title: Let-7b-5p regulates proliferation and apoptosis in multiple myeloma by targeting IGF1R.
abstract: Multiple myeloma (MM) is the most common cause of death from hematological malignancy worldwide, and recent studies have revealed that let-7b-5p can play an inhibitory role in tumorigenesis. However, the role of let-7b-5p in MM still remains unclear. The aim of this study was to elucidate the molecular mechanisms by which let-7b-5p acts as a tumor suppressor in MM. Here, quantitative real-time polymerase chain reaction results showed that the expression of let-7b-5p was remarkably reduced in MM tissues and MM cell lines (RPMI-8226 and U266 cells). Furthermore, over-expression of let-7b-5p significantly suppressed RPMI-8226 cell proliferation and induced S/G2 cell cycle arrest and apoptosis. Luciferase reporter assay results demonstrated that insulin-like growth factor receptor 1 (IGF1R) was negatively regulated by let-7b-5p at the post-transcriptional level. The mRNA and protein levels of IGF1R in RPMI-8226 cells were down-regulated by let-7b-5p. Furthermore, the cell phenotype altered by let-7b-5p inhibitor can be rescued by IGF1R silencing (si-IGF1R). Taken together, our results demonstrated that let-7b-5p functions as a tumor suppressor in MM, suggesting that let-7b-5p may be a potential therapeutic target for MM.
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Honghai
authors.initials: H
authors.lastname: Xu
authors.affiliation: Xi'an Medical University, Xi'an 710021, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of the Faculty of Public Health, Medicine College of Xi'an Jiaotong University, Xi'an 710061, China guox@mail.xjtu.edu.cn.
authors.forename: Xiong
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Zongzhi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Zhenqun
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Yanhai
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Shizhang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Zhengming
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Orthopaedics, the Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an 710068, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Wang
mesh_terms: D020413:3' Untranslated Regions; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000235:genetics; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D017526:Receptor, IGF Type 1; D017451:Receptors, Somatomedin / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; C000597236:IGF1R protein, human; D035683:MicroRNAs; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D017451:Receptors, Somatomedin; C487931:mirnlet7 microRNA, human; D017526:Receptor, IGF Type 1
keywords: apoptosis; let-7b-5p; multiple myeloma; proliferation