Fig. 3

E2F-1 downregulation increased the sensitivity of DDP-resistant NPC cells to DDP via the regulation of ATM. Note: A, B, MTT assay assessed the reversal effect of E2F-1 shRNA on the DDP resistance of CNE2/DDP cells (A) and HNE1/DDP cells (B) via regulation of ATM; C, qRT–PCR determined the expression of drug resistance-related genes (ABCA2 and ABCA5) in DDP-resistant NPC cells. The experiment was repeated independently three times. Comparisons among multiple groups were analyzed using one-way ANOVA, while intergroup differences were tested by Tukey’s HSD test. *, P < 0.05 compared with the blank group and control shRNA group; #, P < 0.05 compared with the E2F-1 shRNA#1 group and E2F-1 shRNA#2 group; &, P < 0.05 compared with the ATM group