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Rs12976445 variant in the pri-miR-125a correlates with a lower level of hsa-miR-125a and ERBB2 overexpression in breast cancer patients.

ABSTRACT: Expression of MIR125A is diminished in breast tumors, however the reason for the hsa-mir-125a decrease in the cancer is not known. HER2 is encoded by ERBB2, a target for hsa-miR-125a which interacts with the 3'UTR of ERBB2 mRNA. The present study reveals that a polymorphism (rs12976445) within the pri-miR-125a sequence correlates with the amount of mature hsa-miR-125a in breast tumor samples. miRNA, RNA and DNA were extracted from breast cancer samples obtained from 26 patients. Following immunohistological evaluation of the samples, the ERBB2, PGR and ESR1 mRNA profiles were also analyzed using real-time PCR. Genomic DNA was sequenced using MIR125A flanking primers. PCR products were analyzed using a BaeGI restriction enzyme specific to the rs12976445 variant. The rs12976445 variant (C/T and C/C) correlated with a lower level of hsa-miR-125a in comparison with the T/T variant. The expression of HER2 mRNA was increased in tumors with the rs12976445 variant (C/T and C/C) compared with T/T. We conclude that rs12976445 may be a potential prognostic marker of HER2 expression in breast cancer. Its predictive value on the efficacy of trastuzumab treatment in patients with HER2-positive breast cancer warrants further study.

SUBMITTER: Lehmann TP

PROVIDER: S-EPMC3573016 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

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rs12976445 variant in the pri-miR-125a correlates with a lower level of hsa-miR-125a and ERBB2 overexpression in breast cancer patients.

Lehmann Tomasz P TP Korski Konstanty K Ibbs Mathew M Zawierucha Piotr P Grodecka-Gazdecka Sylwia S Jagodziński Paweł P PP

Oncology letters 20121122 2

Expression of MIR125A is diminished in breast tumors, however the reason for the hsa-mir-125a decrease in the cancer is not known. HER2 is encoded by ERBB2, a target for hsa-miR-125a which interacts with the 3'UTR of ERBB2 mRNA. The present study reveals that a polymorphism (rs12976445) within the pri-miR-125a sequence correlates with the amount of mature hsa-miR-125a in breast tumor samples. miRNA, RNA and DNA were extracted from breast cancer samples obtained from 26 patients. Following immuno ...[more]

PMID: 23420759

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Project description:BackgroundTwo mature microRNAs (miRNAs), hsa-miR-125a-3p and hsa-miR-125a-5p (collectively referred to as hsa-miR-125a-3p/5p), are derived from 3' and 5' ends of pre-miR-125a, respectively. Although impaired regulation of hsa-miR-125a-5p has been observed in some tumors, the role of this miRNA in invasion and metastasis remains unclear, and few studies have examined the function of hsa-miR-125a-3p. In order to characterize the functions of hsa-miR-125a-3p/5p in invasion and metastasis of non-small cell lung cancer (NSCLC), we investigated the relationships between hsa-miR-125a-3p/5p expression and lymph node metastasis in NSCLC tissues. We also explored the impact of expression of these miRNAs on invasive and migratory capabilities of lung cancer cells.MethodsExpression of hsa-miR-125a-3p/5p in NSCLC tissues was explored using real-time PCR. The relationships between hsa-miR-125a-3p/5p expression and pathological stage or lymph node metastasis were assessed using the Spearman correlation test. For in vitro studies, lung cancer cells were transfected with sense and antisense 2'-O-methyl oligonucleotides for gain-of-function and loss-of-function experiments. Transwell experiments were performed to evaluate cellular migration and invasion.ResultsExpression of hsa-miR-125a-3p/5p was lower in NSCLC tissues than in adjacent normal lung tissues (LAC). Furthermore, the results from the Spearman correlation test showed a negative relationship between hsa-miR-125a-3p expression and pathological stage or lymph node metastasis and an inverse relationship between hsa-miR-125a-5p expression and pathological stage or lymph node metastasis. In vitro gain-of-function experiments indicated that hsa-miR-125a-3p and hsa-miR-125a-5p function in an opposing manner, suppressing or enhancing cell migration and invasion in A549 and SPC-A-1 cell lines, respectively. These opposing functions were further validated by suppression of hsa-miR-125a-3p and hsa-miR-125a-5p expression in loss-of-function experiments.ConclusionHsa-miR-125a-3p and hsa-miR-125a-5p play distinct roles in regulation of invasive and metastatic capabilities of lung cancer cells, consistent with the opposing correlations between the expression of these miRNAs and lymph node metastasis in NSCLC. These results provide new insights into the roles of miR-125a family members in the development of NSCLC.

Project description:Antigen-presenting cells (APCs) regulate the balance of our immune response toward microbes. Whereas immunogenic APCs boost inflammation and activate lymphocytes, the highly plastic cells can switch into a tolerogenic/suppressive phenotype that dampens and resolves the response. Thereby the initially mediated inflammation seems to prime the switch of APCs while the strength of activation determines the grade of the suppressive phenotype. Recently, we showed that pathogen recognition receptor-mediated pro-inflammatory cytokines reprogram differentiating human blood monocytes in vitro toward an immunosuppressive phenotype through prolonged activation of signal transducer and activator of transcription (STAT) 3. The TLR7/8 ligand R848 (Resiquimod) triggers the high release of cytokines from GM-CSF/IL-4-treated monocytes. These cytokines subsequently upregulate T cell suppressive factors, such as programmed death-ligand 1 (PD-L1) and indolamin-2,3-dioxygenase (IDO) through cytokine receptor-mediated STAT3 activation. Here, we reveal an essential role for the microRNA (miR, miRNA) hsa-miR-99b/let-7e/miR-125a cluster in stabilizing the suppressive phenotype of R848-stimulated APCs on different levels. On the one hand, the miR cluster boosts R848-stimulated cytokine production through regulation of MAPkinase inhibitor Tribbles pseudokinase 2, thereby enhancing cytokine-stimulated activation of STAT3. One the other hand, the STAT3 inhibitor suppressor of cytokine signaling-1 is targeted by the miR cluster, stabilizing the STAT3-induced expression of immunosuppressive factors PD-L1 and IDO. Finally, hsa-miR-99b/let-7e/miR-125a cluster regulates generation of the suppressive tryptophan (Trp) metabolite kynurenine by targeting the tryptophanyl-tRNA synthetase WARS, the direct competitor of IDO in terms of availability of Trp. In summary, our results reveal the hsa-miR-99b/let-7e/miR-125a cluster as an important player in the concerted combination of mechanisms that stabilizes STAT3 activity and thus regulate R848-stimulated suppressive APCs.

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Project description:We reported that the class I HDAC inhibitor entinostat induced apoptosis in erbB2-overexpressing breast cancer cells via downregulation of erbB2 and erbB3. Here, we study the molecular mechanism by which entinostat dual-targets erbB2/erbB3. Treatment with entinostat had no effect on erbB2/erbB3 mRNA, suggesting a transcription-independent mechanism. Entinostat decreased endogenous but not exogenous erbB2/erbB3, indicating it did not alter their protein stability. We hypothesized that entinostat might inhibit erbB2/erbB3 protein translation via specific miRNAs. Indeed, entinostat significantly upregulated miR-125a, miR-125b, and miR-205, that have been reported to target erbB2 and/or erbB3. Specific inhibitors were then used to determine whether these miRNAs had a causal role in entinostat-induced downregulation of erbB2/erbB3 and apoptosis. Transfection with a single inhibitor dramatically abrogated entinostat induction of miR-125a, miR-125b, or miR-205; however, none of the inhibitors blocked entinostat action on erbB2/erbB3. In contrast, co-transfection with two inhibitors not only reduced their corresponding miRNAs, but also significantly abrogated entinostat-mediated reduction of erbB2/erbB3. Moreover, simultaneous inhibition of two, but not one miRNA significantly attenuated entinostat-induced apoptosis. Interestingly, although the other HDAC inhibitors, such as SAHA and panobinostat, exhibited activity as potent as entinostat to induce growth inhibition and apoptosis in erbB2-overexpressing breast cancer cells, they had no significant effects on the three miRNAs. Instead, both SAHA- and panobinostat-decreased erbB2/erbB3 expression correlated with the reduction of their mRNA levels. Collectively, we demonstrate that entinostat specifically induces expression of miR-125a, miR-125b, and miR-205, which act in concert to downregulate erbB2/erbB3 in breast cancer cells. Our data suggest that epigenetic regulation via miRNA-dependent or -independent mechanisms may represent a novel approach to treat breast cancer patients with erbB2-overexpressing tumors.

Dataset Information

Rs12976445 variant in the pri-miR-125a correlates with a lower level of hsa-miR-125a and ERBB2 overexpression in breast cancer patients.

Publications

rs12976445 variant in the pri-miR-125a correlates with a lower level of hsa-miR-125a and ERBB2 overexpression in breast cancer patients.

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