title: MicroRNA-21 is induced early in pancreatic ductal adenocarcinoma precursor lesions.
abstract: BACKGROUND
  Pancreatic ductal adenocarcinoma (PDAC) has the poorest overall prognosis among gastrointestinal cancers; however, curative resection in early-stage PDAC greatly improves survival rates, indicating the importance of early detection. Because abnormal microRNA production is commonly detected in cancer, we investigated noninvasive precursor pancreatic intraepithelial neoplasia (PanIN) lesions for microRNA production as a potential early biomarker of PDAC.
  
  
  METHODS
  Pathologists identified and classified ductal lesions. We extracted total RNA from laser-capture microdissected PanIN tissue samples from a conditional KRAS(G12D) mouse model (n = 29) or of human origin (n = 38) (KRAS is v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog). MicroRNA production was quantified by quantitative real-time PCR. Internal controls included 5S and U6 RNAs.
  
  
  RESULTS
  Production of microRNAs miR-21, miR-205, and miR-200 paralleled PanIN progression in the KRAS(G12D) mouse model, compared with microRNA production in samples of nonpathologic ducts. miR-21 demonstrated the highest relative concentrations in the precursor lesions. Interestingly, miR-205 and miR-21 up-regulation preceded phenotypic changes in the ducts. The production of microRNAs miR-21, miR-221, miR-222, and let-7a increased with human PanIN grade, with peak production occurring in hyperplastic PanIN-2/3 lesions. In situ hybridization analysis indicated miR-21 production to be concentrated in pathologic ductal cells. miR-21 production was regulated by KRAS(G12D) and epidermal growth factor receptor in PDAC-derived cell lines.
  
  
  CONCLUSIONS
  Aberrant microRNA production is an early event in the development of PanIN. Our findings indicate that miR-21 warrants further investigation as a marker for early detection of PDAC.
authors.affiliation: INSERM, U858, Institut de Médecine Moléculaire de Rangueil (I2MR), Université Toulouse III Paul Sabatier IFR150, Toulouse, France.
authors.forename: Maël Chalret
authors.initials: MC
authors.lastname: du Rieu
authors.forename: Jérôme
authors.initials: J
authors.lastname: Torrisani
authors.forename: Janick
authors.initials: J
authors.lastname: Selves
authors.forename: Talal
authors.initials: T
authors.lastname: Al Saati
authors.forename: Anny
authors.initials: A
authors.lastname: Souque
authors.forename: Marlène
authors.initials: M
authors.lastname: Dufresne
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tsongalis
authors.forename: Arief A
authors.initials: AA
authors.lastname: Suriawinata
authors.forename: Nicolas
authors.initials: N
authors.lastname: Carrère
authors.forename: Louis
authors.initials: L
authors.lastname: Buscail
authors.forename: Pierre
authors.initials: P
authors.lastname: Cordelier
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics*; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs