Synergism inhibition effect of adenovirus-mediated IL-21 gene combined with ionizing radiation on the growth of pulmonary carcinoma cells

Objective: To explore the synergism inhibition effect of adenovirus-mediated inter-leukin-21(IL-21) gene combined with ionizing radiation on the growth of pulmonary carcinoma cells A549. Methods: A549 cells were divided into four groups: blank control group, Ad-IL-21 group (cells were transfected with Ad-IL-21), radiation group (cells were exposed to 6 Gy ¹³⁷Cs γ-ray) and Ad-IL-21 combined with radiation group (cells were transfected with Ad-IL-21 before exposed to 6 Gy ¹³⁷Cs γ-ray). The cell growth, cell cycle and cell apoptosis of A549 cells were observed. Results: The inhibition rate of Ad-IL-21 combined with radiation group was the highest, reached 40%, which was significantly higher than that of Ad-IL-21 group (about 22%) and radiation group (about 17%)(F = 45.6 and 57.5, both P < 0.05). Cells of Ad-IL-21 combined with radiation group were arrested at G2 phase (35.4%), significantly higher than that of Ad-IL-21 group (25.2%) and radiation group (17.5%)(F = 16.6 and 32.8, both P < 0.05). The cell apoptosis rate of combination group was the highest, reached 33.1% and there were significant differences compared with Ad-IL-21 group (27.8%) and radiation group (14.8%)(F = 15.9 and 41.7, both P < 0.05). Conclusion: Ad-IL-21 transfection combined with radiation shows synergism effect on the inhibition of pulmonary carcinoma cells growth. (authors)