[Effects of peroxisome proliferator-activated receptor-gamma ligand troglitazone on colon cancer cell growth]

To investigate the expression of peroxisome proliferator-activated receptor-gamma (PPARgamma) in colon cancer cell lines and the effects of PPARgamma activation by its ligand troglitazone on cell growth in SW-480 cells.

PPARgamma expression was detected in Lovo, HT-29 and SW-480 cells using western blot. The effects of PPARgamma activation by its ligand troglitazone (TGZ) and selective antagonist T0070907 on cell growth were assessed by MTT and cell count methods; apoptosis was detected by flow cytometry method.

Western blot result revealed that PPARgamma protein was highly expressed in Lovo and HT-29 cells and there was relatively lower expression in SW-480 cells. Cell count method and MTT revealed that activation of SW-480 cells with TGZ resulted in inhibition of growth in a dose dependent manner. The effect of anti-proliferation increased with increasing doses of TGZ. Rates of growth inhibition were 3.3%, 8.3%, 25%, and 29% for different doses 5, 10, 20 and 25 micromol/L respectively. Flow cytometry method detected apoptosis in a dose-dependent manner. When the concentration of TGZ was less than 15 micromol/L , the apoptotic effect was found to be weak. The apoptotic effect was prominent when the concentration exceeded 20 micromol/L. Cell count method revealed that selective antagonist of PPARgamma stimulated cell growth of SW-480 cells in a dose dependent manner.

PPARgamma is expressed in colon cancer cells. Activation of PPARgamma by its ligands in colon cells has potent anti-proliferative and pro-apoptotic effects, suggesting that PPARgamma activation by its ligands may provide therapeutic value for colorectal cancer patients.