MicroRNA-142-3p, a novel target of tumor suppressor menin, inhibits osteosarcoma cell proliferation by down-regulation of FASN

A novel regulatory facet for hypertriglyceridemia: The role of microRNAs in the regulation of triglyceride-rich lipoprotein biosynthesis

Atherosclerotic cardiovascular disease (ASCVD) is one of the major leading global causes of death. Genetic and epidemiological studies strongly support the causal association between triacylglycerol-rich lipoproteins (TAGRL) and atherogenesis, even in statin-treated patients. Recent genetic evidence has clarified that variants in several key genes implicated in TAGRL metabolism are strongly linked to the increased ASCVD risk. There are several triacylglycerol-lowering agents; however, new therapeutic options are in development, among which are miRNA-based therapeutic approaches. MicroRNAs (miRNAs) are small non-coding RNAs (18-25 nucleotides) that negatively modulate gene expression through translational repression or degradation of target mRNAs, thereby reducing the levels of functional genes. MiRNAs play a crucial role in the development of hypertriglyceridemia as several miRNAs are dysregulated in both synthesis and clearance of TAGRL particles. MiRNA-based therapies in ASCVD have not yet been applied in human trials but are attractive. This review provides a concise overview of current interventions for hypertriglyceridemia and the development of novel miRNA and siRNA-based drugs. We summarize the miRNAs involved in the regulation of key genes in the TAGRLs synthesis pathway, which has gained attention as a novel target for therapeutic applications in CVD.

MiR-142-3p enhances chemosensitivity of breast cancer cells and inhibits autophagy by targeting HMGB1

MiR-142-3p has been reported to act as a tumor suppressor in breast cancer. However, the regulatory effect of miR-142-3p on drug resistance of breast cancer cells and its underlying mechanism remain unknown. Here, we found that miR-142-3p was significantly downregulated in the doxorubicin (DOX)-resistant MCF-7 cell line (MCF-7/DOX). MiR-142-3p overexpression increased DOX sensitivity and enhanced DOX-induced apoptosis in breast cancer cells. High-mobility group box 1 (HMGB1) is a direct functional target of miR-142-3p in breast cancer cells and miR-142-3p negatively regulated HMGB1 expression. Moreover, overexpression of HMGB1 dramatically reversed the promotion of apoptosis and inhibition of autophagy mediated by miR-142-3p up-regulation. In conclusion, miR-142-3p overexpression may inhibit autophagy and promote the drug sensitivity of breast cancer cells to DOX by targeting HMGB1. The miR-142-3p/HMGB1 axis might be a novel target to regulate the drug resistance of breast cancer patients.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

miR-142-3p as a novel biomarker for predicting poor prognosis in renal cell carcinoma patients after surgery

BACKGROUND

miR-142-3p has proved to be involved in tumorigenesis and the development of renal cell carcinoma. The present study aimed to explore the prognostic value of miR-142-3p.

METHODS

Total RNA was extracted from renal cell carcinoma specimens and the expression level of miR-142-3p was measured. Pearson Chi-square test, Kaplan-Meier analysis, as well as univariate and multivariate regression analysis were performed to determine the correlation between miR-142-3p and the prognosis of renal cell carcinoma patients. Receiver operating characteristic curves were constructed to evaluate the predictive efficiency of miR-142-3p for the prognosis of renal cell carcinoma patients. Data from The Cancer Genome Atlas (TCGA) were utilized to validate our findings.

RESULTS

Our results demonstrated that upregulation of miR-142-3p was correlated with shorter overall survival (P=0.002) and was, in the meantime, an independent prognostic factor for renal cell carcinoma patients (P=0.002). The receiver operating characteristic curve combining miR-142-3p expression with tumor stage showed an area under the curve of 0.633 (95% confidence interval 0.563, 0.702). The result of TCGA data was consistent with our findings.

CONCLUSIONS

Our results suggest miR-142-3p expression is correlated with poor prognosis of renal cell carcinoma patients and may serve as a prognostic biomarker in the future.

Down-regulation of microRNA-142-3p inhibits the aggressive phenotypes of rheumatoid arthritis fibroblast-like synoviocytes through inhibiting nuclear factor-κB signaling

The present study aimed to investigate the regulatory roles of miR-142-3p on the aggressive phenotypes of rheumatoid arthritis (RA) human fibroblast-like synoviocytes (RA-HFLSs), and reveal the potential mechanisms relating with nuclear factor-κB (NF-κB) signaling. miR-142-3p expression was detected in RA synovial tissues and RA-HFLSs by quantitative real-time PCR (qRT-PCR) and Northern blot analysis. RA-HFLSs were transfected with miR-142-3p inhibitor and/or treated with 10 µg/l tumor necrosis factor α (TNF-α). The viability, colony formation, apoptosis, migration, invasion, and the levels of interleukin (IL)-6, and matrix metalloproteinase 3 (MMP-3) were detected. The mRNA expressions of B-cell lymphoma-2 (Bcl-2), Bax, Bad, IL-6, and MMP-3 were detected by qRT-PCR. Moreover, the expression of Bcl-2, IL-1 receptor-associated kinase 1 (IRAK1), Toll-like receptor 4 (TLR4), NF-κB p65, and phosphorylated NF-κB p65 (p-NF-κB p65) were detected by Western blot. The interaction between IRAK1 and miR-142-3p was identified by dual luciferase reporter gene assay. MiR-142-3p was up-regulated in RA synovial tissues and RA-HFLSs. TNF-α activated the aggressive phenotypes of RA-HFLSs, including enhanced proliferation, migration, invasion, and inflammation, and inhibited apoptosis. miR-142-3p inhibitor significantly decreased the cell viability, the number of cell clones, the migration rate, the number of invasive cells, the contents and expression of IL-6 and MMP-3, and increased the apoptosis rate and the expressions of Bax and Bad, and decreased Bcl-2 expression of TNF-α-treated RA-HFLSs. MiR-142-3p inhibitor significantly reversed TNF-α-induced up-regulation of IRAK1, TLR4, and p-NF-κB p65 in TNF-α-treated RA-HFLSs. Besides, IRAK1 was a target of miR-142-3p. The down-regulation of miR-142-3p inhibited the aggressive phenotypes of RA-HFLSs through inhibiting NF-κB signaling.

MicroRNA-377 exerts a potent suppressive role in osteosarcoma through the involvement of the histone acetyltransferase 1-mediated Wnt axis

It has been demonstrated that microRNAs (miRNAs) may contribute to tumorigenesis and tumor growth in osteosarcoma (OS), which is a primary malignant tumor of bone frequently diagnosed in adolescents and young people. The purpose of our investigation was to evaluate the functional relevance of miR-377 in OS and to investigate whether the mechanism was related to the histone acetyltransferase 1 (HAT1)-mediated Wnt signaling pathway. By screening differentially expressed genes in microarray GSE47572, HAT1 was found to be a candidate gene of interest. Besides, the regulatory miRNA (miR-377) of HAT1 was also selected. The interaction among miR-377, HAT1, and the Wnt signaling pathway was evaluated. In addition, the miR-377 expression was altered in OS cells (U-2OS and SOSP-9607) to assess the in vitro cell apoptosis and the in vivo tumor growth. OS tissues presented elevated HAT1 expression and decreased miR-377 expression. A putative miR-377 binding site in HAT1 3'-UTR HAT1 was verified. Cells with miR-377 overexpression or HAT1 silencing were observed to exhibit reduced HAT1 expression and promoted apoptosis, accompanied by blockade of Wnt signaling. Moreover, the in vivo experiment revealed that miR-377 overexpression or HAT1 silencing inhibited tumor growth and reduced tumor size in nude mice. Taken together, our results conclude that miR-377 may promote OS cell apoptosis through inactivation of the HAT1-mediated Wnt signaling pathway, highlighting the potential therapeutic effect of miR-377 on OS treatment.

Fatty acid synthase is a primary target of MiR-15a and MiR-16-1 in breast cancer

Fatty acid synthase (FASN) is upregulated in breast cancer and correlates with poor prognosis. FASN contributes to mammary oncogenesis and serves as a bona fide target in cancer therapies. MicroRNAs inhibit gene expression through blocking mRNA translation or promoting mRNA degradation by targeting their 3'-UTRs. We identified four microRNAs in two microRNA clusters miR-15a-16-1 and miR-497-195 that share a common seed sequence to target the 3'-UTR of the FASN mRNA. In reporter assays, both of these microRNA clusters inhibited the expression of a reporter construct containing the FASN 3'-UTR. However, only ectopic miR-15a-16-1, but not miR-497-195, markedly reduced the levels of endogenous FASN in breast cancer cells. Both miR-15a and miR-16-1 contributes to inhibiting FASN expression and breast cancer cell proliferation. Consistently, a sponge construct consisting of eight repeats of the FASN 3'-UTR region targeted by these microRNAs could markedly increase endogenous FASN levels in mammary cells. When FASN expression was restored by ectopic expression in breast cancer cells, retarded cell proliferation caused by miR-15a-16-1 was partially rescued. In conclusion, we demonstrated that FASN expression is primarily downregulated by miR-15a and miR-16-1 in mammary cells and FASN is one of the major targets of these two tumor suppressive microRNAs.

MicroRNA-195 inhibits the proliferation and invasion of pancreatic cancer cells by targeting the fatty acid synthase/Wnt signaling pathway

Emerging evidence suggests that microRNAs are critical regulators of cancer development and progression. MicroRNA-195 has been reported as a cancer-related microRNA in many human cancers. However, the role of microRNA-195 in pancreatic cancer remains largely unknown. Here, we show that microRNA-195 is downregulated in pancreatic cancer tissues and cell line. Also, we show that overexpression of microRNA-195 inhibits the proliferation and invasion of pancreatic cancer cells, whereas suppression of microRNA-195 promotes proliferation and invasion. We show that microRNA-195 directly targets the fatty acid synthase enzyme and negatively regulates the expression of fatty acid synthase. Also, we show that fatty acid synthase expression is inversely correlated with microRNA-195 expression in pancreatic cancer tissues. Moreover, our results show that microRNA-195 inhibits Wnt signaling in pancreatic cancer cells. By restoring fatty acid synthase expression, we were able to reverse the antitumor effects of microRNA-195 in pancreatic cancer cells. Taken together, our findings show that microRNA-195 inhibits pancreatic cancer cell proliferation and invasion by regulating the fatty acid synthase/Wnt signaling pathway, suggesting a tumor suppressive role for microRNA-195 in the development and progression of pancreatic cancer. Thus, inhibiting fatty acid synthase by microRNA-195 may serve as a novel therapeutic approach for the treatment of pancreatic cancer.

MEN1 and microRNAs: The link between sporadic pituitary, parathyroid and adrenocortical tumors?

Sporadic tumors of the pituitary, parathyroids and adrenal cortex are unique, as their benign forms are very common, but malignant forms are exceptionally rare. Hereditary forms of these tumors occur in multiple endocrine neoplasia syndrome type 1 (MEN1). We hypothesize that the pathogenic link among the sporadic tumors of these organs of different germ layers might be represented by common molecular pathways involving the MEN1 gene and microRNAs (miR). miR-24 might be a microRNA linking the three tumor entities, but other candidates such as miR-142-3p and microRNAs forming the DLK1-MEG3 miRNA cluster might also be of importance.

MicroRNA-1207-5p inhibits hepatocellular carcinoma cell growth and invasion through the fatty acid synthase-mediated Akt/mTOR signalling pathway

Fatty acid synthase (FASN) has emerged as a unique oncologic target for the treatment of cancers, including hepatocellular carcinoma (HCC). However, effective inhibitors of FASN for cancer treatment are lacking. MicroRNAs (miRNAs) have emerged as novel and endogenic inhibitors of gene expression. In the present study, we aimed to investigate the role of miR‑1207‑5p in HCC and the regulation of FASN through miR‑1207‑5p. The expression of miR-1207-5p was markedly reduced in HCC tissues and cell lines as detected with real‑time quantitative polymerase chain reaction (qPCR). Overexpression of miR-1207-5p significantly suppressed the cell growth and invasion of HCC cells. By contrast, inhibition of miR‑1207‑5p exhibited an opposite effect. Bioinformatics analysis showed that FASN is a predicted target of miR‑1207‑5p which was validated by dual‑luciferase reporter assay, qPCR and western blot analysis. Overexpression of miR‑1207‑5p inhibited the Akt/mTOR signalling pathway, and promotion of this pathway was noted following inhibition of miR‑1207‑5p. Rescue experiments showed that the restoration of FASN expression partially reversed the inhibitory effect of miR‑1207‑5p on cell growth, invasion and Akt phosphorylation. In conclusion, our study suggests that miR‑1207‑5p/FASN plays an important role in HCC, and provides novel insight into developing new inhibitors for FASN for therapeutic interventions for HCC.

MicroRNA-320 was downregulated in non-small cell lung cancer and inhibited cell proliferation, migration and invasion by targeting fatty acid synthase

The expression and functions of microRNA (miR)-320 have been previously investigated in various types of cancer. However, to the best of our knowledge, no previous studies have investigated miR-320 in human lung cancer. The current study determined the expression, biological functions and molecular mechanisms of miR‑320 in human lung cancer. The expression level of miR‑320 in human non‑small cell lung cancer (NSCLC) and normal adjacent tissue samples (NATs), NSCLC cell lines and non‑tumorigenic bronchial epithelial cells was measured by reverse transcription‑quantitative polymerase chain reaction. Following transfection with miR‑320 mimics, 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide, cell migration and cell invasion assays, western blot analysis and luciferase assay were performed in human NSCLC cell lines. The results demonstrated that miR‑320 was significantly downregulated in NSCLC tissue samples and cell lines compared with NATs and a control cell line, respectively. Statistical analysis demonstrated that expression of miR‑320 was significantly associated with the TNM classification and metastasis. It was also observed that miR‑320 inhibited cell growth, migration and invasion in NSCLC cells. Additionally, the present study provided evidence that miR‑320 may directly target fatty acid synthase. These results suggest that miR‑320 may serve as a therapeutic biomarker of NSCLC in the future.

miR-142-3p inhibits cancer cell proliferation by targeting CDC25C

OBJECTIVES

MicroRNAs (miRNAs) contribute to control of cell cycle progression and are frequently deregulated in cancer. The focus of this study was to determine effects of miR-142-3p on the cell cycle progression and cancer cell proliferation.

MATERIALS AND METHODS

RT-qPCR was performed to determine expression of miR-142-3p in a range of cancer cell lines and in clinical cancer specimens. To further understand its role, we restored its expression in cancer cell lines by transfection with miR-142-3p mimics or inhibitors. Effects of miR-142-3p on cell cycle progression and cell proliferation were also determined.

RESULTS

miR-142-3p was down-regulated in both cancer cell lines and cancer specimens. Its overexpression suppressed proliferation, whereas its depletion promoted it. In addition, miR-142-3p lead to cell cycle arrest in G2/M. Moreover, CDC25C was identified as being a target of miR-142-3p, ectopic expression of which reversed suppression of cell proliferation.

CONCLUSIONS

Our observations suggest that miR-142-3p functioned as a tumor suppressor by targeting CDC25C.

microRNA-377 suppresses the proliferation of human osteosarcoma MG-63 cells by targeting CDK6

MicroRNAs (miRNAs) are essential to the progression of osteosarcoma. Previous research using osteosarcoma samples confirmed that miR-377 expression is less than that observed in normal human osteoblast expression. These data suggest a role for miR-377 in osteosarcoma that warrants investigation. To address this concept, we measured miR-377 expression in two cell models, and we also observed that miR-377 was less expressed in osteosarcoma MG-63 cells compared to the hFOB1.19 human fetal osteoblastic cell line. Moreover, miR-377 overexpression reduced cell proliferation and suppressed invasion of MG-63 cells but had no effect on MG-63 cell apoptosis. Because cyclin-dependent kinase 6 (CDK6) may be a potential target of miR-377 in osteosarcoma cells, we overexpressed CDK6 and observed that overexpression attenuated tumor suppressive effects of miR-377 on cell proliferation. Our data suggest that miR-377 can suppress proliferation in MG-63 cells in part by targeting CDK6.