Abstract: BACKGROUND AND AIM: This study was to explore the inhibitory effect of periplocin extracted from cortex periplocae (CPP) on tumor formation activity of human colorectal cancer cell line SW480 in nude mice, and to investigate its antitumor mechanisms. MATERIALS AND METHODS: SW480 cells were injected subcutaneously into nude mice to construct Balb/c-nu/nu mice model of SW480 cells. After treated with CPP, the transplanted tumor volume and weight of nude mice were measured. Morphology of SW480 cells in transplanted tumors were observed under light microscope after HE staining. Expression of β-catenin, Survivin and C-myc involved in Wnt/β-catenin signaling pathway were detected by immunohistochemistry. RESULTS: The growth of transplanted tumor in nude mice was inhibited markedly by CPP, the volume and weight of tumors were significantly less, the inhibition rate was 61.41％ (P<0.01). There were inflamatory cells and noticeable necrosis in transplanted tumor tissue of CPP-treated mice. Expression levels of β-catenin, Survivin and C-myc in transplanted tumor were significantly lower in CPP-treated group than in control group. CONCLUSION: CPP exerted significant inhibitory effect on the proliferation of human colon cancer SW480 cells in nude mice. The mechanisms may be associated with down-regulating the Wnt/β-catenin signaling pathway.

Key words: periplocin extracted from cortex periplocae, SW480 cell, Wnt/β-catenin signaling pathway, apoptosis, transplanted tumor