The Mechanism Of YAP1 Promoting The Conversion Of NFs Into CAFs In Prostate Cancer

Objective: Prostate cancer(PCa),as one of the highest male mortality rates in the world,has been the focus of research for its proliferation and metastasis mechanisms.Tumour microenvironment(TME)has been considered to play an indispensable role in the occurrence and development of tumours.The purpose of this study was to explore the role and mechanism of Yes-associated protein 1(YAP1)protein in prostate TME.Specifically,the possible mechanism of how YAP1 protein converts normal fibroblast(NF)into cancer associated fibroblast(CAF)in prostate cancer.Methods: Collected surgical specimens from clinical patients and divided them into benign prostatic hyperplasia patients and prostate cancer patients.The expression of YAP1 protein in stromal cells between the two groups of patients was detected by immunofluorescence method.The immunohistochemical method was used to detect the expression of stromal cells YAP1 again in the prostate cancer patient group,and the prostate cancer patient group was again divided into the YAP1 high expression group and the YAP1 low expression group according to the staining score.The chi-square test was used to calculate the relationship between the high and low expression of YAP1 in prostate cancer stromal cells and the pathological grade of prostate cancer,lymph node metastasis,and seminal vesicle invasion.Immunofluorescence and Western blot were used to detect the expression of relevant protein markers(?-SMA and FAP)in the cell line used.MTT and Transwell invasion experiments were used to test the conditioned medium of CAF and NF for changes in the proliferation and invasion ability of epithelial cells TrampC1 and RM1.Protein imprinting was used to detect the expression of phosphorylated YAP1 and phosphorylated SRC in the above four cell lines.Protein imprinting,co-immunoprecipitation,chromatin immunoprecipitation,and dual luciferase reporting experiments were used to analyze the interaction between the YAP1 / TEAD1 protein complex and SRC.The expression levels of cytoskeleton protein and actin in the downstream of SRC were detected by protein imprinting and q-PCR.The four kinds of cells were mixed with TrampC1 cells and planted in the skin of nude mice.The growth of subcutaneous xenografts was recorded.The expression of YAP1,SRC,?-SMA,Ki67 and MMP2 in each group of subcutaneously transplanted tumors was detected by protein imprinting and immunohistochemistry.Human primary hCAF and hNF were obtained through primary cell culture.Immunofluorescence and Western blot were used to detect the expression of ?-SMA and FAP in hCAF and hNF,and the relationship between YAP1 and SRC was verified,and the effect of hCAF on the proliferation and invasion of LNCaP and PC3.Results: Compared with benign prostatic hyperplasia tissue stromal cells,the expression level of YAP1 in prostate cancer tissue stromal cells was significantly up-regulated.The high expression of YAP1 in tumor stromal cells suggests that patients with prostate cancer have a higher degree of malignancy and are associated with a poor prognosis.When the expression level of YAP1 in CAF was knocked down,the levels of ?-SMA and FAP were also down-regulated;and when the expression level of YAP1 in NF was increased,the levels of ?-SMA and FAP were also up-regulated.BothCAF and NFoverexpress YAP1's conditioned medium enhanced the proliferation and invasion of tumor epithelial cells,and promoted the "epithelial-mesenchymal transition" of tumor cells.As a transcription cofactor,YAP1 forms a protein complex with the transcription factor TEAD1,which together regulates the transcription of SRC,and then affects the expression levels of cytoskeletal proteins and actin downstream of SRC.Therefore,the conversion from NF to CAF was achieved.Conclusion: Prostate cancer stromal cell YAP1 elevation indicates patients' worsening condition and poor prognosis.YAP1 can convert NF to CAF in the tumor microenvironment of prostate cancer,thereby promoting the growth and metastasis of prostate cancer.Silencing YAP1 in prostate tumor stromal cells can effectively inhibit tumor growth.The YAP1 protein in prostate tumor stroma can be used as a potential target for tumor diagnosis and treatment.