Taxus Cuspidata Foliage Extract (hh03) Of Anti-tumor Effect And Mechanism

Using breast cancer cell line Bcap-37 as the target, the present experiments were designed to analyze the apoptosis-inducing effects of the extracts purified from the leaves and twigs of Taxus cuspidata HH03. The in vivo effects of HH03 on transplated animal tumors (S180 sarcoma, B16 melanoma, Lewis lung tumor and Colon26 carcinoma) and the possible mechanisms involved were also investigated.Tumor cell strains were s.c transplated in the experimental mice, and the effects of i.v HH03 treatment with different doses(250mg/kg, 125mg/kg, 62.5mg/kg) on the changes in tumor volume were compared with that of the non-treated and Taxol treated tumor-bearing animals. The cytotoxic efficacy of HH03 on several cell lines was evaluated by MTT method. Analysis for cell morphology in evaluating the apoptosis effect of HH03 on Bcap-37 cell line was obtained using Wright's staining and Flow cytometric analysis as well as the Guava TUNEL Assay. Microtubule-depolymerizing effect of HH03 on Bcap-37 cell line was examined by immunohistochemistry.HH03 strongly inhibited the tumor growth of transplanted S180 sarcoma, B16 melanoma, Lewis lung tumor and Colon26 carcinoma reaching 74.14 %, 54.2 % , 69.27 % , 55.39 % inhibition respectively at the lowest dose of 125mg/kg. HH03 had potent inhibitory effect on Bcap-37 cell line in a concentration-dependent manner. HH03 induced apoptosis in Bcap-37 cell line with typical morphological alteration, and the flow cytometric analyses suggested the cell cycle was blocked at G2/M phase. Immunohistochemistry microscopic analyses of cells treated with HH03 showed extensive microtubule bundling comparable to Taxol.HH03 exerted its cytotoxic effect on Bcap-37 cells by inducing apoptosis. The mechanism of its anticancer effect may involve the facilitation of the microtubule aggregating in the middle of intermitotic cells.