Cluster miRNAs and cancer: Diagnostic, prognostic and therapeutic opportunities

Hsa-miR-181a-2-3p inhibits the oncogenicity of colon cancer by directly targeting STING

OBJECTIVE

Colon cancer is a common malignant tumor of the gastrointestinal system, which is characterized by high morbidity and mortality. The purpose of this study was to analyze the expression and biological role of miR-181a-2-3p in colon cancer and to investigate the molecular mechanism of its regulatory effect on colon cancer through stimulator of interferon genes (STING).

METHODS

Real-time reverse transcription polymerase chain reaction (qRT-PCR) assay was used to detect the expression of miR-181a-2-3p in colon cancer cell lines and normal intestinal epithelial cells. After overexpression of miR-181a-2-3p in colon cancer cell lines SW480 and HT29, cells were examined by CCK8, Transwell, and flow cytometry assays for alterations in proliferation, migration, apoptosis, and cell cycle. Target genes of miR-181a-2-3p were predicted by bioinformatics and validated by dual luciferase assays. Rescue experiments were performed to explore the role of STING in the effect of miR-181a-2-3p. The effect of miR-181a-2-3p on colon cancer proliferation in vivo was validated by nude mouse tumorigenicity assay.

RESULTS

miR-181a-2-3p was lowly expressed in both colon cancer tissues and cell lines. Overexpression of miR-181a-2-3p led to reduced proliferation and migration, increased apoptosis, and altered cell cycle in colon cancer cell lines SW480 and HT29. STING was a target gene of miR-181a-2-3p. Increased STING expression partially counteracted the effect of overexpression of miR-181a-2-3p on colon cancer cell lines. miR-181a-2-3p also suppressed colon cancer proliferation in vivo.

CONCLUSION

miR-181a-2-3p inhibits the proliferation and oncogenicity of colon cancer, and its molecular mechanism could be inhibited by STING.

Regulation and tumor-suppressive function of the miR-379/miR-656 (C14MC) cluster in cervical cancer

Cervical cancer (CC) is a key contributor to cancer-related mortality in several countries. The identification of molecular markers and the underlying mechanism may help improve CC management. We studied the regulation and biological function of the chromosome 14 microRNA cluster (C14MC; miR-379/miR-656) in CC. Most C14MC members exhibited considerably lower expression in CC tissues and cell lines in The Cancer Genome Atlas (TCGA) cervical squamous cell carcinoma and endocervical adenocarcinoma patient cohorts. Bisulfite Sanger sequencing revealed hypermethylation of the C14MC promoter in CC tissues and cell lines. 5-aza-2 deoxy cytidine treatment reactivated expression of the C14MC members. We demonstrated that C14MC is a methylation-regulated miRNA cluster via artificial methylation and luciferase reporter assays. C14MC downregulation correlated with poor overall survival and may promote metastasis. C14MC activation via the lentiviral-based CRISPRa approach inhibited growth, proliferation, migration, and invasion; enhanced G2/M arrest; and induced senescence. Post-transcriptional regulatory network analysis of C14MC transcriptomic data revealed enrichment of key cancer-related pathways, such as metabolism, the cell cycle, and phosphatidylinositol 3-kinase (PI3K)-AKT signaling. Reduced cell proliferation, growth, migration, invasion, and senescence correlated with the downregulation of active AKT, MYC, and cyclin E1 (CCNE1) and the overexpression of p16, p21, and p27. We showed that C14MC miRNA activation increases reactive oxygen species (ROS) levels, intracellular Ca2+ levels, and lipid peroxidation rates, and inhibits epithelial-mesenchymal transition (EMT). C14MC targets pyruvate dehydrogenase kinase-3 (PDK3) according to the luciferase reporter assay. PDK3 is overexpressed in CC and is inversely correlated with C14MC. Both miR-494-mimic transfection and C14MC activation inhibited PDK3 expression. Reduced glucose uptake and lactate production, and upregulation of PDK3 upon C14MC activation suggest the potential role of these proteins in metabolic reprogramming. Finally, we showed that C14MC activation may inhibit EMT signaling. Thus, C14MC is a tumor-suppressive and methylation-regulated miRNA cluster in CC. Reactivation of C14MC can be useful in the management of CC.

A comprehensive review on the functional role of miRNA clusters in cervical cancer

Cervical cancer (CC) poses a significant health threat in women globally. MicroRNA clusters (MCs), comprising multiple miRNA-encoding genes, are pivotal in gene regulation. Various factors, including circular RNA and DNA methylation, govern MC expression. Dysregulated MC expression correlates strongly with CC development via promoting the acquisition of cancer hallmarks. Certain MCs show promise for diagnosis, prognosis and therapy selection due to their distinct expression patterns in normal, premalignant and tumor tissues. This review explains the regulation and biological functions of MCs and highlights the clinical relevance of abnormal MC expression in CC.

DAE-CFR: detecting microRNA-disease associations using deep autoencoder and combined feature representation

BACKGROUND

MicroRNA (miRNA) has been shown to play a key role in the occurrence and progression of diseases, making uncovering miRNA-disease associations vital for disease prevention and therapy. However, traditional laboratory methods for detecting these associations are slow, strenuous, expensive, and uncertain. Although numerous advanced algorithms have emerged, it is still a challenge to develop more effective methods to explore underlying miRNA-disease associations.

RESULTS

In the study, we designed a novel approach on the basis of deep autoencoder and combined feature representation (DAE-CFR) to predict possible miRNA-disease associations. We began by creating integrated similarity matrices of miRNAs and diseases, performing a logistic function transformation, balancing positive and negative samples with k-means clustering, and constructing training samples. Then, deep autoencoder was used to extract low-dimensional feature from two kinds of feature representations for miRNAs and diseases, namely, original association information-based and similarity information-based. Next, we combined the resulting features for each miRNA-disease pair and used a logistic regression (LR) classifier to infer all unknown miRNA-disease interactions. Under five and tenfold cross-validation (CV) frameworks, DAE-CFR not only outperformed six popular algorithms and nine classifiers, but also demonstrated superior performance on an additional dataset. Furthermore, case studies on three diseases (myocardial infarction, hypertension and stroke) confirmed the validity of DAE-CFR in practice.

CONCLUSIONS

DAE-CFR achieved outstanding performance in predicting miRNA-disease associations and can provide evidence to inform biological experiments and clinical therapy.

Multifaceted role of microRNAs in gastric cancer stem cells: Mechanisms and potential biomarkers

MicroRNAs (miRNAs) have received much attention in the past decade as potential key epigenomic regulators of tumors and cancer stem cells (CSCs). The abnormal expression of miRNAs is responsible for different phenotypes of gastric cancer stem cells (GCSCs). Some specific miRNAs could be used as promising biomarkers and therapeutic targets for the identification of GCSCs. This review summarizes the coding process and biological functions of miRNAs and demonstrates their role and efficacy in gastric cancer (GC) metastasis, drug resistance, and apoptosis, especially in the regulatory mechanism of GCSCs. It shows that the overexpression of onco-miRNAs and silencing of tumor-suppressor miRNAs can play a role in promoting or inhibiting tumor metastasis, apart from the initial formation of GC. It also discusses the epigenetic regulation and potential clinical applications of miRNAs as well as the role of CSCs in the pathogenesis of GC. We believe that this review may help in designing novel therapeutic approaches for GC.

CAFs-derived exosomes promote the development of cervical cancer by regulating miR-18a-5p-TMEM170B signaling axis

Mounting studies have showed that tumor microenvironment (TME) is crucial for cervical cancer (CC), and cancer-related fibroblasts (CAFs) play a major role in it. Recently, exosomal miRNAs secreted by CAFs have been found to be potential targets for cancer diagnosis and therapy. In this paper, we aimed to investigate the function of CAFs-mediated exosome miR-18a-5p (CAFs-exo-miR-18a-5p) in CC. First, in combination with bioinformatic data analysis of the GEO database (GSE86100) and RT-qPCR of CC clinical tissue samples and cell lines, miR-18a-5p was discovered to be markedly up-regulated in CC. Next, CAFs-secreted exosomes were isolated and it was found that miR-18a-5p expression was dramatically promoted in CC cell lines when treated with CAFs-exos. The CAFs-exo-miR-18a-5p was then elucidated to stimulate the proliferation and migration and inhibit the apoptosis of CC cells. In order to clarify the underlying mechanism, we further screened the target genes of miR-18a-5p. TMEM170B was selected by bioinformatic data analysis of online databases combined with RT-qPCR of CC clinical tissues and cells. Luciferase reporter gene analysis combined with molecular biology experiments further elucidated that miR-18a-5p suppressed TMEM170B expression in CC. Finally, both cell and animal experiments demonstrated that TMEM170B over-expression attenuated the oncogenic effect of CAFs-exo-miR-18a-5p. In conclusion, our study indicates that CAFs-mediated exosome miR-18a-5p promotes the initiation and development of CC by suppressing TMEM170B signaling axis, which provides a possible direction for the diagnosis and therapy of CC.

BAP31-Mediated miR-206/133b Cluster Promotes Transendothelial Migration and Metastasis of Colorectal Cancer

Dysregulated B cell receptor-associated protein 31 (BAP31) plays a crucial role in tumor progression. This study aimed to investigate the functions and molecular mechanism of BAP31 on the miR-206/133b cluster in colorectal cancer (CRC). qPCR was conducted to detect miRNA and mRNA levels in tissues and cells. Western blot assays were used to assess the levels of biomarkers and targets, as well as the levels of BAP31 and HOXD10. Wound healing, coculture and transwell assays were conducted to assess the transendothelial migration abilities of CRC cells. A luciferase assay was employed to assess miRNA binding effects on targets, as well as the initiating transcription effect of genomic fragments. Tumor growth and lung metastatic models were established through an in vivo animal study. BAP31 overexpression in CRC cells led to a reduction in the expression of the miR-206/133b cluster. The expression of the miR-206/133b cluster was correlated with the transendothelial migration capability of CRC cells. The miR-206/133b cluster was found to directly regulate cell division cycle 42 (CDC42) and actin-related protein 2/3 complex subunit 5 (ARPC5) in the tight junction pathway (hsa04530). Moreover, a potential transcription regulator of the miR-206/133b cluster was also found to be Homeobox D10 (HOXD10). We further elucidated the molecular mechanisms and functional mechanisms of BAP31's regulatory role in the expression levels of the miR-206/133b cluster by inhibiting HOXD10 translocation from the cytoplasm to the nucleus. In conclusion, this study provides valuable insights into how BAP31 regulates the transcription of the miR-206/133b cluster and how BAP31-related lung metastases arise in CRC.

An integrated analysis of microRNAs regulating DNA damage response in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) remains a clinical challenge due to its aggressive phenotype and limited treatment options for the patients. Many TNBC patients show an inherent defect in the DNA repair capacity primarily by acquiring germline mutations in BRCA1 and BRCA2 genes leading to Homologous Recombination Deficiency (HRD). Epigenetic modifications such as BRCA1 promoter methylation and miRNA expression targeting DNA repair pathway genes have contributed to the HRD phenotype in TNBC. Hence, we aimed to identify microRNAs that are associated with HRD status in the TCGA-BRCA project.

MATERIALS AND METHODS

We implemented a miRNA prediction strategy for identifying miRNAs targeting HR pathway genes using an in silico predicted and experimentally validated list from published literature for their association with genomic instability and factors affecting HRD. In silico analysis was performed to study miRNA expression patterns regulated by DNA methylation and TMB status in the TNBC patients from TCGA-BRCA project. Finally, we analysed selected miRNA expression with immune cell infiltration pattern in the TNBC patient cohort.

RESULTS

Our study identified miRNAs associated with HRD, tumour mutation burden (TMB), and immune cell infiltration. Identified miRNA signatures were associated with the miR-17 ~ 92 cluster, miR-106b ~ 25 cluster, and miR-200b ~ 429 cluster. Pathway analysis of selected miRNAs suggested their association with altered immune cell infiltration in TNBC.

CONCLUSION

Our study identified 6 'HRD associated miRNAs' such as miR-106b, miR-93, miR-17, miR-20a, miR-200b, and miR-429 as novel miRNA-based signatures associated with HR deficiency in TNBC.

Breast Cancer Therapeutics and Hippo Signaling Pathway: Novel MicroRNA-Gene-Protein Interaction Networks

The Hippo signaling pathway is a master regulator of development, cell proliferation, and apoptosis in particular, and it plays an important role in tissue regeneration, controlling organ size, and cancer suppression. Dysregulation of the Hippo signaling pathway has been implicated in breast cancer, a highly prevalent cancer affecting 1 out of every 15 women worldwide. While the Hippo signaling pathway inhibitors are available, they are suboptimal, for example, due to chemoresistance, mutation, and signal leakage. Inadequate knowledge about the Hippo pathway connections and their regulators limits our ability to uncover novel molecular targets for drug development. We report here novel microRNA (miRNA)-gene and protein-protein interaction networks in the Hippo signaling pathway. We employed the GSE miRNA dataset for the present study. The GSE57897 dataset was normalized and searched for differentially expressed miRNAs, and their targets were searched using the miRWalk2.0 tool. From the upregulated miRNAs, we observed that the hsa-miR-205-5p forms the biggest cluster and targets four genes involved in the Hippo signaling pathway. Interestingly, we found a novel connection between two Hippo signaling pathway proteins, angiomotin (AMOT) and mothers against decapentaplegic homolog 4 (SMAD4). From the downregulated miRNAs, hsa-miR-16-5p, hsa-miR-7g-5p, hsa-miR-141-3p, hsa-miR-103a-3p, hsa-miR-21-5p, and hsa-miR-200c-3p, target genes were present in the pathway. We found that PTEN, EP300, and BTRC were important cancer-inhibiting proteins, form hubs, and their genes interact with downregulating miRNAs. We suggest that targeting proteins from these newly unraveled networks in the Hippo signaling pathway and further research on the interaction of hub-forming cancer-inhibiting proteins can open up new avenues for next-generation breast cancer therapeutics.

Downregulation of miR-100-5p in cancer-associated fibroblast-derived exosomes facilitates lymphangiogenesis in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC), an aggressive gastrointestinal tumor, often has high early lymphatic metastatic potential. Cancer-associated fibroblasts (CAFs) are primary components in tumor microenvironment (TME), and the impact of CAFs and its derived exosomes on lymphangiogenesis remains elusive.

MATERIALS AND METHODS

CAFs and the microlymphatic vessel density (MLVD) in ESCC was examined. Exosomes were extracted from primary normal fibroblast (NFs) and CAFs. Subsequently, tumor-associated lymphatic endothelial cells (TLECs) were treated with these exosomes, and the effect on their biological behavior was examined. miR-100-5p was selected as the target miRNA, and its effect on TLECs was examined. The target of miR-100-5p was predicted and confirmed. Subsequently, IGF1R, PI3K, AKT, and p-AKT expression in TLECs and tumors treated with exosomes and miR-100-5p were examined.

RESULTS

A large number of CAFs and microlymphatic vessels were present in ESCC, leading to a poor prognosis. CAF-derived exosomes promoted proliferation, migration, invasion, and tube formation in TLECs. Further, they also enhanced lymphangiogenesis in ESCC xenografts. miR-100-5p levels were significantly lower in CAF-derived exosomes than in NF-derived exosomes. miR-100-5p inhibited proliferation, migration, invasion, and tube formation in TLECs. Further, miR-100-5p inhibited lymphangiogenesis in ESCC xenografts. Mechanistic studies revealed that this inhibition was mediated by the miR-100-5p-induced inhibition of IGF1R/PI3K/AKT axis.

CONCLUSION

Taken together, our study demonstrates that CAF-derived exosomes with decreased miR-100-5p levels exhibit pro-lymphangiogenesis capacity, suggesting a possibility of targeting IGF1R/PI3K/AKT axis as a strategy to inhibit lymphatic metastasis in ESCC.

Epigenetics of Thymic Epithelial Tumors

Thymic epithelial tumors (TETs) arise from the epithelial cells of the thymus and consist in the 1% of all adult malignancies, despite the fact that they are the most common lesions of the anterior mediastinum. TETs can be divided mainly into thymomas, thymic carcinomas, and the rarest ad aggressive neuroendocrine forms. Despite the surgical resection is quite resolving, the diagnosis of TETs is complicated by the absence of symptoms and the clinical presentation aggravated by several paraneoplastic disorders, including myasthenia gravis. Thus, the heterogeneity of TETs prompts the search for molecular biomarkers that could be helpful for tumor characterization and clinical outcomes prediction. With these aims, several researchers investigated the epigenetic profiles of TETs. In this manuscript, we narratively review the works investigating the deregulation of epigenetic mechanisms in TETs, highlighting the need for further studies combining genetic, epigenetic, and expression data to better characterize the different molecular subtypes and identify, for each of them, the most relevant epigenetic biomarkers of clinical utility.

MiR-19 Family Impairs Adipogenesis by the Downregulation of the PPARγ Transcriptional Network

microRNAs (miRNAs) are a class of small endogenous RNA that play pivotal roles in both the differentiation and function of adipocytes during the development of obesity. Despite this, only a few miRNA families have been identified as key players in adipogenesis. Here, we show the relevance of the miR-19 family, miR-19a and miR-19b, in lipid accumulation and the expansion of the adipose tissue in obesity. We observed that miR-19s were upregulated in the abdominal subcutaneous adipose tissue (aSAT) of human patients with morbid obesity, whereas after bariatric surgery, their expression was reduced. In vitro experiments identified miR-19a and b as crucial actors in adipogenesis and lipid accumulation. Overall, our results suggest a novel role of the miR-19 family in the regulatory networks underlying adipogenesis and, therefore, adipose tissue dysfunction.

HDAC2- and EZH2-Mediated Histone Modifications Induce PDK1 Expression through miR-148a Downregulation in Breast Cancer Progression and Adriamycin Resistance

Simple Summary

Epigenetic modification plays an important regulatory role in breast cancer progression. However, the relationship between epigenetic modification with tumor metabolism has not yet been fully elucidated. PDK1, as a key enzyme in glucose metabolism, mediates multiple tumors development. But, the mechanism of epigenetic modification in regulating PDK1 remains unclear in breast cancer. Here, we demonstrated that HDAC2 and EZH2 upregulated PDK1 expression through inhibiting miR-148a. Importantly, miR-148a targeting PDK1 regulated breast cancer cells glycolysis, invasion, epithelial-mesenchymal transition (EMT) and Adriamycin resistance. Our results suggested that the HDAC2/EZH2/miR-148a/PDK1 axis may be a promising potential therapeutic strategy.

Abstract

Background: Breast cancer has one of highest morbidity and mortality rates for women. Abnormalities regarding epigenetics modification and pyruvate dehydrogenase kinase 1 (PDK1)-induced unusual metabolism contribute to breast cancer progression and chemotherapy resistance. However, the role and mechanism of epigenetic change in regulating PDK1 in breast cancer remains to be elucidated. Methods: Gene set enrichment analysis (GSEA) and Pearson’s correlation analysis were performed to analyze the relationship between histone deacetylase 2 (HDAC2), enhancer of zeste homologue 2 (EZH2), and PDK1 in database and human breast cancer tissues. Dual luciferase reporters were used to test the regulation between PDK1 and miR-148a. HDAC2 and EZH2 were found to regulate miR-148a expression through Western blotting assays, qRT-PCR and co-immunoprecipitation assays. The effects of PDK1 and miR-148a in breast cancer were investigated by immunofluorescence (IF) assay, Transwell assay and flow cytometry assay. The roles of miR-148a/PDK1 in tumor growth were investigated in vivo. Results: We found that PDK1 expression was upregulated by epigenetic alterations mediated by HDAC2 and EZH2. At the post-transcriptional level, PDK1 was a new direct target of miR-148a and was upregulated in breast cancer cells due to miR-148a suppression. PDK1 overexpression partly reversed the biological function of miR-148a—including miR-148a’s ability to increase cell sensitivity to Adriamycin (ADR) treatment—inhibiting cell glycolysis, invasion and epithelial–mesenchymal transition (EMT), and inducing apoptosis and repressing tumor growth. Furthermore, we identified a novel mechanism: DNMT1 directly bound to EZH2 and recruited EZH2 and HDAC2 complexes to the promoter region of miR-148a, leading to miR-148a downregulation. In breast cancer tissues, HDAC2 and EZH2 protein expression levels also were inversely correlated with levels of miR-148a expression. Conclusion: Our study found a new regulatory mechanism in which EZH2 and HDAC2 mediate PDK1 upregulation by silencing miR-148a expression to regulate cancer development and Adriamycin resistance. These new findings suggest that the HDAC2/EZH2/miR-148a/PDK1 axis is a novel mechanism for regulating cancer development and is a potentially promising target for therapeutic options in the future.

miR-517b-3p promotes the progression of portal vein tumor thrombus via activating Wnt/β-catenin signaling pathway in hepatocellular carcinoma

AIMS

This study was aimed to investigate the expression patterns and prognostic value of microRNA-517b-3p (miR-517b-3p) in hepatocellular carcinoma (HCC) patients with portal vein tumor thrombus (PVTT).

METHODS

The expression of miR-517b-3p in PVTT tissues and cells was estimated using qRT-PCR. Through Kaplan-Meier survival analysis, Cox regression assay and ROC analysis, the significance of miR-517b-3p was explored. In addition, cell experiments were performed to examine the functional role of miR-517b-3p during progression of PVTT. Moreover, the biological process and biological pathway analysis analyses were conducted through GSEA and FunRich. Besides, the protein-protein interaction (PPI) network of the DEGs was established through cBioPortal website.

RESULTS

Compared with the controls, the miR-517b-3p was upregulated in both PVTT tissues and cells. The upregulated miR-517b-3p, which served as a potential diagnostic biomarker to distinguish PVTT from PT and controls, was associated with poor overall survival and acted as an independent prognostic factor. The cell proliferation, migration and invasion were proved to be enhanced by overexpression of miR-517b-3p. Furthermore, Wnt/β-catenin signaling was suppressed by miR-517b-3p knockdown and might be involved in the progression of PVTT.

CONCLUSION

miR-517b-3p may promote PVTT cell proliferation, migration and invasion via activation of Wnt/β-catenin signaling pathway. Meanwhile, miR-517b-3p has overexpression in PVTT samples, and serves as a candidate diagnostic and prognostic biomarker in HCC patients with PVTT.

Impact of miR-1/miR-133 Clustered miRNAs: PFN2 Facilitates Malignant Phenotypes in Head and Neck Squamous Cell Carcinoma

Based on our original RNA sequence-based microRNA (miRNA) signatures of head and neck squamous cell carcinoma (HNSCC), it was revealed that the expression levels of miR-1-3p, miR-206, miR-133a-3p, and miR-133b were significantly suppressed in cancer specimens. Seed sequences of miR-1-3p/miR-206 and miR-133a-3p/miR-133b are identical. Interestingly, miR-1-3p/miR-133a-3p and miR-206/miR-133b are clustered in the human genome. We hypothesized that the genes coordinately controlled by these miRNAs are closely involved in the malignant transformation of HNSCC. Our in silico analysis identified a total of 28 genes that had putative miR-1-3p/miR-133a-3p and miR-206/miR-133b binding sites. Moreover, their expression levels were upregulated in HNSCC tissues. Multivariate Cox regression analyses showed that expression of PFN2 and PSEN1 were independent prognostic factors for patients with HNSCC (p < 0.05). Notably, four miRNAs (i.e., miR-1-3p, miR-206, miR-133a-3p, and miR-133b) directly bound the 3′untranslated region of PFN2 and controlled expression of the gene in HNSCC cells. Overexpression of PFN2 was confirmed in clinical specimens, and its aberrant expression facilitated cancer cell migration and invasion abilities. Our miRNA-based strategy continues to uncover novel genes closely involved in the oncogenesis of HNSCC.

Role of the Mediator Complex and MicroRNAs in Breast Cancer Etiology

Transcriptional coactivators play a key role in RNA polymerase II transcription and gene regulation. One of the most important transcriptional coactivators is the Mediator (MED) complex, which is an evolutionary conserved large multiprotein complex. MED transduces the signal between DNA-bound transcriptional activators (gene-specific transcription factors) to the RNA polymerase II transcription machinery to activate transcription. It is known that MED plays an essential role in ER-mediated gene expression mainly through the MED1 subunit, since estrogen receptor (ER) can interact with MED1 by specific protein–protein interactions; therefore, MED1 plays a fundamental role in ER-positive breast cancer (BC) etiology. Additionally, other MED subunits also play a role in BC etiology. On the other hand, microRNAs (miRNAs) are a family of small non-coding RNAs, which can regulate gene expression at the post-transcriptional level by binding in a sequence-specific fashion at the 3′ UTR of the messenger RNA. The miRNAs are also important factors that influence oncogenic signaling in BC by acting as both tumor suppressors and oncogenes. Moreover, miRNAs are involved in endocrine therapy resistance of BC, specifically to tamoxifen, a drug that is used to target ER signaling. In metazoans, very little is known about the transcriptional regulation of miRNA by the MED complex and less about the transcriptional regulation of miRNAs involved in BC initiation and progression. Recently, it has been shown that MED1 is able to regulate the transcription of the ER-dependent miR-191/425 cluster promoting BC cell proliferation and migration. In this review, we will discuss the role of MED1 transcriptional coactivator in the etiology of BC and in endocrine therapy-resistance of BC and also the contribution of other MED subunits to BC development, progression and metastasis. Lastly, we identified miRNAs that potentially can regulate the expression of MED subunits.

Identifying and characterizing lincRNA genomic clusters reveals its cooperative functions in human cancer

Background

Emerging evidence has revealed that some long intergenic non-coding RNAs (lincRNAs) are likely to form clusters on the same chromosome, and lincRNA genomic clusters might play critical roles in the pathophysiological mechanism. However, the comprehensive investigation of lincRNA clustering is rarely studied, particularly the characterization of their functional significance across different cancer types.

Methods

In this study, we firstly constructed a computational method basing a sliding window approach for systematically identifying lincRNA genomic clusters. We then dissected these lincRNA genomic clusters to identify common characteristics in cooperative expression, conservation among divergent species, targeted miRNAs, and CNV frequency. Next, we performed comprehensive analyses in differentially-expressed patterns and overall survival outcomes for patients from The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) across multiple cancer types. Finally, we explored the underlying mechanisms of lincRNA genomic clusters by functional enrichment analysis, pathway analysis, and drug-target interaction.

Results

We identified lincRNA genomic clusters according to the algorithm. Clustering lincRNAs tended to be co-expressed, highly conserved, targeted by more miRNAs, and with similar deletion and duplication frequency, suggesting that lincRNA genomic clusters may exert their effects by acting in combination. We further systematically explored conserved and cancer-specific lincRNA genomic clusters, indicating they were involved in some important mechanisms of disease occurrence through diverse approaches. Furthermore, lincRNA genomic clusters can serve as biomarkers with potential clinical significance and involve in specific pathological processes in the development of cancer. Moreover, a lincRNA genomic cluster named Cluster127 in DLK1-DIO3 imprinted locus was discovered, which contained MEG3, MEG8, MEG9, MIR381HG, LINC02285, AL132709.5, and AL132709.1. Further analysis indicated that Cluster127 may have the potential for predicting prognosis in cancer and could play their roles by participating in the regulation of PI3K-AKT signaling pathway.

Conclusions

Clarification of the lincRNA genomic clusters specific roles in human cancers could be beneficial for understanding the molecular pathogenesis of different cancer types.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03179-5.

Megakaryocyte-specific knockout of the Mir-99b/let7e/125a cluster lowers platelet count without altering platelet function

The purpose of this research was to assess the effects of a microRNA (miRNA) cluster on platelet production. Human chromosome 19q13.41 harbors an evolutionarily conserved cluster of three miRNA genes (MIR99B, MIRLET7E, MIR125A) within 727 base-pairs. We now report that levels of miR-99b-5p, miR-let7e-5p and miR-125a-5p are strongly correlated in human platelets, and all are positively associated with platelet count, but not white blood count or hemoglobin level. Although the cluster regulates hematopoietic stem cell proliferation, the function of this genomic locus in megakaryocyte (MK) differentiation and platelet production is unknown. Furthermore, studies of individual miRNAs do not represent broader effects in the context of a cluster. To address this possibility, MK/platelet lineage-specific Mir-99b/let7e/125a knockout mice were generated. Compared to wild type littermates, cluster knockout mice had significantly lower platelet counts and reduced MK proplatelet formation, but no differences in MK numbers, ploidy, maturation or ultra-structural morphology, and no differences in platelet function. Compared to wild type littermates, knockout mice showed similar survival after pulmonary embolism. The major conclusions are that the effect of the Mir-99b/let7e/125a cluster is confined to a late stage of thrombopoiesis, and this effect on platelet number is uncoupled from platelet function.

MicroRNAs and JAK/STAT3 signaling: A new promising therapeutic axis in blood cancers

Blood disorders include a wide spectrum of blood-associated malignancies resulting from inherited or acquired defects. The ineffectiveness of existing therapies against blood disorders arises from different reasons, one of which is drug resistance, so different types of leukemia may show different responses to treatment. Leukemia occurs for a variety of genetic and acquired reasons, leading to uncontrolled proliferation in one or more cell lines. Regarding the genetic defects, oncogene signal transducer and activator of transcription (STAT) family transcription factor, especially STAT3, play an essential role in hematological disorders onset and progress upon mutations, dysfunction, or hyperactivity. Besides, microRNAs, as biological molecules, has been shown to play a dual role in either tumorigenesis and tumor suppression in various cancers. Besides, a strong association between STAT3 and miRNA has been reported. For example, miRNAs can regulate STAT3 via targeting its upstream mediators such as IL6, IL9, and JAKs or directly binding to the STAT3 gene. On the other hand, STAT3 can regulate miRNAs. In this review study, we aimed to determine the role of either microRNAs and STAT3 along with their effect on one another's activity and function in hematological malignancies.

Mechanosensitive pathways are regulated by mechanosensitive miRNA clusters in endothelial cells

Shear stress is known to affect many processes in (patho-) physiology through a complex, multi-molecular mechanism, termed mechanotransduction. The sheer complexity of the process has raised questions how mechanotransduction is regulated. Here, we comprehensively evaluate the literature about the role of small non-coding miRNA in the regulation of mechanotransduction. Regulation of mRNA by miRNA is rather complex, depending not only on the concentration of mRNA to miRNA, but also on the amount of mRNA competing for a single mRNA. The only mechanism to counteract the latter factor is through overarching structures of miRNA. Indeed, two overarching structures are present miRNA families and miRNA clusters, and both will be discussed in details, regarding the latest literature and a previous conducted study focussed on mechanotransduction. Both the literature and our own data support a new hypothesis that miRNA-clusters predominantly regulate mechanotransduction, affecting 65% of signalling pathways. In conclusion, a new and important mode of regulation of mechanotransduction is proposed, based on miRNA clusters. This finding implicates new avenues for treatment of mechanotransduction and atherosclerosis.

Positive correlation between miR-570 and prognosis of colon cancer: inhibition of cell proliferation and invasion

Colon cancer is one of most common cancers. The progression of various cancers is driven by miRNA-570. The role of miRNA-570 in the progression of colon cancer remains unclear. We aimed to investigate the clinical function of miR-570 and its impact on colon cancer cells. We evaluated the expression of miR-570 in colon cancer cells and analyzed its influence on the various clinical parameters. The Kaplan-Meier curve was plotted to understand the clinical role of miR-570. Cox regression analysis was performed to predict the prognostic factors in colon cancer. The Cell Counting Kit-8 was used to investigate the effect of miR-570 on cell proliferation. The transwell migration assay was performed to quantify cell migration and invasion. The quantitative real-time polymerase chain reaction technique was used to analyze the sample system. The results revealed that the level of miR-570 expression in colon cancer tissues and cell lines was low. The abnormal expression of miR-570 was associated with tumor size, extent of differentiation, lymph node metastasis, and tumor-node-metastasis stages. Downregulation of miR-570 indicated poor overall survival (OS), poor relapse-free survival, and unfavorable cancer-specific survival (CSS) rates in patients with colon cancer. The results from Cox regression analysis revealed that miR-570 expression could be used as an independent prognostic biomarker for OS and CSS in colon cancer. Overexpression of miR-570 can potentially result in the inhibition of cell proliferation, migration, and invasion. The results proved that miR-570 could potentially function as a tumor suppressor and a potential prognostic factor in patients with colon cancer.

Emerging Evidence of the Functional Impact of the miR379/miR656 Cluster (C14MC) in Breast Cancer

Many microRNAs exist in clusters that share comparable sequence homology and may target genes in a common pathway. The miR-379/miR-656 (C14MC) cluster is imprinted in the DLK1-Dio3 region of 14q32.3 and contains 42 miRNAs. It plays a functional role in numerous biological pathways including vascular remodeling and early development. With many C14MC miRNAs highlighted as potential tumor suppressors in a variety of cancers, the role of this cluster in breast cancer (BC) has garnered increased attention in recent years. This review focuses on C14MC in BC, providing an overview of the constituent miRNAs and addressing each in terms of functional impact, potential target genes/pathways, and, where relevant, biomarker capacity. Studies have revealed the regulation of key factors in disease progression and metastasis including tyrosine kinase pathways and factors critical to epithelial–mesenchymal transition (EMT). This has potentially important clinical implications, with EMT playing a critical role in BC metastasis and tyrosine kinase inhibitors (TKIs) in widespread use for the treatment of BC. While the majority of studies have reported tumor-suppressing roles for these miRNAs, some have highlighted their potential as oncomiRs. Understanding the collective contribution of miRNAs within C14MC to BC may support improved understanding of disease etiology and present novel approaches to targeted therapy.

A small interfering RNA (siRNA) database for SARS-CoV-2

Coronavirus disease 2019 (COVID-19) rapidly transformed into a global pandemic, for which a demand for developing antivirals capable of targeting the SARS-CoV-2 RNA genome and blocking the activity of its genes has emerged. In this work, we presented a database of SARS-CoV-2 targets for small interference RNA (siRNA) based approaches, aiming to speed the design process by providing a broad set of possible targets and siRNA sequences. The siRNAs sequences are characterized and evaluated by more than 170 features, including thermodynamic information, base context, target genes and alignment information of sequences against the human genome, and diverse SARS-CoV-2 strains, to assess possible bindings to off-target sequences. This dataset is available as a set of four tables, available in a spreadsheet and CSV (Comma-Separated Values) formats, each one corresponding to sequences of 18, 19, 20, and 21 nucleotides length, aiming to meet the diversity of technology and expertise among laboratories around the world. A metadata table (Supplementary Table S1), which describes each feature, is also provided in the aforementioned formats. We hope that this database helps to speed up the development of new target antivirals for SARS-CoV-2, contributing to a possible strategy for a faster and effective response to the COVID-19 pandemic.

ChrXq27.3 miRNA cluster functions in cancer development

MicroRNAs (miRNAs) regulate the expression of their target genes post-transcriptionally; thus, they are deeply involved in fundamental biological processes. miRNA clusters contain two or more miRNA-encoding genes, and these miRNAs are usually coexpressed due to common expression mechanisms. Therefore, miRNA clusters are effective modulators of biological pathways by the members coordinately regulating their multiple target genes, and an miRNA cluster located on the X chromosome q27.3 region has received much attention in cancer research recently. In this review, we discuss the novel findings of the chrXq27.3 miRNA cluster in various types of cancer.

The chrXq27.3 miRNA cluster contains 30 mature miRNAs synthesized from 22 miRNA-encoding genes in an ~ 1.3-Mb region. The expressions of these miRNAs are usually negligible in many normal tissues, with the male reproductive system being an exception. In cancer tissues, each miRNA is dysregulated, compared with in adjacent normal tissues. The miRNA-encoding genes are not uniformly distributed in the region, and they are further divided into two groups (the miR-506-514 and miR-888-892 groups) according to their location on the genome. Most of the miRNAs in the former group are tumor-suppressive miRNAs that are further downregulated in various cancers compared with normal tissues. miR-506-3p in particular is the most well-known miRNA in this cluster, and it has various tumor-suppressive functions associated with the epithelial–mesenchymal transition, proliferation, and drug resistance. Moreover, other miRNAs, such as miR-508-3p and miR-509-3p, have similar tumor-suppressive effects. Hence, the expression of these miRNAs is clinically favorable as prognostic factors in various cancers. However, the functions of the latter group are less understood. In the latter group, miR-888-5p displays oncogenic functions, whereas miR-892b is tumor suppressive. Therefore, the functions of the miR-888–892 group are considered to be cell type- or tissue-specific.

In conclusion, the chrXq27.3 miRNA cluster is a critical regulator of cancer progression, and the miRNAs themselves, their regulatory mechanisms, and their target genes might be promising therapeutic targets.

Epigenetic Regulation of MicroRNA Clusters and Families during Tumor Development

MicroRNAs are small non-coding single-stranded RNA molecules regulating gene expression on a post-transcriptional level based on the seed sequence similarity. They are frequently clustered; thus, they are either simultaneously transcribed into a single polycistronic transcript or they may be transcribed independently. Importantly, microRNA families that contain the same seed region and thus target related signaling proteins, may be localized in one or more clusters, which are in a close relationship. MicroRNAs are involved in basic physiological processes, and their deregulation is associated with the origin of various pathologies, including solid tumors or hematologic malignancies. Recently, the interplay between the expression of microRNA clusters and families and epigenetic machinery was described, indicating aberrant DNA methylation or histone modifications as major mechanisms responsible for microRNA deregulation during cancerogenesis. In this review, the most studied microRNA clusters and families affected by hyper- or hypomethylation as well as by histone modifications are presented with the focus on particular mechanisms. Finally, the diagnostic and prognostic potential of microRNA clusters and families is discussed together with technologies currently used for epigenetic-based cancer therapies.

Aberrant Expression of microRNA Clusters in Head and Neck Cancer Development and Progression: Current and Future Translational Impacts

MicroRNAs are small non-coding RNAs known to negative regulate endogenous genes. Some microRNAs have high sequence conservation and localize as clusters in the genome. Their coordination is regulated by simple genetic and epigenetic events mechanism. In cells, single microRNAs can regulate multiple genes and microRNA clusters contain multiple microRNAs. MicroRNAs can be differentially expressed and act as oncogenic or tumor suppressor microRNAs, which are based on the roles of microRNA-regulated genes. It is vital to understand their effects, regulation, and various biological functions under both normal and disease conditions. Head and neck squamous cell carcinomas are some of the leading causes of cancer-related deaths worldwide and are regulated by many factors, including the dysregulation of microRNAs and their clusters. In disease stages, microRNA clusters can potentially control every field of oncogenic function, including growth, proliferation, apoptosis, migration, and intercellular commutation. Furthermore, microRNA clusters are regulated by genetic mutations or translocations, transcription factors, and epigenetic modifications. Additionally, microRNA clusters harbor the potential to act therapeutically against cancer in the future. Here, we review recent advances in microRNA cluster research, especially relative to head and neck cancers, and discuss their regulation and biological functions under pathological conditions as well as translational applications.

Expression of the chrXq27.3 miRNA cluster in recurrent ovarian clear cell carcinoma and its impact on cisplatin resistance

Ovarian clear cell carcinoma (OCCC) is a histological subtype of epithelial ovarian cancer and exhibits dismal prognosis due to chemoresistance. Moreover, only few effective therapeutic options exist for patients with recurrent OCCC, and an understanding of its molecular characteristics is essential for the development of novel therapeutic approaches. In the present study, we investigated unique MicroRNAs (miRNA) profiles in recurrent/metastatic OCCC and the role of miRNAs in cisplatin resistance. Comprehensive miRNA sequencing revealed that expression of several miRNAs, including miR-508-3p, miR-509-3p, miR-509-3-5p, and miR-514a-3p was remarkably less in recurrent cancer tissues when compared with that in paired primary cancer tissues. These miRNAs are located in the chrXq27.3 region on the genome. Moreover, its expression was negative in omental metastases in two patients with advanced OCCC. In vitro analyses revealed that overexpression of miR-509-3p and miR-509-3-5p reversed cisplatin resistance and yes-associated protein 1 (YAP1) was partially responsible for the resistance. Immunohistochemistry revealed that YAP1 expression was inversely correlated with the chrXq27.3 miRNA cluster expression. In conclusion, these findings suggest that alteration of the chrXq27.3 miRNA cluster could play a critical role in chemoresistance and miRNAs in the cluster and their target genes can be potential therapeutic targets.

Long Non-Coding RNA LINC00239 Functions as a Competitive Endogenous RNA by Sponging microRNA-484 and Enhancing KLF12 Expression to Promote the Oncogenicity of Colorectal Cancer

Background

Long intergenic non-protein coding RNA 239 (LINC00239) is an oncogenic long non-coding RNA in acute myeloid leukemia. We aimed to determine LINC00239 expression in colorectal cancer (CRC) and examine the influences of LINC00239 on tumor behaviors of CRC cells. Furthermore, the mechanism underlying the actions of LINC00239 in CRC was unveiled in detail.

Materials and Methods

Quantitative real-time polymerase chain reaction was used to detect LINC00239 expression in CRC tissues and cell lines. CRC cell proliferation, apoptosis, migration, and invasion were investigated by cell counting kit-8 assays, flow cytometry, and cell migration and invasion assays, respectively. Tumor xenograft experiments were performed to evaluate the tumor growth of CRC cells in vivo. The interactions among LINC00239, microRNA-484 (miR-484), and kruppel-like factor 12 (KLF12) were analyzed by bioinformatics prediction, RNA immunoprecipitation and luciferase reporter assay.

Results

LINC00239 was upregulated in CRC tissues and cell lines. LINC00239 knockdown impaired CRC cell proliferation, migration, and invasion and promoted apoptosis in vitro. Additionally, LINC00239 deficiency inhibited CRC growth in vivo. Mechanistically, LINC00239 functioned as a competing endogenous RNA by directly sponging miR-484, thereby enhancing KLF12 expression. Rescue experiments further corroborated that miR-484 inhibition or KLF12 overexpression reversed the inhibitory actions of LINC00239 knockdown in CRC cells.

Conclusion

The LINC00239/miR-484/KLF12 pathway executed critical roles in CRC oncogenicity and may provide potential targets for CRC treatments.

Identification of dysregulated miRNAs-genes network in ovarian cancer: An integrative approach to uncover the molecular interactions and oncomechanisms

Background

Ovarian (OV) cancer is considered as one of the most deadly malignancies in women, since it is unfortunately diagnosed in advanced stages. Nowadays, the importance of bioinformatics tools and their frequent usage in tracking dysregulated cancer‐related genes and pathways have been highlighted in researches.

Aim

The aim of this study is to investigate dysregulated miRNAs‐genes network and its function in OV tumors based on the integration of microarray data through a system biology approach.

Methods

Two microarray data (GSE119056 and GSE4122) were analyzed to explore the differentially expressed miRNAs (DEmiRs) and genes among OV tumors and normal tissues. Then, through the help of TargetScan, miRmap, and miRTarBase databases, the dysregulated miRNA‐gene network in OV tumors was constructed by Cytoscape. In the next step, co‐expression and protein‐protein interaction networks were made using GEPIA and STRING databases. Moreover, the functional analysis of the hub genes was done by DAVID, KEGG, and Enrichr databases. Eventually, the regulatory network of TF‐miRNA‐gene was constructed.

Results

The potential dysregulated miRNAs‐genes network in OV tumors has been constructed, including 109 differentially expressed genes (DEGs), 25 DEmiRs, and 213 interactions. Two down‐regulated microRNAs, miR‐660‐3p and hsa‐miR‐4510, have the most interactions with up‐expressed oncogenic DEGs. CDK1, PLK1, CCNB1, CCNA2, and EZH2 are involved in protein module, which show significant overexpression in OV tumors according to The Cancer Genome Atlas (TCGA) data. EZH2 shows amplification in OV tumors with remarkable percentage. The transcription factors TFAP2C and GATA4 have the pivotal regulatory functions in oncotranscriptomic profile of OV tumors.

Conclusion

In current study, we have collected and integrated different data to uncover the complex molecular interactions and oncomechanisms in OV tumors. The DEmiRs‐DEGs and TF‐miRNA‐gene networks reveal the potential interactions that could be a significant piece of the OV onco‐puzzle.

The emerging role of miRNA clusters in breast cancer progression

Micro RNAs (miRNAs) are small non-coding RNAs that are essential for regulation of gene expression of the target genes. Large number of miRNAs are organized into defined units known as miRNA clusters (MCs). The MCs consist of two or more than two miRNA encoding genes driven by a single promoter, transcribed together in the same orientation, that are not separated from each other by a transcription unit. Aberrant miRNA clusters expression is reported in breast cancer (BC), exhibiting both pro-tumorogenic and anti-tumorigenic role. Altered MCs expression facilitates to breast carcinogenesis by promoting the breast cells to acquire the various hallmarks of the cancer. Since miRNA clusters contain multiple miRNA encoding genes, targeting cluster may be more attractive than targeting individual miRNAs. Besides targeting dysregulated miRNA clusters in BC, studies have focused on the mechanism of action, and its contribution to the progression of the BC. The present review provides a comprehensive overview of dysregulated miRNA clusters and its role in the acquisition of cancer hallmarks in BC. More specifically, we have presented the regulation, differential expression, classification, targets, mechanism of action, and signaling pathways of miRNA clusters in BC. Additionally, we have also discussed the potential utility of the miRNA cluster as a diagnostic and prognostic indicator in BC.

Knockdown of lncRNA HCP5 Suppresses the Progression of Colorectal Cancer by miR-299-3p/PFN1/AKT Axis

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignant tumors in the digestive system. The lncRNA HCP5 has been reported to affect the progression of tumor in several types of cancer. Here, in this research, we focus on the role and function of lncRNA HCP5 in human colorectal cancer.

MATERIALS AND METHODS

Tissue samples from colorectal cancer patients were used for detecting the expression of HCP5 by qRT-PCR. Proliferation, migration, invasion and apoptotic cells were assessed by CCK-8, colony formation, transwell assays and flow cytometry in SW480 and HCT-116 cells. The interactions between miR-299-3p and HCP5 or PFN1 were analyzed and confirmed by online database and luciferase reporter assays. The changes in PFN1 and AKT proteins were measured by Western blot. In vivo experiment was used to confirm the role of HCP5 in CRC.

RESULTS

The expression of HCP5 had a higher level in colorectal cancer samples and cells by qRT-PCR, comparing with the normal colorectal tissues and human normal colon epithelial cell. It was revealed that knockdown of HCP5 inhibited viabilities, migration and invasion, while inducing apoptosis in SW480 and HCT-116 cells. Then, HCP5 negatively regulated the expressions of miR-299-3p, which negatively regulated the expressions of PFN1 by targeting PFN1. Furthermore, miR-299-3p inhibitor could alleviate the inhibiting effect by si-HCP5 on cell process of SW480 and HCT-116 cells. In addition, the lncHCP5/miR-299-3p/PFN1 axis could affect the progression of CRC through activating the AKT signaling. Last, we confirmed that knockdown of HCP5 inhibited the progression of CRC with an in vivo experiment.

CONCLUSION

The experiments and analyses support our hypothesis that knockdown of lncRNA HCP5 suppresses the progression of colorectal cancer by miR-299-3p/PFN1/AKT axis.

Oncolytic Adenoviruses: Strategies for Improved Targeting and Specificity

Cancer is a major health problem. Most of the treatments exhibit systemic toxicity, as they are not targeted or specific to cancerous cells and tumors. Adenoviruses are very promising gene delivery vectors and have immense potential to deliver targeted therapy. Here, we review a wide range of strategies that have been tried, tested, and demonstrated to enhance the specificity of oncolytic viruses towards specific cancer cells. A combination of these strategies and other conventional therapies may be more effective than any of those strategies alone.

Model-Based Integration Analysis Revealed Presence of Novel Prognostic miRNA Targets and Important Cancer Driver Genes in Triple-Negative Breast Cancers

Background: miRNAs (microRNAs) play a key role in triple-negative breast cancer (TNBC) progression, and its heterogeneity at the expression, pathological and clinical levels. Stratification of breast cancer subtypes on the basis of genomics and transcriptomics profiling, along with the known biomarkers’ receptor status, has revealed the existence of subgroups known to have diverse clinical outcomes. Recently, several studies have analysed expression profiles of matched mRNA and miRNA to investigate the underlying heterogeneity of TNBC and the potential role of miRNA as a biomarker within cancers. However, the miRNA-mRNA regulatory network within TNBC has yet to be understood. Results and Findings: We performed model-based integrated analysis of miRNA and mRNA expression profiles on breast cancer, primarily focusing on triple-negative, to identify subtype-specific signatures involved in oncogenic pathways and their potential role in patient survival outcome. Using univariate and multivariate Cox analysis, we identified 25 unique miRNAs associated with the prognosis of overall survival (OS) and distant metastases-free survival (DMFS) with “risky” and “protective” outcomes. The association of these prognostic miRNAs with subtype-specific mRNA genes was established to investigate their potential regulatory role in the canonical pathways using anti-correlation analysis. The analysis showed that miRNAs contribute to the positive regulation of known breast cancer driver genes as well as the activation of respective oncogenic pathway during disease formation. Further analysis on the “risk associated” miRNAs group revealed significant regulation of critical pathways such as cell growth, voltage-gated ion channel function, ion transport and cell-to-cell signalling. Conclusion: The study findings provide new insights into the potential role of miRNAs in TNBC disease progression through the activation of key oncogenic pathways. The results showed previously unreported subtype-specific prognostic miRNAs associated with clinical outcome that may be used for further clinical evaluation.

lncTUG1/miR-144-3p affect the radiosensitivity of esophageal squamous cell carcinoma by competitively regulating c-MET

Background

Long noncoding RNAs (lncRNAs) are involved in the progression of various cancers and affect the response to radiotherapy. This study focused on clarifying the underlying mechanism by which lncTUG1 affects the radiosensitivity of esophageal squamous cell carcinoma (ESCC).

Methods

lncTUG1, miR-144-3p and MET expression levels were detected in ESCC tissues and cells by qRT-PCR. Western blotting was used to examine the protein levels of MET, p-AKT and EGFR. The dual-luciferase reporter system and RNA immunoprecipitation (RIP) assays were used to confirm the interaction between lncTUG1 and miR-144-3p or miR-144-3p and MET. MTT, colony formation and flow cytometry assays were applied to examine the behavioral changes in EC9706 and KYSE30 cells.

Results

lncTUG1 was upregulated in ESCC cells and tissues, and lncTUG1 expression was associated with an advanced pathological stage. The bioinformatics analysis revealed that lncTUG1 could specifically bind to miR-144-3p, which was downregulated in ESCC. There was a negative correlation between lncTUG1 and miR-144-3p. LncTUG1 inhibition retarded proliferation and colony formation and induced apoptosis in ESCC cells. Moreover, lncTUG1 knockdown dramatically improved the effect of radiotherapy on ESCC development both in vivo and in vitro. Furthermore, MET was revealed as a downstream target of miR-144-3p and is downregulated by it. LncTUG1 promoted the progression of ESCC and elevated radiotherapy resistance in ESCC cells, accompanied by a high level of MET expression. Moreover, we found that knockdown of lncTUG1 enhanced the radiosensitivity of ESCC cells via the p-AKT signaling pathway.

Conclusion

Our results indicate that lncTUG1 enhances the radiotherapy resistance of ESCC by lowering the miR-144-3p level and modulating the MET/EGFR/AKT axis.

MicroRNA-937 is overexpressed and predicts poor prognosis in patients with colon cancer

Background

Colon cancer is a heterogeneous tumor and a leading cause of cancer-related mortality. MicroRNA (miRNA) has been proposed as the biomarker in cancers. The aim of this study was to investigate the clinical significance and potential functional role of miR-937 in colon cancer.

Methods

In the present study, reverse transcription-quantitative polymerase chain reaction (qRT-PCR) was conducted to examine the expression levels of miR-937 in colon cancer tissues and cell lines. Kaplan-Meier curve and Cox regression analyses were used to determine the prognostic impact of miR-937 on survival. Cell Counting Kit-8 and Transwell assays were performed to examine cell proliferation, migration, and invasion, respectively.

Results

miR-937 was significantly upregulated in colon cancer tissues and cell lines. Clinical analysis results showed that miR-937 expression was associated with lymph node metastasis and TNM stage. Patients with high miR-937 expression predicted a shorter overall survival rate. Functionally, overexpression of miR-937 promoted cell proliferation, migration, and invasion, while inhibition of miR-937 inhibited these cellular behaviors in vitro.

Conclusions

These results suggested that miR-937 may act as a prognostic biomarker and a potential target for therapeutic strategy, as well as promote proliferation, migration, and invasion of colon cancer.

miR-454-3p promotes of human glioma cell growth by targeting EGR3

Gliomas are the most common primary brain tumors in adults and are associated with high mortality rates. In the present study, the aim was to evaluate the role of miR-454-3p in the pathogenesis of human glioma and to explore the underlying mechanism. Reverse transcription-quantitative PCR was performed to compare the expression levels of miR-454-3p in glioma and adjacent normal tissue. The effects of miR-454-3p on cell proliferation was tested by combining MTT and colony formation assays. Dual-luciferase assay was used to identify the target gene of miR-454-3p. The results showed that miR-454-3p was upregulated in glioma tissues where it exerts a positively regulatory role on cell growth. Dual-luciferase assay confirmed Early Growth Response 3 (EGR3) to be a target for miR-454-3p. Overexpression of EGR3 in glioma cells was found to impair miR-454-3p mimic-induced cell proliferation. These results suggested that upregulated miR-454-3p served an important role in glioma tumorigenesis by targeting EGR3, which provided valuable insights into the underlying mechanism of the disease that may lead to possible novel therapeutic strategies.

miR-190-5p in human diseases

miRNAs, a major class of small noncoding RNAs approximately 18-25 nucleotides in length, function by repressing the expression of target genes through binding to complementary sequences in the 3'-UTRs of target genes. Emerging evidence has highlighted their important roles in numerous diseases, including human cancers. Recently, miR-190 has been shown to be dysregulated in various types of human cancers that participates in cancer-related biological processes, including proliferation, apoptosis, metastasis, drug resistance, by regulating associated target genes, and to predict cancer diagnosis and prognosis. In this review, we summarized the roles of miR-190-5p in human diseases, especially in human cancers. Then we classified its target genes in tumorigenesis and progression, which might provide evidence for cancer diagnosis and prognosis, promising tools for cancer treatment, or leads for further investigation.