Effects of Glutamine on Proliferation of Human Hepatoma Cell Line SMMC-7721 in vitro

Background: Glutamine is closely related to tumorigenesis, but its mechanism in promoting the proliferation of cultured tumor cells in vitro remains unclear. Aims: To investigate the possible mechanism of glutamine on the proliferation of human hepatoma cell line SMMC-7721 in vitro. Methods: Human hepatoma cell line SMMC-7721 was cultured with different concentrations of glutamine (0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mmol/L) for 24 hours. The cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) colorimetric assay; the cell cycle was measured by flow cytometry; the expression of heat shock protein (HSP) 70 was detected by reverse transcriptase polymerase chain reaction (RT-PCR). Results: Glutamine promoted the proliferation of human hepatoma cell line SMMC-7721 significantly, which was reflected by increased S-phase fraction and the proliferation index (PI). The expression of HSP70 in glutamine-treated cells was significantly higher as compared with that in non-treated cells. The expression of HSP70 was consistent with glutamine concentration. Both the cell proliferation and HSP70 expression showed a dose-dependent relationship with the concentration of glutamine. Glutamine at a concentration of 2.0 mmol/L showed a maximum effect. Conclusions: Glutamine can up-regulate the expression of HSP70 in human hepatoma cell line SMMC-7721 in vitro, which may be one of its the mechanisms of growth promotion of cancers.