125I Seed Promotes Apoptosis in Non-small Lung Cancer Cells via the p38 MAPK-MDM2-p53 Signaling Pathway
Tao Zhang, Zhiqiang Mo, Guangfeng Duan, Rijie Tang, Fujun Zhang, Mingjian Lu
Abstract
Purpose: 125 I seeds were effective in the treatment of non-small cell lung cancer in previous research. However, the exact signaling pathway-mediated apoptosis mechanism is still unclear. The present study analyzed the effects and potential mechanisms of 125 I seed on the growth and migration of A549 cells. Methods: Lung cancer A549 cells were irradiated with 125 I seed for various times. MTT, invasion assay, and flow cytometry were used to detect the proliferation, invasion, and apoptosis of treated cells, respectively. A Nimblegen genome-wide expression profile chip was used to evaluate gene expression changes in 125 I seed-treated A549 cells. Validation studies were performed using phosphorylated protein chip technology, Western blot, nude mouse tumor xenograft assay, and immunohistochemical experiments. All statistical analyses were performed using unpaired Student's t tests and Kruskal-Wallis test. Results: Irradiation with 125 I seed inhibited A549 cell proliferation and invasion and induced apoptosis (primarily early apoptosis). Irradiation with 125 I seed also caused the downregulation of p38MAPK, degradation of mouse double-minute 2 homolog (MDM2), and higher expression of p53, which eventually resulted in non-small cell lung cancer cell apoptosis. Conclusion: 125 I seed irradiation activated the p38MAPK/MDM2/p53 signaling pathway and promoted non-small cell lung cancer cell apoptosis. Future clinical studies targeting this signal may provide a new potential therapeutic approach for non-small cell lung cancer.