Effects of the C-terminal of endostatin on the tumorigenic potential of H22 cells

Abstract

Abstract.Endostatin is an endogenous angiogenesis inhibitor whose specific functional site has not yet been determined. In the present experiment, 13 amino acids (LCIENSFMTSFSK) were selectively deleted from the C-terminal of endostatin and the resulting mutant endostatin was named EM13. To determine the effect of the C-terminal deletion on the biological activity of endostatin, EM13, wild-type endostatin and empty plasmid were transfected into H22 cells. After 48 h, the three types of transfected cells were harvested and injected into nude mice. The results demonstrated that there was no significant difference in tumor size, as determined by hematoxylin and eosin staining, between the EM13-transfected group and the endostatin and empty plasmid groups, although the nude mice that were injected with EM13-transfected H22 cells exhibited smaller tumors and lower density of blood vessels compared to those injected with endostatin-and empty plasmid-transfected H22 cells. The results suggested that the 13 amino acids of the C-terminal of endostatin do not play an important role in the tumorigenic potential of H22 cells. This experiment was unsuccessful in reproducing the results of several investigators. Therefore, the mechanism underlying the tumorigenesis of H22 cells remains to be elucidated.

Efficacy of pEgr-1-endostatin combined with ionizing radiation on hypoxic conditions in nude mice bearing SKOV3 ovarian carcinoma

“…Our results indicated that endostatin was successfully increased in the endostatin-IR-treated group compared with that in the control and the IR-treated groups. This is consistent with our previous study's finding that the anti-tumor effects of pEgr-1-endostatin-tumor necrosis factor-α recombinant plasmid expression were successfully induced by IR ( 18 ). Administration of endostatin in vivo led to a strong suppression of tumor-induced angiogenesis ( 17 ).…”

“…Endostatin is an endogenous 20-kDa COOH-terminal fragment of collagen XVIII, and is activated by proteolytic processing ( 17 , 18 ). It was first identified in murine hemangioendothelioma cells, and was subsequently demonstrated to be a potent angiogenesis inhibitor ( 19 ).…”

Evaluation of the diagnostic value of the immunoblotting and ELISA tests using recombinant Em18 antigen in human alveolar echinococcosis from Xingjiang China

“…Further studies are needed to analyze the relationship of the B-cell epitopes and Em18. The serodiagnostic performance of rEm13 protein (sensitivity and specificity) has also been analyzed (24,25), however, only a small numbers of serum samples were tested. Our results here suggest that the diagnostic performance of rEm18-GST by both IB and ELISA may be better than other reported reagents, particularly when a large number of serum samples were tested.…”