Podophyllotoxin acetate blocks IR-induced invasion of non-small cell lung cancer cell, A549

Some research result presented that local radiotherapy administered to primary tumors speeds their metastatic growth in vivo (4-6), thereby suggesting that besides its therapeutic effects, IR promotes the malignant behaviors of surviving cancer cells. Our findings demonstrate podophyllotoxin acetate (PA), one of new natural products, prevented side effects of IR such as invasion or metastasis promotion for improve the efficacy of radiotherapy. In this study, we demonstrated that PA inhibits IR-induced invasion and migration of A549 cells. We also observed that IR stimulates several intracellular pathway involving EMT and MAPKinses; EMT-associated events including an increase of vimentin levels and increased phosphorylation of p38 ERK, JNK in A549 cells. PA could decrease these activations of several intracellular signaling molecules. Therefore, PA might inhibit IRinduced invasion and migration via blocking EMT and MAPKiase pathway of A549 cells