Effects of adenovirus-mediated interleukin-37 on the growth and radiosensitivity of non-small cell lung cancer cell line A549 / 肿瘤研究与临床

ABSTRACT

Objective:To analyze the effects of adenovirus-mediated interleukin-37 (IL-37) on the growth and radiosensitivity of human non-small cell lung cancer (NSCLC) cell line A549, and to explore the possibility of IL-37 as a new radiosensitizer.Methods:Human NSCLC cell line A549 was used as the research object. A549 cells were divided into three groups normal A549 cells (control group), empty virus transfected A549 group [NC group, the multiple of infection (MOI) was 100], Ad-IL-37 group (A549 cells were transfected by adenovirus with IL-37, MOI was 100). The expression of IL-37 protein in three groups was detected by Western blot. The three groups were irradiated with 4 Gy irradiation dose at the same time. The methyl thiazolyl tetrazolium (MTT) method was used to detect the absorbance (A) values and observe the proliferation of A549 cells; flow cytometry was used to observe the phase changes of A549 cells in each group after irradiation; Western blot was used to detect the expressions of apoptosis-related proteins (bax, bcl-2, Caspase-3, and Survivin) in each group after irradiation.Results:The expression level of IL-37 in the control group was 0.17±0.04, NC group was 0.29±0.14, and Ad-IL-37 group was 1.17±0.23 (F = 24.263, P = 0.001); there was no statistical difference in A values among the three groups at 24 h after irradiation (F = 2.587, P = 0.160), while the differences of A values among the three groups at 48, 72, 96, 108 h after irradiation were statistically significant (F values were 21.662, 33.635, 33.663, and 31.909, P values were 0.005, 0.001, 0.001, and 0.001, respectively). There was no significant difference in the cell proliferation inhibition rate between NC group and Ad-IL-37 group at 24 h after irradiation (t = 1.620, P = 0.247), while the differences were statistically significant at 48, 72, 96, 108 h after irradiation (t values were 5.414, 7.233, 15.306, and 19.035, P values were 0.032, 0.019, 0.004, and 0.003, respectively). The combination of IL-37 and radiation could affect the cell cycle, the proportion of S-phase cells was (36.4±1.0)% in the control group, (31.3±0.6)% in the NC group, and (27.2±2.9)% in the Ad-IL-37 group (F = 12.96, P = 0.007), and the proportion of in G 2/M-phase cells was (20.5±0.8)% in the control group, (24.7±2.9)% in the NC group, and (41.4±4.1)% in the Ad-IL-37 group, (F = 27.92, P = 0.001). IL-37 could up-regulate the expressions of pro-apoptotic factors bax and Caspase-3 proteins in A549 cells after irradiation (F values were 10.31 and 14.51, P values were both 0.01), and down-regulate the expressions of apoptotic factors bcl-2 and Survivin proteins (F values were 8.95 and 5.52, P values were 0.02 and 0.04). Conclusion:IL-37 could inhibit the growth of human NSCLC cell line A549 and has potential radiosensitization effects, which may be caused by affecting the apoptosis of tumor cells.