title: Let-7a inhibits growth and migration of breast cancer cells by targeting HMGA1.
abstract: Let-7 is one of the earliest discovered microRNAs (miRNAs) and has been reported to regulate self renewal and tumorigenicity of breast cancer cells. Let-7a is a member of this family and its function has not been fully characterized in breast cancer. First, total RNAs of breast cancer cells (MDA-MB-231, MCF-7), breast cancer tissues and corresponding adjacent normal tissues were extracted and used to detect let-7a expression by qRT-PCR. Secondly, the effects of let-7a on proliferation, colony formation, migration and invasion of breast cancer cells were assessed by in vitro cell culture experiments. Finally, western blotting was performed to demonstrate how let-7a regulated HMGA1 expression. We found that let-7a expression was significantly lower in breast cancer cells and breast cancer tissues compared to corresponding adjacent normal tissues. Cell proliferation, colony formation, migration and invasion were decreased after overexpression of let-7a in breast cancer cells and vice versa. Furthermore, we identified the high mobility group A1 (HMGA1) as a potential target gene of let-7a. Protein expression of the target gene was significantly downregulated in let-7a mimic transfected breast cancer cells and significantly upregulated in let-7a inhibitor transfected breast cancer cells. Our data suggest that let-7a plays an important role as a tumor suppressor gene by targeting HMGA1, which may open novel perspectives for clinical treatments against breast cancer.
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Kui
authors.initials: K
authors.lastname: Liu
authors.affiliation: The Second People's Hospital of Kunshan, Kunshan, Jiangsu 215300, P.R. China.
authors.forename: Chunfu
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Ding
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Tu
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Zhou
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Wenkai
authors.initials: W
authors.lastname: Qi
authors.affiliation: Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Huabiao
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Medicine, Jiangsu University, Jiangsu Key Laboratory of Clinical Laboratory Medicine, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Sun
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D025741:HMGA1a Protein / Q000235:genetics*; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000235:genetics*
chemical_list: D035683:MicroRNAs; C487931:mirnlet7 microRNA, human; D025741:HMGA1a Protein