Study On SOX4 Expression And Its Influence On Wnt/β-catenin Pathway In Melanoma

Part 1 Expression of SOX4 in melanomaObjective:To study the expression of SOX4 in melanoma tissues and to explore the possible role of SOX4 in hunman melanoma.Methods:SOX4 protein was detected by immunohistochemistry and normal skin of human was used as control.Results:Positive expression of SOX4 in nuclear was detected in 17 of all 30 melanoma tissues.However,no nuclear expression was found in all normal skin tissues.Conclusions:Our work showed that SOX4 was overexpressed in melanoma tissues.There should be some relationship between SOX4 and melanoma.Part 2 Gene silence of SOX4 by RNA interference and its influence on Wnt/β-catenin pathway in melanoma cellsObjective:To investigate the effects of siRNA mediated SOX4 gene silencing on Wnt/β-catenin pathway of human malignant melanoma cells.Methods:Two types of dsRNA of SOX4 were constructed and transfected into A375 cells,untreated cells and cells transfected by scramble RNA were used as control groups.The expression levels of mRNA and protein of SOX4,Wnt3A,P-catenin were detected by real-time PCR and Western blot respectively. TOPflash/FOPflash reporter assay was uesd for assessing Wnt/β-catenin signaling pathway activity.Results:Our results showed that the two types of SOX4 siRNA were transferred into A375 cells successfully.Compared with control cells, SOX4 siRNAs had no significant influence on Wnt3A.Nevertheless, SOX4 siRNAs led to the decrease ofβ-catenin protein without significant change ofβ-catenin mRNA expression. Wnt/β-catenin signaling pathway activity was inhibited significantly.Conclusions:Our study suggested that SOX4 may play an important role in Wnt/β-catenin signaling pathway in human malignant melanoma cells by influenceβ-catenin protein.lt may be a possible mechanism of SOX4 in the progression of malignant melanoma.Part 3 Effects of SOX4 siRNA on Survivin expression and proliferation of melanoma cellsObjective:To explore the role of SOX4 in A375 cell proliferation and the possible mechanism.Methods:The expression levels of mRNA and protein of survivin were detected by real-time PCR and Western blot respectively. MTT assay was used to observe cell proliferation.Resuls:Our results showed that SOX4 siRNA reduced Survivin expression at both mRNA level and protein level. SOX4 siRNAs inhibited proliferation of A375 cells significantly.Conclusions:SOX4 promotes Survivin expression and cell proliferation of A375 cells by one possible mechanism of increasing the activity of Wnt/β-catenin signaling pathway.