The effect of fatty acid-CoA ligase 4 on the growth of hepatic cancer cells

Abstract

In this study, we detected the expression of FACL4 mRNA in 40 patients with hepatic carcinoma and its adjacent normal tissues by semi-quantitative RT-PCR. The changes of proliferation and apoptosis of hepatic cancer cell line HepG2 with FACL4 protein expression were examined by MTT and flow cytometry respectively after FACL4 selective inhibitor triacsin C treatment. The activity related to apoptosis of proteinases, caspase-3, caspase-8 and caspase-9, were detected by colorimetry. The expression related to apoptosis of protein, wt-p53，Bax, and Bcl-2, in HepG2 cells were evaluated by S-P immunocytochemical dyeing. The results were: (1) FACL4 mRNA was expressed in 95.0% of hepatic cancer tissue, while the positive expression of FACL4 mRNA was 82.5% in cancer adjacent normal liver tissues. Moreover, there was a statistically significant increased in quantity of FACL4 mRNA in cancer tissues compared with adjacent normal liver tissues. (2) The concentration of triacsin C（0.5-2mg/L）could inhibit the proliferation and induce the apoptosis of HepG2 cells significantly in a dose- and time-effect. (3) During the apoptosis of HepG2 cells induced by triacsin C, flow cytometry coupled with Rhodamine 123 dyeing showed that mitochiondrial transmembrane potential of HepG2 declined significantly，and the activity of caspase-9 and caspase-3 increased more remarkably than caspase-8. Besides, the increased apoptosis was accompanied by increased Bax, and decreased wt-p53 and Bcl-2 protein levels. The present study suggested that FACL4 might play a role in the growth of hepatic cancer cells. FACL4 selective inhibitor triacsin C leads to a marked growth inhibition of human liver tumor cells, based on the inhibition of proliferation and induction of apoptosis. The apoptotic process was mediated by intrinsic mitochondrial apoptotic pathway due to activation of caspase-9 and caspase-3. The increased apoptosis was accompanied by upregulation of Bax, and decreased wt-p53 and Bcl-2 protein level.