Fig. 7: PARP inhibitor enhances radiotherapy in FBL highly expressed colorectal cancer.

A Cell viability of HCT8 cell lines stably overexpressing empty vector Flag or Flag-FBL. The cells were exposed to 10 μM olaparib or 2 Gy IR as indicated and then analysed by CCK8 assay. (*p < 0.05, ***p < 0.001, error bar = ±SEM, n = 6). B Cell viability of SW480 cell lines stably overexpressing empty vector Flag or Flag-FBL. The cells were exposed to 10 μM olaparib or 2 Gy IR as indicated and then analysed by CCK8 assay. (*p < 0.05, ***p < 0.001, error bar = ±SEM, n = 6). C Schematic diagram of nude mice implant model and treatment schedule. Mice of HCT8 Flag/ Flag-FBL cell line were randomized to 4 groups as indicated (n = 5): (1) the vehicle group (10%DMSO / 30%PEG300 / saline solution for 3 days by intraperitoneal injection); (2) the olaparib group (olaparib (50 mg/kg/day) for 3 days by intraperitoneal injection); (3) the irradiation group (10%DMSO / 30%PEG300 / saline solution for 3 days by intraperitoneal injection, tumor-localized irradiation (2 Gy) given 1 h after the dose of DMSO); (4) the combination group (olaparib (50 mg/kg/day) for 3 days by intraperitoneal injection, tumor lacalized irradiation (2 Gy) given 1 h after the dose of olaparib). D Tumors isolated from individual mice. E Growth curve of xenograft tumors derived from indicated group of Flag and Flag-FBL HCT8 cells. Tumor volumes were measured at indicate time points. (n = 5, Error bars represent SEM, *p < 0.05, **p < 0.01, ***p < 0.001, two-sided, unpaired t-test). F The tumor weight measured at the end of the treatments (n = 5, Error bars represent SEM, *p < 0.05, *** P < 0.001, two-sided, unpaired t-test). G Representative image of immunohistochemical (IHC) staining for DNA damage maker γH2AX in tumor samples derived from indicated xenografts in nude mice. Scale bar, 100 µm. H Quantitation of the normalized histological score (H score) of γH2AX with three individual view for each tumor in different treatment groups as indicated.