title: Epigenetic silencing of miR-130b in ovarian cancer promotes the development of multidrug resistance by targeting colony-stimulating factor 1.
abstract: OBJECTIVE
  The purpose of this study was to investigate the role of miR-130b in the development of multidrug-resistant ovarian cancer.
  
  
  METHODS
  The expression of miR-130b was assessed in ovarian tissues and cell lines by qRT-PCR. In vitro, miR-130b level was manipulated by transfection with mimics or inhibitors. Methylation level of miR-130b was evaluated by quantitative methylation-specific PCR (qMSP). CSF-1 expression in ovarian tissues and cells was determined by qRT-PCR, immunohistochemistry and ELISA, respectively. CSF-1 regulated by miR-130b was detected using Dual Luciferase Reporter system.
  
  
  RESULTS
  Down-regulation of miR-130b in ovarian cancer was associated with FIGO III-IV clinical stages and poorer histological differentiation. MiR-130b was downregulated in multidrug resistant ovarian cancer cells. Restoration of miR-130b expression could sensitize these cells to anticancer drugs. MiR-130b hypermethylation was found in ovarian cancer tissues as well as in drug resistant cell lines and the methylation level was negatively correlated with its expression. Demethylation with 5-aza-CdR led to reactivation of miR-130b expression in drug resistant ovarian cancer cell lines concomitant with increase of sensibility to cisplatin and taxol. CSF-1 expression was negatively associated with miR-130b level in ovarian tissues and cell lines. Luciferase assay validated CSF-1 is a direct target of miR-130b. Knock-down of CSF-1 sensitized ovarian cancer cells to anticancer drugs and could partially attenuate the resistance inducing effect of miR-130b inhibitors.
  
  
  CONCLUSIONS
  Downregulation of miR-130b promotes the development of multidrug resistant ovarian cancer partially by targeting the 3'-UTR of CSF-1, and the silencing of miR-130b may be mediated by DNA methylation.
authors: Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
authors: Chun
authors: C
authors: Yang
authors: Jing
authors: J
authors: Cai
authors: Qiyue
authors: Q
authors: Wang
authors: Huijuan
authors: H
authors: Tang
authors: Jin
authors: J
authors: Cao
authors: Liying
authors: L
authors: Wu
authors: Zehua
authors: Z
authors: Wang
mesh_terms: D045744:Cell Line, Tumor; D018899:CpG Islands; D003596:Cytosine / Q000378:metabolism; D019175:DNA Methylation; D015536:Down-Regulation; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D057890:Epigenomics; D005260:Female; D020868:Gene Silencing; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics; D014162:Transfection
chemical_list: C554019:MIRN130 microRNA, human; D035683:MicroRNAs; D034741:RNA, Small Interfering; D016173:Macrophage Colony-Stimulating Factor; D003596:Cytosine