Fig. 6

Mechanism of PARGi sensitivity in OCMs. A Representative immunoblots showing PAR chain formation in OCMs following 96 h of treatment with DMSO (C), 1 μM PARPi (Pi) or 1 μM PARGi (Gi). B Quantification of PAR staining in response to PARGi (Gi) or PARGi co-treated with PARPi (Gi + Pi) using single-cell immunofluorescence microscopy, normalised to DMSO-treated cells (Control). Mean of 3 biological replicates. Error bars represent SEM. C Quantification of γH2AX foci per nucleus and nuclear pKAP1 intensity after 72 h of 1 μM PARGi using single-cell immunofluorescence microscopy, normalised to DMSO-treated cells (Control) and represented as fold change. Mean of 3 biological replicates. Error bars represent SEM. Statistics: 2-way ANOVA with Dunnett’s multiple comparisons test, selected comparisons were between drug treatments and DMSO control. D Representative images of pan-nuclear γH2AX and pKAP1 immunofluorescence staining in OCM.109 after 96 h treatment with 1 μM PARGi. Scale bar: 20 μm. E Quantification of RPA foci per nucleus after 48 h of 1 μM PARGi using single-cell immunofluorescence microscopy, left panel normalised to DMSO-treated cells (Control) and represented as fold change. Mean of 3 biological replicates. Error bars represent SEM. Statistics: 2-way ANOVA with Dunnett’s multiple comparisons test, selected comparisons were between drug treatments and DMSO control. F Representative images of nuclear RPA foci immunofluorescence staining after 96 h of 1 μM PARGi. Scale bar: 10 μm. G Representative immunoblots of pChk1 expression in PARGi-sensitive (109 and 246) and PARGi-resistant (105) OCMs following 96 h of treatment with DMSO (C), 1 μM PARPi (Pi), 1 μM PARGi (Gi) or 10 Gy of ionising radiation (IR). Tao1 serves as loading control. H Cell fate profiling, showing cell behaviour over 120 h treatment with 1 μM PARGi or DMSO (Control). See Fig. 3 and Fig. S8. **p < 0.01, ***p < 0.001, ****p < 0.0001