RESUMO
RAS proteins are GTPases that lie upstream of a signaling network impacting cell fate determination. How cells integrate RAS activity to balance proliferation and cellular senescence is still incompletely characterized. Here, we identify ZNF768 as a phosphoprotein destabilized upon RAS activation. We report that ZNF768 depletion impairs proliferation and induces senescence by modulating the expression of key cell cycle effectors and established p53 targets. ZNF768 levels decrease in response to replicative-, stress- and oncogene-induced senescence. Interestingly, ZNF768 overexpression contributes to bypass RAS-induced senescence by repressing the p53 pathway. Furthermore, we show that ZNF768 interacts with and represses p53 phosphorylation and activity. Cancer genomics and immunohistochemical analyses reveal that ZNF768 is often amplified and/or overexpressed in tumors, suggesting that cells could use ZNF768 to bypass senescence, sustain proliferation and promote malignant transformation. Thus, we identify ZNF768 as a protein linking oncogenic signaling to the control of cell fate decision and proliferation.
Assuntos
Senescência Celular/genética , Genes ras/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Carcinogênese , Ciclo Celular , Diferenciação Celular , Proliferação de Células , Transformação Celular Neoplásica , Replicação do DNA , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Genômica , Células HeLa , Humanos , Oncogenes , Fenótipo , Fosfoproteínas , Fosforilação , Repressão Psicológica , Transdução de Sinais , Proteínas ras/genéticaRESUMO
We recently identified Zinc-finger protein 768 (ZNF768) as a novel transcription factor controlling cell fate decision downstream of Rat sarcoma virus (RAS). We showed that ZNF768 depletion impairs cell cycle progression and triggers cellular senescence, while its overexpression allows cells to bypass oncogene-induced senescence. Elevated ZNF768 levels is common in tumors, suggesting that ZNF768 may help to escape cellular senescence, sustain proliferation and promote malignant transformation. Here, we discuss these recent findings and highlight key questions emerging from our work.