An investigation into anti-proliferative effects of microRNAs encoded by the miR-106a-363 cluster on human carcinoma cells and keratinocytes using microarray profiling of miRNA transcriptomes

miRNA Profiles of Canine Intestinal Carcinomas, Lymphomas and Enteritis Analysed by Digital Droplet PCR from FFPE Material

Most canine intestinal tumours are B-cell or T-cell lymphomas or carcinomas. They have to be distinguished from cases of enteritis. Non-invasive biomarkers such as miRNAs would be a step towards faster diagnosis. The aim of this study was to investigate shifts in miRNA expression in tissue samples collected from cases of enteritis, carcinoma and lymphoma of the small and large intestine to better understand the potential of miRNA as biomarkers for tumour diagnosis and classification. We selected two oncogenic miRNAs (miR-18b and 20b), two tumour suppressive miRNAs (miR-192 and 194) and two potential biomarkers for neoplasms (miR-126 and 214). They were isolated from FFPE material, quantified by ddPCR, normalised with RNU6B and compared with normal tissue values. Our results confirmed that ddPCR is a suitable method for quantifying miRNA from FFPE material. Expression of miR-18b and miR-192 was higher in carcinomas of the small intestine than in those of the large intestine. Specific miRNA patterns were observed in cases of enteritis, B-cell and T-cell lymphoma and carcinoma. However, oncogenic miR-18b and 20b were not elevated in any group and miR-126 and 214 were down-regulated in T-cell and B-cell lymphoma, as well as in carcinomas and lymphoplasmacytic enteritis of the small intestine.

The Regulation of Lymph Node Pre-Metastatic Niche Formation in Head and Neck Squamous Cell Carcinoma

In many distinct forms of malignancies, there is a close relationship between lymph node (LN) metastases and further dissemination to distant organs, and this is a critical prognostic factor. At the beginning of the process, the original tumor secretes soluble substances or releases extracellular vesicles (EVs) that are carried through lymphatic channels to draining (sentinel) LN. The tumor-derived factors then drive LN remodeling. These significant alterations occur prior to the emergence of the first metastatic cell, bringing about the development of a pre-metastatic niche that allows metastatic cells to survive and thrive. In this review, we discuss current information available about the regulation of lymph node pre-metastatic niche in head and neck squamous cell carcinoma (HNSCC), and the role of EVs in forming the pre-metastatic niche.

The roles of extracellular vesicles in the development, microenvironment, anticancer drug resistance, and therapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the main malignant tumours affecting human health, mainly due to delayed diagnosis and high invasiveness. Extracellular vehicles (EVs) are membranous vesicles released by cells into the extracellular matrix that carry important signalling molecules and stably and widely exist in various body fluids, such as plasma, saliva, cerebrospinal fluid, breast milk, urine, semen, lymphatic fluid, synovial fluid, amniotic fluid, and sputum. EVs transport almost all types of bioactive molecules (DNA, mRNAs, microRNAs (miRNAs), proteins, metabolites, and even pharmacological compounds). These "cargoes" can act on recipient cells, reshaping the surrounding microenvironment and altering distant targets, ultimately affecting their biological behaviour. The extensive exploration of EVs has deepened our comprehensive understanding of HNSCC biology. In this review, we not only summarized the effect of HNSCC-derived EVs on the tumour microenvironment but also described the role of microenvironment-derived EVs in HNSCC and discussed how the "mutual dialogue" between the tumour and microenvironment mediates the growth, metastasis, angiogenesis, immune escape, and drug resistance of tumours. Finally, the clinical application of EVS in HNSCC was assessed.

hsa-miR-20b-5p and hsa-miR-363-3p Affect Expression of PTEN and BIM Tumor Suppressor Genes and Modulate Survival of T-ALL Cells In Vitro

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy arising from T lymphocyte precursors. We have previously shown by miRNA-seq, that miRNAs from the mir-106a-363 cluster are overexpressed in pediatric T-ALL. In silico analysis indicated their potential involvement in the regulation of apoptosis. Here, we aimed to test the hypothesis on the pro-tumorigenic roles of these miRNAs in T-ALL cells in vitro. We demonstrate, for the first time, that hsa-miR-20b-5p and hsa-miR-363-3p from the mir-106a-363 cluster, when upregulated in T-ALL cells in vitro, protect leukemic cells from apoptosis, enhance proliferation, and contribute to growth advantage. We show, using dual luciferase reporter assays, Ago2-RNA immunoprecipitation, RT-qPCR, and Western blots, that the oncogenic effects of these upregulated miRNAs might, at least in part, be mediated by the downregulation of two important tumor suppressor genes, PTEN and BIM, targeted by both miRNAs. Additionally, we demonstrate the cooperative effects of these two miRNAs by simultaneous inhibition of both miRNAs as compared to the inhibition of single miRNAs. We postulate that hsa-miR-20b-5p and hsa-miR-363-3p from the mir-106a-363 cluster might serve as oncomiRs in T-ALL, by contributing to post-transcriptional repression of key tumor suppressors, PTEN and BIM.

MicroRNAs in ovarian follicular atresia and granulosa cell apoptosis

MicroRNAs (miRNAs) are short, noncoding RNAs that posttranscriptionally regulate gene expression. In the past decade, studies on miRNAs in ovaries have revealed the key roles of miRNAs in ovarian development and function. In this review, we first introduce the development of follicular atresia research and then summarize genome-wide studies on the ovarian miRNA profiles of different mammalian species. Differentially expressed miRNA profiles during atresia and other biological processes are herein compared. In addition, current knowledge on confirmed functional miRNAs during the follicular atresia process, which is mostly indicated by granulosa cell (GC) apoptosis, is presented. The main miRNA families and clusters, including the let-7 family, miR-23-27-24 cluster, miR-183-96-182 cluster and miR-17-92 cluster, and related pathways that are involved in follicular atresia are thoroughly summarized. A deep understanding of the roles of miRNA networks will not only help elucidate the mechanisms of GC apoptosis, follicular development, atresia and their disorders but also offer new diagnostic and treatment strategies for infertility and other ovarian dysfunctions.

Extracellular vesicle microRNA cargo is correlated with HPV status in oropharyngeal carcinoma

BACKGROUND

The incidence of human papilloma virus positive (HPV⁺ ) oropharyngeal squamous cell carcinoma (OPSCC) has increased rapidly in recent decades. These tumours have a favourable outcome compared to HPV-negative (HPV^- ) OPSCC. However, HPV⁺ tumours are more likely to metastasise to distant sites, suggesting a difference in how these tumour subtypes interact with the metastatic niche. Extracellular vesicles (EVs) have emerged as important players in cell-to-cell communication and are a potential source of biomarkers for cancer diagnosis. This study aims to characterise the microRNA cargo of small EVs released by HPV⁺ and HPV^- OPSCC cell lines.

METHODS

Extracellular vesicles produced by HPV⁺ (SCC2 and SCC90) and HPV^- (SCC72 an SCC89) OPSCC cells were characterised by tunable resistive pulse sensing (TRPS) and western blotting. RNA was extracted from EVs and analysed by small RNA sequencing. A bioinformatics approach was used to identify EV miRNA signatures associated with HPV status.

RESULTS

HPV^- OPSCC cells produced more EVs than HPV⁺ OPSCC cells. EVs were positive for the common EV markers CD63, CD9 and TSG101. Unbiased hierarchical clustering analysis of EV miRNA cargo revealed that samples clustered based on HPV status. 14 miRNA were enriched in HPV⁺ cell-derived EVs, whereas 19 miRNA were enriched in EVs derived from HPV^- cell lines.

CONCLUSIONS

Here, we identify EV miRNA signatures indicative of the HPV status of the parent cell. This may provide a platform from which to validate salivary or blood-based biomarkers with utility for early detection and stratifying risk in OPSCC patients.

MicroRNA-106a-5p Inhibited C2C12 Myogenesis via Targeting PIK3R1 and Modulating the PI3K/AKT Signaling

The microRNA (miR)-17 family is widely expressed in mammalian tissues and play important roles in various physiological and pathological processes. Here, the functions of miR-106a-5p, a member of miR-17 family, were explored during myogenic differentiation in C2C12 cell line. First, miR-106a-5p was found to be relatively lower expressed in two-month skeletal muscle tissues and gradually decreased upon myogenic stimuli. Forced expression of miR-106a-5p significantly reduced the differentiation index, fusion index as well as the expression of myogenic markers (MyoD, MyoG, MyHC, Myomixer, Myomarker). Meanwhile, the levels of phosphorylated AKT were reduced by overexpression of miR-106a-5p, and administration of insulin-like growth factor 1 (IGF1), a booster of myogenic differentiation, could recover all the inhibitory effects above of miR-106a-5p. Furthermore, miR-106a-5p was elevated in aged muscles and dexamethasone (DEX)-treated myotubes, and up-regulation of miR-106a-5p significantly reduced the diameters of myotubes accompanied with increased levels of muscular atrophy genes and decreased PI3K/AKT activities. Finally, miR-106a-5p was demonstrated to directly bind to the 3'-UTR of PIK3R1, thus, repress the PI3K/AKT signaling.

Cholesterol and Morpholine Grafted Cationic Amphiphilic Copolymers for miRNA-34a Delivery

miR-34a is a master tumor suppressor playing a key role in the several signaling mechanisms involved in cancer. However, its delivery to the cancer cells is the bottleneck in its clinical translation. Herein we report cationic amphiphilic copolymers grafted with cholesterol (chol), N, N-dimethyldipropylenetriamine (cation chain) and 4-(2-aminoethyl)morpholine (morph) for miR-34a delivery. The copolymer interacts with miR-34a at low N/P ratios (∼2/1) to form nanoplexes of size ∼108 nm and a zeta potential ∼ +39 mV. In vitro studies in 4T1 and MCF-7 cells indicated efficient transfection efficiency. The intracellular colocalization suggested that the copolymer effectively transported the FAM labeled siRNA into the cytoplasm within 2 h and escaped from the endo-/lysosomal environment. The developed miR-34a nanoplexes inhibited the breast cancer cell growth as confirmed by MTT assay wherein 28% and 34% cancer cell viability was observed in 4T1 and MCF-7 cells, respectively. Further, miR-34a nanoplexes possess immense potential to induce apoptosis in both cell lines.

miR-363-3p inhibits tumor growth by targeting PCNA in lung adenocarcinoma

Increasing evidence suggests that microRNAs play key roles in lung cancer. Our previous study demonstrated that microRNA 363-3p (miR-363-3p) is downregulated in lung cancer tissues. In this study, we demonstrated that overexpression of miR-363-3p inhibits the proliferation and colony formation of A549 and H441 cells, while silencing of miR-363-3p has the converse effects. The anti-oncogenic function of miR-363-3p was verified in a mouse tumor xenograft model. Furthermore, cell cycle analysis showed miR-363-3p can induce S phase arrest by downregulating Cyclin-D1 and upregulating Cyclin-dependent kinase-2 in lung adenocarcinoma cells. Additionally, miR-363-3p enhances cell apoptosis, whereas miR-363-3p inhibitor prevents apoptosis and leads to downregulation of Bax and Bak expression. The anti-proliferative function of miR-363-3p toward lung cancer cells may be explained by its ability to inhibit the activation of the mTOR and ERK signaling pathways. Using target prediction software and luciferase reporter assays, we identified PCNA as a specific target of miR-363-3p. miR-363-3p can decreased the accumulation of endogenous PCNA in lung adenocarcinoma cells. Moreover, exogenous expression of PCNA relieve the inhibition of miR-363-3p on cell proliferation, colony formation and mTOR and ERK signaling pathways. Taken together, our data indicate that miR-363-3p suppresses tumor growth by targeting PCNA in lung adenocarcinoma.

miR-363-5p as potential prognostic marker for hepatocellular carcinoma indicated by weighted co-expression network analysis of miRNAs and mRNA

BACKGROUND

This study aimed to investigate potential miRNAs and genes associated with the prognosis of hepatocellular carcinoma (HCC).

METHODS

Weighted co-expression network analysis was utilized to analyze the mRNA and miRNA sequencing data of HCC from TCGA (The Cancer Genome Atlas) database. Significant network modules were identified, and then functions of genes in the gene network modules and target genes of miRNAs in the miRNA network modules were explored. Additionally, correlations between network modules and prognostic factors of HCC were analyzed.

RESULTS

In total, 10 mRNA network modules were identified, three of which were significantly related to tumor stage, NAFLD (non-alcoholic fatty liver disease) and patient age. Four miRNA network modules were identified, of which one was associated with tumor stage. Targets of hsa-miR-363-5p were found distributed in the gene network modules, such as RGPD5, RGPD6, ZNF445 and ZNF780B. Kaplan-Meier test revealed that low expression of hsa-miR-363-5p was associated with better overall survival of HCC patients.

CONCLUSION

hsa-miR-363-5p may be a potential prognostic marker for HCC.

Inhibition of miR-363 protects cardiomyocytes against hypoxia-induced apoptosis through regulation of Notch signaling

Cardiomyocyte apoptosis contributes to the pathological process of ischemic heart diseases, such as myocardial infarction. Emerging evidence suggests that microRNAs (miRNAs) play critical roles in the pathological process of myocardial infarction by regulating cardiomyocyte apoptosis. Previous studies have reported that miR-363 is an apoptosis-related miRNA. However, whether miR-363 is involved in regulating cardiomyocyte apoptosis remains unclear. This study aimed to investigate the potential role of miR-363 in the regulation of hypoxia-induced cardiomyocyte apoptosis. We found that miR-363 expression was significantly increased in hypoxic cardiomyocytes and that inhibition of miR-363 effectively protected cardiomyocytes against hypoxia-induced apoptosis. Bioinformatics analysis predicted that Notch1 is a potential target gene of miR-363. This finding was validated by dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. miR-363 inhibition significantly promoted the activation of Notch signaling in hypoxic cardiomyocytes. However, knockdown of Notch1 markedly reversed the protective effects induced by miR-363 inhibition. Furthermore, blocking the Notch signaling also significantly abrogated the protective effects of miR-363 inhibition. Overall, these findings suggest that inhibition of miR-363 protects cardiomyocytes against hypoxia-induced apoptosis through promotion of Notch1 expression and activation of Notch signaling. Our study provides a novel understanding of the molecular basis of hypoxia-induced cardiomyocyte apoptosis and suggests a potential therapeutic target for myocardial infarction.

The Three Paralogous MicroRNA Clusters in Development and Disease, miR-17-92, miR-106a-363, and miR-106b-25

MicroRNAs (miRNAs) form a class of noncoding RNA genes whose products are small single-stranded RNAs that are involved in the regulation of translation and degradation of mRNAs. There is a fine balance between deregulation of normal developmental programs and tumor genesis. An increasing body of evidence suggests that altered expression of miRNAs is entailed in the pathogenesis of human cancers. Studies in mouse and human cells have identified the miR-17-92 cluster as a potential oncogene. The miR-17-92 cluster is often amplified or overexpressed in human cancers and has recently emerged as the prototypical oncogenic polycistron miRNA. The functional analysis of miR-17-92 is intricate by the existence of two paralogues: miR-106a-363 and miR-106b-25. During early evolution of vertebrates, it is likely that the three clusters commenced via a series of duplication and deletion occurrences. As miR-106a-363 and miR-106b-25 contain miRNAs that are very similar, and in some cases identical, to those encoded by miR-17-92, it is feasible that they regulate a similar set of genes and have overlapping functions. Further understanding of these three clusters and their functions will increase our knowledge about cancer progression. The present review discusses the characteristics and functions of these three miRNA clusters.

MicroRNA 17-5p regulates autophagy in Mycobacterium tuberculosis-infected macrophages by targeting Mcl-1 and STAT3

Autophagy plays a crucial role in the control of bacterial burden during Mycobacterium tuberculosis infection. MicroRNAs (miRNAs) are small non-coding RNAs that regulate immune signalling and inflammation in response to challenge by pathogens. Appreciating the potential of host-directed therapies designed to control autophagy during mycobacterial infection, we focused on the role of miRNAs in regulating M. tuberculosis-induced autophagy in macrophages. Here, we demonstrate that M. tuberculosis infection leads to downregulation of miR-17 and concomitant upregulation of its targets Mcl-1 and STAT3, a transcriptional activator of Mcl-1. Forced expression of miR-17 reduces expression of Mcl-1 and STAT3 and also the interaction between Mcl-1 and Beclin-1. This is directly linked to enhanced autophagy, because Mcl-1 overexpression attenuates the effects of miR-17. At the same time, transfection with a kinase-inactive mutant of protein kinase C δ (PKCδ) (an activator of STAT3) augments M. tuberculosis-induced autophagy, and miR-17 overexpression diminishes phosphorylation of PKCδ, suggesting that an miR-17/PKC δ/STAT3 axis regulates autophagy during M. tuberculosis infection.

Inhibition of Ovarian Epithelial Carcinoma Tumorigenesis and Progression by microRNA 106b Mediated through the RhoC Pathway

Epithelial ovarian cancer (EOC) is the most lethal of the gynecological malignancies. Exploring the molecular mechanisms and major factors of invasion and metastasis could have great significance for the treatment and prognosis of EOC. Studies have demonstrated that microRNA 106b (miR-106b) may be a promising therapeutic target for inhibiting breast cancer bone metastasis, but the role of miR-106b in EOC is largely unknown. In this work, miRNA-106b expression was quantified in various ovarian tissues and tumors. Ovarian carcinoma cell lines were transfected with miR-106b, after which, cell phenotype and expression of relevant molecules was assayed. Dual-luciferase reporter assays and xenograft mouse models were also used to investigate miR-106b and its target gene. MiR-106b mRNA expression was found to be significantly higher in normal ovarian tissues and benign tumors than in ovarian carcinomas and borderline tumors (p < 0.01), and was negatively associated with differentiation (Well vs. Por & Mod) and the International Federation of Gynecology and Obstetrics (FIGO) staging (stage I/II vs. stage III/IV) in ovarian carcinoma (p < 0.05). MiR-106b transfection reduced cell proliferation; promoted G1 or S arrest and apoptosis (p < 0.05); suppressed cell migration and invasion (p < 0.05); reduced Ras homolog gene family member C (RhoC), P70 ribosomal S6 kinase (P70S6K), Bcl-xL, Matrix metallopeptidase 2 (MMP2), MMP9 mRNA and protein expression; and induced p53 expression (p < 0.05). Dual-luciferase reporter assays indicated that miR-106b directly targets RhoC by binding its 3’UTR. MiR-106b transfection also suppressed tumor development and RhoC expression in vivo in xenograft mouse models. This is the first demonstration that miR-106b may inhibit tumorigenesis and progression of EOC by targeting RhoC. The involvement of miR-106b-mediated RhoC downregulation in EOC aggression may give extended insights into molecular mechanisms underlying cancer aggression. Approaches aimed at overexpressing miR-106b may serve as promising therapeutic strategies for treating EOC patients.