title: Natriuretic peptide receptor a as a novel target for prostate cancer.
abstract: BACKGROUND
  The receptor for the cardiac hormone atrial natriuretic peptide (ANP), natriuretic peptide receptor A (NPRA), is expressed in cancer cells, and natriuretic peptides have been implicated in cancers. However, the direct role of NPRA signaling in prostate cancer remains unclear.
  
  
  RESULTS
  NPRA expression was examined by western blotting, RT-PCR and immunohistochemistry. NPRA was downregulated by transfection of siRNA, shRNA and NPRA inhibitor (iNPRA). Antitumor efficacy of iNPRA was tested in mice using a TRAMP-C1 xenograft. Here, we demonstrated that NPRA is abundantly expressed on tumorigenic mouse and human prostate cells, but not in nontumorigenic prostate epithelial cells. NPRA expression showed positive correlation with clinical staging in a human PCa tissue microarray. Down-regulation of NPRA by siNPRA or iNPRA induced apoptosis in PCa cells. The mechanism of iNPRA-induced anti-PCa effects was linked to NPRA-induced expression of macrophage migration inhibitory factor (MIF), a proinflammatory cytokine over-expressed in PCa and significantly reduced by siNPRA. Prostate tumor cells implanted in mice deficient in atrial natriuretic peptide receptor A (NPRA-KO) failed to grow, and treatment of TRAMP-C1 xenografts with iNPRA reduced tumor burden and MIF expression. Using the TRAMP spontaneous PCa model, we found that NPRA expression correlated with MIF expression during PCa progression.
  
  
  CONCLUSIONS
  Collectively, these results suggest that NPRA promotes PCa development in part by regulating MIF. Our findings also suggest that NPRA is a potential prognostic marker and a target for PCa therapy.
authors.affiliation: Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Wang
authors.forename: Payal
authors.initials: P
authors.lastname: Raulji
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Mohapatra
authors.forename: Ronil
authors.initials: R
authors.lastname: Patel
authors.forename: Gary
authors.initials: G
authors.lastname: Hellermann
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Kong
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Vera
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Meyer-Siegler
authors.forename: Domenico
authors.initials: D
authors.lastname: Coppola
authors.forename: Subhra
authors.initials: S
authors.lastname: Mohapatra
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D018450:Disease Progression; D015536:Down-Regulation; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D008263:Macrophage Migration-Inhibitory Factors / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000503:physiopathology*; D034741:RNA, Small Interfering / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D047368:Tumor Burden / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D008263:Macrophage Migration-Inhibitory Factors; D010455:Peptides; D034741:RNA, Small Interfering; D017461:Receptors, Atrial Natriuretic Factor; C091715:atrial natriuretic factor receptor A; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human