Accession ID: MIRT000815 [miRNA, hsa-miR-15a ::
BCL2, target gene]
| pre-miRNA ID | hsa-mir-15a LinkOut: [miRBase ] |
|---|---|
| Synonyms | MIRN15A, hsa-mir-15a, miRNA15A, MIR15A |
| Description | Homo sapiens miR-15a stem-loop |
| Comment | Reference . |
| 2nd Structure of pre-miRNA |  |
| Mature miRNA | hsa-miR-15a-3p |
|---|---|
| Mature Sequence | 51| CAGGCCAUAUUGUGCUGCCUCA |72 |
| Evidence | Experimental |
| Experiments | Cloned |
| Putative hsa-miR-15a-3p Targets | LinkOut: [ TargetScanS 5.1 | MicroCosm | microRNA.org | miRecords | miRDB | miRo | miRNAMap 2.0 ] |
| Mature miRNA | hsa-miR-15a-5p |
| Mature Sequence | 14| UAGCAGCACAUAAUGGUUUGUG |35 |
| Evidence | Experimental |
| Experiments | Cloned |
| Putative hsa-miR-15a-5p Targets | LinkOut: [ TargetScanS 5.1 | MicroCosm | microRNA.org | miRecords | miRDB | miRo | miRNAMap 2.0 ] |
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| Gene Symbol | BCL2 LinkOut: [ Entrez Gene | BioGPS | Wikipedia | iHop ] | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Synonyms | Bcl-2 | ||||||||||||||||||||
| Description | B-cell CLL/lymphoma 2 | ||||||||||||||||||||
| Transcript | NM_000633 LinkOut: [ RefSeq ] | ||||||||||||||||||||
| Other Transcripts | NM_000657 | ||||||||||||||||||||
| Expression | LinkOut: [ BioGPS ] | ||||||||||||||||||||
| KEGG Pathway |
hsa04210 Apoptosis - Homo sapiens (human) hsa04510 Focal adhesion - Homo sapiens (human) hsa04722 Neurotrophin signaling pathway - Homo sapiens (human) hsa05014 Amyotrophic lateral sclerosis (ALS) - Homo sapiens (human) hsa05200 Pathways in cancer - Homo sapiens (human) hsa05210 Colorectal cancer - Homo sapiens (human) hsa05215 Prostate cancer - Homo sapiens (human) hsa05222 Small cell lung cancer - Homo sapiens (human) |
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| Putative miRNA Targets on BCL2 | LinkOut: [ TargetScan 5.1 | MicroCosm | miRNAMap 2.0 ] | ||||||||||||||||||||
| 3'UTR of BCL2 (miRNA target sites are highlighted) |
>BCL2|NM_000633|3'UTR 1 TGAAGTCAACATGCCTGCCCCAAACAAATATGCAAAAGGTTCACTAAAGCAGTAGAAATAATATGCATTGTCAGTGATGT 81 ACCATGAAACAAAGCTGCAGGCTGTTTAAGAAAAAATAACACACATATAAACATCACACACACAGACAGACACACACACA 161 CACAACAATTAACAGTCTTCAGGCAAAACGTCGAATCAGCTATTTACTGCCAAAGGGAAATATCATTTATTTTTTACATT 241 ATTAAGAAAAAAAGATTTATTTATTTAAGACAGTCCCATCAAAACTCCTGTCTTTGGAAATCCGACCACTAATTGCCAAG 321 CACCGCTTCGTGTGGCTCCACCTGGATGTTCTGTGCCTGTAAACATAGATTCGCTTTCCATGTTGTTGGCCGGATCACCA 401 TCTGAAGAGCAGACGGATGGAAAAAGGACCTGATCATTGGGGAAGCTGGCTTTCTGGCTGCTGGAGGCTGGGGAGAAGGT 481 GTTCATTCACTTGCATTTCTTTGCCCTGGGGGCTGTGATATTAACAGAGGGAGGGTTCCTGTGGGGGGAAGTCCATGCCT 561 CCCTGGCCTGAAGAAGAGACTCTTTGCATATGACTCACATGATGCATACCTGGTGGGAGGAAAAGAGTTGGGAACTTCAG 641 ATGGACCTAGTACCCACTGAGATTTCCACGCCGAAGGACAGCGATGGGAAAAATGCCCTTAAATCATAGGAAAGTATTTT 721 TTTAAGCTACCAATTGTGCCGAGAAAAGCATTTTAGCAATTTATACAATATCATCCAGTACCTTAAGCCCTGATTGTGTA 801 TATTCATATATTTTGGATACGCACCCCCCAACTCCCAATACTGGCTCTGTCTGAGTAAGAAACAGAATCCTCTGGAACTT 881 GAGGAAGTGAACATTTCGGTGACTTCCGCATCAGGAAGGCTAGAGTTACCCAGAGCATCAGGCCGCCACAAGTGCCTGCT 961 TTTAGGAGACCGAAGTCCGCAGAACCTGCCTGTGTCCCAGCTTGGAGGCCTGGTCCTGGAACTGAGCCGGGGCCCTCACT 1041 GGCCTCCTCCAGGGATGATCAACAGGGCAGTGTGGTCTCCGAATGTCTGGAAGCTGATGGAGCTCAGAATTCCACTGTCA 1121 AGAAAGAGCAGTAGAGGGGTGTGGCTGGGCCTGTCACCCTGGGGCCCTCCAGGTAGGCCCGTTTTCACGTGGAGCATGGG 1201 AGCCACGACCCTTCTTAAGACATGTATCACTGTAGAGGGAAGGAACAGAGGCCCTGGGCCCTTCCTATCAGAAGGACATG 1281 GTGAAGGCTGGGAACGTGAGGAGAGGCAATGGCCACGGCCCATTTTGGCTGTAGCACATGGCACGTTGGCTGTGTGGCCT 1361 TGGCCCACCTGTGAGTTTAAAGCAAGGCTTTAAATGACTTTGGAGAGGGTCACAAATCCTAAAAGAAGCATTGAAGTGAG 1441 GTGTCATGGATTAATTGACCCCTGTCTATGGAATTACATGTAAAACATTATCTTGTCACTGTAGTTTGGTTTTATTTGAA 1521 AACCTGACAAAAAAAAAGTTCCAGGTGTGGAATATGGGGGTTATCTGTACATCCTGGGGCATTAAAAAAAAAATCAATGG 1601 TGGGGAACTATAAAGAAGTAACAAAAGAAGTGACATCTTCAGCAAATAAACTAGGAAATTTTTTTTTCTTCCAGTTTAGA 1681 ATCAGCCTTGAAACATTGATGGAATAACTCTGTGGCATTATTGCATTATATACCATTTATCTGTATTAACTTTGGAATGT 1761 ACTCTGTTCAATGTTTAATGCTGTGGTTGATATTTCGAAAGCTGCTTTAAAAAAATACATGCATCTCAGCGTTTTTTTGT 1841 TTTTAATTGTATTTAGTTATGGCCTATACACTATTTGTGAGCAAAGGTGATCGTTTTCTGTTTGAGATTTTTATCTCTTG 1921 ATTCTTCAAAAGCATTCTGAGAAGGTGAGATAAGCCCTGAGTCTCAGCTACCTAAGAAAAACCTGGATGTCACTGGCCAC 2001 TGAGGAGCTTTGTTTCAACCAAGTCATGTGCATTTCCACGTCAACAGAATTGTTTATTGTGACAGTTATATCTGTTGTCC 2081 CTTTGACCTTGTTTCTTGAAGGTTTCCTCGTCCCTGGGCAATTCCGCATTTAATTCATGGTATTCAGGATTACATGCATG 2161 TTTGGTTAAACCCATGAGATTCATTCAGTTAAAAATCCAGATGGCAAATGACCAGCAGATTCAAATCTATGGTGGTTTGA 2241 CCTTTAGAGAGTTGCTTTACGTGGCCTGTTTCAACACAGACCCACCCAGAGCCCTCCTGCCCTCCTTCCGCGGGGGCTTT 2321 CTCATGGCTGTCCTTCAGGGTCTTCCTGAAATGCAGTGGTGCTTACGCTCCACCAAGAAAGCAGGAAACCTGTGGTATGA 2401 AGCCAGACCTCCCCGGCGGGCCTCAGGGAACAGAATGATCAGACCTTTGAATGATTCTAATTTTTAAGCAAAATATTATT 2481 TTATGAAAGGTTTACATTGTCAAAGTGATGAATATGGAATATCCAATCCTGTGCTGCTATCCTGCCAAAATCATTTTAAT 2561 GGAGTCAGTTTGCAGTATGCTCCACGTGGTAAGATCCTCCAAGCTGCTTTAGAAGTAACAATGAAGAACGTGGACGTTTT 2641 TAATATAAAGCCTGTTTTGTCTTTTGTTGTTGTTCAAACGGGATTCACAGAGTATTTGAAAAATGTATATATATTAAGAG 2721 GTCACGGGGGCTAATTGCTGGCTGGCTGCCTTTTGCTGTGGGGTTTTGTTACCTGGTTTTAATAACAGTAAATGTGCCCA 2801 GCCTCTTGGCCCCAGAACTGTACAGTATTGTGGCTGCACTTGCTCTAAGAGTAGTTGATGTTGCATTTTCCTTATTGTTA 2881 AAAACATGTTAGAAGCAATGAATGTATATAAAAGCCTCAACTAGTCATTTTTTTCTCCTCTTCTTTTTTTTCATTATATC 2961 TAATTATTTTGCAGTTGGGCAACAGAGAACCATCCCTATTTTGTATTGAAGAGGGATTCACATCTGCATCTTAACTGCTC 3041 TTTATGAATGAAAAAACAGTCCTCTGTATGTACTCCTCTTTACACTGGCCAGGGTCAGAGTTAAATAGAGTATATGCACT 3121 TTCCAAATTGGGGACAAGGGCTCTAAAAAAAGCCCCAAAAGGAGAAGAACATCTGAGAACCTCCTCGGCCCTCCCAGTCC 3201 CTCGCTGCACAAATACTCCGCAAGAGAGGCCAGAATGACAGCTGACAGGGTCTATGGCCATCGGGTCGTCTCCGAAGATT 3281 TGGCAGGGGCAGAAAACTCTGGCAGGCTTAAGATTTGGAATAAAGTCACAGAATTAAGGAAGCACCTCAATTTAGTTCAA 3361 ACAAGACGCCAACATTCTCTCCACAGCTCACTTACCTCTCTGTGTTCAGATGTGGCCTTCCATTTATATGTGATCTTTGT 3441 TTTATTAGTAAATGCTTATCATCTAAAGATGTAGCTCTGGCCCAGTGGGAAAAATTAGGAAGTGATTATAAATCGAGAGG 3521 AGTTATAATAATCAAGATTAAATGTAAATAATCAGGGCAATCCCAACACATGTCTAGCTTTCACCTCCAGGATCTATTGA 3601 GTGAACAGAATTGCAAATAGTCTCTATTTGTAATTGAACTTATCCTAAAACAAATAGTTTATAAATGTGAACTTAAACTC 3681 TAATTAATTCCAACTGTACTTTTAAGGCAGTGGCTGTTTTTAGACTTTCTTATCACTTATAGTTAGTAATGTACACCTAC 3761 TCTATCAGAGAAAAACAGGAAAGGCTCGAAATACAAGCCATTCTAAGGAAATTAGGGAGTCAGTTGAAATTCTATTCTGA 3841 TCTTATTCTGTGGTGTCTTTTGCAGCCCAGACAAATGTGGTTACACACTTTTTAAGAAATACAATTCTACATTGTCAAGC 3921 TTATGAAGGTTCCAATCAGATCTTTATTGTTATTCAATTTGGATCTTTCAGGGATTTTTTTTTTAAATTATTATGGGACA 4001 AAGGACATTTGTTGGAGGGGTGGGAGGGAGGAAGAATTTTTAAATGTAAAACATTCCCAAGTTTGGATCAGGGAGTTGGA 4081 AGTTTTCAGAATAACCAGAACTAAGGGTATGAAGGACCTGTATTGGGGTCGATGTGATGCCTCTGCGAAGAACCTTGTGT 4161 GACAAATGAGAAACATTTTGAAGTTTGTGGTACGACCTTTAGATTCCAGAGACATCAGCATGGCTCAAAGTGCAGCTCCG 4241 TTTGGCAGTGCAATGGTATAAATTTCAAGCTGGATATGTCTAATGGGTATTTAAACAATAAATGTGCAGTTTTAACTAAC 4321 AGGATATTTAATGACAACCTTCTGGTTGGTAGGGACATCTGTTTCTAAATGTTTATTATGTACAATACAGAAAAAAATTT 4401 TATAAAATTAAGCAATGTGAAACTGAATTGGAGAGTGATAATACAAGTCCTTTAGTCTTACCCAGTGAATCATTCTGTTC 4481 CATGTCTTTGGACAACCATGACCTTGGACAATCATGAAATATGCATCTCACTGGATGCAAAGAAAATCAGATGGAGCATG 4561 AATGGTACTGTACCGGTTCATCTGGACTGCCCCAGAAAAATAACTTCAAGCAAACATCCTATCAACAACAAGGTTGTTCT 4641 GCATACCAAGCTGAGCACAGAAGATGGGAACACTGGTGGAGGATGGAAAGGCTCGCTCAATCAAGAAAATTCTGAGACTA 4721 TTAATAAATAAGACTGTAGTGTAGATACTGAGTAAATCCATGCACCTAAACCTTTTGGAAAATCTGCCGTGGGCCCTCCA 4801 GATAGCTCATTTCATTAAGTTTTTCCCTCCAAGGTAGAATTTGCAAGAGTGACAGTGGATTGCATTTCTTTTGGGGAAGC 4881 TTTCTTTTGGTGGTTTTGTTTATTATACCTTCTTAAGTTTTCAACCAAGGTTTGCTTTTGTTTTGAGTTACTGGGGTTAT 4961 TTTTGTTTTAAATAAAAATAAGTGTACAATAAGTGTTTTTGTATTGAAAGCTTTTGTTATCAAGATTTTCATACTTTTAC 5041 CTTCCATGGCTCTTTTTAAGATTGATACTTTTAAGAGGTGGCTGATATTCTGCAACACTGTACACATAAAAAATACGGTA 5121 AGGATACTTTACATGGTTAAGGTAAAGTAAGTCTCCAGTTGGCCACCATTAGCTATAATGGCACTTTGTTTGTGTTGTTG 5201 GAAAAAGTCACATTGCCATTAAACTTTCCTTGTCTGTCTAGTTAATATTGTGAAGAAAAATAAAGTACAGTGTGAGATAC 5281 TG Target sites Provided by authors Predicted by miRanda |
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| miRNA-target interactions (Predicted by miRanda) |
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] | ||||||
|---|---|---|---|---|---|---|---|
| Validation Method | Luciferase reporter assay , qRT-PCR , Western blot | ||||||
| Conditions | CLL patient samples | ||||||
| Location of target site | 3'UTR | ||||||
| Original Description (Extracted from the article) | ... BCL2 Is a Target of Posttranscriptional Repression by miR-15 and miR-16.//both mutants completely abolish the interaction between miR-15a and miR-16-1 and the 3'UTR of BCL2 (Fig. 2C).//These data indicate that both miRNAs directly interact with the 3'UTR of BCL2. ... - Cimmino, A. Calin, G. A. Fabbri, M. Iorio, et al., 2005, Proc Natl Acad Sci U S A. |
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| miRNA-target interactions (Provided by authors) |
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| Article |
- Cimmino, A.
Calin, G. A.
Fabbri, M.
Iorio, et al. - Proc Natl Acad Sci U S A, 2005
Chronic lymphocytic leukemia (CLL) is the most common human leukemia and is characterized by predominantly nondividing malignant B cells overexpressing the antiapoptotic B cell lymphoma 2 (Bcl2) protein. miR-15a and miR-16-1 are deleted or down-regulated in the majority of CLLs. Here, we demonstrate that miR-15a and miR-16-1 expression is inversely correlated to Bcl2 expression in CLL and that both microRNAs negatively regulate Bcl2 at a posttranscriptional level. BCL2 repression by these microRNAs induces apoptopsis in a leukemic cell line model. Therefore, miR-15 and miR-16 are natural antisense Bcl2 interactors that could be used for therapy of Bcl2-overexpressing tumors.
LinkOut: [PMID: 16166262]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | Microarray , qRT-PCR |
| Conditions | HL60, NB41A3 |
| Location of target site | 3'UTR |
| Tools used in this research | microRNA.org, miRanda, PicTar |
| Original Description (Extracted from the article) | ... we report the miRNA gene expression profile of an APL cell line (NB4) upon granulocytic differentiation with ATRA. The results were also confirmed in HL-60 cells, another mycloid leukemia cell line that undergoes granulocytic differentiation upon ATRA treatment and in primary APL patient samples treated in vitro with ATRA ... - Garzon, R. Pichiorri, F. Palumbo, T. et al., 2007, Oncogene. |
| Article |
- Garzon, R.
Pichiorri, F.
Palumbo, T. et al. - Oncogene, 2007
MicroRNAs (miRNAs) are small non-coding RNAs of 19-25 nucleotides that are involved in the regulation of critical cell processes such as apoptosis, cell proliferation and differentiation. However, little is known about the role of miRNAs in granulopoiesis. Here, we report the expression of miRNAs in acute promyelocytic leukemia patients and cell lines during all-trans-retinoic acid (ATRA) treatment by using a miRNA microarrays platform and quantitative real time-polymerase chain reaction (qRT-PCR). We found upregulation of miR-15a, miR-15b, miR-16-1, let-7a-3, let-7c, let-7d, miR-223, miR-342 and miR-107, whereas miR-181b was downregulated. Among the upregulated miRNAs, miR-107 is predicted to target NFI-A, a gene that has been involved in a regulatory loop involving miR-223 and C/EBPa during granulocytic differentiation. Indeed, we have confirmed that miR-107 targets NF1-A. To get insights about ATRA regulation of miRNAs, we searched for ATRA-modulated transcription factors binding sites in the upstream genomic region of the let-7a-3/let-7b cluster and identified several putative nuclear factor-kappa B (NF-kappaB) consensus elements. The use of reporter gene assays, chromatin immunoprecipitation and site-directed mutagenesis revealed that one proximal NF-kappaB binding site is essential for the transactivation of the let-7a-3/let-7b cluster. Finally, we show that ATRA downregulation of RAS and Bcl2 correlate with the activation of known miRNA regulators of those proteins, let-7a and miR-15a/miR-16-1, respectively.
LinkOut: [PMID: 17260024]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | Luciferase reporter assay |
| Article |
- Calin, G. A.
Pekarsky, Y.
Croce, C. M. - Best Pract Res Clin Haematol, 2007
New findings support the view that chronic lymphocytic leukemia (CLL) is a genetic disease in which the main alterations occur in a new class of genes named microRNAs (miRNAs). Cases with good prognostic features typically are characterized by miRNA down-regulation of genes miR-15a and miR-16-1, located at 13q14.3. Both microRNAs negatively regulate BCL2 at a post-transcriptional level. On the other hand, in CLL cases that use unmutated immunoglobulin heavy-chain variable-region genes (IgV(H)) or have high-level expression of the 70-kD zeta-associated protein (ZAP-70) have high levels of TCL1 due to low-level expression of miR-29 and miR-181, which directly target this oncogene. Conceivably, these miRNAs might be used to target BCL2 or TCL1 for therapy of this disease.
LinkOut: [PMID: 17707831]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | qRT-PCR , proteomics analysis |
| Location of target site | 3'UTR |
| Original Description (Extracted from the article) | ... changed ... - Calin, G. A. Cimmino, A. Fabbri, M. et al., 2008, Proc Natl Acad Sci U S A. |
| Article |
- Calin, G. A.
Cimmino, A.
Fabbri, M. et al. - Proc Natl Acad Sci U S A, 2008
MicroRNAs (miRNAs) are short noncoding RNAs regulating gene expression that play roles in human diseases, including cancer. Each miRNA is predicted to regulate hundreds of transcripts, but only few have experimental validation. In chronic lymphocytic leukemia (CLL), the most common adult human leukemia, miR-15a and miR-16-1 are lost or down-regulated in the majority of cases. After our previous work indicating a tumor suppressor function of miR-15a/16-1 by targeting the BCL2 oncogene, here, we produced a high-throughput profiling of genes modulated by miR-15a/16-1 in a leukemic cell line model (MEG-01) and in primary CLL samples. By combining experimental and bioinformatics data, we identified a miR-15a/16-1-gene signature in leukemic cells. Among the components of the miR-15a/16-1 signature, we observed a statistically significant enrichment in AU-rich elements (AREs). By examining the Gene Ontology (GO) database, a significant enrichment in cancer genes (such as MCL1, BCL2, ETS1, or JUN) that directly or indirectly affect apoptosis and cell cycle was found.
LinkOut: [PMID: 18362358]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | |
| Location of target site | |
| Article |
- Xia, L.
Zhang, D.
Du, R.
Pan, Y.
Zhao, L. et al. - Int J Cancer, 2008
microRNAs are endogenous small noncoding RNAs that regulate gene expression negatively at posttranscriptional level. This latest addition to the complex gene regulatory circuitry revolutionizes our way to understanding physiological and pathological processes in the human body. Here we investigated the possible role of microRNAs in the development of multidrug resistance (MDR) in gastric cancer cells. microRNA expression profiling revealed a limited set of microRNAs with altered expression in multidrug- resistant gastric cancer cell line SGC7901/VCR compared to its parental SGC7901 cell line. Among the downregulated microRNAs are miR-15b and miR-16, members of miR-15/16 family, whose expression was further validated by qRT-PCR. In vitro drug sensitivity assay demonstrated that overexpression of miR-15b or miR-16 sensitized SGC7901/VCR cells to anticancer drugs whereas inhibition of them using antisense oligonucleotides conferred SGC7901 cells MDR. The downregulation of miR-15b and miR-16 in SGC7901/VCR cells was concurrent with the upregulation of Bcl-2 protein. Enforced mir-15b or miR-16 expression reduced Bcl-2 protein level and the luciferase activity of a BCL2 3' untranslated region-based reporter construct in SGC7901/VCR cells, suggesting that BCL2 is a direct target of miR-15b and miR-16. Moreover, overexpression of miR-15b or miR-16 could sensitize SGC7901/VCR cells to VCR-induced apoptosis. Taken together, our findings suggest that miR-15b and miR-16 could play a role in the development of MDR in gastric cancer cells at least in part by modulation of apoptosis via targeting BCL2.
LinkOut: [PMID: 18449891]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | Luciferase reporter assay |
| Conditions | HEK293 |
| Location of target site | 3'UTR |
| Tools used in this research | FASTH |
| Original Description (Extracted from the article) | ... Assessed by p-value, this decrease was significant for the TSPYL2 and WNT9B constructs at 10 and 50 nM, and for the BCL2 and TNFSF12 constructs at 50 nM. BCL2 mRNA has previously been validated as a target for has-miR-15a inhibition [30]. The CREBBP construct showed ,32% mean reduction at 50 nM, although this reduction is not significant as assessed by p-value.//A recent study shows that hsa-miR-15a and miR-16 induce apoptosis by targeting the BCL2 mRNA, and our results confirm this targeting for hsa-miR-15a. ... - Ragan, C. Cloonan, N. Grimmond, S. M. et al., 2009, PLoS One. |
| Article |
- Ragan, C.
Cloonan, N.
Grimmond, S. M. et al. - PLoS One, 2009
Transcriptional regulation by microRNAs (miRNAs) involves complementary base-pairing at target sites on mRNAs, yielding complex secondary structures. Here we introduce an efficient computational approach and software (FASTH) for genome-scale prediction of miRNA target sites based on minimizing the free energy of duplex structure. We apply our approach to identify miRNA target sites in the human and mouse transcriptomes. Our results show that short sequence motifs in the 5' end of miRNAs frequently match mRNAs perfectly, not only at validated target sites but additionally at many other, energetically favourable sites. High-quality matching regions are abundant and occur at similar frequencies in all mRNA regions, not only the 3'UTR. About one-third of potential miRNA target sites are reassigned to different mRNA regions, or gained or lost altogether, among different transcript isoforms from the same gene. Many potential miRNA target sites predicted in human are not found in mouse, and vice-versa, but among those that do occur in orthologous human and mouse mRNAs most are situated in corresponding mRNA regions, i.e. these sites are themselves orthologous. Using a luciferase assay in HEK293 cells, we validate four of six predicted miRNA-mRNA interactions, with the mRNA level reduced by an average of 73%. We demonstrate that a thermodynamically based computational approach to prediction of miRNA binding sites on mRNAs can be scaled to analyse complete mammalian transcriptome datasets. These results confirm and extend the scope of miRNA-mediated species- and transcript-specific regulation in different cell types, tissues and developmental conditions.
LinkOut: [PMID: 19478946]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | Western blot |
| Conditions | OV-202 |
| Original Description (Extracted from the article) | ... MiR-15a and miR-16 also target Bcl-2 in ovarian cancer cell lines. ... - Bhattacharya, R. Nicoloso, M. Arvizo, R. et al., 2009, Cancer Res. |
| Article |
- Bhattacharya, R.
Nicoloso, M.
Arvizo, R. et al. - Cancer Res, 2009
Oncogenic activation of Bmi-1 is found in a wide variety of epithelial malignancies including ovarian cancer, yet a specific mechanism for overexpression of Bmi-1 has not been determined. Thus, realizing the immense pathologic significance of Bmi-1 in cancer, we wanted to investigate if microRNA (miRNA) aberrations played a role in the regulation of Bmi-1 in ovarian cancer. In this report, we identify two miRNAs, miR-15a and miR-16, that are underexpressed in ovarian cell lines and in primary ovarian tissues. We show that these miRNAs directly target the Bmi-1 3' untranslated region and significantly correlate with Bmi-1 protein levels in ovarian cancer patients and cell lines. Furthermore, Bmi-1 protein levels are downregulated in response to miR-15a or miR-16 expression and lead to significant reduction in ovarian cancer cell proliferation and clonal growth. These findings suggest the development of therapeutic strategies by restoring miR-15a and miR-16 expression in ovarian cancer and in other cancers that involve upregulation of Bmi-1.
LinkOut: [PMID: 19903841]
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| miRNA:Target | hsa-miR-15a :: BCL2 [ Functional MTI ] |
|---|---|
| Validation Method | Western blot |
| Conditions | MCF-7, MDA-MB-231 |
| Location of target site | 3'UTR |
| Original Description (Extracted from the article) | ... These results further implicate the BCL-2 targeting miR-15a/16 as important regulators of BCL-2 expression and tamoxifen response and suggest that oncogene suppression of miR-15a and/or miR-16 may represent an important mechanism of tamoxifen resistance. ... - Cittelly, D. M. Das, P. M. Salvo, V. A. et al., 2010, Carcinogenesis. |
| Article |
- Cittelly, D. M.
Das, P. M.
Salvo, V. A. et al. - Carcinogenesis, 2010
Tamoxifen is the most commonly prescribed therapy for patients with estrogen receptor (ERalpha) positive breast tumors. Tumor resistance to tamoxifen remains a serious clinical problem especially in patients with tumors that also overexpress HER2. Current preclinical models of HER2 overexpression fail to recapitulate the clinical spectrum of endocrine resistance associated with HER2/ER positive tumors. Here we show that ectopic expression of a clinically important oncogenic isoform of HER2, HER2Delta16, which is expressed in over 30% of ER positive breast tumors, promotes tamoxifen resistance and estrogen independence of MCF-7 xenografts. MCF-7/HER2Delta16 cells evade tamoxifen through upregulation of BCL-2, whereas RNAi-mediated suppression of BCL-2 expression or treatment of MCF-7/HER2Delta16 cells with the BCL-2 family pharmacological inhibitor ABT-737 restores tamoxifen sensitivity. Tamoxifen-resistant MCF-7/HER2Delta16 cells upregulate BCL-2 protein levels in response to suppressed ERalpha signaling mediated by estrogen withdrawal, tamoxifen treatment, or fulvestrant treatment. In addition, HER2Delta16 expression results in suppression of BCL-2 targeting microRNAs miR-15a and miR-16. Reintroduction of miR-15a/16 reduced tamoxifen-induced BCL-2 expression and sensitized MCF-7/HER2Delta16 to tamoxifen. Conversely, inhibition of miR-15a/16 in tamoxifen sensitive cells activated BCL-2 expression and promoted tamoxifen resistance. Our results suggest that HER2Delta16 expression promotes endocrine-resistant HER2/ERalpha positive breast tumors and in contrast to wild-type HER2, preclinical models of HER2Delta16 overexpression recapitulate multiple phenotypes of endocrine resistant human breast tumors. The mechanism of HER2Delta16 therapeutic evasion, involving tamoxifen induced upregulation of BCL-2 and suppression of miR-15a/16, provides a template for unique therapeutic interventions combining tamoxifen with modulation of microRNAs and/or ABT-737 mediated BCL-2 inhibition and apoptosis.
LinkOut: [PMID: 20876285]
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