Down-Regulation of hsa-miR-10a in Chronic Myeloid Leukemia CD34(+) Cells Increases USF2-Mediated Cell Growth
ABSTRACT MicroRNAs (miRNA) are small noncoding, single-stranded RNAs that inhibit gene expression at a posttranscriptional level, whose abnormal expression has been described in different tumors. The aim of our study was to identify miRNAs potentially implicated in chronic myeloid leukemia (CML). We detected an abnormal miRNA expression profile in mononuclear and CD34(+) cells from patients with CML compared with healthy controls. Of 157 miRNAs tested, hsa-miR-10a, hsa-miR-150, and hsa-miR-151 were down-regulated, whereas hsa-miR-96 was up-regulated in CML cells. Down-regulation of hsa-miR-10a was not dependent on BCR-ABL1 activity and contributed to the increased cell growth of CML cells. We identified the upstream stimulatory factor 2 (USF2) as a potential target of hsa-miR-10a and showed that overexpression of USF2 also increases cell growth. The clinical relevance of these findings was shown in a group of 85 newly diagnosed patients with CML in which expression of hsa-miR-10a was down-regulated in 71% of the patients, whereas expression of USF2 was up-regulated in 60% of the CML patients, with overexpression of USF2 being significantly associated with decreased expression of hsa-miR-10a (P = 0.004). Our results indicate that down-regulation of hsa-miR-10a may increase USF2 and contribute to the increase in cell proliferation of CML implicating a miRNA in the abnormal behavior of CML.
- SourceAvailable from: Alexander Vlassov
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- "Table S2. miRNA-target interactions demonstrated by reporter assay [8,17,47-112]. Table S3. "
ABSTRACT: MicroRNAs (miRNAs) bind to mRNAs and target them for translational inhibition or transcriptional degradation. It is thought that most miRNA-mRNA interactions involve the seed region at the 5[prime] end of the miRNA. The importance of seed sites is supported by experimental evidence, although there is growing interest in interactions mediated by the central region of the miRNA, termed centered sites. To investigate the prevalence of these interactions, we apply a biotin pull-down method to determine the direct targets of ten human miRNAs, including four isomiRs that share centered sites, but not seeds, with their canonical partner miRNAs. We confirm that miRNAs and their isomiRs can interact with hundreds of mRNAs, and that imperfect centered sites are common mediators of miRNA-mRNA interactions. We experimentally demonstrate that these sites can repress mRNA activity, typically through translational repression, and are enriched in regions of the transcriptome bound by AGO. Finally, we show that the identification of imperfect centered sites is unlikely to be an artefact of our protocol caused by the biotinylation of the miRNA. However, the fact that there was a slight bias against seed sites in our protocol may have inflated the apparent prevalence of centered site-mediated interactions. Our results suggest that centered site-mediated interactions are much more frequent than previously thought. This may explain the evolutionary conservation of the central region of miRNAs, and has significant implications for decoding miRNA-regulated genetic networks, and for predicting the functional effect of variants that do not alter protein sequence.Genome biology 03/2014; 15(3):R51. DOI:10.1186/gb-2014-15-3-r51 · 10.81 Impact Factor
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- "For example, miR-10a is deregulated in head and neck squamous cell carcinomas and also in hepatocellular carcinoma , . Furthermore, in human cervical cancer, miR-10a serves as an oncogene by regulating CHL1 ; down-regulation of miR-10a in chronic myeloid leukemia promotes CD34+ cells proliferation . However, the function of miR-10a and the mechanism underlying gastric carcinogenesis remain unclear. "
ABSTRACT: MicroRNAs act as posttranscriptional regulators of gene expression in many biological processes. Their deregulations occur commonly in gastric cancer (GC). Although DNA methylation constitutes an important mechanism for microRNA deregulation in cancer, this field largely remains unexplored. Total RNA was extracted from the tissues of 100 patients with GC and four gastric cancer cell lines. The expression levels of miR-10a were determined by real-time PCR with specific TaqMan probes. Moreover, a functional analysis of miR-10a in regulating cell proliferation, migration and invasion was performed. Subsequently, quantitative methylation-specific PCR (qMSP) was used to detect the DNA methylation status in the CpG islands upstream of miR-10a. In this study, we found that the expression of miR-10a in GC cells was lower than that in normal cells, which was due to the hypermethylation of the CpG islands upstream of miR-10a. We also validated the slightly lower expression of miR-10a in GC tissues than their adjacent non-neoplastic tissues in 100 GC patients and confirmed the hypermethylation of CpG islands upstream of miR-10a in some patients. Furthermore, re-introduction of miR-10a into GC cells was able to inhibit cell proliferation, migration and invasion. Bioinformatic and immunoblot analysis indicated that the tumor suppressor roles of miR-10a in GC cells were possibly through targeting HOXA1. Our data indicate that miR-10a acts as a tumor suppressor in GC cells and is partially silenced by DNA hypermethylation in GC, suggesting that miR-10a may serve as a potential diagnostic or therapeutic target of GC.PLoS ONE 01/2014; 9(1):e88057. DOI:10.1371/journal.pone.0088057 · 3.23 Impact Factor
- "This miRNA down regulates ABL1, including infusion with BCR.  miR-224/326/422b/520a Down regulated in IM-responding CML patients  miR-564 BCR/ABL-dependent down regulation in CML cells  a c t a h a e m a t o l o g i c a p o l o n i c a x x x ( 2 0 1 3 ) x x x – x x x "
Article: Crosstalk between BCR/ABL and RNAi[Show abstract] [Hide abstract]
ABSTRACT: Chronic myeloid leukemia (CML) is a malignant disease of progenitor myeloid cells caused by chromosomal translocation that results in the forming of diminutive Philadephia chromosome that harbors BCR/ABL fusion oncogene. The product of this oncogene, a tyrosine kinase, alters several important regulatory pathways related to cell growth and differentiation thus leading to cancer transformation. Major form of CML therapy is based on tyrosine kinase inhibitors, first of all imatinib (IM). Some patients develop resistance to IM in the course of treatment. In the process of leukemogenesis the activity of miRNAs – one of groups of RNAs involved in RNA interference (RNAi) – is altered. Signatures of altered miRNAs activity may serve as a prognostic factor in the development and therapy of several diseases. Moreover, other group of RNAs involved in RNAi – siRNA – might be valuable addition to array of specific therapeutics targeted the BCR/ABL kinase.Acta haematologica Polonica 10/2013; DOI:10.1016/j.achaem.2013.07.001