title: Biological function and mechanism of miR-33a in prostate cancer survival and metastasis: via downregulating Engrailed-2.
abstract: OBJECTIVE
  Recent studies have identified Engrailed-2 (EN-2), a homeobox-containing transcription factor, as a candidate oncogene in prostate cancer (PC). Therapeutic targeting on EN-2, however, is limited because the mechanism underlying EN-2 overexpression in prostatic cancer cells is unknown. This study was to investigate the potential regulatory role of miR-33a on EN-2 expression and explore this signaling axis in ability of prostate cancer survival and metastasis.
  
  
  METHODS
  The relative expression of miR-33a and EN-2 in paired prostate cancer tissue and adjacent normal tissue as well as in prostate cancer cell lines, PC3 and DU145, was determined using quantitative real-time PCR or western blot, respectively. Cells survival, migration and invasion were evaluated by assays of MTT, TUNEL and Boyden chamber assays, respectively. Direct regulation of EN-2 by miR-33a was examined by luciferase reporter assay.
  
  
  RESULTS
  The data showed that miR-33a was upregulated and EN-2 was downregulated in both prostate cancer tissue and prostate cancer cells. miR-33a overexpression suppresses prostate cancer cell survival and metastasis. miR-33a can directly act on EN-2 expression by binding to 3'UTR of its mRNA. Also, miR-33a negatively regulated EN-2 mRNA and protein expression. In pcDNA-EN-2 and miR-33a mimic co-transfected PC3 and DU145 cells, EN-2 overexpression reverses the anti-cell survival and metastasis actions of miR-33a overexpression. The pivotal role of miR-33a in inhibiting prostate tumor growth was confirmed in xenograft models of prostate cancer.
  
  
  CONCLUSIONS
  Our data suggest that the functional interaction of miR-33a and EN-2 is involved in tumorigenesis of prostate cancer. Also in this process EN-2 serves as a negative responder for miR-33a.
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhengzhou University, Institute of Urology of Henan Province, No 1, Jianshe East Road, Zhengzhou, 450052, Henan, China. li_rechee@163.com.
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhengzhou University, Institute of Urology of Henan Province, No 1, Jianshe East Road, Zhengzhou, 450052, Henan, China.
authors.forename: S
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Neonatel Intensive Care Unit, Zhengzhou First People's Hospital, Zhengzhou, 450004, China.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Pharmacy, Zhengzhou University, Zhengzhou, 450001, China.
authors.forename: G
authors.initials: G
authors.lastname: Hou
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhengzhou University, Institute of Urology of Henan Province, No 1, Jianshe East Road, Zhengzhou, 450052, Henan, China.
authors.forename: L
authors.initials: L
authors.lastname: Yan
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhengzhou University, Institute of Urology of Henan Province, No 1, Jianshe East Road, Zhengzhou, 450052, Henan, China.
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhengzhou University, Institute of Urology of Henan Province, No 1, Jianshe East Road, Zhengzhou, 450052, Henan, China.
authors.forename: B
authors.initials: B
authors.lastname: Qiao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D064593:Heterografts; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology*; D060888:Real-Time Polymerase Chain Reaction; D000099266:Engrailed 2 Protein
chemical_list: D018398:Homeodomain Proteins; D035683:MicroRNAs; D009419:Nerve Tissue Proteins; D000099266:Engrailed 2 Protein; C550416:MIRN33a microRNA, human
keywords: Engrailed-2; MiR-33a; Migration; Prostate cancer