The Role And Mechanism Of SCIN In The Development Of Castration?resistant Prostate Cancer

Objective:Prostate cancer is one of the most common malignant tumors in the genitourinary system.In the USA,the incidence of prostate cancer has surpassed that of lung cancer,becoming the leading risk factor for men's health.In China,with the development of prostate biopsy technology,the popularization of PSA screening and lifestyle changes,the incidence of prostate cancer is increasing rapidly.Comprehensive therapy usually brings a relatively good prognosis for early prostate cancer patients,but there are still many prostate cancer patients after distant metastasis can be diagnosed,leading to poor prognosis.Although patients with advanced prostate cancer can be controlled and improved by endocrine therapy,most patients with prostate cancer will eventually develop the castration-resistant form characterized by metastasis with poor prognosis.Cytoskeleton constituents including F-actin play important roles in maintaining epithelial integrity.Therefore,its deregulation is a major cause of cancer progression.We previously showed that scinderin(SCIN)is highly expressed in poorly differentiated cancer tissues and this study aimed to explore the mechanism of its cell proliferation regulation.Method:(1)In this study,we used cell transfection,RNA isolation and quantitative reverse transcriptase polymerase chain reaction(qRT-PCR)to determine the expression of SCIN in prostate cancer samples.(2)We used shRNA lentivirus interference technique to knock down the expression of SCIN in prostate cancer cells.Western blot and qRT-PCR were employed to detect the related proteins and gene expression,which were significantly affected after SCIN knock down.(3)To evaluate the effect of SCIN on EGF stimulated cell survival,the survival rate of EGF stimulated cells was detected by MTT assay after transfection of PC3/DU145 cells with SCIN small interfering RNA.(4)Through Annexin V cell apoptosis test and gene chip data analysis,the apoptotic pathway related to the promotion of prostate cancer cell apoptosis after knockout SCIN was found.(5)The effect of SCIN on the growth of transplanted prostate cancer cells in mice was determined by the determination of tumorigenicity in vivo.The mice were divided into two groups according to the different treatment of castration?resistant prostate cancer sample cells: shSCIN group(transfection of SCIN interference sequence)and shCon group(transfection blank sequence).Results and Conclusions:(1)There was a general increase in SCIN expression in prostate cancersamples compared with normal prostate tissues.(2)The mRNA and protein levels of the two cancer cell lines in the shSCINgroup were significantly lower than those in the shCon group.It was furtherfound that the expression of EGFR and RPS6KA2 was regulated by SCIN andits downstream MEK/ERK signaling pathway might be affected by SCIN.(3)MTT assay showed that the expression of EGFR and RPS6KA2 might beaffected by SCIN.The results of MTT assay showed that EGF(50 ng/mL)significantly promoted the proliferation of shCon cells,but not in shSCINgroup.In addition,EGF upregulated the phosphorylation of MEK(p-MEK)and ERK(p-ERK)in shCon cells,while SCIN knockout weakened the effectof EGF on MEK / ERK signaling pathway.However,SCIN gene knockout didnot affect p-Akt.(4)In the Annexin V cell apoptosis test,the early and late apoptosis rates inthe shSCIN group were significantly higher than those in the shCongroup.Gene chip analysis showed that multiple apoptotic pathway moleculeswere up-regulated in the shSCIN group.Independent cell assay showed that theexpression of Fas and Fas ligand(FASLG)mRNA was significantly increasedin PC-3 and DU145 cells without SCIN deletion.Compared with shCon group,the levels of cytochrome caspase 9,caspase 3 and PARP in PC-3 and DU145cells were increased in shSCIN group.In addition,the level of Bcl-xl proteindecreased in both cell lines in the shSCIN group.(5)The growth of transplanted tumor in shSCIN group was significantlyslower than that in shCon group.Conclusions:We believe that SCIN can promote the survival of castration?resistant prostate cancer cells by stabilizing EGFR and MEK/ERK signals,and knock down SCIN can reduce the expression of epidermal growth factor receptor and promote the apoptosis of castrated resistant prostate cancer cells.