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Xiong Q.,CAS Wuhan Institute of Hydrobiology | Zhong Q.,Antituberculosis Research Institute of Guangdong Province | Zhang J.,CAS Wuhan Institute of Hydrobiology | Zhang J.,CAS Institute of Biophysics | And 5 more authors.
Journal of Proteome Research | Year: 2012

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. © 2012 American Chemical Society. Source


Zheng P.,CAS Wuhan Institute of Hydrobiology | Zhong Q.,Antituberculosis Research Institute of Guangdong Province | Xiong Q.,CAS Wuhan Institute of Hydrobiology | Yang M.,CAS Wuhan Institute of Hydrobiology | And 5 more authors.
Journal of Proteomics | Year: 2012

Signal transducers and activators of transcription 3 (Stat3) has been reported to be involved in the pathogenesis of various human diseases and is constitutively active in human multiple myeloma (MM) U266 cells. The Stat3-regulated mechanisms involved in these processes, however, are not fully defined. To further understand the regulation of Stat3 activity, we performed a systematic proteomic analysis of Stat3 interacting proteins in U266 cells. This analysis, termed quantitative immunoprecipitation combined with knockdown (QUICK), combines RNAi, stable isotope labeling with amino acids in cell culture (SILAC), immunoprecipitation, and quantitative MS. As a result, quantitative mass spectrometry analysis allowed us to distinguish specific Stat3 interacting proteins from background proteins and led to the identification of a total of 38 proteins. Three Stat3 interacting proteins - 14-3-3ζ, PRKCB and Hsp90 - were further confirmed by reciprocal co-immunoprecipitations and surface plasmon resonance (SPR) analysis. Our results therefore not only uncover a number of Stat3 interacting proteins that possess a variety of cellular functions, but also provide new insight into the mechanisms that regulate Stat3 activity and function in MM cells. © 2011 Elsevier B.V. Source


Sun Y.,Applied Genomics | Sun Y.,Hong Kong University of Science and Technology | Li S.,Southern Medical University | Zhou L.,Southern Medical University | And 10 more authors.
Applied Microbiology and Biotechnology | Year: 2014

Rapid detection of drug-resistant Mycobacterium tuberculosis is critical to the effective early treatment and prevention of the transmission of tuberculosis. However, conventional drug susceptibility tests for M. tuberculosis require up to several weeks. In the present study, the One Label Extension genotyping method was adapted for rapid detection of drug resistance-associated sequence variations in six genes of M. tuberculosis, viz. rpoB, rpsL, rrs, embB, katG, or inhA. The method utilizes polymerase chain reaction amplified fragments of the drug resistant genes as reaction templates, and proceeds with template-directed primer extension incorporating a fluorescence-labeled nucleotide, which is then measured by fluorescence polarization. A total of 121 M. tuberculosis isolates from clinical sputum specimens were examined by this genotyping method and verified by direct sequencing of polymerase chain reaction amplicons harboring previously reported mutational sites associated with M. tuberculosis drug resistance. Based on phenotyping results obtained from microbiology-based drug susceptibility tests, the sensitivity, specificity, and test efficiency estimated for One Label Extension assays were respectively 83.9 %, 95.5 %, and 92.4 % with ropB in rifampin resistance, 67.3 %, 97.1 %, and 84.3 % with rpsL and rrs in streptomycin resistance, 60.0 %, 96.0 %, and 91.4 % with embB in ethambutol resistance, 68.4 %, 94.9 %, and 86.3 % with inhA and katG in isoniazid resistance, and 74.1 %, 98.9 %, and 93.2 % in multiple drug resistance defined as resistance to at least both isoniazid and rifampin. In conclusion, examination of clinical sputum specimens by One Label Extension based genotyping provides a valid method for the rapid molecular detection of drug-resistant M. tuberculosis. © 2014 Springer-Verlag. Source

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