Inhibitory Effect of Recombinant Polypeptide of Fibronectin CH50 on Invasion Ability of Melanoma B16 Cells and the Mechanism

Objective To investigate the inhibitory effect of recombinant polypeptide of fibronectin CH50 on melanoma B16 cells and the mechanism.Methods Melanoma B16 cells were labeled with CFSE,and injected into mouse through tail vein.The lungs were removed 6 h and 24 h later and used for frozen sectioning.The accumulation of B16 cells in lung and the invasion of them into lung tissue were observed.The difference of metastatic loci formed by B16 cells in lung was observed 15 days after tumor inoculation. The effect of CH50 on the binding of B16 cells to fibronectin and fibrinogen was detected.The expression levels of metastasis-related genes in B16 cells were detected by RT-PCR.Zymography was used to analyze the activity of MMP-9.Results The interaction of CH50 with B16 cells within a short period of time could inhibit the accumulation of B16 cells in lung,and result in the significant decrease of fluorescent loci in lung 6 h after the injection of tumor cells.The action of CH50 on B16 cells for a longer time could inhibit the invasion ability of B16 cells into tissue,resulting in more significant decrease of fluorescent loci in lung 24 h after the injection of tumor cells.The lung metastasis of B16 cells was significantly suppressed after treatment with CH50.Polypeptide CH50 could inhibit the binding of B16 cells to fibronectin and fibrinogen,and the spreading of cells after the binding.The expression of genes such as cdc2,αv,β3 and MMP-9 by B16 cells was down-regulated and the activity of MMP-9 was significantly decreased by CH50.Conclusion Polypeptide CH50 can inhibit the invasion ability of melanoma B16 cells.The main mechanisms involve the inhibition of the binding of tumor cells to adhesive molecules and down-regulation of the expression of genes related to metastasis,which change the biological characteristics of tumor cells.