ABSTRACT
ObjectiveTo study the inhibitory effect of polyphyllin Ⅰ （PPI） on the growth of colorectal cancer cells and its molecular mechanism. MethodRKO cells were cultured and divided into a blank group and PPI treatment groups with concentrations of 0.6， 0.8， 1.0 μmol·L-1， respectively. HRT18 cells were cultured and divided into a blank group and PPI treatment groups with concentrations of 1.2， 1.4， 1.6 μmol·L-1， respectively. The effects of PPI on the proliferation and morphology of colorectal cancer were detected by cell proliferation toxicity assay， trypan blue exclusion assay， plate clone formation assay， and confocal high-intension cell imaging analysis system. Flow cytometry was used to detect the apoptosis rate of colorectal cancer cells. The pQCXIP-GFP-LC3 plasmid transfection assay was used to detect the formation of autophagosomes in colorectal cancer cells after PPI treatment. Western blot was used to detect the expression of apoptosis-related proteins Caspase-3， Caspase-8， and poly ADP ribose polymerase （PARP）， the expression of autophagy related protein LC3Ⅱ， and the expression and phosphorylation of Hippo signaling pathway proteins LATS1 and YAP. In the plvx-Flag-YAP plasmid transfection assay， YAP was overexpressed and treated with PPI， and the proliferation of colorectal cancer cells was detected by cytotoxicity assay. The expression of LC3Ⅱ and PARP in colorectal cancer cells was detected by Western blot. SwissADME predicted pharmacokinetic parameters of PPI. ResultAs compared with the blank group， the survival rate and clone formation ability of colorectal cancer cells in the PPI group were significantly decreased （P<0.01）， the cell area of colorectal cancer cells in the PPI group was significantly decreased， and the roundness of colorectal cancer cells was significantly increased （P<0.01）. As compared with the blank group， the apoptosis rate of colorectal cancer cells in PPI treatment groupw was significantly increased （P<0.01）， the expression of apoptotic proteins Caspase-3 and Caspase-8 protein precursor in PPI treatment groups was decreased， and the cleavage of PARP was increased （P<0.01）. As compared with the blank group， the expression level of autophagy-related protein LC3Ⅱ in colorectal cancer cells in PPI treatment groups was significantly increased， and the formation of autophagosomes was promoted （P<0.01）. As compared with the blank group， the expression of YAP protein in colorectal cancer cells in PPI treatment groups was significantly decreased， and the expressions of phosphorylated LATS1 and YAP were significantly increased （P<0.01）. As compared with the blank group， overexpression of YAP could significantly antagonize the effect of PPI on apoptosis， autophagy activation， and proliferation inhibition of colorectal cancer cells. SwissADME simulation results showed that PPI had good drug like activity. ConclusionPPI can induce apoptosis and autophagy of colorectal cancer cells through targeted activation of Hippo signaling pathway， thereby inhibiting their proliferation.