Pien Tze Huang Inhibits Proliferation, Induces Apoptosis And Differentiation Of Colorectal Cancer Stem Cells Via Suppressing Notch Signaling Pathway

Objective:To evaluate the effect of Pien Tze Huang (PZH) on colorectal cancer stem cells in vitro, and investigate the underlying mechanisms.Methods:1. In vitro study:In this study we isolated the stem-like side population (SP) from the human colorectal cancer (CRC) SW480 and HT-29 cell lines to investigate its effect on cancer stem cells (CSCs) as well as the possible molecular mechanism. To evaluate the effect of PZH on cancer stem cells, we determined the percentage of SP cells. Cell viability by MTS assay was examined to determine the effect of PZH on cell proliferation. Hoechst staining was used to assess cell apoptosis. Q-PCR and Western-Blot were used to determine the mRNA and protein expression of CK20 to evaluate the differentiation of CSCs. Q-PCR and Western-blot were used to determine the mRNA and protein expression of Notchl and Hesl in Notch signaling pathway.2. Molecular mechanism:In SW480 SP cells, Q-PCR and Western-blot were used to determine the mRNA and protein expression of Notchl and Hesl in Notch signaling pathway.Result:1. The effect of PZH on colorectal cancer stem cells:Similar to the positive control, PZH significantly and dose-dependently decrease the SP proportion in both SW480 and HT-29 cell lines (P<0.05). MTS assay showed that PZH treatment significantly decreased the cell viability of CSCs in dose-dependent manners (P<0.05). Hoechst staining showed that PZH-treated cells displayed condensed chromatin and fragmented nuclear morphology which are typical apoptotic morphological features. Q-PCR and Western-blot analysis showed that PZH treatment up-regulated the expression of CK20, indicated that PZH treatment may induced CSCs differentiation (P<0.05)2. Molecular mechanism:In SW480 SP cells, Q-PCR and Western Blot analysis showed that PZH treatment significantly down-regulated the expression of Notchl and Hesl in Notch signaling pathway (P<0.05)Conclusion:PZH may negatively modulate the characteristics of CSCs through suppression of the Notchl signaling pathway. These molecular effects lead to the inhibition of cell proliferation, induction of apoptosis and differentiation, eventually resulting in the effect of PZH on CSCs of colorectal cancer in vitro.