Fig. 5: The vulnerability of DHX9^K120R cells to genotoxic stress can be rescued by RNH.

a-d DHX9^K120R cells exhibited increased susceptibility to genotoxic drugs. HeLa inducible clones were transfected with siDHX9 to deplete endogenous DHX9. The expression of SFB-DHX9^WT and SFB-DHX9^K120R was induced with doxycycline. The cells were treated with CPT (a), HU (b), cisplatin (c), and berzosertib (d) at the indicated concentrations for 24 h. Cell viability was assessed using Cell Titer-Glo 2.0 and is presented as mean ± SEM of three independent experiments (two-way ANOVA). e, f Overexpression of RNH mitigated R-loop-associated DNA damage. HeLa inducible clones with DHX9 depletion were transfected with or without RNH. The percentages of γH2AX-positive cells (e) and RNH-positive cells (f) were determined using Flow Cytometry. Data are presented as mean ± SEM of three independent experiments (ns = no significance) analyzed by two-sided t-test. g RNH overexpression rescued the cell survival of DHX9-depleted or DHX9^K120R cells. HeLa inducible clones transfected with siDHX9 for 1 d were introduced with or without RNH for an additional 3 d before cell counting was performed. Data are presented as mean ± SEM of three independent experiments analyzed by two-sided t-test. Source data are provided as a Source Data file.