Study of inhibition of GABA on proliferation of cholangiocarcinoma cell line QBC939 and its mechanism

Abstract

Objective To explore the effect of gamma-aminobutyric acid (GABA) on the growth, apoptosis and telomerase activity of Cholangiocarcinoma cell line QBC939. Methods Cholangiocarcinoma cell line QBC939 was cultured by routine method, and then treated with different concentrations of GABA (1-1000 μmmol/L). The proliferation, apoptosis and cell cycle of QBC939 cells was investigated by MTT, Flow cytometry and transmission electron microscopy. The telomer-ase activity of QBC939 cells was examined by modified PCR-ELISA assay. Radioimmunoassay was used to measure the intracellular cyclic adenosine monophosphate(cAMP) content. Results The dif-ferent concentrations of GABA inhibited the growth of QBC939 cells and promoted the apoptosis. The apop-totic rate of QBC939 cells was increased from 4. 8% to 28. 03%, which had significant difference (P<0.05). It had no effect for distribution of cell cycle. Cell nuclear condensation and apoptotic bodies were seen by transmission electron microscopy. Telomerase activity was inhibited by GABA(0. 82±0. 048 vs 0.56±0. 054, P<0.05). The content of intracellular cAMP was increased with the increase of GABA concentration in a dose-dependent manner [(0. 59±0. 049) nmol/L vs (0. 82±0. 033)nmol/L, P<0. 05]. Conclusion GABA can inhibit the proliferation of QBC939 cells by promoting apoptosis and inhibiting telomerase activi-ty, which may be mediated by the information transmission of post-receptor. Key words: Bile duct neoplasm; Gamma-aminobutyric acid; Cell proliferation; Apoptosis; Telomerase