ZNF768 links oncogenic RAS to cellular senescence

KEY FINDINGS ZNF768 is phosphorylated and degraded upon RAS activation ZNF768 depletion impairs proliferation and causes cellular senescence ZNF768 binds and represses p53 and its overexpression suffices to bypass senescence Elevated ZNF768 levels in human tumors may serve to avoid cellular senescence and support proliferation RAS-induced senescence is a safeguarding process against tumour development. Here, the authors show that RAS activation destabilises the transcription factor ZNF768, which blocks ZNF768- dependent repression of p53 activity and thus induces senescence. 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.

Automated summary

The study reveals that RAS activation destabilizes the transcription factor ZNF768, leading to cellular senescence by derepression of the p53 pathway; Overexpression of ZNF768 can bypass RAS-induced senescence and promote proliferation; ZNF768 is often overexpressed in tumors, suggesting its role in evading senescence and promoting malignant transformation.