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. 2016 Dec 17;8(4):6057–6066. doi: 10.18632/oncotarget.14011

Figure 1. A subset of OCCC cells is unable to elicit RAD51 foci in the presence of DNA DSBs.

Figure 1

A panel of 12 OCCC cell lines were subjected to RAD51 foci formation assays to determine their homologous recombination (HR) function in the presence of DNA double strand breaks (DSBs). Cell lines were treated with ionising radiation before immunofluorescent detection of γH2AX foci (markers of DNA DSBs) and RAD51 foci (markers of competent HR) was undertaken (A). Akin to CAPAN1 (BRCA2-mutant) and SUM149 (BRCA1-mutant) control cells, five OCCC cell lines showed reduced RAD51 foci formation (i.e. TOV-21G, KOC-7c, SMOV-2, RMG-1, and KK) (B). The remaining seven OCCC cell lines displayed RAD51 foci formation at similar levels to HR-competent SKBR3 and SUM44 cells (B). All cell lines showed similar levels of γH2AX foci formation (C). Western blot analysis of PTEN, MRE11, BRCA1 and BRCA2 in 12 OCCC cell lines. Beta-tubulin was employed as loading control. Two cell lines (TOV-21G and KOC-7c) showed loss of PTEN expression (D). PTEN Sanger sequencing traces of TOV-21G (top) and KOC-7c (bottom), which both harboured a PTEN frameshift mutation (c.795het_delA in TOV-21G and c.968het_delA in KOC-7c), red arrows, (E). The top sequencing trace in each panel represents the wild type sequence, while the cell line sequence showing the mutation is shown below it. In all panels, cell lines with reduced RAD51 foci formation (HR defective) are marked in red, those with normal RAD51 foci formation (HR competent) are marked in black, those with BRCA1 or BRCA2 loss of function are marked in blue, and those previously documented to be HR competent in purple.