| Objective:Using tissue specific knock-out mouse model,this project is designed to study the role of Pin1 in skin stem cell maintenance,proliferation and differentiation on levels of molecule,cell and animal,followed by exploring the mechanism in skin stem cell maintenance and activation,skin growth and development,further assessing the effect of Pin1 on tumorigenesis and metastasis.Methods:1.Observe the localization of Pin1 in mouse skin and human skin cancer tissue by immunohistochemistry.2.Observe the effect of Pin1 on mouse skin’s development and differentiation,hair growth and skin tumorigenesis using skin specific Pin1-knock-out mouse model.Observe the influence of Pin1 on the stemness of mouse skin stem cell using primary cell colony formation assay.3.Detect the expression of Pin1 at different mouse hair cycles and skin cancer using Immunostaining,Western blot and Real-Time PCR.4.Investigate the role of Pin1 in cancer cells proliferation,migration,colony formation and tumor formation under nude mice skin by knocking down Pin1 in SCC and A431 cell line.5.Screen Pin1 downstream factors by Western blot to identify related proteins and signal pathways regulated by Pin1 in skin development and skin tumorigenesis.Results:1.In normal skin,Pin1 is primarily located in epidermis and hair follicle,in skin cancer,Pin1 is enriched in the area of tumor stem cell.2.Pin1 knockout does not have any effect on the development and differentiation of mouse epidermis,slightly influences the mouse hair cycle and the stemness of skin stem cell.However,its knockout dramatically inhibits skin tumorigenesis induced by DMBA/TPA.3.Pin1 is up regulated at anagen and down regulated at telogen,and it reduces gradually as mouse grows older.Pin1 is highly expressed in skin cancer tissue in comparison with normal skin tissue.4.Pin1-knockdown in SCC13 cell line suppress cells proliferation,migration and tumor formation under nude mouse skin.Pin1-knockdown in A431 cell line significantly inhibits the ability of tumor formation under nude mouse skin.5.Cox2 may act downstream of Pin1 to regulate skin tumorigenesis. |
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