The Study On The Function And Mechanism Of Runx3 In Inhibiting Melanoma Cell Migration

In recent years,the incidence and mortality of cancer have remained in a high level,showing a variety of cancer types,and the incidence of malignant melanoma has increased year by year.Malignant melanoma is an invasive skin cancer.In most cases,melanoma begins with the conversion of benign nevi,develops into a dysplastic lesion,then enters the primary melanoma,invads into the dermis and regional lymph nodes,and finaly spreads to distal metastatic sites.However,there are no good prognostic biomarkers in melanoma to predict the progression of metastasis.which is not conducive to the diagnosis and treatment of the disease.Tumor metastasis is the cause of high mortality in cancer,and it is also an indicator for distinguishing benign tumors from malignant tumors and judging tumor malignancy.Studies have shown that important genetic mutations often occur during cancer development,usually as inactivation or deletion of tumor suppressor genes,the activation or expression of oncogenes.The transcription factor Runx3 is a known tumor suppressor gene.Studies have shown that Runx3 is often expression loss in malignant melanoma and is negatively correlated with the degree of malignancy of melanoma.However,the potential impact of Runx3 expression loss on melanoma development and progression remains unclear.In our study,it was confirmed that when Runx3 was re-expressed in B16-F10 malignant melanoma cells,the shape of the cells changed from elongation and branching to spreading and no branching,which not only enhanced the formation of stress fibers,but also promoted the maturity of the focal adhesion.In addition,the re-expression of Runx3 can attenuate the migration of malignant melanoma cells at the cellular level and inhibit the lung metastasis of malignant melanoma cells in mice.However,it does not affect the formation of subcutaneous xenografts.Subsequently,we found that Gbp2 is one of the Runx3 regulated genes.When Gbp2 was overexpressed in B16-F10 cells,the morphology of the cells changed from elongated branching to spreading squares,and the migration ability of the cells was weakened.Overexpression of Gbp2 also enhanced the formation of stress fibers,promoted the maturity of the adhesion spots.Conversely,Gbp2 was knocked down in B16-F10 cells overexpressing Runx3,the morphology of the cells returned to an elongated branching shape,and the cells regained migration ability.In this case,the number of stress fibers and mature focal adhesions decreased.When a mature adhesion spot is formed,it will co-localize with the stress fiber skeleton.Furthermore,the Runx3-induced cell shapechanging phenotype was also observed when cultured melanoma cells on fibronectin-coated coverslips,suggesting that fibronectin may be involved in mediating cell shape changes in Runx3-induced melanoma cells.Our results suggest that Runx3 may alter the morphology of cells by transcriptionally regulating Gbp2,which enhances stress fibers,promotes the maturation of focal adhesions,and forms extracellular matrix(ECM)associated fibronectin to regulate cell shape and inhibits melanoma cell migration,invasion and tumor metastasis.Our current study provides further evidence for the idea that cell shape changes are potentially associated with melanoma development and progression,which may make more solid theoretical basis for find a better target to treat melanoma.