Emerging functions of microRNA-146a/b in development and breast cancer: microRNA-146a/b in development and breast cancer

Identification of proteins' expression pathway and the effective miRNAs for the treatment of human papillomavirus-induced cervical cancer: in-silico analyses-experimental research

Introduction

Cervical cancer is the fourth most common cancer in women. The risk factors for cervical cancer include human papillomavirus (HPV) infection, age, smoking, number of pregnancies, use of oral contraceptives, and diet. However, long-term HPV infection appears to be the main risk factor for developing cervical cancer. This in-silico analysis aims to identify the expression network of proteins and the miRNAs that play a role in the development of HPV-induced cervical cancer.

Methods

The critical proteins and miRNAs were extracted using the DisGeNET and miRBase databases. String and Gephi were applied to the network analysis. The GTEx web tool was utilized to Identify tissue expression levels. The Enrichr website was used to explore the molecular function and pathways of found genes.

Results

Ten proteins, TP53, MYC, AKT1, TNF, IL6, EGFR, STAT3, CTNNB1, ESR1, and JUN, were identified as the most critical shared gene network among cervical cancer and HPV. Seven miRNAs were found, including hsa-mir-146a, hsa-mir-27, hsa-mir-203, hsa-mir-126, hsa-mir-145, hsa-mir-944, and hsa-mir-93, which have a common expression in cervical cancer and HPV.

Conclusion

Overall, the gene network, including TP53, MYC, AKT1, TNF, IL6, EGFR, STAT3, CTNNB1, ESR1, and JUN, and Also, hsa-mir-145, hsa-mir-93, hsa-mir-203, and hsa-mir-126 can be regarded as a gene expression pathway in HPV-induced cervical cancer.

In vitro maturation in the presence of Leukemia Inhibitory Factor modulates gene and miRNA expression in bovine oocytes and embryos

Members of the interleukin-6 (IL-6) family of cytokines are important for reproductive function that are mediated through changes in gene and miRNA expression. Herein, we characterized the expression of miR-21, miR-155, miR-34c and miR-146a in bovine oocytes and cumulus cells during in vitro maturation (IVM) with leukemia inhibitory factor (LIF), IL-6 and IL-11 or unsupplemented controls. LIF-exposed COCs showed higher expression of miR-21 and miR-155 in oocytes, whereas miR-146a expression was increased in oocytes matured with IL-6 and IL-11. In cumulus cells, miR-155 expression was elevated by all treatments while only LIF increased miR-21 expression. Based on these results, we next examined how LIF exposure during IVM affected oocyte competence, through IVF and the expression of specific genes in GV- and MII-oocytes, in 2- and 8-cell embryos, and in Day 8-blastocysts. LIF supplementation did not affect cleavage rate, blastocyst yield or several other developmental parameters, but did increase hatching rate. LIF suppressed DPPA3, ZAR1 and NPM2 expression in 2 cell- and/or 8-cell embryos. LIF increased the expression of KAT2A and HSPA1A in MII-oocytes, and that of HDAC1, KAT2A and HSP90AA1 and the BAX:BCL2L1 ratio in 2-cell embryos. In contrast, HDAC1, KAT2A and HSP90AA1 expression and BAX:BCL2L1 ratio was lower in 8-cell embryos derived from LIF oocytes. IVM with LIF also increased the expression of DNMT3A, HSPA1A and HSP90AA1 in blastocysts. In conclusion, supplementation with LIF during IVM was consistently associated with changes in the relative abundance of transcripts in mature bovine oocytes and in specific embryo developmental stages.

Mammary gland stem cells and their application in breast cancer

The mammary gland is an organ comprising two primary lineages, specifically the inner luminal and the outer myoepithelial cell layers. Mammary gland stem cells (MaSCs) are highly dynamic and self-renewing, and can give rise to these mammary gland lineages. The lineages are responsible for gland generation during puberty as well as expansion during pregnancy. In recent years, researchers have focused on understanding how MaSCs are regulated during mammary gland development and transformation of breast cancer. Here, we summarize the identification of MaSCs, and how they are regulated by the signaling transduction pathways, mammary gland microenvironment, and non-coding RNAs (ncRNAs). Moreover, we debate the evidence for their serving as the origin of breast cancer, and discuss the therapeutic perspectives of targeting breast cancer stem cells (BCSCs). In conclusion, a better understanding of the key regulators of MaSCs is crucial for the clinical treatment of breast cancer.

miR-146a promotes growth of osteosarcoma cells by targeting ZNRF3/GSK-3β/β-catenin signaling pathway

MicroRNA-146a-5p (miR-146a) functions as a tumor suppressor or oncogene involved in multiple biological processes. But, the underlying molecular mechanisms by which miR-146a contributes to osteosarcoma (OS) remain unclear. The correlation of miR-146a expression with clinicopathologic characteristics and prognosis of OS patients was analyzed by Kaplan-Meier and Cox regression analysis. Cell growth in vitro and in vivo was assessed by MTT, cell colony formation and animal models. The target of miR-146a was identified by bioinformatics software and gene luciferase reporter. As a result, miR-146a expression was substantially elevated in OS tissues and was positively associated with the tumor size (P=0.001) and recurrence (P=0.027) of OS patients. Moreover, knockdown of miR-146a suppressed cell proliferation and colony formation in vitro and in vivo. In addition, zinc and ring finger 3 (ZNRF3) was identified as a direct target of miR-146a in OS cells, and was negatively correlated with miR-146a expression in OS tissues. Overexpression of ZNRF3 inhibited cell growth and rescued the tumor-promoting role of miR-146a via inhibition of GSK-3β/β-catenin signaling pathway. Taken together, miR-146a may function as an oncogene in OS cells by targeting ZNRF3/GSK-3β/β-catenin signaling pathway, and represent a promising biomarker for OS patients.

Functional diversity of miR-146a-5p and TRAF6 in normal and oral cancer cells

Numerous studies implicate miR-146a as pleiotropic regulator of carcinogenesis; however, its roles in carcinogenesis are not fully understood. A clue from expression analyses of miR-146a-5p in all 13 oral squamous cell carcinoma (OSCC) cell lines examined and in OSCC tissues, whole blood and whole saliva of OSCC patients in vivo revealed that miR‑146a-5p expression was highly upregulated. Particularly, we widened the view of its upregulation in saliva, implicating that high miR-146a-5p expression is not only correlated closely to the development of human oral cancer, but also to a possible candidate as a diagnostic marker of OSCC. Indeed, further examination showed that exogenous miR-146a-5p expression showed pleiotropic effects on cell proliferation and apoptosis which were partially based on the contextual responses of activation of JNK, downstream of TRAF6 that was targeted by miR-146a-5p in normal human keratinocytes and OSCC cell lines. TRAF6 suppression by a TRAF6-specific siRNA resulted in contradictory consequences on cellular processes in normal and OSCC cells. Notably, TRAF6 downregulation by both miR-146a-5p and TRAF6-specific siRNA deactivated JNK in SCC-9, but not in normal human keratinocytes. In support of the proliferation-promoting effect of miR-146a-5p, silencing of endogenous miR-146a-5p significantly reduced proliferation of SCC-9. Together, these results suggest that miR-146a-5p affects proliferation and apoptosis in a cellular context-dependent manner and selectively disarms the TRAF6-mediated branch of the TGF-β signaling in OSCC cell lines by sparing Smad4 involvement.

Single nucleotide polymorphisms at miR-146a/196a2 and their primary ovarian insufficiency-related target gene regulation in granulosa cells

MicroRNAs post-transcriptionally regulate gene expression in animals and plants. The aim of this study was to identify new target genes for microRNA polymorphisms (miR-146aC>G and miR-196a2T>C) in primary ovarian insufficiency (POI). We cloned and transfected miR-146aC>G and miR-196a2T>C into human granulosa cells and used microarrays and qPCR-arrays to examine the changes in the messenger RNA expression profile. We show miR-146aC>G and miR-196a2T>C change the mRNA expression patterns in granulosa cell. In each case, mRNAs were up or down-regulated after treatments with miR-146a C or G and miR-196a2 T or C. We found that miR-146a led to a significantly altered regulation of the mRNA levels of FOXO3, FOXL2 and CCND2 compared to controls. We also found that the polymorphisms of miR-146a led to a significantly altered regulation of CCND2 and FOXO3. Our results suggest that miR-146aC>G and miR-196a2T>C can regulate the levels of many of their target transcripts. In addition, specific target genes of miR-146aC>G polymorphisms may be involved in granulosa cell regulation.

A risk of digestive tract neoplasms susceptibility in miR-146a and miR-196a2

Genome-wide association studies have identified many genes associated with digestive tract neoplasms. However, the published findings have been conflicting. The aim of our study was to evaluate the involvement of two polymorphisms (miR-146a rs2910164, miR-196a2 rs11614913) in digestive tract neoplasms risk and explore how miR-146a and miR-196a2 influence this risk. Systemic research of the PubMed, EBSCO, CBM and VIP databases was performed. The software STATA 12.0 was used to calculate odd ratios and 95% confidence intervals. There were 14 studies (6,053 cases and 6,527 controls) available for rs2910164 and 15 studies (5,648 cases and 6,607 controls) involved in rs11614913. Rs2910164G>C was statistically significantly associated with digestive tract neoplasms (OR 1.134, 95% CI 1.076-1.194, P < 0.001). In the subgroup analysis by ethnicity, significant association was observed in Asian individuals (OR 1.145, 95% CI 1.084-1.209, P < 0.001). We found a correlation between rs11614913 and only colorectal cancer (OR 1.325, 95% CI 1.102-1.594, P = 0.003). This study suggested that digestive tract neoplasms might associate with miR-146a variants, but not miR-196a2 variants.

Non-coding RNAs in Mammary Gland Development and Disease

Non-coding RNAs (ncRNAs) are untranslated RNA molecules that function to regulate the expression of numerous genes and associated biochemical pathways and cellular functions. NcRNAs include small interfering RNAs (siRNAs), microRNAs (miRNAs), PIWI-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs) and long non-coding RNAs (lncRNAs). They participate in the regulation of all developmental processes and are frequently aberrantly expressed or functionally defective in disease. This Chapter will focus on the role of ncRNAs, in particular miRNAs and lncRNAs, in mammary gland development and disease.

Quercetin inhibits proliferation and invasion acts by up-regulating miR-146a in human breast cancer cells

Breast cancer is the most common female malignancies in the world which seriously impacts the female health. In recent years, various studies have been reported to determine the relevance of miRNAs to human cancer. One of these miRNAs, miR-146a has been down-regulated in multiple human cancer types, but up-regulation showed inducing apoptosis. To determine the role of quercetin treated on breast cancer, we investigated the effect of quercetin on cell proliferation in human breast cancer cell lines MCF-7 and MDA-MB-231 with/without transfection of miR-146a mimic or anti-miR-146a. Furthermore, the expressions of bax and cleaved-caspase-3, mainly were increased in control and overexpression miR-146a groups, however, the expression of EGFR was inverse. All the results demonstrated that quercetin exhibited excellent effect on inhibiting cell proliferation in human breast cancer cells, which was performed by up-regulating miR-146a expression, then via inducing apoptosis through caspase-3 activation and mitochondrial-dependent pathways, and inhibiting invasion through down-regulating the expression of EGFR.

The STAT5-regulated miR-193b locus restrains mammary stem and progenitor cell activity and alveolar differentiation

The transcription factor STAT5 mediates prolactin signaling and controls functional development of mammary tissue during pregnancy. This study has identified the miR-193b locus, also encoding miRNAs 365-1 and 6365, as a STAT5 target in mammary epithelium. While the locus was characterized by active histone marks in mammary tissue, STAT5 binding and expression during pregnancy, it was silent in most non-mammary cells. Inactivation of the miR-193b locus in mice resulted in elevated mammary stem/progenitor cell activity as judged by limiting dilution transplantation experiments of primary mammary epithelial cells. Colonies formed by mutant cells were larger and contained more Ki-67 positive cells. Differentiation of mammary epithelium lacking the miR-193b locus was accelerated during puberty and pregnancy, which coincided with the loss of Cav3 and elevated levels of Elf5. Normal colony development was partially obtained upon ectopically expressing Cav3 or upon siRNA-mediated reduction of Elf5 in miR-193b-null primary mammary epithelial cells. This study reveals a previously unknown link between the mammary-defining transcription factor STAT5 and a microRNA cluster in controlling mammary epithelial differentiation and the activity of mammary stem and progenitor cells.

The roles of the epithelial-mesenchymal transition marker PRRX1 and miR-146b-5p in papillary thyroid carcinoma progression

Thyroid carcinoma is the most common endocrine malignancy, and papillary thyroid carcinoma represents the most common thyroid cancer. Papillary thyroid carcinomas that invade locally or metastasize are associated with a poor prognosis. We found that, during epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1), papillary thyroid carcinoma cells acquired increased cancer stem cell-like features and the transcription factor paired-related homeobox protein 1 (PRRX1; alias PRX-1), a newly identified EMT inducer, was markedly up-regulated. miR-146b-5p was also transiently up-regulated during EMT, and in siRNA experiments miR-146b-5p had an inhibitory role on cell proliferation and invasion during TGF-β1-induced EMT. We conclude that papillary thyroid carcinoma tumor cells exhibit increased cancer stem cell-like features during TGF-β1-induced EMT, that miR-146b-5p has a role in cell proliferation and invasion, and that PRRX1 plays an important role in papillary thyroid carcinoma EMT and disease progression.

Krüppel-like factor 8 promotes tumorigenic mammary stem cell induction by targeting miR-146a

The properties of stem cells can be induced during the epithelial to mesenchymal transition (EMT). The responsible molecular mechanisms, however, remain largely undefined. Here we report the identification of the microRNA-146a (miR-146a) as a common target of Krüppel-like factor 8 (KLF8) and TGF-β, both of which are known EMT-inducers. Upon KLF8 overexpression or TGF-β treatment, a significant portion of the MCF-10A cells gained stem cell traits as demonstrated by an increased expression of CD44(high)/CD24low, activity of aldehyde dehydrogenase (ALDH), mammosphere formation and chemoresistance. Along with this change, the expression of miR-146a was highly upregulated in the cells. Importantly, we found that miR-146a was aberrantly co-overexpressed with KLF8 in a panel of invasive human breast cancer cell lines. Ectopic expression of KLF8 failed to induce the stem cell traits in the MCF-10A cells if the cells were pre-treated with miR-146a inhibitor, whereas overexpression of miR-146a in the MCF-10A cells alone was sufficient to induce the stem cell traits. Co-staining and luciferase reporter analyses indicated that miR-146a targets the 3'-UTR of the Notch signaling inhibitor NUMB for translational inhibition. Overexpression of KLF8 dramatically potentiated the tumorigenecity of MCF-10A cells expressing the H-Ras oncogene, which was accompanied by a loss of NUMB expression in the tumors. Taken together, this study identifies a novel role and mechanism for KLF8 in inducing pro-tumorigenic mammary stem cells via miR-146a potentially by activating Notch signaling. This mechanism could be exploited as a therapeutic target against drug resistance of breast cancer.

A functional polymorphism in the miR-146a gene is associated with the risk of childhood acute lymphoblastic leukemia: a preliminary report

Growing evidence showed that microRNAs (miRs) are involved in normal hematopoiesis and the pathogenesis of several hematological malignancies. Genetic variations or mutations occurring in the miR gene region may affect the property of miRs through altering miR expression and/or maturation. The aim of the present study was to evaluate the possible relationship between two miRs polymorphisms, hsa-miR-146a (rs2910164 G>C) and hsa-miR-499 (rs3746444 T>C), and the susceptibility to childhood acute lymphoblastic leukemia (ALL) in a sample of Iranian population. This case-control study was performed on 75 children diagnosed with ALL and 115 age- and sex-matched children with no history of cancer of any type (as the control group). Tetra-primer amplification refractory mutation system-polymerase chain reaction was applied for genotyping the variants. We found that the rs2910164 G>C variant of hsa-miR-146a significantly increased the risk of ALL (CC vs. GG, OR = 4.24, 95% CI = 1.52-11.87, P = 0.006; GC vs. GG, OR = 3.55, 95% CI = 1.41-8.93, P = 0.007; C vs. T, OR = 1.73, 95% CI = 1.13-2.67, P = 0.012). With respect to hsa-miR-499 rs3746444 T/C, no significant difference in allele and genotype frequencies of the rs3746444 variant between ALL patients and controls was observed. Our results for the first time demonstrated that the miR-146a rs2910164, but not miR-499 rs3746444 variant, was associated with increased risk for developing pediatrics ALL in an Iranian population.