The Role Of JAK-STAT Signal Pathway In Damage And Repair In Epidermoid Carinoma Cells A431

Skin cancer is regarded as the most common malignant tumor,and ultraviolet radiation is a major cause of skin cancer.Mounting evidence shows that exposure of the skin to solar UV radiation results in DNA damage,and dysregulation of key genes about performing DNA damage repair,maintaining genomic stability,controlling cellular signaling pathways,regulation of cell proliferation,differentiation and apoptosis thereby results in skin cancer.JAK-STAT has a significant effect on DNA damage and repair,this study mainly focuses on the effects of JAK-STAT signaling pathway in A431 cells treated with UV irradiation.In this study,a UV-induced DNA damage and repair model was first built.We established this model through distinct dose of UV irradiation,and tested to the cellular genome damage degree and proliferation ability by some experimental methods including comet assay,colony formation assay,PFGE in order to find suitable UV dose.On the basis of this model,this study detected the effects of JAK-STAT on DNA damage.The results showed that STAT3 reduced the degree of DNA damage,and enhanced the proliferation in A431 cells treated with U-V.Furthermore,the expression of anti-apoptosis markers(Bcl-1,CCND1)was detected by RT-PCR,Western Blot and TUNEL.The results demonstrated that STAT3 could increase the expression of anti-apoptosis markers and down-regulate the cell death.Results above showed that JAK-STAT signaling pathway inhibited UV damage and apoptosis,promoted cell proliferation in A431 cells.Next,this study explored the effects of JAK-STAT on DNA repair.First of all,this study detected the expression of ATM/ATR which plays an important role in DNA damage response,expression of the repair related gene from the promoter transcriptional activity,mRNA level,protein level with luciferase report gene activity assay,RT-PCR,Western Blot.The results showed that STAT3 can raise the expression of those genes.Secondly,we explored the molecular mechanisms of STAT3 promoting repair.miR-383 can promote the expression repair related gene by RT-PCR.More importantly,microRNA-383 suppressed ATR expression by targeting 3’UTR of ATR in A431 cells,by RT-PCR,Western Blot,and luciferase report gene activity assay.Meanwhile,STAT3 down-regulated the transcription of miR-383 promoter by luciferase report gene activity assay.Taken together,these studies suggest that JAK-STAT signaling pathway enhancing repair,and the molecular mechanisms may STAT3 down-regulate ATR-regulated miR-383.The results made foundation for the research of the role of JAK-STAT on DNA damage and repair,also provided clues for further exploring the specific mechanism of JAK-STAT on this field.