Fig. 3

NS1-BP radiosensitizes ESCC cells in vitro. a Colony formation assay showing that the survival capacity of ESCC cells ectopically overexpressing NS1-BP was lower than that of control cells after IR (**P < 0.01). b Enhanced expression of NS1-BP promoted IR-induced apoptosis in both KYSE-30 and TE-1 cells. Annexin V and propidium iodide staining was used to determine the percentage of apoptotic cells. Data represent mean values and SD (*P < 0.05; **P < 0.01, Student’s t test). c Ectopic overexpression of NS1-BP the amount of increased unrepaired DNA damages-DNA double strand breaks (DSBs) induced by IR. Cells were subjected to 4 Gy IR and fixed for immunofluorescence 24 h later. Staining for antibodies against γ-H2AX (green) as a measure of DSBs is shown. Quantification of the average number of IR-induced γH2AX foci per cell is also shown (lower panel). Data represent mean values and SD d Ectopic overexpression of NS1-BP significantly decreased IR-induced G₂/M cell cycle arrest after 4 Gy X-ray irradiation in both ESCC cell lines. Panel shows percentage of cells in G₂/M. e Western blot showing that NS1-BP overexpression of increased cleaved caspase 3 and PARP in both TE-1 and KYSE-30 cells exposed to 4-Gy irradiation (*P < 0.05; **P < 0.01, according to Student’s t test)