Fig. 4: DNA damage-related phenotypes in Brca1∆11;Trp53bp1‒/‒ cells exposed to ART558.
From: Polθ inhibitors elicit BRCA-gene synthetic lethality and target PARP inhibitor resistance
a γH2AX foci per nucleus in Brca1∆11, Trp53bp1‒/‒ or Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure. Data are means ± SD, n = 500. b RPA foci per PCNA-positive nucleus in Brca1∆11, Trp53bp1‒/‒ or Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure. Data are means ± SD, n = 300. c pRPA (S4/S8) foci per nucleus in Brca1∆11 or Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure. One-way ANOVA with Tukey post hoc test was used to calculate p values (a–c). d Nuclear intensity of BrdU in ssDNA in Brca1∆11, Trp53bp1‒/‒ or Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure. Data represents percentage of cells with BrdU foci, n = 3 independent experiments. Two-tailed Student’s t test was used to calculate p values. e Representative images of BrdU foci induction following ART558 exposure in Brca1∆11, Trp53bp1‒/‒ or Brca1∆11;Trp53bp1‒/‒ MEFs, scale bar = 10 μm. f Bar plots illustrating SF of Brca1∆11;Trp53bp1‒/‒ MEFs transfected with the indicated siRNA SMARTpools and exposure to DMSO or 5 μM ART558 for 4 days. SF ± SD are shown relative to median DMSO siCON1, n = 3. Two-tailed Student’s t test was used to calculate p values. g Bar plots illustrating surviving fraction of Brca1∆11;Trp53bp1‒/‒ MEFs transfected with the indicated individual siRNA and exposure to DMSO or 5 μM ART558 for four days. Surviving fractions ± SD are shown relative to median DMSO siCON1, n = 3. Two-tailed Student’s t test was used to calculate p values, ** = 0.0021, *** = 0.0002, ****<0.0001. h Fold change in γH2AX foci per nucleus in Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure after transfection with the indicated siRNAs. Data are means ± SD, n = 50 nuclei per condition. Two-tailed Student’s t test was used to calculate p values. i Fold change in pRPA (S4/S8) foci per nucleus in Brca1∆11;Trp53bp1‒/‒ MEFs following ART558 exposure after transfection with the indicated siRNAs. n = 3. Two-tailed Student’s t test was used to calculate p values. j A model for the proposed mechanism driving the sensitivity of BRCA1 and 53BP1 deficient cancers to Polθi.
