miRNAs involved in LY6K and estrogen receptor α contribute to tamoxifen-susceptibility in breast cancer

Micro-RNAs targeting the estrogen receptor alpha involved in endocrine therapy resistance in breast cancer

Endocrine therapy resistance (ETR) in breast cancer (BC) is a multicausal phenomenon with diverse alterations in the tumor cell interactome. Within these alterations, non-coding RNAs (ncRNAs) such as micro-RNAs (miRNAs) modulate the expression of tumor suppressor genes and proto-oncogenes, such as the ESR1 gene encoding estrogen receptor alpha (ERα). This work aims to review the effects of miRNAs targeting ERα mRNA and their mechanisms related to ETR in BC. A thorough review of the literature and an in silico study were carried out to elucidate the involvement of each miRNA, thus contributing to the understanding of ETR in BC.

miRNA-dependent resistance mechanisms to anti-hormonal therapies in estrogen receptor-positive breast cancer patients

The estrogen receptor (ERα) is expressed in 70%-80% of breast cancers and is a target of endocrine therapy. However, resistance to endocrine therapy poses a significant clinical challenge. MicroRNAs (miRNAs) have emerged as critical players in oncogenesis and as modulators of therapy response. This review provides an overview of miRNAs that modulate anti-hormonal drug responses. We identified 56 miRNAs associated with resistance to endocrine therapy. These miRNAs had a total of 40 proven target genes that were grouped based on their function under currently known resistance mechanisms, including ER modulation, signaling pathway activation, cell-cycle modulation, and other mechanisms. For a limited number of miRNA-target gene interactions, the relevance of the identified target gene(s) was confirmed by copy or rescue of the miRNA-induced phenotype. Overall, this review highlights critical roles of miRNAs as crucial mediators of resistance to anti-hormonal therapy. The identified miRNA-target gene interactions can serve as a foundation for future functional studies exploring the potential of selected miRNAs in overcoming drug resistance, which might improve outcomes for breast cancer patients.

Blood-derived microRNAs are related to cognitive domains in the general population

INTRODUCTION

Blood-derived microRNAs (miRNAs) are potential candidates for detecting and preventing subclinical cognitive dysfunction. However, replication of previous findings and identification of novel miRNAs associated with cognitive domains, including their relation to brain structure and the pathways they regulate, are still lacking.

METHODS

We examined blood-derived miRNAs and miRNA co-expression clusters in relation to cognitive domains, structural magnetic resonance imaging measures, target gene expression, and genetic variants in 2869 participants of a population-based cohort.

RESULTS

Five previously identified and 14 novel miRNAs were associated with cognitive domains. Eleven of these were also associated with cortical thickness and two with hippocampal volume. Multi-omics analysis showed that certain identified miRNAs were genetically influenced and regulated genes in pathways like neurogenesis and synapse assembly.

DISCUSSION

We identified miRNAs associated with cognitive domains, brain regions, and neuronal processes affected by aging and neurodegeneration, making them promising candidate blood-based biomarkers or therapeutic targets of subclinical cognitive dysfunction.

HIGHLIGHTS

We investigated the association of blood-derived microRNAs with cognitive domains. Five previously identified and 14 novel microRNAs were associated with cognition. Eleven cognition-related microRNAs were also associated with cortical thickness. Identified microRNAs were linked to genes associated with neuronal functions. Results provide putative biomarkers or therapeutic targets of cognitive aging.

Upregulation of LY6K induced by FTO-mediated demethylation promotes the tumorigenesis and metastasis of oral squamous cell carcinoma via CAV-1-mediated ERK1/2 signaling activation

Lymphocyte antigen 6 complex locus K (LY6K) has been demonstrated to play a significant role in cancers and identified as a therapeutic biomarker for head and neck squamous cell carcinoma. However, the role of LY6K in oral squamous cell carcinoma (OSCC) has not been explored. The current study discovered that LY6K was aberrantly upregulated in OSCC cell lines and tissues and that high LY6K expression significantly correlated with poorer survival of OSCC patients. Through stable knockdown of LY6K, we found that the growth, colony formation, migration, and invasion of OSCC cells were substantially suppressed. In addition, tumor growth and lung metastasis in vivo were effectively inhibited by LY6K depletion. Mechanically, LY6K binds with CAV-1 and activates CAV-1-mediated MAPK/ERK signaling to exert its oncogenic effects on OSCC. In addition, LY6K expression in OSCC was discovered to be regulated by FTO-mediated RNA N6-methyladenosine (m6A) modification in an IGF2BP1-dependent manner. Generally, LY6K expression was upregulated by FTO-mediated demethylation in OSCC, which promoted the tumorigenesis and metastasis of OSCC via activating the CAV-1-mediated ERK1/2 signaling pathway.

The Impact of miRNAs on the Efficacy of Tamoxifen in Breast Cancer Treatment: A Systematic Review

Seventy percent of breast cancer patients have an active estrogen receptor. Tamoxifen interferes with estrogen's ability to bind to cancer cells. The most challenging aspect of tamoxifen, however, is that breast cancer cells become resistant to its effects. Some studies have shown that alterations in miRNA expression contribute significantly to drug resistance in breast cancer. Therefore, the present systematic review aims to investigate miRNAs that significantly influence the response to tamoxifen treatment. The present study follows the PRISMA instructions. The Web of Science, PubMed, and Scopus databases were searched to retrieve English articles. The searches were conducted up to September 11, 2022. The search strategy included the terms "Tamoxifen", "Breast Neoplasm", and "MicroRNA". The inclusion criteria of this study are English, original, and experimental studies investigating miRNAs that are effective in the treatment efficacy of tamoxifen. A total of 565 articles were retrieved. After screening, 75 studies met our inclusion criteria. This systematic review study examined 105 miRNAs, of which 44 have a positive effect, and 47 miRNAs inhibit tamoxifen function. Fourteen miRNAs have a controversial effect, ie, some studies show positive and negative effects. The study of miRNAs affecting tamoxifen function in breast cancer patients may facilitate the identification of individuals at higher risk of disease recurrence. Conversely, it can potentially utilize appropriate interventions to defeat drug resistance effectively.

miR-192 family in breast cancer: Regulatory mechanisms and diagnostic value

There is a growing interest in the role of the miRNA family in human cancer. The miRNA-192 family is a group of conserved small RNAs, including miR-192, miR-194, and miR-215. Recent studies have shown that the incidence and mortality of breast cancer have been increasing epidemiologically year by year, and it is urgent to clarify the pathogenesis of breast cancer and seek new diagnostic and therapeutic methods. There is increasing evidence that miR-192 family members may be involved in the occurrence and development of breast cancer. This review describes the regulatory mechanism of the miRNA-192 family affecting the malignant behavior of breast cancer cells and evaluates the value of the miRNA-192 family as a diagnostic and prognostic biomarker for breast cancer. It is expected that summarizing and discussing the relationship between miRNA-192 family members and breast cancer, it will provide a new direction for the clinical diagnosis and treatment of breast cancer and basic medical research.

Silencing LY6D Expression Inhibits Colon Cancer in Xenograft Mice and Regulates Colon Cancer Stem Cells' Proliferation, Stemness, Invasion, and Apoptosis via the MAPK Pathway

This study explored the role of lymphocyte antigen 6 family member D (LY6D) in colon cancer stem cells' (CCSCs) proliferation and invasion. LY6D was knocked down using siRNA, and the down-regulation of LY6D was verified using Western blotting. After LY6D knockdown, CCSCs' proliferation, stemness, and invasion were suppressed, whereas apoptosis was increased. Gene Ontology (GO) enrichment analysis revealed that the differentially expressed genes (DEGs) between siLY6D and the negative control groups were significantly enriched in the cell-substrate adherens junction, focal adhesion, and cell-substrate junction terms. Meanwhile, the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the DEGs were significantly enriched in the MAPK pathway. In addition, Western blotting results showed that pBRAF and pERK1/2, cascade kinases of the MAPK pathway, were significantly down-regulated after LY6D knockdown. In addition, nude mice xenograft experiments showed that the siLY6D treatment decreased tumor sizes and weights and improved tumor-bearing mice survival rates compared with the control group. In conclusion, these findings indicate that LY6D, which is highly expressed in CCSCs, is a key factor involved in tumor growth and development and might be a potential cancer marker and therapeutic target for colon cancer.

Identification and panoramic analysis of drug response-related genes in triple negative breast cancer using as an example NVP-BEZ235

Taking NVP-BEZ235 (BEZ235) as an example to screen drug response-related genes (DRRGs) and explore their potential value in triple-negative breast cancer (TNBC). Through high-throughput technique, multidimensional transcriptome expression data (mRNA, miRNA and lncRNA) of BEZ235-treated and -untreated MDA-MB-468 cell lines were obtained. Combined with transcriptome data of the MDA-MB-468 cells and TCGA-TNBC tissues, differential gene expression analysis and WGCNA were performed to identify DRRGs associated with tumor trait by simulating the drug response microenvironment (DRM) of BEZ235-treated patients. Based on DRRGs, we constructed a ceRNA network and verified the expression levels of three key molecules by RT-qPCR, which not only demonstrated the successful construction of a BEZ235-treated cell line model but also explained the antitumor mechanism of BEZ235. Four molecular subtypes related to the DRM with survival difference were proposed using cluster analysis, namely glycolysis subtype, proliferation depression subtype, immune-suppressed subtype, and immune-activated subtype. A novel prognostic signature consisting of four DRRGs was established by Lasso-Cox analysis, which exhibited outstanding performance in predicting overall survival compared with several excellent reported signatures. The high- and low-risk groups were characterized by enrichment of metabolism-related pathways and immune-related pathways, respectively. Of note, the low-risk group had a better response to immune checkpoint blockade. Besides, pRRophetic analysis found that patients in the low-risk group were more sensitive to methotrexate and cisplation, whereas more resistant to BEZ235, docetaxel and paclitaxel. In conclusion, the DRRGs exemplified by BEZ235 are potential biomarkers for TNBC molecular typing, prognosis prediction and targeted therapy. The novel DRRGs-guided strategy for predicting the subtype, survival and therapy efficacy, might be also applied to more cancers and drugs other than TNBC and BEZ235.

Non-Coding RNAs Modulating Estrogen Signaling and Response to Endocrine Therapy in Breast Cancer

The largest part of human DNA is transcribed into RNA that does not code for proteins. These non-coding RNAs (ncRNAs) are key regulators of protein-coding gene expression and have been shown to play important roles in health, disease and therapy response. Today, endocrine therapy of ERα-positive breast cancer (BC) is a successful treatment approach, but resistance to this therapy is a major clinical problem. Therefore, a deeper understanding of resistance mechanisms is important to overcome this resistance. An increasing amount of evidence demonstrate that ncRNAs affect the response to endocrine therapy. Thus, ncRNAs are considered versatile biomarkers to predict or monitor therapy response. In this review article, we intend to give a summary and update on the effects of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) on estrogen signaling in BC cells, this pathway being the target of endocrine therapy, and their role in therapy resistance. For this purpose, we reviewed articles on these topics listed in the PubMed database. Finally, we provide an assessment regarding the clinical use of these ncRNA types, particularly their circulating forms, as predictive BC biomarkers and their potential role as therapy targets to overcome endocrine resistance.

Molecular Mechanisms of Anti-Estrogen Therapy Resistance and Novel Targeted Therapies

Breast cancer (BC) is the most commonly diagnosed cancer in women, constituting one-third of all cancers in women, and it is the second leading cause of cancer-related deaths in the United States. Anti-estrogen therapies, such as selective estrogen receptor modulators, significantly improve survival in estrogen receptor-positive (ER+) BC patients, which represents about 70% of cases. However, about 60% of patients inevitably experience intrinsic or acquired resistance to anti-estrogen therapies, representing a major clinical problem that leads to relapse, metastasis, and patient deaths. The resistance mechanisms involve mutations of the direct targets of anti-estrogen therapies, compensatory survival pathways, as well as alterations in the expression of non-coding RNAs (e.g., microRNA) that regulate the activity of survival and signaling pathways. Although cyclin-dependent kinase 4/6 and phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) inhibitors have significantly improved survival, the efficacy of these therapies alone and in combination with anti-estrogen therapy for advanced ER+ BC, are not curative in advanced and metastatic disease. Therefore, understanding the molecular mechanisms causing treatment resistance is critical for developing highly effective therapies and improving patient survival. This review focuses on the key mechanisms that contribute to anti-estrogen therapy resistance and potential new treatment strategies alone and in combination with anti-estrogen drugs to improve the survival of BC patients.

A Novel-Defined Necroptosis-Related miRNA Signature for Forecasting the Prognosis of Low-Grade Glioma

Background

Increasing evidence has shown that necroptosis has enormous significance in the generation and deterioration of cancer, and miRNA molecular markers involved in necroptosis in low-grade gliomas (LGGs) have not been thoroughly reported.

Methods

Using the miRNA data of 512 samples from The Cancer Genome Atlas (TCGA), 689 miRNAs from LGG samples were split into high immunity score and low immunity score groups for analysis. The differential miRNAs related to necroptosis were analyzed by univariate Cox regression analysis. On the basis of the outcome of univariate Cox regression analysis, miRNAs with significant differences were selected to construct a multivariate Cox regression model and calculate the risk score. Then, we evaluated whether the risk score could be used as an unaided prognostic factor.

Results

Overall, six differential miRNAs were identified (hsa-miR-148a-3p, hsa-miR-141-3p, hsa-miR-223-3p, hsa-miR-7-5p, hsa-miR-500a-3p, and hsa-miR-200a-5p). Univariate and multivariate Cox regression analyses were performed, and the c index was 0.71. Then, by mixing the risk score with clinicopathological factors, univariate Cox regression (HR: 2.7146, 95% CI: 1.8402−4.0044, P < 0.0001) and multivariate Cox regression analyses (HR: 2.3280, 95% CI: 1.5692−3.4536, P < 0.001) were performed. The data suggested that the risk score is an unaided prognostic indicator, which is markedly related with the overall survival time of LGG sufferers. Thus, a lower risk score is correlated with better prediction of LGG.

Conclusion

In order to achieve the ultimate goal of improving the living conditions of patients, we established prognostic risk model using 6 miRNAs related to necroptosis, which has the ability to predict the prognosis of LGG. It is possible to further enrich the therapeutic targets for LGG and provide clinical guidance for the treatment of LGG in the future.

miR-500a-3p is a Potential Prognostic Biomarker in Hepatocellular Carcinoma

Purpose

miR-500a-3p has been extensively reported to be implicated in the development and progression in several human cancer types. This study aimed to investigate the diagnostic and prognostic significance of miR-500a-3p as a biomarker in hepatocellular carcinoma (HCC).

Methods

miR-500a-3p expression was evaluated by in situ hybridization (ISH) and real-time PCR in 10 adjacent normal tissues (ANT), 21 liver fibrosis tissues, and 110 HCC tissues. Statistical analysis was used to investigate the correlation of miR-500a-3p expression with clinicopathological features in HCC patients. Kaplan–Meier survival analysis was performed to evaluate the prognostic significance of miR-500a-3p in overall survival and recurrence-free survival in HCC patients.

Results

In this study, we found that expression levels of miR-500a-3p were enhanced in HCC tissues. High miR-500a-3p levels were positively correlated with multiple clinicopathological features, including advanced clinical stage, distant metastatic status, increased AFP levels and poor tumor differentiation degree. More importantly, high miR-500a-3p levels predicted poor overall survival and early recurrence in HCC patients. Finally, a strong and positive correlation of miR-500a-3p mRNA expression with ISH staining scores was observed in clinical HCC tissues.

Conclusion

Our findings suggest that miR-500a-3p might be used as a novel biomarker to facilitate early diagnosis and predict prognosis in HCC patients.

From Micro to Long: Non-Coding RNAs in Tamoxifen Resistance of Breast Cancer Cells

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer mortality among women. Two thirds of patients are classified as hormone receptor positive, based on expression of estrogen receptor alpha (ERα), the main driver of breast cancer cell proliferation, and/or progesterone receptor, which is regulated by ERα. Despite presenting the best prognosis, these tumors can recur when patients acquire resistance to treatment by aromatase inhibitors or antiestrogen such as tamoxifen (Tam). The mechanisms that are involved in Tam resistance are complex and involve multiple signaling pathways. Recently, roles for microRNAs and lncRNAs in controlling ER expression and/or tamoxifen action have been described, but the underlying mechanisms are still little explored. In this review, we will discuss the current state of knowledge on the roles of microRNAs and lncRNAs in the main mechanisms of tamoxifen resistance in hormone receptor positive breast cancer. In the future, this knowledge can be used to identify patients at a greater risk of relapse due to the expression patterns of ncRNAs that impact response to Tam, in order to guide their treatment more efficiently and possibly to design therapeutic strategies to bypass mechanisms of resistance.

Emerging Role of MiR-192-5p in Human Diseases

MicroRNAs (miRNAs) are a type of small non-coding RNAs that play an essential role in numerous biological processes by regulating the post-transcriptional expression of target genes. Recent studies have demonstrated that miR-192-5p, a member of the miR-192 family, partakes in several human diseases, especially various cancers, including cancers of the lung, liver, and breast. Importantly, the levels of miR-192-5p are abundant in biofluids, including the serum and urine, and the exosomal levels of miR-192-5p in circulation can aid in the diagnosis and prognosis of various diseases, such as chronic hepatitis B (CHB) infection disease. Notably, recent studies suggest that miR-192-5p is regulated by long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs). However, there are no comprehensive overviews on the role of miR-192-5p in human diseases. This review discusses the significant studies on the role of miR-192-5p in various human diseases, with special emphasis on the diseases of the respiratory and digestive systems.

miRNA Expression Profiles in Luminal A Breast Cancer-Implications in Biology, Prognosis, and Prediction of Response to Hormonal Treatment

Breast cancer, which is the most common malignancy in women, does not form a uniform nosological unit but represents a group of malignant diseases with specific clinical, histopathological, and molecular characteristics. The increasing knowledge of the complex pathophysiological web of processes connected with breast cancercarcinogenesis allows the development of predictive and prognostic gene expressionand molecular classification systems with improved risk assessment, which could be used for individualized treatment. In our review article, we present the up-to-date knowledge about the role of miRNAs and their prognostic and predictive value in luminal A breast cancer. Indeed, an altered expression profile of miRNAs can distinguish not only between cancer and healthy samples, but they can classify specific molecular subtypes of breast cancer including HER2, Luminal A, Luminal B, and TNBC. Early identification and classification of breast cancer subtypes using miRNA expression profilescharacterize a promising approach in the field of personalized medicine. A detection of sensitive and specific biomarkers to distinguish between healthy and early breast cancer patients can be achieved by an evaluation of the different expression of several miRNAs. Consequently, miRNAs represent a potential as good diagnostic, prognostic, predictive, and therapeutic biomarkers for patients with luminal A in the early stage of BC.

MicroRNAs and Epigenetics Strategies to Reverse Breast Cancer

Breast cancer is a sporadic disease with genetic and epigenetic components. Genomic instability in breast cancer leads to mutations, copy number variations, and genetic rearrangements, while epigenetic remodeling involves alteration by DNA methylation, histone modification and microRNAs (miRNAs) of gene expression profiles. The accrued scientific findings strongly suggest epigenetic dysregulation in breast cancer pathogenesis though genomic instability is central to breast cancer hallmarks. Being reversible and plastic, epigenetic processes appear more amenable toward therapeutic intervention than the more unidirectional genetic alterations. In this review, we discuss the epigenetic reprogramming associated with breast cancer such as shuffling of DNA methylation, histone acetylation, histone methylation, and miRNAs expression profiles. As part of this, we illustrate how epigenetic instability orchestrates the attainment of cancer hallmarks which stimulate the neoplastic transformation-tumorigenesis-malignancy cascades. As reversibility of epigenetic controls is a promising feature to optimize for devising novel therapeutic approaches, we also focus on the strategies for restoring the epistate that favor improved disease outcome and therapeutic intervention.

Emerging Role of Lymphocyte Antigen-6 Family of Genes in Cancer and Immune Cells

Stem Cell Antigen-1 (Sca-1/Ly6A) was the first identified member of the Lymphocyte antigen-6 (Ly6) gene family. Sca-1 serves as a marker of cancer stem cells and tissue resident stem cells in mice. The Sca-1 gene is located on mouse chromosome 15. While a direct homolog of Sca-1 in humans is missing, human chromosome 8—the syntenic region to mouse chromosome 15—harbors several genes containing the characteristic domain known as LU domain. The function of the LU domain in human LY6 gene family is not yet defined. The LY6 gene family proteins are present on human chromosome 6, 8, 11, and 19. The most interesting of these genes are located on chromosome 8q24.3, a frequently amplified locus in human cancer. Human LY6 genes represent novel biomarkers for poor cancer prognosis and are required for cancer progression in addition to playing an important role in immune escape. Although the mechanism associated with these phenotype is not yet clear, it is timely to review the current literature in order to address the critical need for future advancements in this field. This review will summarize recent findings which describe the role of human LY6 genes—LY6D, LY6E, LY6H, LY6K, PSCA, LYPD2, SLURP1, GML, GPIHBP1, and LYNX1; and their orthologs in mice at chromosome 15.

Transgenic overexpression of human LY6K in mice suppresses mature T cell development in the thymus

Lymphocyte antigen 6 family member K (LY6K) is upregulated in a number of types of cancer and promotes tumor cell proliferation and metastasis. In addition, LY6K is involved in tamoxifen resistance in breast cancer. However, the in vivo molecular mechanism of LY6K has not yet been investigated. In the present study, transgenic mice overexpressing human LY6K (hLY6K) were generated using the pMAMneo vector, and the effect of LY6K upregulation in vivo was investigated. A total of 4 transgenic mice were generated, and the gene copy number was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RT-qPCR demonstrated that mRNA of hLY6K was overexpressed in the thymus and spleen of the transgenic mice compared with wild-type mice. Flow cytometric analysis demonstrated that the proportions of B and T cells in the spleen were similar in wild-type and transgenic mice; however, the proportion of thymic mature T cells decreased in the transgenic mice, while there was an increase in the proportion of naïve T cells. These findings suggest that the overexpression of LY6K suppresses T cell development, and that LY6K is a potential therapeutic target for cancer.

Emerging Role of Novel Biomarkers of Ly6 Gene Family in Pan Cancer

Stem cell antigen-1 (Sca-1) is the first identified member of mouse Ly6 gene family. We discovered that Sca-1 disrupts TGFβ signaling and enhances mammary tumorigenesis in a DMBA-induced mammary tumor model. Sca-1 gene is lost during evolution in humans. Human Ly6 genes Ly6D, LyE, LyH, and LyK on human chromosome 8q24.3 genes are syntenic to the mouse chromosome 15 where Sca-1 is located. We found that Ly6D, E, H, and K are upregulated in human cancer compared to normal tissue and that the increased expression of these genes are associated with poor prognosis of multiple types of human cancer. Several other groups have indicated increased expression of Ly6 genes in human cancer. Here we described the relevance of expression of human Ly6D, LyE, LyH, and LyK in functioning of normal tissues and tumor progression.

hsa-miR-500a-3P alleviates kidney injury by targeting MLKL-mediated necroptosis in renal epithelial cells

MLKL is a central mediator for necroptosis. Its knockout significantly relieves acute kidney injury (AKI). However, its upstream regulatory mechanism in AKI has not been fully elucidated. We recently reviewed how microRNAs (miRNAs), a type of well-studied epigenetic regulator, play critical roles in AKI. Here, we evaluated miRNAs that potentially target MLKL and evaluated their function in human tubular epithelial cells in response to toxic and ischemic insults. TargetScan analysis showed that miR-194-5P, miR-338-3P, miR-500a-3P, and miR-577 had MLKL binding sites. Although all 4 miRNAs are reduced in AKI, our data show that only hsa-miR-500a-3P was significantly suppressed in cisplatin-treated human tubular epithelial (HK2) cells. We further found that hsa-miR-500a-3P alleviated cisplatin-induced HK2 cell death, which was confirmed by transmission electron microscopy and flow cytometry. In addition, overexpression of hsa-miR-500a-3P decreased kidney injury molecule-1 mRNA and protein levels. Real-time PCR, ELISA, and immunofluorescence data show that hsa-miR-500a-3P protected against inflammatory response, evidenced by decreased monocyte chemotactic protein-1 and proinflammatory cytokines TNF-α and IL-8. Further, hsa-miR-500a-3P attenuated P65 NF-κB phosphorylation and promoter activity. Mechanistically, luciferase reporter assay showed that hsa-miR-500a-3P bound the 3'UTR of MLKL, thereby suppressing phosphorylation and membrane translocation of MLKL. In agreement with these findings, we identified that overexpression of hsa-miR-500a-3P attenuated cell injury and the inflammatory response in response to sodium azide treatment in an in vitro model. Results show that circulating exosomes from patients with AKI down-regulated miR-500a-3P, which suppressed cell injury and inflammation in HK2 cells. hsa-miR-500a-3P alleviated toxic and ischemic insults that were triggered by cell necroptosis and the inflammatory response in human HK2 cells by targeting MLKL. This may serve as a novel therapeutic target for treatment of AKI.-Jiang, L., Liu, X.-Q., Ma, Q., Yang, Q., Gao, L., Li, H.-D., Wang, J.-N., Wei, B., Wen, J., Li, J., Wu, Y.-G., Meng, X.-M. hsa-miR-500a-3P alleviates kidney injury by targeting MLKL-mediated necroptosis in renal epithelial cells.

microRNA Regulation in Estrogen Receptor-Positive Breast Cancer and Endocrine Therapy

As de novo and acquired resistance to standard first line endocrine therapies is a growing clinical challenge for estrogen receptor-positive (ER⁺) breast cancer patients, understanding the mechanisms of resistance is critical to develop novel therapeutic strategies to prevent therapeutic resistance and improve patient outcomes. The widespread post-transcriptional regulatory role that microRNAs (miRNAs) can have on various oncogenic pathways has been well-documented. In particular, several miRNAs are reported to suppress ERα expression via direct binding with the 3’ UTR of ESR1 mRNA, which can confer resistance to estrogen/ERα-targeted therapies. In turn, estrogen/ERα activation can modulate miRNA expression, which may contribute to ER⁺ breast carcinogenesis. Given the reported oncogenic and tumor suppressor functions of miRNAs in ER⁺ breast cancer, the targeted regulation of specific miRNAs is emerging as a promising strategy to treat ER⁺ breast cancer and significantly improve patient responsiveness to endocrine therapies. In this review, we highlight the major miRNA-ER regulatory mechanisms in context with ER⁺ breast carcinogenesis, as well as the critical miRNAs that contribute to endocrine therapy resistance or sensitivity. Collectively, this comprehensive review of the current literature sheds light on the clinical applications and challenges associated with miRNA regulatory mechanisms and novel miRNA targets that may have translational value as potential therapeutics for the treatment of ER⁺ breast cancer.

miR-500a-3p promotes cancer stem cells properties via STAT3 pathway in human hepatocellular carcinoma

BACKGROUND

miR-500a-3p has been demonstrated to be involved in the development, progression and metastasis in several human cancers. Constitutive activation of JAK/STAT3 signaling pathway has been reported to play an important role in the development and progression of hepatocellular carcinoma (HCC).The purpose of this study was to determine the biological roles and clinical significance of miR-500a-3p in HCC and to identify whether miR-500a-3p has an effect on the activity of JAK/STAT3 signaling in HCC.

METHODS

miR-500a-3p expression was examined by real-time PCR in 8 paired HCC tissues and individual 120 HCC tissues respectively. Statistical analysis was performed to explore the clinical correlation between miR-500a-3p expression and clinicopathological features and overall and relapse-free survival in HCC patients. In vitro and in vivo assays were performed to investigate the biological roles of miR-500a-3p in HCC. The bioinformatics analysis, real-time PCR, western blot and luciferase reporter assay were performed to discern and examine the relationship between miR-500a-3p and its potential targets. Clinical correlation of miR-500a-3p with its targets was examined in HCC tissues.

RESULTS

miR-500a-3p is dramatically elevated in HCC tissues and cells and high expression of miR-500a-3p correlates with poor overall and relapse-free survival in HCC patients. Upregulating miR-500a-3p enhances, while silencing miR-500a-3p suppresses, the spheroid formation ability, fraction of side population and expression of cancer stem cell factors in vitro and tumorigenicity in vivo in HCC cells. Our findings further reveal miR-500a-3p promotes the cancer stem cell characteristics via targeting multiple negative regulators of JAK/STAT3 signaling pathway, including SOCS2, SOCS4 and PTPN11, leading to constitutive activation of STAT3 signaling. Moreover, the inhibitory effects of anti-miR-500a-3p on cancer stem cell phenotypes and activity of STAT3 signaling were reversed by silencing SOCS2, SOCS4 and PTPN11 in miR-500a-3p-downexpressing cells, respectively. Clinical correlation of miR-500a-3p with the targets was examined in human HCC tissues.

CONCLUSION

our results uncover a novel mechanism by which miR-500a-3p promotes the stemness maintenance of cancer stem cell in HCC, suggesting that silencing miR-500a-3p may serve as a new therapeutic strategy in the treatment of hepatocellular carcinoma.