Purpose: RNA interference (RNAi) of survivin gene can induce cancer apoptosis. In the current study, combined survivin shRNA (small hairpin RNA) and radiotherapy is expected to enhance the efficacy of radiotherapy in human lung cancer in vitro and in vivo.
Methods: The pGenesil2 expression vectors containing survivin shRNAs was used to transfect A549 human lung adenocarcinoma cells and nude mouse grafts, followed by 5 Gy X-rays radiation. The MTT assay was performed to determine cell proliferation. Flow cytometry was used to detect the apoptosis of A549 cells. Tumor volumes were measured. Quantitative real-time PCR and Western blotting were performed to detect both mRNA and protein levels of survivin and caspase-3 in both A549 cells and nude mouse grafts.
Results: A549 cell proliferation and nude mouse grafts were inhibited in the shRNA alone, 5 Gy alone and shRNA+5 Gy groups, in particular the shRNA+5 Gy group. Apoptotic percentage increased in the 5 Gy, shRNA and shRNA+5 Gy groups, in particular the shRNA+5 Gy group. Survivin mRNA and protein levels in both A549 cells and nude mouse grafts decreased in the shRNA alone and shRNA+5 Gy groups. Caspase-3 protein in both A549 cells and nude mouse grafts increased in the shRNA alone, 5 Gy alone and shRNA+5 Gy groups, in particular the shRNA+5 Gy group.
Conclusion: Combined survivin shRNA and X-ray radiation can enhance the efficacy of radiotherapy by promoting the apoptosis of lung adenocarcinoma via upregulation of caspase-3 in vitro and in vivo. Combined survivin-targeted genotherapy and radiotherapy may be a potential strategy for treating lung cancer.Author(s): Chang-Feng Li, Yue Wang, Xin-Ying Li, Jing-Peng Jin, Bin Zhang, Dan-Dan Li