title: MicroRNA-26a inhibits proliferation by targeting high mobility group AT-hook 1 in breast cancer.
abstract: OBJECTIVE
  To investigate the crucial role of miR-26a in breast cancer and to validate whether miR-26a could regulate proliferation of breast cancer cells by targeting high mobility group AT-hook 1 (HMGA1).
  
  
  METHODS
  Reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the expression levels of miR-26a in breast cancer and adjacent non-cancerous breast tissues. MTT, cell migration and invasion assay were carried out to characterize the miR-26a function. Finally, to validate the target gene of miR-26a, luciferase reporter assay was employed, followed by RT-PCR and Western blot confirmation.
  
  
  RESULTS
  Compared with normal tissues, a significant down-regulation of miR-26a expression was observed in breast cancer tissues (P=0.002). miR-26a suppresses MDA-MB-231 and Mcf-7 breast cancer cell lines proliferation and motility. The luciferase activity was significantly decreased after co-transfection with psiCHECK-2/HMGA1 3'-UTR and miR-26a mimics in comparison with control cells, and qRT-PCR and Western blotting analysis found that HMGA1 expression at the mRNA and protein levels decreased in the miR-26a mimic-treatment group relative to NC. MTT assay showed that down regulation of HMGA1 by siRNA could significantly enhance the tumor-suppressive effect of miR-26a (P < 0.05).
  
  
  CONCLUSIONS
  The results of the present study indicate that miR-26a may be associated with human breast carcinogenesis, which inhibits tumor cell proliferation by targeting HMGA1.
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Xi-Xue
authors.initials: XX
authors.lastname: Zhao
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Qing-Zhong
authors.initials: QZ
authors.lastname: Yuan
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Dong-Po
authors.initials: DP
authors.lastname: Mu
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Di-Wen
authors.initials: DW
authors.lastname: Sun
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Qing-Ao
authors.initials: QA
authors.lastname: Bo
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Guo-Zheng
authors.initials: GZ
authors.lastname: Pan
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Li
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Cui
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Peng-Peng
authors.initials: PP
authors.lastname: Ding
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Fa-Ping
authors.initials: FP
authors.lastname: You
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Long
authors.initials: L
authors.lastname: Hao
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Ming-Xin
authors.initials: MX
authors.lastname: Wang
authors.affiliation: Department of Hepatobiliary and Breast Surgery, Shengli Oilfield Central Hospital Dongying 257034, Shandong, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D049109:Cell Proliferation / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D024003:HMGA Proteins / Q000096:biosynthesis*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D024003:HMGA Proteins; D035683:MicroRNAs; C528163:MIRN26 microRNA, human
keywords: Breast cancer; HMGA1; miR-26a; proliferation