Weichang'an and 5-fluorouracil suppresses colorectal cancer in a mouse model.

Aim: To examine the effect of Weichang'an (WCA) and 5-fluorouracil (5-FU) on colorectal tumor and hepatic metastasis in a mouse model.

Methods: Quantitative determination of hesperidin, the effective component in WCA decoction, was performed using HPLC. In vitro cytotoxicity of WCA was determined by treating HCT-116 cells with WCA diluents or serum extracted from rats that received WCA by oral gavage for 1 wk and MTT assays. Forty-eight nude mice received cecum implantation with tumor blocks subcutaneously amplified from human colon cancer cell line HCT-116. Mice were randomly divided into four treatment groups: control (CON), WCA, 5-FU and combination (WCA+5-FU). Pathological examination of tumors consisted of tissue sectioning and hematoxylin and eosin staining. Tumor weight and size were measured, and the number of metastatic lesions was counted. Serum carcinoembryonic antigen (CEA) level was determined by ELISA. The expression levels of tumor genesis and metastasis-related proteins β-catenin and matrix metalloproteinase (MMP)-7 were measured by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry and immunoblotting. Cell fractionation was used to investigate intracellular distribution of β-catenin.

Results: Parenchymal tumors were palpable in the abdomens of nude mice 2 wk post-implantation and orthotopic tumor formation rate was 100% in all groups. 5-FU treatment alone significantly decreased tumor weight compared to the CON group (1.203±0.284 g vs 1.804±0.649 g, P<0.01). WCA treatment alone reduced the rate of metastasis (50% vs 100%, P<0.05). Combination treatment of WCA+5-FU was the most effective, reducing the tumor weight (1.140±0.464 g vs 1.804±0.649 g, P<0.01) and size (1493.438±740.906 mm3 vs 2180.259±816.556 mm3, P<0.05), the rate of metastases (40% vs 100%, P<0.01), and serum CEA levels (31.263±7.421 μg/L vs 43.040±11.273 μg/L, P<0.05). Expression of β-catenin and MMP-7 was decreased in drug-treated groups compared to controls, as detected using real-time quantitative RT-PCR, immunohistochemistry and immunoblotting, respectively. Cell fractionation assays revealed that nuclear translocation of β-catenin was reduced by WCA and/or 5-FU treatments.

Conclusion: Combination of WCA with 5-FU significantly inhibited colon tumor growth and hepatic metastases. Decreased expression of β-catenin and MMP-7 may be important.