Fig. 4: Analysis of cisplatin response in XRCC3 knockout cells.

a Schematic overview of a large genomic deletion of a region including XRCC3 in HBCx-14. Coloured boxes below indicate exons of genes, with gene names and transcriptional direction (arrows) shown in the bottom of the figure. The 3 panels below show the splice junction tracts in IGV for WT (T250 primary), HBCx-14 primary and HBCx-14 xenograft. Splice junctions connecting exons are represented by blue and red arcs, with transcriptional direction of genes indicated by colour. HBCx-14 primary and PDX tumours show a junction from APOPT1 exon 2 to ZFYVE21 exon 2 that is not found in the WT sample. Numbers above and below arcs indicating the junction depth show loss of coverage in the region spanned by the APOPT1-ZFYVE21 junction in HBCx-14 compared to WT, with similar or higher junction coverage outside this region. IGV coverage tracks for WES also shows similar read depth (indicated by numbers above the peaks) outside the region between APOPT1 exon 2 to ZFYVE21 exon 2, with little to no reads inside that region in HBCx-14 tumours. b Clonogenic survival assay in HEK293T cells left wild-type (WT) or carrying a frameshifting mutation in XRCC3. Value of each data point in survival graph is calculated as a percentage of average absorbance of untreated cells. Survival graph shows a representative of three independent experiments, mean ± SEM. p < 0.0001, two-tailed t-test. c Clonogenic assay in RPE-hTERT p53 KO cells transduced with a non-targeting guide RNA or a guide RNA targeting XRCC3. One representative experiment out of three biological replicates. Mean +/− SEM. p = 0.0017 (2.5 μM) and p = 0.0028 (5 μM), a two-tailed t-test. d Quantification of RAD51 foci in HEK293T cells. Mean +/− SD. 3 independent experiments are depicted. p = 0.0019, two-tailed t-test. e Representative images of RAD51 foci after cisplatin treatment for HEK293T WT and the XRCC3 knockout clones. Images show untreated cells and cells treated with 10 µM cisplatin for 3 h, then stained for formation of RAD51 foci and geminin. RAD51 foci are shown in red, Geminin is shown in green, DAPI is shown in blue.