[Mechanism of ursolic acid in regulating colorectal cancer cell HCT116 autophagy through hedgehog signaling pathway]

To prove that ursolic acid(UA)could activate the autophagy of colorectal cancer HCT116 cells by inhibiting hedgehog signaling pathway. The effect of UA on the viability of HCT116 cells was determined by MTT assay. The effect of UA on the proliferation and migration of HCT116 cells was detected by crystal violet staining and scratch test. In the study on autophagy, the time points were screened out first: the autophagy fluorescence intensity of UA acting on HCT116 at different time points were detected by Cell Meter~(TM) Autophagy Assay Kit; Western blot was used to detect the expression of autophagy protein P62 at different time points. Then, Cell Meter~(TM) Autophagy Assay Kit was used to detect the effect of UA on autophagy fluorescence intensity of HCT116 cells. The effect of different doses of UA on the expressions of LC3Ⅱ and P62 proteins in HCT116 cells were detected by Western blot. Further, AdPlus-mCherry-GFP-LC3 B adenovirus transfection was used to detect the effects of UA on autophagy flux of HCT116 cells; UA combined with autophagy inhibitor chloroquine(CQ) was used to detect the expression of LC3Ⅱ by Western blot. In terms of mechanism, the effect of UA on hedgehog signaling pathway-related proteins in HCT116 cells was detected by Western blot. The results showed that UA inhibited the activity, proliferation and migration of HCT116 cells. UA enhanced the fluorescence intensity of autophagy in HCT116 cells, while promoting the expression of LC3Ⅱ and inhibiting the expression of P62, in a time and dose dependent manner. UA activated the autophagy in HCT116 cells, which manifested that UA resulted in the accumulation of fluorescence spots and strengthened the fluorescence intensity of autophagosomes; compared with UA alone, UA combined with autophagy inhibitor CQ promoted the expression of LC3Ⅱ. UA reduced the expressions of PTCH1, GLI1, SMO, SHH and c-Myc in hedgehog signaling pathway, while increased the expression of Sufu. In conclusion, our study showed that UA activated autophagy in colorectal cancer HCT116 cells, which was related to the mechanism in inhibiting hedgehog signaling pathway activity.