Fig. 3

circCDYL2 enhances radiotherapy resistance in nasopharyngeal carcinoma by promoting DNA homologous recombination repair. A. Flow cytometry was performed to measure the GFP expression in DR-GFP-U2OS and EJ5-GFP-U2OS cells. Cells were transfected with the overexpression plasmid or ASO of circCDYL2. SiRNAs of BRCA1 or 53BP1 were selected as positive controls. Each group was co-transfected with the HA-Isce1 overexpression plasmid. B. Immunofluorescence showed that circCDYL2 enhanced the number of RAD51 irradiation-induced foci (IRIF) in HNE2 and CNE2 cell nuclei after irradiation. Scale bar = 10 μm. On the right, the quantification of IRIF per 30 cells was presented. C. The expression of RAD51 in the nucleus after irradiation was detected by western blotting. The results showed that circCDYL2 promoted the accumulation of RAD51 in the nucleus following irradiation. D. Western blotting showed that circCDYL2 promoted the expression of RAD51 protein in NPC cells after overexpression or knockdown of circCDYL2. Data were represented as mean ± SD. ns, not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001