title: MicroRNAs reprogram normal fibroblasts into cancer-associated fibroblasts in ovarian cancer.
abstract: Cancer-associated fibroblasts (CAF) are a major constituent of the tumor stroma, but little is known about how cancer cells transform normal fibroblasts into CAFs. microRNAs (miRNA) are small noncoding RNA molecules that negatively regulate gene expression at a posttranscriptional level. Although it is clearly established that miRNAs are deregulated in human cancers, it is not known whether miRNA expression in resident fibroblasts is affected by their interaction with cancer cells. We found that in ovarian CAFs, miR-31 and miR-214 were downregulated, whereas miR-155 was upregulated when compared with normal or tumor-adjacent fibroblasts. Mimicking this deregulation by transfecting miRNAs and miRNA inhibitors induced a functional conversion of normal fibroblasts into CAFs, and the reverse experiment resulted in the reversion of CAFs into normal fibroblasts. The miRNA-reprogrammed normal fibroblasts and patient-derived CAFs shared a large number of upregulated genes highly enriched in chemokines, which are known to be important for CAF function. The most highly upregulated chemokine, CCL5, (C-C motif ligand 5) was found to be a direct target of miR-214. These results indicate that ovarian cancer cells reprogram fibroblasts to become CAFs through the action of miRNAs. Targeting these miRNAs in stromal cells could have therapeutic benefit.
  
  
  CONCLUSIONS
  The mechanism by which quiescent fibroblasts are converted into CAFs is unclear. The present study identifies a set of 3 miRNAs that reprogram normal fibroblasts to CAFs. These miRNAs may represent novel therapeutic targets in the tumor microenvironment.
authors.affiliation: Department of Obstetrics and Gynecology/Section of Gynecologic Oncology, The University of Chicago, Chicago, IL 60611, USA.
authors.forename: Anirban K
authors.initials: AK
authors.lastname: Mitra
authors.forename: Marion
authors.initials: M
authors.lastname: Zillhardt
authors.forename: Youjia
authors.initials: Y
authors.lastname: Hua
authors.forename: Payal
authors.initials: P
authors.lastname: Tiwari
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Murmann
authors.forename: Marcus E
authors.initials: ME
authors.lastname: Peter
authors.forename: Ernst
authors.initials: E
authors.lastname: Lengyel
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D014162:Transfection; D014183:Transplantation, Heterologous; D059016:Tumor Microenvironment
chemical_list: D035683:MicroRNAs