Experimental Study On Anti-tumor Effects Of Gecko Alcohol Extract In Vitro And In Vivo

OBJECTIVE: To investigate the antitumor effects and mechanisms of GAE on S180 sarcoma transplanted under the renal capsule in Kunming mice in vivo and human esophageal carcinoma-109 cells in vitro. METHODS: A model of S180 sarcoma transplanted under the renal capsule of normal immunocompetent mouse used in this study. Forty model mice were randomly divided into four groups (n = 10). GAE groups (2.4 g/kg/d, or 1.2 g/kg/d, intraperitoneal injection), normal control group (equal volume of saline, intraperitoneal injection) and the CTX group (0.1 g/kg Cytoxan, intraperitoneal injection at the first day). After 6 days of treatment, the antitumor activity of GAE was evaluated by tumor volume. Its impact on immune organ was detected based on the thymus index and spleen index. The protein expression of VEGF was detected by immunohistochemistry. The inhibitory effect of GAE on proliferation of EC-109 cells was measured by MTT assay. Morphological changes were observed by optical microscopy. The apoptosis morphous changes induced by GAE in EC-109 cells were detected by Hoechst 33342 staining. Apoptosis rates were determined by flow cytometry. The protein expression levels of Caspase-3 and Fas in EC-109 cells of GAE were measured by immunohistochemistry assay. RESULTS: GAE could inhibit the growth of S180 sarcoma in mice. In CTX group, the high and low dose of GAE groups, the mean inhibitory rate of tumor was 74.5%, 77.5%, 57.5% respectively and FBW/IBW was 0.94, 1.03, 0.99 respectively. Compared with the NS group, the thymus index and Spleen index of mice in GAE groups had no significant difference. The immunoreactive score of VEGF protein expression of GAE groups by immunohistochemical staining were lowered significantly. In vitro, at 48h, 72h, the inhibitory ratio (2.5, 3.0, 3.5, 4.0, 4.3, 4.6 mg/mL) was 3.3%, 14.3%, 16.5%, 25.7%, 62.4%, 77.9% and 25.5%, 30.1%, 32.6%, 46.8%, 84.9%, 96.9% on EC-109 cells, respectively. EC-109 cells treated with GAE showed typical characteristics of apoptosis, the cells became round and small, cell detachment, membrane blebbing, cell shrinkaged with acondensed cytoplasm, and vesicle formation. Typical apoptotic characteristics were seen in EC-109 cells treated with GAE (blue grain fluorescence with dense-dyed appeared in the nucleolus). The apoptosis rate of EC-109 cells treated with GAE was 19.43%. Compared with control group, the expression level of Fas or Caspase-3 was significantly up-regulated in the GAE group. CONCLUSION : GAE has anti-tumor effects in vivo and in vitro. The down-regulation of protein expression of VEGF and up-regulation of protein expression of Fas and Caspase-3 may be contributed to anti-tumor effects of GAE.