title: MicroRNA-574-3p, identified by microRNA library-based functional screening, modulates tamoxifen response in breast cancer.
abstract: Most primary breast cancers express estrogen receptor α and can be treated via endocrine therapy using anti-estrogens such as tamoxifen; however, acquired endocrine resistance is a critical issue. To identify tamoxifen response-related microRNAs (miRNAs) in breast cancer, MCF-7 cells infected with a lentiviral miRNA library were treated with 4-hydroxytamoxifen (OHT) or vehicle for 4 weeks, and the amounts of individual miRNA precursors that had integrated into the genome were evaluated by microarray. Compared to the vehicle-treated cells, 5 'dropout' miRNAs, which were downregulated in OHT-treated cells, and 6 'retained' miRNAs, which were upregulated in OHT-treated cells, were identified. Of the dropout miRNAs, we found that miR-574-3p expression was downregulated in clinical breast cancer tissues as compared with their paired adjacent tissues. In addition, anti-miR-574-3p reversed tamoxifen-mediated suppression of MCF-7 cell growth. Clathrin heavy chain (CLTC) was identified as a miR-574-3p target gene by in silico algorithms and luciferase reporter assay using the 3' untranslated region of CLTC mRNA. Interestingly, loss and gain of miR-574-3p function in MCF-7 cells causes CLTC to be upregulated and downregulated, respectively. These results suggest that functional screening mediated by miRNA libraries can provide new insights into the genes essential for tamoxifen response in breast cancer.
authors.affiliation: 1] Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan [2] Department of Obstetrics and Gynecology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ujihira
authors.affiliation: Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Departments of Pathology and Histotechnology, Tohoku University, Graduate School of Medicine, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: 1] Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan [2] Departments of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan [3] Departments of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yamaga
authors.affiliation: Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
authors.forename: W
authors.initials: W
authors.lastname: Sato
authors.affiliation: Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Horie-Inoue
authors.affiliation: Department of Breast Oncology, International Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shigekawa
authors.affiliation: Department of Breast Oncology, International Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Osaki
authors.affiliation: Department of Breast Oncology, International Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saeki
authors.affiliation: Division of Cancer Differentiation, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: Department of Obstetrics and Gynecology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takeda
authors.affiliation: 1] Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan [2] Departments of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan [3] Departments of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Inoue
mesh_terms: D020413:3' Untranslated Regions; D000465:Algorithms; D018931:Antineoplastic Agents, Hormonal / Q000633:toxicity*; D001483:Base Sequence; D001665:Binding Sites; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D002966:Clathrin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects*; D005260:Female; D015723:Gene Library; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D016415:Sequence Alignment; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000633:toxicity; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D020413:3' Untranslated Regions; D018931:Antineoplastic Agents, Hormonal; D002966:Clathrin; C558811:MIRN574 microRNA, human; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D013629:Tamoxifen; C016601:afimoxifene