title: MicroRNA-30a downregulation contributes to chemoresistance of osteosarcoma cells through activating Beclin-1-mediated autophagy.
abstract: Autophagy has been recognized as an important element of tumor cell migration, invasion, and chemo-resistance, and our previous results showed that Beclin-1-mediated autophagy contributed to osteosarcoma chemoresistance. However, the regulating mechanism of autophagy is still unclear. In this study, our aim was to clarify microRNA (miRNA)-related mechanisms underlying Beclin-1-mediated autophagy followed by chemotherapy in osteosarcoma. First, miRNA screening using qRT-PCR identified that miR-30a was significantly reduced in Dox-resistant osteosarcoma cells. Second, the autophagy activity in Dox-resistant increased while miR-30a expression reduced after chemotherapy agents as indicated by the enhanced expression of Beclin-1, the increased conversion of microtubule-associated protein LC3-I to LC3-II. Furthermore, overexpression of miR-30a significantly promoted chemotherapy-induced apoptosis and reduced autophagy activity responding to chemotherapy. Moreover, rapamycin, an autophagy promoter was able to partly reverse the effect of miR-30a and Luciferase reporter assay identified that miR-30a directly binds to the 3'-UTR of Beclin-1 gene, which further confirmed that miR-30a reduced chemoresistance via suppressing Beclin-1-mediated autophagy. Collectively these results indicate miR-30a and its downstream target gene Beclin-1 can be used in treatment of osteosarcoma chemo-resistance in the future.
authors.affiliation: Department of Orthopaedic Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Ruida
authors.initials: R
authors.lastname: Xu
authors.affiliation: Department of Orthopaedic Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Shuzhong
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Orthopaedic Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Haihong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Orthopaedic Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Lao
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis* / Q000235:genetics; D001343:Autophagy / Q000187:drug effects; D000071186:Beclin-1; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D020123:Sirolimus / Q000008:administration & dosage
chemical_list: D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C546086:MIRN30b microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; D004317:Doxorubicin; D020123:Sirolimus