RPA枯渇はSLFN11を活性化し、複製ストレス亢進細胞を除去する

SLFN11 is epigenetically silenced and confers chemoresistance in half of all cancers. In response to replication stress, SLFN11 triggers translation shutdown and p53-independent apoptosis, but how DNA damage activates SLFN11 remains unclear. Here through CRISPR-based screens we implicate SLFN11 as the critical determinant of cisplatin sensitivity in cells lacking primase-polymerase (PrimPol)-mediated repriming. SLFN11 and the downstream integrated stress response uniquely promote cisplatin-driven apoptosis in PrimPol-deficient cells. We demonstrate that replication protein A (RPA) exhaustion and single-stranded DNA exposure trigger SLFN11 activation and cell death when PrimPol is inactivated. We further identify the USP1-WDR48 deubiquitinase complex as a positive modulator of SLFN11 activation in PrimPol-deficient cells, revealing an addiction to the Fanconi anaemia pathway to resolve cisplatin lesions. Finally, we demonstrate that rapid RPA exhaustion on chemical inhibition of DNA polymerase α activates SLFN11-dependent cell death. Together, our results implicate RPA exhaustion as a general mechanism to activate SLFN11 in response to heightened replication stress.