DEK loss in HeLa cells does not alter genotoxic stress sensitivity and DNA damage response

DEK, a chromatin-associated oncoprotein, is involved in various cellular processes. Previous siRNA/shRNA-mediated DEK knockdown studies reported increased genotoxic stress sensitivity and altered γH2AX signaling. Whether DEK knockout cells recapitulate these phenotypes remains elusive. Using CRISPR/Cas9-generated DEK knockout HeLa cells, we assessed survival, γH2AX levels, and genomic integrity after DNA damage. DEK loss caused moderate, context-dependent changes in viability and damage accumulation. γH2AX induction and resolution were largely comparable between wild-type and knockout cells. Comet assays revealed moderate DNA damage upon DEK loss. Thus, complete DEK loss yields less pronounced DNA damage responses than knockdown, suggesting compensatory effects in HeLa cells.