Fig. 1: PC3-15 increases the sensitivity of TNBC cells.

A PC3-15 inhibits pCHK1 levels in TNBC cells. MDA-MB-231, HCC1806 and MC1 cell lines were pretreated with PC3-15 (20 μm) for 2 h before IR (10 Gy) and harvested for WB at 0, 30, and 60 min. B PC3-15 pretreatment increased the accumulation of \({\rm{\gamma }}\)H2AX after IR in both MC1 and HCC1806 cells. MC1 and HCC1806 cells were pretreated with PC3-15 (20 μm) for 2 h before IR (10 Gy) and harvested for WB at 1-3 days. C PC3-15 pretreatment decreased survived clones with the increase of IR. Clonogenic survival in response to IR of MC1 and HCC1806 cells pretreated with PC3-15 (20 μm) for 2 h. The column represents the number of clones when only PC3-15 (20 μm) is pretreated. Data are mean ± SD. Statistical analysis was performed using two-tailed unpaired t-tests. Data are representative of three independent experiments. *p < 0.05 and **p < 0.01; n.s, not significant. D. Schematic diagram of characterization of PC3-15 combined with irradiation therapy in TNBC patient-derived xenografts. E–H PC3-15 increased radiotherapy sensitivity of MC-1 in vivo. MC1 cells were injected into the fat pat of nude mice. Mice carried MC1 xenografts were randomly distributed into four groups equally when the tumor size reached around 70 mm³ and were administrated with 50 mg/kg PC3-15 or vehicle following with and without IR (3 Gy×4) by intraperitoneal injection. After 12 days of 4 times therapy, the mice were euthanized, the image of tumors was shown (E), and the tumor weight (F) and TUNEL positive ratio (G, H) were recorded. Data are mean ± SD. Statistical analysis was performed using two-tailed unpaired t-tests. *P < 0.05 and **P < 0.01; ns, not significant. Scale bar, 100 μm.