过表达核凋亡诱导因子1增强鼻咽癌细胞放射敏感性

Overexpression of nuclear apoptosis⁃inducing factor 1 enhances the radiosensitivity of nasopharyngeal carcinoma cells

目的探究核凋亡诱导因子1(nuclear apoptosis-inducing factor 1,NAIF1)对鼻咽癌细胞CNE-2R放射敏感性的影响。方法采用Western blot检测NAIF1在鼻咽癌细胞CNE-2和CNE-2R的表达水平。通过慢病毒感染技术将NAIF1过表达慢病毒(LV-NAIF1组)及其阴性对照慢病毒(LV-NC组)分别感染CNE-2R细胞,采用RT-qPCR和Western blot检测NAIF1的mRNA和蛋白表达水平;采用CCK-8、克隆形成实验分别检测各组细胞在不同照射剂量(0、2、4、6、8 Gy)照射下的增殖能力、克隆形成能力并计算相应的存活分数,采用流式细胞术实验检测各组细胞6 Gy照射前后的细胞周期分布情况。结果与CNE-2细胞相比,NAIF1在CNE-2R细胞中的蛋白表达水平显著降低(P<0.001)。与LV-NC组相比,LV-NAIF1组CNE-2R细胞中NAIF1的mRNA和蛋白表达水平均显著升高(均P<0.001)。经不同剂量照射后,与LV-NC组相比,过表达NAIF1可以抑制CNE-2R细胞的增殖能力(均P<0.05),降低CNE-2R细胞的克隆形成数和存活分数(P<0.05)。经6 Gy照射后,与LV-NC组相比,过表达NAIF1可使更多的CNE-2R细胞滞留在G2/M期(P<0.01)。结论NAIF1在鼻咽癌细胞CNE-2R中低表达,过表达NAIF1可能通过抑制细胞增殖并将细胞周期阻滞在G2/M期,从而增强鼻咽癌细胞CNE-2R的放射敏感性。

Objective To investigate the effect of nuclear apoptosis⁃inducing factor 1(NAIF1)on the radiosensitivity of nasopharyngeal carcinoma(NPC)CNE⁃2R cells.Methods The expression levels of NAIF1 in NPC CNE⁃2 and CNE⁃2R cells were detected by Western blot.CNE⁃2R cells were infected with overexpressed NAIF1 lentivirus(LV⁃NAIF1 group)and its negative control lentivirus(LV⁃NC group)respectively.The mRNA and protein expression levels of NAIF1 were detected by RT⁃qPCR and Western blot.The CCK⁃8 assay and colony formation assay were performed to evaluate the proliferation and colony formation ability in each group of cells under different doses of irradiation(0,2,4,6,8 Gy)and the corresponding survival fractions were calculated.The cell cycle distributions of cells before and after exposure to 6 Gy of X⁃ray in each group were analyzed by flow cytometry.Results Compared with CNE⁃2 cells,the protein expression level of NAIF1 was significantly decreased in CNE⁃2R cells(P<0.001).Compared with the LV⁃NC group,the mRNA and protein expression levels of NAIF1 in CNE⁃2R cells were significantly increased in the LV⁃NAIF1 group(all P<0.001).After different doses of irradiation,overexpressed NAIF1 inhibited the proliferation ability of CNE⁃2R cells(P<0.05),and significantly decreased the colony formation number and survival fraction of CNE⁃2R cells(P<0.05).After irradiation with 6 Gy,compared with the LV⁃NC group,overexpressed NAIF1 made more CNE⁃2R cells arrest in the G2/M phase which was the most radiosensitive phase of a cell cycle(P<0.01).Conclusions NAIF1 is down⁃regulated in NPC CNE⁃2R cells.The overexpression of NAIF1 may enhance the radiosensitivity of NPC CNE⁃2R cells by inhibiting cell proliferation and arresting the cell cycle at the G2/M phase.