Fig 1: Control of HR by RNA-binding proteins in breast cancer(A) Images of cells treated with either 10 nM of the splicing inhibitor pladienolide B or a DMSO vehicle control, 24 h prior to irradiation (5 Gy). Images show Rad51 foci indicative of HR repair (green), as well as proliferating (S phase) cells with EdU (red), and DAPI nuclear stain (blue).(B) Quantification of percentage of cycling (EdU+) cells that exhibit Rad51 foci. N = 3. Student’s t test. ∗p < 0.05, ∗∗p < 0.01. Mean ± SEM.(C and D) Viability of TNBC cells following a 5-day incubation with the splicing inhibitor pladienolide B (concentration indicated on top x axis), PARP inhibitor BMN673 (concentration indicated on bottom x axis), or a combination thereof, relative to a DMSO vehicle control for MDA-MB-231 cells (C) and BT-549 cells (D). Mean ± SEM. C.I., Chou-Talalay combination index. N = 2.(E) Quantification of IR-induced Rad51 foci in cycling (EdU+) TNBC cell lines following siRNA-mediated depletion of the indicated RBPs. N = 2 per cell line. Mean ± SD.(F) Viability of individual MDA-MB-231 cell lines with stable single knockdowns of RBPs DDX3X and SF3B3, as well as HR protein BRCA2, following a 5-day treatment with BMN673. Mean ± SD.(G) As in (F) but following a 5-day treatment with AZD2281. Mean ± SD.(H) Clonogenic assay with MDA-MB-231 cells with stable knockdown of RBPs DDX3X and SF3B3, following a 2-week treatment with BMN673. N = 2, and points represent independent biological replicates. See also Figure S5. Mean ± SD.