Selenious-?-lactoglobulin Induces The Apoptosis Of Human Lung Cancer A549 Cells Via An Intrinsic Mitochondrial Pathway

In this study, the cytotoxic activity of Selenious-?-Lactoglobulin (Se-?-Lg) in human lung cancer A549 cells was investigated in vitro and the anticancer mechanism was illustrated. The changes of cell morphological, cell cycle, apoptosis-related proteins and mRNA expression which were induced by Se-P-Lg were explored by MTT assay, Hoechst 33342/PI staning, flow cytometry, Real-time PCR and Western blot assay.The MTT assay showed that a significant suppression on the proliferation of A549 cells was observed with 200 ?g/mL Se-?-Lg and the maximum inhibition rate could reach 90 % at 72 h, however, the cytotoxicity of Se-?-Lg towards HEK293 cells was unobvious.Hoechst 33342/PI staning and inverted microscope assay both revealed that treatment with 200 ?g/mL Se-?-Lg appeared typical apoptotic characteristics such as cell volume reduction and chromatin shrinkage. Flow cytometry analysis determined that 200 ?g/mL Se-?-Lg could significantly induce cell cycle arrest at G0/G1 phase and cell apoptosis mainly by the decrease of mitochondrial membrane potential (??m) and the accumulation of ROS in a time-dependent manner. Meanwhile, it was determined that 200 ?g/mL Se-?-Lg could also induce the opening of MPTP in A549 cells.Furthermore, Real-time PCR and Western blot assay revealed that Se-?-Lg could suppress the expression of Bcl-2 and enhance the level of Bax, then lead to the release of cytochrome c from mitochondria to the cytoplasm and active the expression of caspase-3 in A549 cells.Taken together, it was illustrated that Se-?-Lg could induce A549 cells apoptosis via an intrinsic mitochondrial signaling pathway and the Se-?-Lg might be served as a potential therapeutic agent for lung cancer.