title: MicroRNA-34a modulates chemosensitivity of breast cancer cells to adriamycin by targeting Notch1.
abstract: OBJECTIVE
  MicroRNA-34a (miR-34a) as a tumor suppressor has been reported in many other studies. However, its role in modulating the sensitivity of breast cancer cells to adriamycin (ADR) remains unclear. The aim of this study is to evaluate the role of miR-34a in the sensitivity of breast cancer cells to ADR.
  
  
  METHODS
  The role of miR-34a in breast cancer cells was detected using MTT assay, flow cytometry assay, real-time PCR and Western blot, etc. The association of miR-34a and Notch1 was analyzed by dual-luciferase reporter assay and Notch1-siRNA technology. Real-time PCR assay was performed to test the expression of miR-34a and Notch1 in 38 selective breast cancer tissue samples.
  
  
  RESULTS
  Ectopic overexpression of miR-34a could sensitize MCF-7 breast cancer cells to ADR. MiR-34a mimic could inhibit the luciferase activity of the construct containing wild-type 3' UTR of Notch1 in MCF-7/ADR cells. Notch1-siRNA could partially reverse the effect of miR-34a inhibitor in inducing chemoresistance of MCF-7 cells to ADR. Further, there was an inverse association between Notch1 and miR-34a expression in breast cancer.
  
  
  CONCLUSIONS
  Dysregulation of miR-34a plays critical roles in the acquired ADR resistance of breast cancer, at least in part via targeting Notch1.
authors.affiliation: Department of Oncology, Xuzhou Medical College, Jiangsu, PR China.
authors.forename: Xiu-juan
authors.initials: XJ
authors.lastname: Li
authors.forename: Ming-hua
authors.initials: MH
authors.lastname: Ji
authors.forename: Shan-liang
authors.initials: SL
authors.lastname: Zhong
authors.forename: Quan-bing
authors.initials: QB
authors.lastname: Zha
authors.forename: Jin-jin
authors.initials: JJ
authors.lastname: Xu
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Zhao
authors.forename: Jin-hai
authors.initials: JH
authors.lastname: Tang
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001483:Base Sequence; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020360:Neoadjuvant Therapy; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051881:Receptor, Notch1 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D000903:Antibiotics, Antineoplastic; C522425:MIRN34 microRNA, human; D035683:MicroRNAs; C497761:NOTCH1 protein, human; D034741:RNA, Small Interfering; D051881:Receptor, Notch1; D004317:Doxorubicin