Effects of lentivirus-mediated DKC1 gene silence on radiosensitivity of human cervical cancer HeLa cells

Objective: To investigate the effect of decreasing DKC1 gene expression on radiosensitivity of HeLa cells. Methods: A cell model with low expression of DKC1 gene was established by shRNA technology with lentivirus as vector, and the interference efficiency was verified by RT-PCR and Western blot assay. Cells were divided into two groups of interference (Lv-shDKC1) and its negative control. Telomerase activity was detected by TRAP-ELISA, and telomere length was measured by Real-time PCR. Cell survival was obtained through clone formation assay and fitted by multi-target single-hit model, and radiobiological parameters (D₀, D_q, N, SF₂) and radiosensitization ratio (SER) were calculated. Results: After DKC1 interfering, the expression levels of mRNA and protein of DKC1 in HeLa cells were significantly decreased by (71.330 ± 4.112)% (t = 25.53, P < 0.05) and (35.520 ± 3.804)% (t = 4.833, P < 0.05), respectively. Compared with the blank control group and negative control group, the telomerase activity of Lv-shDKC1 group decreased significantly from 0.900 ± 0.044 and 0.897 ± 0.031 to 0.713 ± 0.021 (F = 31.44, P < 0.05), the relative telomere length was significantly decreased from 4.233 ± 0.306 and 4.633 ± 0.379 to 2.667 ± 0.404 (F = 39.15, P < 0.05). The telomerase activity and relative telomere length of blank control group and Lv-shDKC1 negative control group had no significant difference (P > 0.05). SF₂ in the interference group (0.571 ± 0.006) was significantly lower than that of the blank control group (0.861 ± 0.009) and the Lv-shDKC1 negative control group (0.807 ± 0.002) (F = 1812, P < 0.05), and the radiosensitization ratio (SER) of shDKC1 interference was 1.508. Conclusions: Downregulation of DKC1 in human cervical cancer HeLa cells enhances the radiosensitivity through inhibiting the activity of telomerase and shortening the length of telomere. DKC1 gene may become a new target of radiosensitization. (authors)