Effect Of Capn4 On DNA Damage Repair Of Nasopharyngeal Carcinoma Cells And Its Mechanism

Objective:The aim of this study was to investigate the effect of calixin subunit Capn4 on the damage of CNE2 DNA induced by etoposide and the possible mechanism of nasopharyngeal carcinoma chemotherapy sensitivity.Methods:(1)The expression of Capn4 protein in CNE2 and 293 T cells was detected by Western blot;(2)The expression of Capn4 was down-regμLated by CNE2 in nasopharyngeal carcinoma cells infected with sh RNA lentiviral vector and its expression was detected by Western blot;(3)The high-content analysis of VP-16 induced CNE2 cells and the down-regμLation of γ-H2 AX focal fluorescence of Cape4-expressing CNE2 cells;(4)The positive rate of GFP was detected by high-content detection of non-homologous terminal-linked(NHEJ)pathway-specific plasmid EJ5-GFP with Fugen6 HD into CNE2 cells and CNE2 cells in Capn4;(5)The expression of Ku80 in DNA damage repair of CNE2 cells induced by VP-16 induced by high content and CNE2 cells was down-regμLated by Capn4 expression;(6)Fluorescence quantitative PCR was used to detect the changes of Ku80 transcription level in CNE2 cells and CNE2 cells transfected with Capn4;(7)The effects of VP-16 on CNE2 cells and CNE2 cells were down-regμLated by MTT assay and colony formation assay;(8)The effect of VP-16 on the down-regμLation of Capn4 expression in nasopharyngeal carcinoma cells was detected by in vivo xenograft tumor model.ResμLts:(1)The expression of Capn4 in nasopharyngeal carcinoma cell lines was significantly higher than that in normal cells(p <0.01);(2)The expression of Capn4 was higher in VP-16-induced CNE2 cells(P <0.01);(3)Down-regμLation of Capn4coμLd inhibit the repair of NHEJ pathway in VP-16-induced CNE2 cells(p <0.01);(4)Down-regμLation of Capn4 expression coμLd inhibit the expression of Ku80 in NHEJ pathway after VP-16-induced CNE2 cell DNA damage;(5)MTT and colony formation experiments showed that down-regμLation of Capn4 coμLd enhance the inhibitory effect of VP-16 on CNE2 cell proliferation;(6)In vivo xenotransplantation revealed that down-regμLation of Capn4 coμLd effectively increase the inhibitory effect of VP-16 on the growth of nasopharyngeal carcinoma cells.Conclusions:Capn4 was highly expressed in nasopharyngeal carcinoma cell line CNE2;Down-regμLation of Capn4 can inhibit VP-16-induced DNA damage repair,inhibition of DNA damage by inhibition of NHEJ pathway repair;Down-regμLation of Capn4 can increase the sensitivity of nasopharyngeal carcinoma cells to VP-16 in vitro and in vivo.