title: Essential role of NADPH oxidase-dependent reactive oxygen species generation in regulating microRNA-21 expression and function in prostate cancer.
abstract: OBJECTIVE
  Oncogenic microRNAs (miRs) promote tumor growth and invasiveness. One of these, miR-21, contributes to carcinogenesis in prostate and other cancers. In the present study, we tested the hypothesis that NADPH oxidase-dependent reactive oxygen species (ROS) regulate the expression and function of miR-21 and its target proteins, maspin and programmed cell death 4 (PDCD4), in prostate cancer cells.
  
  
  RESULTS
  The highly aggressive androgen receptor negative PC-3M-MM2 prostate cancer cells demonstrated high expression of miR-21 and p47(phox) (an essential subunit of NADPH oxidase). Using loss-of-function strategy, we showed that transfection of PC-3M-MM2 cells with anti-miR-21- and p47(phox) siRNA (si-p47(phox)) led to reduced expression of miR-21 with concurrent increase in maspin and PDCD4, and decreased the invasiveness of the cells. Tail-vein injections of anti-miR-21- and si-p47(phox)-transfected PC-3M-MM2 cells in severe combined immunodeficient mice reduced lung metastases. Clinical samples from patients with advanced prostate cancer expressed high levels of miR-21 and p47(phox), and low expression of maspin and PDCD4. Finally, ROS activated Akt in these cells, the inhibition of which reduced miR-21 expression.
  
  
  METHODS
  The levels of NADPH oxidase-derived ROS are high in prostate cancer cells, which have been shown to be involved in their growth and migration. This study demonstrates that ROS produced by this pathway is essential for the expression and function of an onco-miR, miR-21, in androgen receptor-negative prostate cancer cells.
  
  
  CONCLUSIONS
  These data demonstrate that miR-21 is an important target of ROS, which contributes to the highly invasive and metastatic phenotype of prostate cancer cells.
authors.affiliation: 1 Department of Pharmacology, Southern Illinois University School of Medicine , Springfield, Illinois.
authors.forename: Sarvesh
authors.initials: S
authors.lastname: Jajoo
authors.forename: Debashree
authors.initials: D
authors.lastname: Mukherjea
authors.forename: Tejbeer
authors.initials: T
authors.lastname: Kaur
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Sheehan
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sheth
authors.forename: Vikrant
authors.initials: V
authors.lastname: Borse
authors.forename: Leonard P
authors.initials: LP
authors.lastname: Rybak
authors.forename: Vickram
authors.initials: V
authors.lastname: Ramkumar
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D016513:Mice, SCID; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009361:Neoplasm Invasiveness / Q000235:genetics; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015843:Serpins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D051017:Apoptosis Regulatory Proteins; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; C114487:PDCD4 protein, human; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D017382:Reactive Oxygen Species; C085344:SERPIN-B5; D015843:Serpins; D019255:NADPH Oxidases