OBJECTIVETo investigate the inhibitory effect of recombinant polypeptide CH50 of fibronectin on invasion and angiogenesis of tumors, and analyze the possible molecular mechanism of the therapeutic effect of polypeptide CH50 on tumors.

METHODSThe tumor model was established by inoculation of H22 hepatocarcinoma cells in mice. The tumor gene therapy was performed by in vivo gene transfection with a method based on hydrodynamics to express polypeptide CH50. After treatment, the inhibitory effect on tumor invasion and angiogenesis was observed by histotology with HE staining of tumor tissues. The expresison of MMP-9 mRNA and protein at the edge of tumor tissue was evaluated by RT-PCR and gelatin zymography, respectively. RT-PCR was used to detect the expression of the related genes in H22 cells treated with polypeptide CH50. Cell adhesion assay was used to analyze the influence of polypeptide CH50 on the binding of cells to fibrinogen.

RESULTS(1) Eukaryotic expression plasmid pCH510 was expressed in vivo in a non-targeting manner and produced a significant inhibitory effect on tumor growth. The therapy with polypeptide CH50 resulted in pronounced necrosis of tumor cells in pCH510 group, compared with that in control groups at histological level. (2) Polypeptide CH50 could inhibit the growth, invasion and angiogenesis of the tumor, and interfere the formation of new collateral circulation in the tumor. (3) The expression level of MMP-9 protein at the edge of tumor tissue was significantly decreased after treatment, especially the activation of pro-MMP-9 was inhibited significantly, whereas the expression level of MMP-9 mRNA was not influenced. (4) The expression of alphav, 33 and cdc2 mRNAs in H22 cells treated with polypeptide CH50 was down-regulated. (5) Cell adhesion assay manifested that polypeptide CH50 can affect the adhesion ability of H22 cells.

CONCLUSIONPolypeptide CH50 can inhibit tumor growth and angiogenesis by suppressing the functions of MMP-9 and integrin alphavbeta3.