Identification of novel miR-21 target proteins in multiple myeloma cells by quantitative proteomics.
Substantial evidence indicates that microRNA-21 (miR-21) is a key oncomiR in carcinogenesis and is significantly elevated in multiple myeloma (MM). In this study, we explored the role of miR-21 in human MM cells and searched for miR-21 targets. By knocking down the expression of endogenous miR-21 in U266 myeloma cells, we observed reduced growth, an arrested cell cycle, and increased apoptosis. To further understand its molecular mechanism in the pathogenesis of MM, we employed a SILAC (stable isotope labeling by amino acids in cell culture)-based quantitative proteomic strategy to systematically identify potential targets of miR-21. In total, we found that the expression of 178 proteins was up-regulated significantly by miR-21 inhibition, implying that they could be potential targets of miR-21. Among these, the protein inhibitor of activated STAT3 (PIAS3) was confirmed as a direct miR-21 target by Western blotting and reporter gene assays. We further demonstrated that miR-21 enhances the STAT3-dependent signal pathway by inhibiting the function of PIAS3 and that down-regulation of PIAS3 contributes to the oncogenic function of miR-21. This elucidation of the role of PIAS3 in the miR-21-STAT3 positive regulatory loop not only may shed light on the molecular basis of the biological effects of miR-21 observed in MM cells but also has direct implications for the development of novel anti-MM therapeutic strategies.
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
Qian
Q
Xiong
Qiu
Q
Zhong
Jia
J
Zhang
Mingkun
M
Yang
Chongyang
C
Li
Peng
P
Zheng
Li-Jun
LJ
Bi
Feng
F
Ge
D017209:Apoptosis / Q000235:genetics; D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D007553:Isotope Labeling; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D009101:Multiple Myeloma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics / Q000378:metabolism; D020543:Proteome / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D015203:Reproducibility of Results; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D018832:Molecular Chaperones; C484745:PIAS3 protein, human; D050828:Protein Inhibitors of Activated STAT; D020543:Proteome; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human