oncogene-induced senescence (OIS) is a potent tumor suppressor mechanism. To identify senescence regulators relevant to cancer, we screened an shRNA library targeting genes deleted in hepatocellular carcinoma (HCC). Here, we describe how knockdown of the SWI/SNF component ARID1B prevents OIS and cooperates with RAS to induce liver tumors. ARID1B controls p16INK4a and p21CIP1a transcription but also regulates DNA damage, oxidative stress, and p53 induction, suggesting that SWI/SNF uses additional mechanisms to regulate senescence. To systematically identify SWI/SNF targets regulating senescence, we carried out a focused shRNA screen. We discovered several new senescence regulators, including ENTPD7, an enzyme that hydrolyses nucleotides. ENTPD7 affects oxidative stress, DNA damage, and senescence. Importantly, expression of ENTPD7 or inhibition of nucleotide synthesis in ARID1B-depleted cells results in re-establishment of senescence. Our results identify novel mechanisms by which epigenetic regulators can affect tumor progression and suggest that prosenescence therapies could be employed against SWI/SNF-mutated cancers.
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