title: Activation of nuclear factor κB pathway and downstream targets survivin and livin by SHARPIN contributes to the progression and metastasis of prostate cancer.
abstract: BACKGROUND
  Nuclear factor κB (NFκB) signaling is strongly associated with tumor progression, and studies have shown that SHANK-associated RH domain interacting protein (SHARPIN) is crucial for NFκB pathway activation. However, the expression and functions of SHARPIN in prostate cancer (PCa) have not yet been defined.
  
  
  METHODS
  The expression of SHARPIN in PCa cell lines and tissues was evaluated with western blotting, quantitative real-time polymerase chain reaction, and immunohistochemistry. After SHARPIN was silenced in the PCa cell lines, western blots were used to confirm that SHARPIN physically associated with components of the NFκB pathway and the downstream targets (survivin and livin). The functions of SHARPIN in cell proliferation, migration, and invasion in vitro were measured with 5-(3-carboxymethoxyphenyl)-2-(4,5-dimenthylthiazoly)-3-(4-sulfophenyl)tetrazolium, inner salt (MTS), Transwell, and invasion assays, respectively. Flow cytometry was employed to evaluate cell apoptosis. Furthermore, tumorigenesis in vivo was examined with tumorigenicity assays.
  
  
  RESULTS
  SHARPIN expression was upregulated in PCa cell lines and tissues. The knockdown of SHARPIN or incubation with Bay 11-7082 (an NFκB inhibitor) led to dramatically decreased levels of phosphorylated IκBα and phosphorylated p65 in comparison with the control group. Downregulation of survivin and livin due to SHARPIN inhibition was attributable to transcriptional repression (P < .05). Decreases in cell viability, migration, invasion, and survival with a higher sensitivity to docetaxel in vitro and with repressed tumorigenesis in vivo were observed upon SHARPIN silencing, and this was consistent with the results from inhibition of the NFκB pathway and its downstream targets.
  
  
  CONCLUSIONS
  The current study demonstrates that overexpression of SHARPIN promotes activation of the NFκB pathway and downstream targets survivin and livin, which potentially contributes to PCa development.
authors.affiliation: Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China; Department of Urology, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hai
authors.initials: H
authors.lastname: Huang
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhou
authors.forename: Tao
authors.initials: T
authors.lastname: Du
authors.forename: Lexiang
authors.initials: L
authors.lastname: Zeng
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.forename: Jieqing
authors.initials: J
authors.lastname: Chen
authors.forename: Yiming
authors.initials: Y
authors.lastname: Lai
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Ganping
authors.initials: G
authors.lastname: Wang
authors.forename: Zhenghui
authors.initials: Z
authors.lastname: Guo
mesh_terms: D017209:Apoptosis / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D018450:Disease Progression; D006801:Humans; D007150:Immunohistochemistry; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction; D000077022:Survivin; D014162:Transfection; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D016328:NF-kappa B; C575183:SHARPIN protein, human; D000077022:Survivin; D014452:Ubiquitins
keywords: NFκB pathway; SHARPIN; chemotherapy; docetaxel; livin; prostate cancer; survivin