[Mechanism of inhibition of tumor angiogenesis by Bletilla colloid: an experimental study].
OBJECTIVE
To study the mechanism of inhibition of tumor angiogenesis by Bletilla colloid.


METHODS
Human Hep-G2 hepatocellular carcinoma cells were cultured and treated with Bletilla colloid of different concentrations. Pure culture of Hep-G2 cells was used as control and pure culture medium without Hep-G2 cell was used as blank control. The concentration of vascular endothelial growth factor (VEGF) in the supernatant was detected by ELISA. The apoptosis and proliferation of the Hep-G2 cells were examined by flow cytometry. Cells of human endothelial cell line ECV-304 were cultured in the supernatant of culture media of Hep-G2 treated with Bletilla colloid of different concentrations. MTT method was used to observe the growth of the ECV-304 endothelial cells. Eighty rats were made animal model of transplanted Walker-256 hepatoma and then randomly divided into 4 groups of 20 rats 12 - 14 days after to undergo transarterial chemoembolization (TACE) treated with normal saline, 5-fluouracil (5-Fu), iodized poppy seed oil, and 5-Fu-Blettila microsphere respectively. Two weeks after, the rats were killed and the tumors were taken out. Immunohistological staining was conducted to detect the expression and localization of factor VIII, VEGF, and basic fibroblast growth factor (b-FGF). The microvcascular density (MVD) was calculated by counting the factor VIII positive endothelial cells.


RESULTS
There was no statistically significant difference in the apoptosis rate, proliferation rate and supernatant VEGF level between the control group and the Bletilla groups. The inhibition rates of ECV-304 endothelial cell growth were 57.6%, 66.7%, 86.4%, 87.5%, and 94.8% in the groups of Bletilla of the concentrations of 0.5, 1.0, 2.0, 4.0, and 8.0 micro g/ml respectively in a dose-dependent manner. The MVD of tumor was 59 +/- 34 per field in the 5-Fu-Blatilla group,significantly lower than those in the other 3 groups (F = 5.177, P = 0.003). The expression of VEGF and the expression of b-FGF were not significantly different among the 4 TACE groups.


CONCLUSIONS
Bletilla colloid inhibits angiogenesis after TACE, potentially, through inhibition of the binding of vascular endothelial growth factor to its receptor.
Feng
Gan-Sheng
GS
Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Li
Xin
X
Zheng
Chuan-Sheng
CS
Zhou
Cheng-Kai
CK
Liu
Xi
X
Wu
Han-Ping
HP
D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000098:blood supply*; D016461:Chemoembolization, Therapeutic; D003102:Colloids; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply*; D008297:Male; D009389:Neovascularization, Pathologic; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
D020533:Angiogenesis Inhibitors; D003102:Colloids; D004365:Drugs, Chinese Herbal; D016222:Fibroblast Growth Factor 2