Curcumin suppresses PPARδ expression and related genes in HT-29 cells

AIM:To investigate the effects of curcumin on the expression of peroxisome proliferator-activated receptorδ(PPARδ)and related genes in HT-29 cells. METHODS:HT-29 cells were treated with curcumin (0-80μmol/L)for 24 h.The effects of curcumin on the morphology of HT-29 cells were studied by Hoechst 33342 staining.The activity of caspase-3 was determined using DEVD-p NA as substrate.The levels of peroxisome PPARδ,14-3-3εand vascular endothelial growth factor(VEGF)in HT-29 cells were determined by Western blotting analysis and their mRNA expression was determined by real-time quantitative RT-PCR. RESULTS:Treatment with 10-80μmol/L curcumin induced typical features of apoptosis and activated the caspase-3 in HT-29 cells.The expression of PPARδ, 14-3-3εand VEGF was reduced and the activity of β-catenin/Tcf-4 signaling was inhibited by curcumin treatment. CONCLUSION:Curcumin can induce apoptosis of HT-29 cells and down-regulate the expression of PPARδ,14-3-3εand VEGF in HT-29.

Curcumin induces apoptosis through the mitochondria-mediated apoptotic pathway in HT-29 cells

Objective： To investigate the effects of curcumin on release of cytochrome c and expressions of Bcl-2, Bax, Bad, Bcl-xL, caspase-3, poly ADP-ribose polymerase （PARP）, and survivin of HT-29 cells. Methods： HT-29 cells were treated with curcumin （0-80 μmol/L） for 24 h. The release of cytochrome c from the mitochondria and the apoptosis-related proteins Bax, Bcl-2, Bcl-xL, Bad, caspase-3, PARP, and survivin were determined by Western blot analysis and their mRNA expressions by reverse transcriptase-polymerase chain reaction （RT-PCR）. Results： Curcumin significantly induced the growth inhibition and apoptosis of HT-29 cells. A decrease in expressions of Bcl-2, Bcl-xL and survivin was observed after exposure to 10-80 μmol/L curcumin, while the levels of Bax and Bad increased in the curcumin-treated cells. Curcumin also induced the release of cyto- chrome c, the activation ofcaspase-3, and the cleavage of PARP in a dose-dependent manner. Conclusion： These data suggest that curcumin induced the HT-29 cell apoptosis possibly via the mitoehondria-mediated pathway.