title: Reduced Let-7a Is Associated with Chemoresistance in Primary Breast Cancer.
abstract: Chemotherapy resistance remains an important problem in the breast cancer clinic. The ability to predict the patients who would respond to a distinct therapy would help to optimize tailored treatment options. miRNAs can mediate a number of genes in response to drug-induced acute cellular stress. Several studies suggest that let-7 miRNA may be involved in the chemosensitivity of cancer cell lines in vitro. However, it is not known whether this phenomenon occurs in clinical breast tumors. The present study showed that lower let-7a expression was associated with epirubicin resistance in primary breast tumors. Moreover, upregulation of let-7a expression sensitized resistant breast tumor cell lines to epirubicin by enhancing cellular apoptosis in vitro. Collectively, these findings indicate that lower expression of let-7a miRNA can induce chemoresistance in breast cancer by enhancing cellular apoptosis and suggest that let-7a may be used as a therapeutic target to modulate epirubicin-based chemotherapy resistance.
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China; Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Jiannan
authors.initials: J
authors.lastname: Wu
authors.affiliation: Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Shunrong
authors.initials: S
authors.lastname: Li
authors.affiliation: Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Weijuan
authors.initials: W
authors.lastname: Jia
authors.affiliation: Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Heran
authors.initials: H
authors.lastname: Deng
authors.affiliation: Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Liling
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China; Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Fengyan
authors.initials: F
authors.lastname: Yu
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China; Depart of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun-Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Fengxi
authors.initials: F
authors.lastname: Su
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D015251:Epirubicin / Q000494:pharmacology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis*; D012334:RNA, Neoplasm / Q000096:biosynthesis*
chemical_list: D035683:MicroRNAs; D012334:RNA, Neoplasm; C487931:mirnlet7 microRNA, human; D015251:Epirubicin