[Inhibitory effect of thalidomide on growth of human hepatoma cell line SMMC-7721 cells].

OBJECTIVE: The aim of this study was to investigate the effect of thalidomide on the growth of human hepatoma cell line SMMC-7721 cells in vitro, and to explore the curative possibility of hepatocellular carcinoma with thalidomide. METHODS: SMMC-7721 cells were treated with Thalidomide at different concentrations. The cell growth and proliferation was assessed by MTT assay. DNA ladder, apoptosis rate and changes of cell nuclei were studied by agarose electrophresis, fluorescence microscopy and flow cytometry, respectively. The expression of caspase-3 was analyzed with flow cytometry. The VEGF content of SMMC-7721 cells in culture medium was tested by ELSIA. RESULTS: When the concentration of Thalidomide solution was increased from 3.125 microg/ml to 200 microg/ml, the cell growth was inhibited by from 11.7% to 34.2%. Compared with the control group, the thalidomide solution at a concentration of 25, 50, 100 and 200 microg/ml solution significantly inhibited the proliferation of SMMC-7721 cells (P < 0.05). A ladder pattern of DNA fragments appeared after SMMC-7721 cells exposed to 200 microg/ml thalidomide for 24 h, especially for 48 h. Fluorescence microscopy revealed that the cell nuclei were condensed and fragmented after the cells were exposed to 200 microg/ml thalidomide for 48 h. In cells treated with 200 microg/ml thalidomide for 12, 24, 48 and 72 h, the apoptotic rate was 3.1% +/- 0.5%, 8.4% +/- 1.3%, 19.4% +/- 3.5% and 25.8% +/- 2.1%, respectively, significantly higher than that in the negative control group 1.6% +/- 0.6%. The cells treated with thalidomide at a concentration of 50, 100, 200 microg/ml for 48 h, the apoptotic rate was 8.7% +/- 1.2%, 16.8% +/- 2.5% and 25.4% +/- 4.5%, respectively, increasing in a dose-dependent manner, also significantly than that in the cells of control group 2.1% +/- 0.5%, (all were P < 0.05). The caspase-3 positivity of SMMC-7721 cells treated with thalidomide was increasing along with the increase of treatment time or drug concentration, but not in the control cells. The VEGF content in SMMC-7721 cells was lowering when thalidomide was used in an increasing concentration. CONCLUSION: Under the conditions used in this study, thalidomide can inhibit the proliferation of SMMC-7721 cells in vitro. Induction of apoptosis and inhibition of angiogenesis may be possibly two mechanisms for its anticancer action.

[Construction of an angiostatin eukaryotic expression vector and characterization of its inhibitory efficiency in B16 melanoma bearing mice].

Recent studies have demonstrated that angiostatin, a newly discovered specific inhibitor of endothelial cells, may significantly suppress the growth of a variety of tumors. We constructed an eukaryotic expression vector containing angiostatin (pAG3 ). To study the effect of pAG3, we intramuscularly injected pAG3 into B16 melanoma bearing C57 mice, we found that pAG3 could obviously inhibit tumor growth and reduce the size of tumors in B16 melanoma bearing C57 mice compared to the untreated control mice. In addition, we also investigated whether pre-treatment of pAG3 can prevent the tumor formation in mice treated with B16 melanoma. Normal C57 mice which received 5 days of treatment of pAG3 prior to implanting tumors resulted in the inhibitory effect when compared to control mice. No promotive effect was observed when pAG3 was combined with DTIC (Dacarbazine). These findings provide a basis for the further development of nonviral delivery of angiogenic gene therapy.