Effects And Mechanisms Of KAI1 Gene On Invasion And Metastasis Of MHCC97-H Human Hepatocellular Carcinoma Cells

Background and aims:Hepatocellular carcinoma(HCC) is one of the most common malignant tumors in China.Metastasis and recurrence are the most principal factors for their prognosis of the patients with the tumor.KAI1 gene is a newly found tumor metastasis suppressor gene.Many studies showed decreased KAI1 expression was observed not only in human prostate cancer but also in many solid epithelial tumors.The aim of this study is to explore the effects and mechanisms of KAI1 gene on invasion and metastasis of MHCC97-H human hepatocellular carcinoma cells.Methods: MHCC97-H cells with high metastatic potential transfected with sense, antisense KAI1 expression plasmid or its control vector pCI-neo without KAI1 gene in our previous experiments are renamed as MHCC97-H-S cells, MHCC97-H-AS cells, MHCC97-H-pCI cells respectively.In this study,we observed their viscoelastic properties,cell adhesion forces, subcutaneous tumorigenicity and metastasis after implanted orthotopicly into nude mice liver,and the expression of ECM and intercellular adhesion mollecular.Results:(1)Cell viscoelastic properties: The elastic coefficients K1,K2 and μof the MHCC97-H cells were significantly higher after transfected with sense KAI1 expression plasmid(P﹦0.007), lower after transfected with antisense KAI1 expression plasmid(P﹦0.000),and no significantly difference after transfected with its control vector pCI-neo without KAI1 gene(P ﹦0.444),as compared with their paternal MHCC97-H cells.(2) Cell adhesion forces:On FN coated surfaces,the cell adhesion forces were quantitatively described by means of micropipette aspiration technique. The forces of the MHCC97-H cells were significantly higher after transfected with antisense KAI1 expression plasmid(P<0.01), lower after transfected with sense KAI1 expression plasmid(P<0.01), and no significantly difference after transfected with its control vector pCI-neo without KAI1 gene(P>0.1),as compared with their paternal MHCC97-H cells.(3) Subcutaneous tumorigenicity: The different kinds of cells inoculated subcutaneously all had tumorigenicity. There was no significant difference in the speed of tumor growth among different groups, but the antisense group showed stronger invasion ability than others.(4) Tumorigenicity and metastasis after implanted orthotopicly into nude mice liver: The spontaneous metastasis to lung occurred in latency period of seven weeks via orthotopic implantation of tumor tissue. Immunostaining showed strongly positive for AFP in lung metastatic lesions,which indicates those were lung metastatic lesions from hepatocellular carcinoma.The number of lung metastatic lesions increased dramaticly in antisense group(p=0.00158),decreased significantly in sense group (p=0.00465)and no significantly difference in vector pCI-neo group(p=0.15166,as compared with their paternal MHCC97-H group.(5) Expression of ECM and intercellular adhesion mollecular: ①FN: posivity distribution of FN belonged to continuous peritrabecular or interrupted type in MHCC97-H-S groups, the staining of cell surface belonged to discontinous annular type;the expression on the wall of liver sinus and cell surface is rarely found,but found in matri and cytoplasm of some cancer cells in MHCC97-H-AS groups;but in MHCC97-H-pCI and MHCC97-H groups,the staining of FN showed discontinuous line circling the nests of cancer.②collagen IV and LN: posivity distribution of collagen IV and LN belonged to discontinuous peritrabecular or periacinar type or negative staining in MHCC97-H-AS groups,continous peritrabecular type in MHCC97-H-S groups and discontinuous peritrabecular type in MHCC97-H-pCI and MHCC97-H groups; ③ICAM-1:the positive staining located almost in membrane or cytoplasm,and positve rate is 67% in MHCC97-H-AS groups;cancer cells showed weakly or negatively in MHCC97-H-S groups;there were positive staining in some cells of MHCC97-H-pCI and MHCC97-H groups,the positive rate is 42%,significantly different compared with MHCC97-H-AS groups(p<0.01).Conclusions:we can get some conclusions from our study as f...