The effect of down-regulating the expression of mTOR on the thermosensitivity of human hepatocellular carcinoma cell line SMMC-7721 / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effect of hyperthermia on human hepatocellular carcinoma cell line SMMC-7721 after down-regulating the expression of mTOR,and its possible mechanisms.Methods An antisense mTOR (mammalian target of rapamycin) gene eukaryotic expression vector was transfected into SMMC-7721 cells.The expression of mTOR mRNA and protein were detected using RT-PCR and Western blotting,respectively.Hyperthermia was applied after the transfection,and the vitality of cell proliferation was evaluated using CCK-8 assays and the clone formation rate was determined by colony-forming assays.The migration of SMMC-7721 cells was measured using scratch assays.Apoptosis and the cell cycle were analyzed by flow cytometry.Results The expression of mTOR mRNA and protein were significantly decreased after transfection,indicating that the antisense vector could down-regulate the mTOR gene effectively.The proliferation,clone formation and migration of SMMC-7721 cells all were decreased markedly by hyperthermia after transfection.Flow cytometry showed that the rate of apoptosis was significantly increased.The number of cells in the S phase was increased and the cell cycle was induced to arrest at the S phase.Conclusions Down-regulating the expression of mTOR can increase the thermosensitivity of SMMC-7721 cells.The mechanism involves increased apoptosis and S phase arrest.