Fig. 2

Inhibition of RPA enhances the antitumor effect of irradiation in NPC. a The proliferation of NPC cells with single or combination treatment was monitored with an IncuCyte system every 6 h after seeding. b Clonogenic growth assay of NPC cell lines treated for 12 days with the indicated treatment (HAMNO, 0, 5 and 10 μM). Cells were visualized using crystal violet staining. c Tumorsphere formation assay in NPC cells treated with a single inhibitor or combined with IR (left) following 10 days of culture. The cellular sphere volume was measured by ImageJ (right). d The percentage of apoptotic cells induced by RPAi (0, 5 and 10 μM) or IR alone or in combination for 48 h was determined via flow cytometry and Annexin V/7-AAD staining. The histogram represents the quantification of three independent experiments. The apoptosis rate was defined as the proportion of Annexin V-APC-positive and 7-AAD-negative cells out of the total number of cells. e–g Tumor formation in xenografted mice; representative tumor size images e of S26 cells in nude mice treated with HAMNO at 1 mg/kg, tumor volume over time (f) and average weight G of the excised tumors. h HE staining and IHC staining of Ki-67 and cleaved caspase 3 in tumor sections from mice with different treatments (left). Scale bar = 50 μm or 25 μm. Quantification of the proportion of Ki-67- and cleaved caspase-3-positive cells in each group of S26 xenograft tumors (right). The statistical analysis for H was performed using the Kolmogorov‒Smirnov test, and the data are presented as medians with 95% CI