Inhibitory Effect Of Procyanidins On Human Colorectal Carcinoma Cells And Its Molecular Mechanism

Objective:To explore the molecular mechanism of Procyanidin on the proliferatory inhibition effects and inducing apoptosis of human colorectal cancer cells.Methods:The effect of Procyanidin on the proliferatory inhibition of SW620 cells were evaluated by WST assay and clone forming assay. The morphological changes were detected by fluorescence microscopy assay. DNA ploidy and apoptotic cell percentage were calculated by the flow cytometry. The expression of Bcl-XL, Mcl-1, Bax, Caspase-9, Caspase-3, PARP was analyzed by Western blot. The membrane potential of mitochondria was detected by JC-1 fluorescence microscopy assay.Results:Our results demonstrated that Procyanidin could inhibit the proliferation of SW620 and LOVO cells, the IC50 value was 56.49 mg/1 and 50.12 mg/1 respectivily. Many SW620 cells stained with Hoechst 33258 exhibited apoptotic morphology such as cell shrinkage, nuclear condensation and nuclear fragmentation. Furthermore, the percentage of cell hypodiploid was increased in a dose-dependent manner, cell apoptosis rates of Procyanidin treatmented groups were increased compared with the control group. The membrane potential of mitochondria was reduced. The protein levels of pro-Caspase-9, pro-Caspase-3, Bcl-XL and Mcl-1 were decreased significantly, and the cut bands were seen among Casepase-9 and PARP proteins Conclusion:The results suggest that Procyanidin could suppress the proliferation of human colorectal Cancer SW620 cells through induction of mitochondria-dependent apoptotic cell death, as reduced anti-apoptotic Bcl-2 family proteins, reduced mitochondria membrane potential, decreased the ratio of Bcl-XL/Bax and Mcl-1/Bax, activated caspase-9 and caspase-3 and PARP.