Mechanisms Of Integrin β4 In Hepatocellular Carcinoma Metastasis

Objective:Compare the expression level of ITGB4 in HCC tissues and adjacent nontumorous liver tissue (ANLT); Compare the expression of ITGB4 in different HCC cell lines; Explore the relationships between the expression level of ITGB4 and clinic-pathological characteristics of HCC. Figure out the roles of ITGB4 in HCC metastasis.Methods:Specimens of 68 HCC tissues were collected from patients who performed hepatic resection at the Hepatic Surgery Centre, Tongji Hospital of Huazhong University of Science and Technology (HUST).7 HCC cell lines with different ability of metastasis were collected. The expression level of ITGB4 in HCC, ANLT and different HCC cell lines was detected by western blot and IHC. Relationships between the expression level of ITGB4 and clinic-pathological characteristics were analyzed statistically.Results:ITGB4 is overexpressed in HCC tissues. The expression level of ITGB4 in ANLT is very low or undetectable. High ITGB4 expression significantly associates with the aggressive tumor phenotypes of local invasion and poor differentiation. High ITGB4 expression was found in those cells with high aggressive behavior (HLF, MHCC97L, MHCC97H, HCCLM3), while the less aggressive HCC cell lines (Hep3B, HepG2, Huh7) had low or no ITGB4 expression.Conclusions:ITGB4 is overexpressed in HCC tissues and high aggressive HCC cell lines. ITGB4 plays a role as a tumor promoter in HCC progression.Objective:Elucidate the roles and mechanisms of ITGB4 in anchorage independence of HCC.Methods:Downregulate the expression of ITGB4 in HLF and HCCLM3 by RNAi (RNA interference). Evaluate the roles of ITGB4 in anchorage-independent growth by soft agarose colony formation assay and anoikis assay. Figure out the signal pathway regulated by ITGB4, which has an effect on anchorage independence of HCC, by western blot, Co-Immunoprecipitation, Immunofluorescence and so on.Results:ITGB4 enhances anchorage independence of HCC; AKT/PKB acts downstream of ITGB4 to promote anchorage independence; ITGB4 interacts with EGFR in a ligand-independent manner; ITGB4 and EGFR coordinately activate AKT by FAK rather than SRC.Conclusions:The ITGB4-EGFR unit activates the FAK-AKT axis to confer anchorage independence.Objective:Explore the roles of ITGB4 in in vivo tumor growth and pulmonary metastasis of HCC.Methods:Evaluate the effect of ITGB4 on in vivo tumor growth by tumorigenicity assay. Detect the role of ITGB4 in in vivo HCC lung metastasis by tail vein injection of HCC cells lung metastasis model.Results:The ITGB4-EGFR unit activated FAK-AKT signal pathway promoted tumor growth in vivo. The ITGB4-EGFR unit activated FAK-AKT signal pathway enhanced HCC lung metastasis.Conclusions:The ITGB4-EGFR-FAK-AKT axis enhances tumor growth and lung metastases of HCC in vivo.