OBJECTIVETo explore the effect of human endostatin expressed by host cells on the growth of human liver carcinoma in vivo.

METHODSHuman endostain gene was transferred into SMMC7721 cells by retroviral pLncx to build endostatin-transfected cell line. PCR, immunohistochemistry and Western blot analysis were applied to examine the transfection, expression and secretion of endostatin. Endothelial cell proliferation assay was used to determine the biological activity of expressed endostatin. The in vivo and in vitro growth rates of the endostatin-transfected and control SMMC7721 cells were also observed.

RESULTSPCR proved that the genome of endostatin-transfected SMMC7721 cells contained a 550 bp specific fragment of endostatin. The expression and secretion of human endostatin from endostatin-transfected SMMC7721 cells were confirmed by immunohistochemistry and Western blot analysis. Endostatin expressed by host cells could inhibit the proliferation of human umbilical vein endothelial cells by 48% (P < 0.01). In vitro proliferation assay showed that endostatin-transfected SMMC7721 cells had no change in proliferation rate compared to control SMMC7721 cells. In comparison with control group, however, tumor growth rate in vivo from endostatin-transfected SMMC7721 cells was inhibited greatly by 94.5%, 22 days after inoculation into nude mice (P < 0.01).

CONCLUSIONHuman endostatin mediated by retroviral gene transfer can inhibit greatly the growth of human liver carcinoma SMMC7721 in vivo.