Expression Of miR-21 In Tumors Research Articles

Hypomethylation Causes MIR21 Overexpression in Tumors

miR-21 is an oncogenic microRNA (miRNA) that is upregulated in many solid tumors. However, the effect of MIR21 hypomethylation on miR-21 expression in tumors and the mechanism of miR-21 DNA demethylation remain unclear. In this study, we confirmed that the expression of miR-21 was significantly increased in multiple tumors. We analyzed eight types of cancer, including breast cancer (BRCA), lung adenocarcinoma (LUAD), renal and renal clear cell carcinoma (KIRC), bladder urothelial carcinoma (BLCA), hepatocellular carcinoma (LIHC), lung squamous cell cancer (LUSC), renal papillary cell carcinoma (KIRP), and pancreatic adenocarcinoma (PAAD). MIR21 DNA methylation levels were elevated in these cancers. CpG loci located approximately 200 bp upstream of the transcription initiation site strongly affect MIR21 expression. We also confirmed MIR21 hypomethylation by pyrosequencing of fresh clear cell renal cell carcinoma (ccRCC) samples. Demethylating agent was proved to increase hsa-miR-21-5p level in HEK293T cells, while knockdown of DNA demethylases TET3 and TDG decreased MIR21 expression. In addition, we showed that the cg02515217 CpG locus in MIR21 promoter was a conserved binding site of transcription factors CEBPB, MEIS3, and TEAD4, which were co-expressed with miR-21 in tumors. These observations identified that gene hypomethylation regulated the expression of MIR21 in tumors.

Comprehensive transcriptomic analyses of tissue, serum, and serum exosomes from hepatocellular carcinoma patients

BackgroundThe expression of microRNAs (miRNAs) is a promising prognostic and diagnostic tool in hepatocellular carcinoma (HCC). Here we performed small RNA sequencing (sRNA-seq) of tissue, serum and serum exosomes to investigate changes in miRNA expression between the different sample types and correlated the expression with clinical parameters. We also performed gene expression arrays on tumor and normal tissue.ResultsPaired tissue, serum and serum exosomes sequencing revealed consistent positive correlation of miR-21 between serum exosomes and tumor tissue, indicating that miR-21 could be exported from tissue to circulation via exosomes. We found that let-7 miRNAs are generally upregulated in serum exosomes compared to whole serum, indicating that these miRNAs could be preferentially loaded into exosomes. Comparing serum from HCC patients with serum from healthy individuals revealed a global increase of miRNAs in serum from HCC patients, including an almost 4-fold increase of several miRNAs, including the liver-specific miR-122. When correlating miRNA expression with clinical parameters we detected significant association between hepatitis B virus (HBV) infection and miR-122 in serum as well as several serum and tissue-miRNAs that correlated with surgery type. We found that miR-141 and miR-146 correlated with cirrhosis in tumor tissue and normal tissue, respectively. Finally, high expression of miR-21 in tumors were associated with poor survival. Focusing on gene expression we found several significant messenger RNAs (mRNAs) between tumor and normal tissue and a Gene Ontology (GO) analysis revealed that these changes were mainly related to cell cycle and metabolism. Further, we detected mRNAs that correlated with cirrhosis and HBV infection in tissue. Finally, GO analysis of predicted targets for miRNAs down-regulated in tumor found that these were enriched for functions related to collagen synthesis.ConclusionsOur combined data point to altered miRNA and mRNA expression contributing to both generally impaired lipid metabolism and increased cell proliferation and a miRNA-driven increase in collagen synthesis in HCC. Our results further indicate a correlation in miRNA expression between exosomes, serum, and tissue samples suggesting export from tumors via exosomes. This correlation could provide a basis for a more tumor-specific miRNA profile in serum.

173PD MicroRNA MIR21, T cells, and PTGS2 expression in

Background Prostaglandin-endoperoxide synthase 2 (PTGS2, cyclooxygenase-2) produces inflammatory mediator prostaglandin E2 (PGE2), and contributes to suppresses antitumorT-cell-mediated immunity. PTGS2-driven inflammatory responses can induce tumorexpressionof microRNAMIR21 (miR-21) thatcanincreaselocalPGE2levelby downregulatingPGE2-metabolizingenzymes. Thus,wehypothesizedthattheprognostic associationoftumorMIR21 expressionlevelincolorectalcarcinomamightdependon PTGS2 expression and that tumor MIR21 expression might be inversely associated with T- cell density in colorectal carcinoma tissue. Methods Utilizing 765 rectal and colon cancer specimens in the Nurses' Health Study and the Health Professionals Follow-up Study, we measured MIR21 expression by quantitative reverse-transcription PCR, and PTGS2 expression by immunohistochemistry. Densities of CD3+, CD8+, CD45RO (pTpRC)+ and FOXP3+ cells in tumor tissue were determined by tissue microarray immunohistochemistry and computer-assisted image analysis. Multivariable analyses were conducted to assess the statistical interaction between MIR21 and PTGS2 in colorectal cancer-specific survival analysisandtheassociationofMIR21 expression withT-celldensity, controlling for potential confounders including microsatellite instability, CpG island methylator phenotype, LINE-1 methylation level, and KRAS, BRAF, and PIK3CA mutations. Results The association between MIR21 expression and colorectal cancer-specific mortality was statistically significant in PTGS2-high cancers (multivariable hazard ratio ofthehighestvs. lowestquartileofMIR21, 2.28;95%confidenceinterval, 1.42 to3.67; Ptrend= 0.0004) butnotinPTGS2-absent/lowcancers (Ptrend= 0.22;Pinteraction= 0.0004). Tumor MIR21 expression was inversely associated with densities of CD3+ and CD45RO+ cells (Pt rend < 0.0005). Conclusions:Ourdatasupportapossibleroleoftumorepigeneticderegulationbynon- coding RNA in suppressing antitumor T-cell-mediated immune response, and suggest MIR21 as a potential target for immunotherapy and treatment in colorectal cancer. Legal entity responsible for the study USA National Institutes of Health (NIH) Funding USA National Institutes ofHealth (NIH) Disclosure All authors have declared no conflicts ofinterest.

MicroRNA MIR21 (miR-21) and PTGS2 Expression in Colorectal Cancer and Patient Survival.

Prostaglandin-endoperoxide synthase 2 (PTGS2, cyclooxygenase-2; a target of aspirin) produces inflammatory mediator prostaglandin E2 (PGE2), and contributes to colorectal neoplasia development. PTGS2-driven inflammatory responses can induce tumor expression of microRNA MIR21 (miR-21) that can increase local PGE2 level by downregulating PGE2-metabolizing enzymes. We hypothesized that the prognostic association of tumor MIR21 expression level in colorectal carcinoma might depend on inflammatory tumor microenvironment and be stronger in tumors expressing high-level PTGS2. Utilizing 765 rectal and colon cancer specimens in the Nurses' Health Study and the Health Professionals Follow-up Study, we measured MIR21 expression by quantitative reverse transcription PCR, and PTGS2 expression by immunohistochemistry. Cox proportional hazards regression model was used to assess statistical interaction between MIR21 and PTGS2 in colorectal cancer-specific survival analysis, controlling for potential confounders including microsatellite instability, CpG island methylator phenotype, LINE-1 methylation level, and KRAS, BRAF, and PIK3CA mutations. Tumor MIR21 expression level was associated with higher colorectal cancer-specific mortality (Ptrend = 0.029), and there was a statistically significant interaction between MIR21 and PTGS2 (Pinteraction = 0.0004). The association between MIR21 expression and colorectal cancer-specific mortality was statistically significant in PTGS2-high cancers (multivariable hazard ratio of the highest vs. lowest quartile of MIR21, 2.28; 95% confidence interval, 1.42-3.67; Ptrend = 0.0004) but not in PTGS2-absent/low cancers (Ptrend = 0.22). MIR21 expression level in colorectal carcinoma is associated with worse clinical outcome, and this association is stronger in carcinomas expressing high-level PTGS2, suggesting complex roles of immunity and inflammation in tumor progression. Clin Cancer Res; 22(15); 3841-8. ©2016 AACR.

MicroRNA MIR21 and T Cells in Colorectal Cancer.

The complex interactions between colorectal neoplasia and immune cells in the tumor microenvironment remain to be elucidated. Experimental evidence suggests that microRNA MIR21 (miR-21) suppresses antitumor T-cell-mediated immunity. Thus, we hypothesized that tumor MIR21 expression might be inversely associated with T-cell density in colorectal carcinoma tissue. Using 538 rectal and colon cancer cases from the Nurses' Health Study and the Health Professionals Follow-up Study, we measured tumor MIR21 expression by a quantitative reverse-transcription PCR assay. Densities of CD3(+), CD8(+), CD45RO (PTPRC)(+), and FOXP3(+) cells in tumor tissue were determined by tissue microarray immunohistochemistry and computer-assisted image analysis. Ordinal logistic regression analysis was conducted to assess the association of MIR21 expression (ordinal quartiles as a predictor variable) with T-cell density (ordinal quartiles as an outcome variable), adjusting for tumor molecular features, including microsatellite instability; CpG island methylator phenotype; KRAS, BRAF, and PIK3CA mutations; and LINE-1 methylation. We adjusted the two-sided α level to 0.012 for multiple hypothesis testing. Tumor MIR21 expression was inversely associated with densities of CD3(+) and CD45RO(+) cells (Ptrend < 0.0005). The multivariate odds ratio of the highest versus lowest quartile of MIR21 for a unit increase in quartile categories of CD3(+) or CD45RO(+) cells was 0.44 [95% confidence interval (CI), 0.28 to 0.68] or 0.41 (95% CI, 0.26-0.64), respectively. Our data support a possible role of tumor epigenetic deregulation by noncoding RNA in suppressing the antitumor T-cell-mediated adaptive immune response and suggest MIR21 as a potential target for immunotherapy and prevention in colorectal cancer.

High tumor cell expression of microRNA-21 in node positive non-small cell lung cancer predicts a favorable clinical outcome

BackgroundMicroRNA (miR)-21 has been revealed as an oncogene in cancer development, and is one of the miRNAs closely connected to angiogenesis. We aimed to explore the impact of miR-21 expression in both tumor and stromal compartments of non-small cell lung cancer (NSCLC), and correlations between miR-21 and angiogenic protein markers.MethodsFrom 335 unselected stage I to IIIA NSCLC carcinomas, duplicate tumor and tumor-associated stromal cores were collected in tissue microarrays (TMAs). In situ hybridization (ISH) was used to detect the expression of miR-21 separately in tumor cells and stromal cells of the tumor, and immunohistochemistry (IHC) was used to detect the expression of the protein markers protein kinase B (Akt), phosphatidylinositol-3-kinase (PI3K), hypoxia induced factor 1 (HIF1α) and vascular endothelial growth factor-A (VEGF-A).ResultsIn univariate analyses, high tumor cell expression of miR-21 in patients with lymph node metastasis was a positive prognostic factor (P = 0.024). High stromal miR-21 expression had a negative prognostic impact (P = 0.022). In the multivariate analysis, low tumor mir-21 expression in node positive patients was an independent adverse prognostic factor (HR 2.03, CI 95% 1.09-3.78, P = 0.027).ConclusionsIn patients with lymph node metastasis, miR-21 expression in tumor cells is an independent positive prognostic factor. High stromal miR-21 expression is a negative prognostic factor.

Co-regulated expression of TGF-β Variants and miR-21 in bladder cancer.

To investigate a potential alteration in the expression levels of transforming growth factor β (TGF-β) and miR-21 in bladder cancer tissues. Using real-time polymerase chain reaction (PCR) method, we examined a potential correlated expression of miR-21 and TGF-β variants in 30 bladder tumors and their marginal/non-tumor biopsy specimens obtained from the same patients. Our data revealed a significant down-regulation of TGF-β variants (P = .03) along with a non-significant alteration in the expression of miR-21 in tumor vs. non-tumor samples. However, in contrast to low-grade tumors, the expression of miR-21 was upregulated in high-grade ones, and the expression level can efficiently discriminate low-grade tumors from high-grade ones (P = .03). In accordance to the observed similarity between TGF-β variants and miR-21 gene expression alterations in bladder tumors, treating 5637 bladder cancer cell line with TGF-β recombinant protein caused a significant upregulation of miR-21. The later finding further confirmed a correlated expression of TGF-β and miR-21 in bladder tumors.