The Role And Mechanism Of LINC00675 In The Development Of Castration Resistant Prostate Cancer

Prostate Cancer(PCa)is the most common malignant tumor among male population and one of the leading causes of cancer death.PCa is currently considered to be a hormone-dependent disease.Androgen deprivation therapy(ADT)is used as regular treatment,but still primary PCa would gradually progress to castration resistant prostate cancer(CRPC).Moreover,the mechanism of PCa and its effective treatment remains unclear to us.This study used two groups of androgen sensitive/insensitive cell lines and screened differentially expressed long non-coding RNAs(lncRNAs)by RNA-Seq,which were verified by qRT-PCR.Among those lncRNAs,LINC00675 was considered to be correlated with PCa through loss-of-function assays.We used several tissue sections of CRPC and primary PCa patients for RNAscope to clarify that LINC00675 was with higher expression level in CRPC tissues than in primary PCa tissues.Then the biological functions of LINC00675 were studied in vitro and in vivo.CCK-8,colony formation,cell cycle and cell migration assays were displayed,which indicated that LINC00675 could promote tumor cells progression.The results of subcutaneous tumor formation in BALB/c nude mice were consistent with those in vitro.Further studies revealed that LINC00675 affected the level of androgen receptor(AR)protein.By treatment with cycloheximide(CHX)and MG132,we found that LINC00675 could slow down AR ubiquitination.Endogenous and exogenous co-immunoprecipitation(co-IP)of AR and Ub with LINC00675 knocking down or overexpression confirmed the finding.Furthermore,LINC00675 decreased the binding of AR and its E3 ubiquitination enzyme MDM2.Finally,RNA pulldown and RIP coimmunoprecipitation assays were performed to determine the interaction between LINC00675 and AR and to explore their binding sites.In summary,LINC00675 plays as an oncogenic driver in the development of CRPC and can be used as a promising prognostic molecular marker.The LINC00675/AR/MDM2 complex provides a new therapeutic target for ADT of CRPC.