miR-205 Function Research Articles

Regulation of antitumor miR-205 targets oncogenes: Direct regulation of lymphoid specific helicase and its clinical significance

Heading aimsBreast cancer is one of the most common malignant tumors with a high incidence and leading cancer-related death in women worldwide. MiR-205 plays a crucial role in breast cancer initiation and progression. Here, we identified the relationship between miR-205 and lymphoid specific helicase and confirmed the significance of the miR-205/lymphoid specific helicase (miR-205/HELLS) axis. Materials and methodsData from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database were analyzed to investigate the expression level of miR-205 and HELLS in breast cancer. The TargetScan, Starbase and miRWalk databases were used to predict the candidate target genes of miR-205. Proliferation and migration abilities were examined using cell counting kit-8 assay, colony formation assays, transwell assay and wound-healing assay. Dual-luciferase reporter assay was utilized to confirm the binding of miR-205 and HELLS. Quantitative RT-PCR, western blot assays or immunohistochemistry were conducted to detect the expression level of genes in breast cancer cells or tissues. Mice xenograft models were constructed to explore the function of miR-205 and HELLS in vivo. Key findingsOverexpressed miR-205 alleviated cancer cell proliferation and migration and influenced patients' prognosis by negatively regulating the HELLS gene. Consistently, animal experiments revealed that both overexpressing miR-205 and knocking down HELLS exhibited significant tumor growth inhibition in vivo. SignificanceOur study demonstrated that miR-205 targets HELLS to regulate tumor progression. MiR-205 and HELLS could be considered a novel diagnosis and therapeutic molecular marker of breast cancer.

MiR-205 suppressed the malignant behaviors of breast cancer cells by targeting CLDN11 via modulation of the epithelial-to-mesenchymal transition.

Some Aberrant expression of miRNAs plays an important role in the occurrence and distant metastasis of breast cancer. This study aimed to identify crucial miRNA signatures for breast cancer using microarray data from the Gene Expression Omnibus database, including ductal carcinoma in situ and invasive duct carcinoma. In this study, we founded that miR-205 was significantly down-regulated in breast cancer, and the low expression of miR-205 was significantly associated with the TNM stage of breast cancer. In vitro, functional studies revealed that over-expression of miR-205 inhibited the proliferation and promoted apoptosis of breast cancer cells MDA-MB-231. Mechanistically, claudin 11 (CLDN11) was found to be the direct target of miR-205; the function of miR-205 could be exerted via downregulation of the target gene CLDN11 in breast cancer cells. Furthermore, the over-expression of miR-205 promoted the expression of the epithelial marker E-cadherin but reduced the mesenchymal markers in breast cancer cells. These results collectively indicated the tumor-suppressive role of miR-205 in breast cancer by targeting CLDN11; implying miR-205 may serve as a novel therapeutic target for breast cancer.

LEADeR role of miR-205 host gene as long noncoding RNA in prostate basal cell differentiation

Though miR-205 function has been largely characterized, the nature of its host gene, MIR205HG, is still completely unknown. Here, we show that only lowly expressed alternatively spliced MIR205HG transcripts act as de facto pri-miRNAs, through a process that involves Drosha to prevent unfavorable splicing and directly mediate miR-205 excision. Notably, MIR205HG-specific processed transcripts revealed to be functional per se as nuclear long noncoding RNA capable of regulating differentiation of human prostate basal cells through control of the interferon pathway. At molecular level, MIR205HG directly binds the promoters of its target genes, which have an Alu element in proximity of the Interferon-Regulatory Factor (IRF) binding site, and represses their transcription likely buffering IRF1 activity, with the ultimate effect of preventing luminal differentiation. As MIR205HG functions autonomously from (albeit complementing) miR-205 in preserving the basal identity of prostate epithelial cells, it warrants reannotation as LEADeR (Long Epithelial Alu-interacting Differentiation-related RNA).

MiR-205 mediates the inhibition of cervical cancer cell proliferation using olmesartan.

Objective:The renin-angiotensin-aldosterone system has become known as a prerequisite for tumor angiogenesis that is now recognized as a crucial step in the development of tumors, including cervical cancer. The Ang II-AT1R pathway is known to play an important role in tumor angiogenesis. MicroRNAs (miRNAs) are a class of small, regulating RNAs that participate in tumor genesis, differentiation and proliferation. The current study focused on the anti-tumor mechanism of olmesartan, a novel angiotensin II antagonist, on cervical cancer cells.Materials and methods:qRT-PCR and Western blot were used to demonstrate the effect of olmesartan on miR-205 and VEGF-A expression. miR-205 mimics and VEGF-A shRNA plasmid were separately transfected into HeLa and Siha cells to further validate the function of miR-205 and VEGF-A in cervical cancer cell proliferation.Results:It was found that olmesartan could upregulate miR-205 and inhibit VEGF-A expression in HeLa and Siha cells. In addition, VEGF-A was proven to be a target gene of miR-205.Conclusion:This result provides a new idea on the anti-tumor mechanism of olmesartan, which may be used as a novel therapeutic target of cervical cancer.

Rs3842530 Polymorphism in MicroRNA-205 Host Gene in Lung and Breast Cancer Patients.

BackgroundThe expression of miR-205 is closely related to the occurrence, development, and prognosis of lung cancer and breast cancer. However, studies show that it plays opposite roles in different tumor types. Because the expression and regulation of miR-205 are primarily confined to epigenetic areas, whether genetic variation of miR-205 is related to the occurrence or to the development of tumors has not been reported. The aim of this study was to screen genetic variation of miR-205 gene and to investigate its association with the risk and development of lung and breast cancer.Material/MethodsGenomic DNA was extracted from cultured tumor cell lines and formalin-fixed and paraffin-embedded lung and breast tissue samples. Bisulfite Clone Sequencing (BCS) and qRT-PCR were employed to detect the DNA methylation status and gene expression of the miR-205 gene, respectively. Genetic variation of miR-205 and miR-205HG were genotyped with PCR-sequencing method. Immunohistochemical analysis for ER, PR, and HER2 was performed on breast tissue samples.ResultsA polymorphism, rs3842530, located downstream of the miR-205 gene and in the fourth exon of the miR-205 host gene (miR-205HG), was screened. rs3842530 had no correlation with the risk of breast cancer, but was associated with the risk of lung cancer (P<0.05).ConclusionsThese results indicate that the functional association of rs3842530 in miR-205HG and lung cancer might provide a possible explanation for the tissue-dependent function of miR-205 in different tumors.

Tumor Suppressive Function of mir-205 in Breast Cancer Is Linked to HMGB3 Regulation

Identifying targets of dysregulated microRNAs (miRNAs) will enhance our understanding of how altered miRNA expression contributes to the malignant phenotype of breast cancer. The expression of miR-205 was reduced in four breast cancer cell lines compared to the normal-like epithelial cell line MCF10A and in tumor and metastatic tissues compared to adjacent benign breast tissue. Two predicted binding sites for miR-205 were identified in the 3’ untranslated region of the high mobility group box 3 gene, HMGB3. Both dual-luciferase reporter assay and Western blotting confirmed that miR-205 binds to and regulates HMGB3. To further explore miR-205 targeting of HMGB3, WST-1 proliferation and in vitro invasion assays were performed in MDA-MB-231 and BT549 cells transiently transfected with precursor miR-205 oligonucleotide or HMGB3 small interfering RNA (siRNA). Both treatments reduced the proliferation and invasion of the cancer cells. The mRNA and protein levels of HMGB3 were higher in the tumor compared to adjacent benign specimens and there was an indirect correlation between the expression of HMGB3 mRNA and patient survival. Treatment of breast cancer cells with 5-Aza/TSA derepressed miR-205 and reduced HMGB3 mRNA while knockdown of the transcriptional repressor NRSF/REST, reduced miR-205 and increased HMGB3. In conclusion, regulation of HMGB3 by miR-205 reduced both proliferation and invasion of breast cancer cells. Our findings suggest that modulating miR-205 and/or targeting HMGB3 are potential therapies for advanced breast cancer.

Abstract 4204: miR-205 functions as a tumor suppressor in breast cancer by targeting HMGB3.

Abstract Breast cancer is the most commonly diagnosed cancer and the second leading cause of death among women. Triple Negative Breast Cancer (TNBC) represents 10-20% of breast cancer patients. It is considered the most aggressive and challenging type of breast cancer due to the lack of effective targeted therapies. Metastatic TNBC commonly migrates to the lung, brain and liver. Chemotherapy is the only option for these patients and it is hard to predict the success of chemotherapy. It is crucial to investigate the molecular changes leading to TNBC and develop new therapies targeting the molecular changes that cause this disease. microRNA (miRNA) has been implicated in many cancers by deregulating the expression of genes having key roles in cancer initiation and/or progression. We measured the mature levels of miR-205 in five breast cell lines: MCF10A non-tumorigenic normal like epithelial cell line, MCF7 cancer cell line expressing both estrogen and progesterone receptors (ER+/PR+); MDA-MB-436, MDA-MB-231 and BT549 TNBC cell lines (ER-/PR-/HER2-). We also assayed miR-205 in 33 human breast tissues (benign, tumor and metastatic). miR-205 levels were significantly down regulated in breast cancer cell lines compared to normal-like breast epithelial cells and in tumor and metastatic tissues compared to benign. We identified two miR-205 predicted binding sites in the 3’ untranslated region of the high mobility group gene, HMGB3. Both Dual-luciferase reporter assay and Western blotting confirmed that miR-205 regulates HMGB3. To explore the function of miR-205 and HMGB3 in breast cancer, WST-1 proliferation and Matrigel invasion assays were done using the TNBC cell lines MDA-MB-231 and BT549 transiently transfected with precursor miR-205 oligonucleotide (pre-miR-205 oligo) or HMGB3 small interfering RNA (siRNA). Both treatments reduced the proliferation and invasion of the cancer cells, demonstrating that knockdown of HMGB3 with miRNA or siRNA is effective in reducing the malignant phenotype of this protein. The messenger RNA (mRNA) levels of HMGB3 significantly increased in the tumor and metastatic groups in a stage dependent manner suggesting a tumor initiating and progression role. Western blotting of HMGB3 protein from 5 matched pairs of breast tissue showed that HMGB3 protein was not detected in benign tissues but was present in tumor. In conclusion, regulation of HMGB3 by miR-205 reduced both proliferation and invasion of breast cancer cells. Since the down regulation of miR-205 in patients’ tumor specimens correlate with the high HMGB3 protein levels in tumor, our findings suggest that reintroducing miR-205 and targeting HMGB3 are potential therapies for TNBC. Citation Format: Ola Elgamal, Jong-Kook Park, Thomas D. Schmittgen. miR-205 functions as a tumor suppressor in breast cancer by targeting HMGB3. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4204. doi:10.1158/1538-7445.AM2013-4204

MicroRNA-184 antagonizes microRNA-205 to maintain SHIP2 levels in epithelia

Despite their potential to regulate approximately one-third of the whole genome, relatively few microRNA (miRNA) targets have been experimentally validated, particularly in stratified squamous epithelia. Here we demonstrate not only that the lipid phosphatase SHIP2 is a target of miRNA-205 (miR-205) in epithelial cells, but, more importantly, that the corneal epithelial-specific miR-184 can interfere with the ability of miR-205 to suppress SHIP2 levels. This is the first example of a miRNA negatively regulating another to maintain levels of a target protein. Interfering with miR-205 function by using a synthetic antagomir, or by the ectopic expression of miR-184, leads to a coordinated damping of the Akt signaling pathway via SHIP2 induction. This was associated with a marked increase in keratinocyte apoptosis and cell death. Aggressive squamous cell carcinoma (SCC) cells exhibited elevated levels of miR-205. This was associated with a concomitant reduction in SHIP2 levels. Partial knockdown of endogenous miR-205 in SCCs markedly decreased phosphorylated Akt and phosphorylated BAD levels and increased apoptosis. We were able to increase SHIP2 levels in SCC cells after inhibition of miR-205. Therefore, miR-205 might have diagnostic value in determining the aggressivity of SCCs. Blockage of miR-205 activity with an antagomir or via ectopic expression of miR-184 could be novel therapeutic approaches for treating aggressive SCCs.