| Background Soy isof lavonoids are soy secondary metabolites. A major metabolite of soy is genistein (Gen, 4,5,7-thihyoxyisoflavone). It was reported that Gen is beneficial for health, such as antitumor, antioxidation, phytoestrogen activity, and so on.Resent years, the studies have found that Gen can inhibit the growth of var ious cancer cell lines in vitro and in vivo. Gen induces the apoptosis of tumor cells may be the reason, which inhibits carcinogenesis. Apoptosis has been a hotspot in research of tumor therapy.Cell apoptosis is relative to the metastatic progress. The manipulation of the apoptotic cascade may be a new approach to interrupt tumor metastasis.Malignant cells invade by lymphatic compartments is the most general metastatic approach. Studies on the inhibitory effects of drugs on the lymphatic metastasis of tumor are few. There weren't reports about the effects of Gen on tumor cells with different metastatic potential, which originate from the same cell line.Objective In this study, we chose murine hepatocarcinoma cell line with different lymphatic metastatic potential, HepA-H(murinehepatocarcinomacell with highly lymphatic metastatic potential)and HepA-L(murine hepatocarcinoma cell with poorly lymphatic metastatic potential) as objects to explore the antitumor effects of Gen. Furthmore, the mechanism that Gen inhibits the lymphatic metastasis of tumor cells will be discussed.Methods In vitro, the inhibitory effects on the growth of HepA-H and HepA-L cells were evaluated by microculture tetrazolium assay (MTT). Gen-inducing apoptosis in HepA-H and HepA-L cells was observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), DNA agarose electrophoresis, and flow cytometry. In vivo, HepA-H and HepA-L cells were injected subcutaneously to foot pad of NIH mice to establish the animal model. The popliteal lymph nodes were taken and the metastatic rates were calculated after Gen treatment for 14 days. Using TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) method, the apoptosis of HepA-H and HepA-L cells was checked and apoptosis index(AI) was calculated.Results In vitro, Gen exhibited antiproliferative activity. The proliferation inhibition rate of Gen on HepA-H was higher than that on HepA-L. Gen induced the apoptosis of HepA-H and HepA-L in vitro. The microvilli reduction, the cell membrane vesiculation, the cell shirinkage, the chromatin condensation and the apoptotic bodies were observed under SEM and TEM after the treatment of 50mg/L Gen for 48 h. The typical DNA ladder of HepA-H was demonstrated on agarose gel electrophoresis, but the DNA ladder of HepA-L only appeared at 100mg/L Gen for 48 h. The DNA content analysis of FCM showed the apoptotic rates induced by Gen were depended on dosage and time, too (P<0.01) , and the apoptotic rates of HepA-H cells was higher than that of HepA-L. In vivo, Gen could inhibit the tumor cells invading into lymphtic vessels and reduce the size of tumor. The prohibition of Gen on the tumor of HepA-H cells was better than that onthe tumor of HepA-L cells. The size of tumor come from HepA-H and HepA-L cells was 394. 63±89. 77mm3 and 188. 43±68. 74mm3 respectively after 14 days without Gen, After Gen using (200mg.kg-1.d-1) for 14 days, the size of tumor of HepA-H and HepA-L was 122. 53+22. 73 mm3 and 73. 72±49. 18 mm3 respectively. Gen(200mg.kg-1.d-1) could also inhibit the metastatic rates of the popliteal lymph node in the experiment groups inoculated by HepAH(25.00%) and the experiment groups inoculated by HepA-L (8. 33%) groups, compared to the control groups inoculated by HepA-H (91.67%) and the control groups inoculated by HepA-L(25.00%). The nuclei of the apoptotic cells were stained brown by the TUNEL assay. AI of experiment groups affected by Gen was higher than control groups (P<0.01) , and AI of tumor come from HepA-H cells (3.87%) was higher than that from HepA-L cells (1.69%)when Gen was administered at 200 mg.kg-1.d-1.Conclusion (1) Gen has a remarkable antitumor activity. Gen inhibited... |
PDF Full Text Request