title: Clinical correlations of miR-21 expression in colorectal cancer patients and effects of its inhibition on DLD1 colon cancer cells.
abstract: OBJECTIVE
  MicroRNA-21 (miR-21) is one of the miRNAs that are frequently and highly overexpressed in tumor tissue of colorectal cancer (CRC) patients; however, only a little is known about its functional role in CRC.
  
  
  METHODS
  We examined the expression level of miR-21 in 44 paired samples of tumoral and non-tumoral colon tissues diagnosed for CRC using TaqMan real-time PCR method. Furthermore, we used miR-21 inhibitor (anti-miR-21) to transient knockdown of miR-21 in DLD-1 colon cancer cells and examined the effects of miR-21 silencing on viability, apoptosis, chemosensitivity, cell cycle, and migration of DLD1 cells.
  
  
  RESULTS
  The expression levels of miR-21 were significantly increased in CRC tumor tissue (P < 0.0001). Significant differences in miR-21 levels were observed also between CRC tissues of patients with CRC in different clinical stages: I vs. II (P = 0.033) and I vs. IV (P = 0.021). Kaplan-Meier analysis proved that the miR-21 expression levels are correlated to shorter overall survival of CRC patients (P = 0.0341). MiR-21 silencing in DLD1 cell line had no effect on the cell viability; however, when combined with chemotherapeutics (5-FU, L-OHP, and SN38), it contributed to the decrease of cell viability. Suppression of miR-21 decreased cell migration ability of DLD-1 cells by nearly 30 % (P = 0.016).
  
  
  CONCLUSIONS
  We have confirmed the overexpression of miR-21 in CRC samples and its correlation with advanced disease and shorter overall survival. These findings could be described in part by the fact that CRC cells with increased expression of miR-21 have higher migration ability.
authors.affiliation: Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic.
authors.forename: Petra
authors.initials: P
authors.lastname: Faltejskova
authors.forename: Andrej
authors.initials: A
authors.lastname: Besse
authors.forename: Sabina
authors.initials: S
authors.lastname: Sevcikova
authors.forename: Lenka
authors.initials: L
authors.lastname: Kubiczkova
authors.forename: Marek
authors.initials: M
authors.lastname: Svoboda
authors.forename: Jan
authors.initials: J
authors.lastname: Smarda
authors.forename: Igor
authors.initials: I
authors.lastname: Kiss
authors.forename: Rostislav
authors.initials: R
authors.lastname: Vyzula
authors.forename: Ondrej
authors.initials: O
authors.lastname: Slaby
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged
chemical_list: D000970:Antineoplastic Agents; C524940:MIRN21 microRNA, human; D035683:MicroRNAs