MiR-370 functions as oncogene in melanoma by direct targeting pyruvate dehydrogenase B

Metformin Increases the Response of Cholangiocarcinoma Cells to Gemcitabine by Suppressing Pyruvate Kinase M2 to Activate Mitochondrial Apoptosis

BACKGROUND

Cholangiocarcinoma (CCA) is a malignant tumor with a high mortality rate. Resistance to chemotherapy remains a major challenge related to cancer treatment, and increasing the sensitivity of cancer cells to therapeutic drugs is a major focus of cancer treatment.

AIMS

We purposed to explore the role of Metformin in CCA involved in chemotherapeutic sensitivity and Pyruvate kinase M2 (PKM2) through regulating mitochondrial apoptosis in the present study.

METHODS

CCA cell lines of HCC9810 and RBE were treated with Metformin companied with antagonists or agonists of PKM2, cells sensitivity to Gemcitabine, cell migration and invasion along with apoptosis, which is mediated by JC-1 and LDH were assayed.

RESULTS

Our results indicated that Metformin and Gemcitabine exhibit synergistic effect on inhibition of cholangiocarcinoma cell viability, cell migration and invasion as well as promotion apoptosis of cholangiocarcinoma cells. In vivo, Metformin combined with Gemcitabine has cooperation in inhibiting the growth of cholangiocarcinoma cell-derived tumors. Moreover, Metformin and Gemcitabine inhibited expression of PKM2 and PDHB in HCC9810 and RBE.

CONCLUSION

Our study suggested that Metformin may increase the response of cholangiocarcinoma cells to Gemcitabine by suppressing PKM2 to activate mitochondrial apoptosis.

Relationship between transcriptional expression of pyruvate dehydrogenase and local control of disease in patients with oral cavity carcinomas

BACKGROUND

The altered cellular metabolism is one of the hallmarks of the cancer cells, favoring the process of aerobic glycolysis, known as the Warburg effect. The pyruvate dehydrogenase (PDH) complex is one of the elements involved in this metabolic process. The present study aims to evaluate the relationship between the transcriptional expression of PDHB and the risk of local recurrence in patients with oral cavity carcinomas.

METHODS

We determined the transcriptional expression of PDHB in biopsies from 41 patients with oral cavity carcinomas treated with surgery. The PDHB expression was categorized according to the local control of the disease with a recursive partitioning analysis.

RESULTS

During the follow-up period 13 patients (31.7%) had a local recurrence of the tumor. Considering local disease control as the dependent variable, the recursive partitioning analysis classified the patients in two categories according to high (n=16, 39.0%) or low (n=25, 61.0%) PDHB expression. Five-year local recurrence-free survival for patients with high PDHB expression was 84.8% (95% CI: 65.2-100%), and for patients with low expression it was 54.3% (95% CI: 34.3-74.2 %) (P=0.034). The results of multivariate analysis showed that patients with a low PDHB expression had a 4.90 times higher risk of local recurrence of the tumor (95% CI: 1.02-22.68, P=0.042).

CONCLUSION

There is a relationship between the metabolic characteristics of the tumor and its aggressiveness. According to our results, patients with oral cavity carcinomas with low transcriptional expression levels of PDHB have a significantly higher risk of local tumor recurrence.

Physcion increases the sensitivity of hepatocellular carcinoma to sorafenib through miRNA-370/PIM1 axis-regulated glycolysis

BACKGROUND

Resistance to sorafenib has become a challenge in clinical treatment of hepatocellular carcinoma (HCC). Physcion is a common bioactive anthraquinone that has potential as an anticancer agent.

AIM

To study the effect of physcion on sensitizing HCC cells to sorafenib.

METHODS

Sorafenib-resistant HCC cells were established and treated with sorafenib and/or physcion. The cell viability, proliferation and apoptosis were measured by cell counting kit-8, colony formation, flow cytometry, and in vivo xenograft model. Glucose uptake, lactate acid production, extracellular acidification rate (ECAR), and oxygen consumption rate (OCR) were measured to analyze glycolysis. Expression of glycolysis-related regulators was assessed by western blotting.

RESULTS

The addition of physcion significantly enhanced the antitumor effects of sorafenib on sorafenib-resistant HCC cells, manifested by enhanced apoptosis and suppressed cell growth. The glucose uptake, lactate acid production, and ECAR were elevated, and OCR was suppressed by physcion treatment. The level of PIM1 was elevated and miR-370 was suppressed in sorafenib-resistant HCC cells compared with the parental cells, which was suppressed by physcion treatment. Inhibition of miR-370 notably reversed the effects of physcion on sorafenib-resistant HCC cells.

CONCLUSION

Our data indicated that physcion enhanced the sensitivity of HCC cells to sorafenib by enhancing miR-370 to suppress PIM1-promoted glycolysis.

Correlation Between Endoglin and Malignant Phenotype in Human Melanoma Cells: Analysis of hsa-mir-214 and hsa-mir-370 in Cells and Their Extracellular Vesicles

Endoglin (CD105) is an auxiliary receptor of transforming growth factor (TGF)-β family members that is expressed in human melanomas. It is heterogeneously expressed by primary and metastatic melanoma cells, and endoglin targeting as a therapeutic strategy for melanoma tumors is currently been explored. However, its involvement in tumor development and malignancy is not fully understood. Here, we find that endoglin expression correlates with malignancy of primary melanomas and cultured melanoma cell lines. Next, we have analyzed the effect of ectopic endoglin expression on two miRNAs (hsa-mir-214 and hsa-mir-370), both involved in melanoma tumor progression and endoglin regulation. We show that compared with control cells, overexpression of endoglin in the WM-164 melanoma cell line induces; (i) a significant increase of hsa-mir-214 levels in small extracellular vesicles (EVs) as well as an increased trend in cells; and (ii) significantly lower levels of hsa-mir-370 in the EVs fractions, whereas no significant differences were found in cells. As hsa-mir-214 and hsa-mir-370 are not just involved in melanoma tumor progression, but they can also target endoglin-expressing endothelial cells in the tumor vasculature, these results suggest a complex and differential regulatory mechanism involving the intracellular and extracellular signaling of hsa-mir-214 and hsa-mir-370 in melanoma development and progression.

Reduced CircSMOC1 Level Promotes Metabolic Reprogramming via PTBP1 (Polypyrimidine Tract-Binding Protein) and miR-329-3p in Pulmonary Arterial Hypertension Rats

BACKGROUND

Pulmonary arterial hypertension maintains rapid cell proliferation and vascular remodeling through metabolic reprogramming. Recent studies suggested that circRNAs play important role in pulmonary vascular remodeling and pulmonary arterial smooth muscle cells proliferation. However, the relationship between circRNA, cell proliferation, and metabolic reprogramming in pulmonary arterial hypertension has not been investigated.

METHODS

RNA-seq and qRT-PCR reveal the differential expression profile of circRNA in pulmonary arteries of pulmonary arterial hypertension rat models. Transfection was used to examine the effects of circSMOC1 on pulmonary artery smooth muscle cells, and the roles of circSMOC1 in vivo were investigated by adenoassociated virus. Mass spectrometry, RNA pull-down, RNA immunoprecipitation, and dual-luciferase reporter assay were performed to investigate the signaling pathway of circSMOC1 regulating the metabolic reprogramming.

RESULTS

CircSMOC1 was significantly downregulated in pulmonary arteries of pulmonary arterial hypertension rats. CircSMOC1 knockdown promoted proliferation and migration and enhanced aerobic glycolysis of pulmonary artery smooth muscle cells. CircSMOC1 overexpression in vivo alleviates pulmonary vascular remodeling, right ventricular pressure, and right heart hypertrophy. In the nucleus, circSMOC1 directly binds to PTBP1 (polypyrimidine tract-binding protein), competitively inhibits the specific splicing of PKM (pyruvate kinase M) premRNA, resulting in the upregulation of PKM2 (pyruvate kinase M2), the key enzyme of aerobic glycolysis, to enhance glycolysis. In the cytoplasm, circSMOC1 acted as a miR-329-3p sponge, and its reduction in pulmonary arterial hypertension suppressed PDHB (pyruvate dehydrogenase E1 subunit beta) expression, leading to the impairment of mitochondrial oxidative phosphorylation.

CONCLUSIONS

circSMOC1 is crucially involved in the metabolic reprogramming of pulmonary artery smooth muscle cells through PTBP1 and miR-329-3p to regulate pulmonary vascular remodeling in pulmonary arterial hypertension.

Cuproptosis-related gene signature stratifies lower-grade glioma patients and predicts immune characteristics

Cuproptosis is the most recently discovered type of regulated cell death and is mediated by copper ions. Studies show that cuproptosis plays a significant role in cancer development and progression. Lower-grade gliomas (LGGs) are slow-growing brain tumors. The majority of LGGs progress to high-grade glioma, which makes it difficult to predict the prognosis. However, the prognostic value of cuproptosis-related genes (CRGs) in LGG needs to be further explored. mRNA expression profiles and clinical data of LGG patients were collected from public sources for this study. Univariate Cox regression analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression model were used to build a multigene signature that could divide patients into different risk groups. The differences in clinical pathological characteristics, immune infiltration characteristics, and mutation status were evaluated in risk subgroups. In addition, drug sensitivity and immune checkpoint scores were estimated in risk subgroups to provide LGG patients with precision medication. We found that all CRGs were differentially expressed in LGG and normal tissues. Patients were divided into high- and low-risk groups based on the risk score of the CRG signature. Patients in the high-risk group had a considerably lower overall survival rate than those in the low-risk group. According to functional analysis, pathways related to the immune system were enriched, and the immune state differed across the two risk groups. Immune characteristic analysis showed that the immune cell proportion and immune scores were different in the different groups. High-risk group was characterized by low sensitivity to chemotherapy but high sensitivity to immune checkpoint inhibitors. The current study revealed that the novel CRG signature was related to the prognosis, clinicopathological features, immune characteristics, and treatment perference of LGG.

MicroRNAs as Regulators of Cancer Cell Energy Metabolism

To adapt to the tumor environment or to escape chemotherapy, cancer cells rapidly reprogram their metabolism. The hallmark biochemical phenotype of cancer cells is the shift in metabolic reprogramming towards aerobic glycolysis. It was thought that this metabolic shift to glycolysis alone was sufficient for cancer cells to meet their heightened energy and metabolic demands for proliferation and survival. Recent studies, however, show that cancer cells rely on glutamine, lipid, and mitochondrial metabolism for energy. Oncogenes and scavenging pathways control many of these metabolic changes, and several metabolic and tumorigenic pathways are post-transcriptionally regulated by microRNA (miRNAs). Genes that are directly or indirectly responsible for energy production in cells are either negatively or positively regulated by miRNAs. Therefore, some miRNAs play an oncogenic role by regulating the metabolic shift that occurs in cancer cells. Additionally, miRNAs can regulate mitochondrial calcium stores and energy metabolism, thus promoting cancer cell survival, cell growth, and metastasis. In the electron transport chain (ETC), miRNAs enhance the activity of apoptosis-inducing factor (AIF) and cytochrome c, and these apoptosome proteins are directed towards the ETC rather than to the apoptotic pathway. This review will highlight how miRNAs regulate the enzymes, signaling pathways, and transcription factors of cancer cell metabolism and mitochondrial calcium import/export pathways. The review will also focus on the metabolic reprogramming of cancer cells to promote survival, proliferation, growth, and metastasis with an emphasis on the therapeutic potential of miRNAs for cancer treatment.

Is Tissue Still the Issue? The Promise of Liquid Biopsy in Uveal Melanoma

Uveal melanoma (UM) is the second most frequent type of melanoma. Therapeutic options for UM favor minimally invasive techniques such as irradiation for vision preservation. As a consequence, no tumor material is obtained. Without available tissue, molecular analyses for gene expression, mutation or copy number analysis cannot be performed. Thus, proper patient stratification is impossible and patients’ uncertainty about their prognosis rises. Minimally invasive techniques have been studied for prognostication in UM. Blood-based biomarker analysis has become more common in recent years; however, no clinically standardized protocol exists. This review summarizes insights in biomarker analysis, addressing new insights in circulating tumor cells, circulating tumor DNA, extracellular vesicles, proteomics, and metabolomics. Additionally, medical imaging can play a significant role in staging, surveillance, and prognostication of UM and is addressed in this review. We propose that combining multiple minimally invasive modalities using tumor biomarkers should be the way forward and warrant more attention in the coming years.

Comparative mRNA/micro-RNA co-expression network drives melanomagenesis by promoting epithelial-mesenchymal transition and vasculogenic mimicry signaling

This study aimed to identify a novel disease-associated differentially co-expressed mRNA-microRNA (miRNA) that is associated with vasculogenic mimicry (VM) and epithelial-to-mesenchymal transition (EMT) network at different stages of melanoma. By applying weighted gene co-expression network analysis, we constructed a VM+EMT biological network with the available microarray dataset downloaded from a public database. Quantitative real-time PCR, immunohistochemical staining, and CD31-periodic acid solution dual staining were performed to confirm the expression of genes associated with EMT and VM formation in subjects with malignant melanoma (n = 18) and primary melanoma (n = 13) and in healthy subjects (n = 10). Our findings suggested that phosphatidylserine-specific phospholipase A1-alpha (PLA1A) and dermokine (DMKN) genes function as oncogenes that trigger VM and EMT processes during melanomagenesis on interaction with miR-370, miR-563, and miR-770-5p. PLA1A and DMKN genes can be considered potential VM+EMT network-based diagnostic biomarkers for distinguishing between melanoma patients. We postulate that a network with altered PLA1A/miR-563 and DMNK/miR-770-5p/miR-370 may contribute to melanomagenesis by triggering the EMT signaling pathway and VM formation. This study provides a potentially valuable approach for the early diagnosis and prognosis of melanoma progression.

One Omics Approach Does Not Rule Them All: The Metabolome and the Epigenome Join Forces in Haematological Malignancies

Aberrant DNA methylation, dysregulation of chromatin-modifying enzymes, and microRNAs (miRNAs) play a crucial role in haematological malignancies. These epimutations, with an impact on chromatin accessibility and transcriptional output, are often associated with genomic instability and the emergence of drug resistance, disease progression, and poor survival. In order to exert their functions, epigenetic enzymes utilize cellular metabolites as co-factors and are highly dependent on their availability. By affecting the expression of metabolic enzymes, epigenetic modifiers may aid the generation of metabolite signatures that could be utilized as targets and biomarkers in cancer. This interdependency remains often neglected and poorly represented in studies, despite well-established methods to study the cellular metabolome. This review critically summarizes the current knowledge in the field to provide an integral picture of the interplay between epigenomic alterations and the cellular metabolome in haematological malignancies. Our recent findings defining a distinct metabolic signature upon response to enhancer of zeste homolog 2 (EZH2) inhibition in multiple myeloma (MM) highlight how a shift of preferred metabolic pathways may potentiate novel treatments. The suggested link between the epigenome and the metabolome in haematopoietic tumours holds promise for the use of metabolic signatures as possible biomarkers of response to treatment.

Emerging roles of circUBAP2 targeting miR-370-3p in proliferation, apoptosis, and invasion of papillary thyroid cancer cells

Circular RNAs (circRNAs) have been documented to be aberrantly expressed in many types of malignancies and involved in cancer progression. However, their role in thyroid cancer (TC) remains largely unknown. Our study aimed to explore the role and mechanism of circUBAP2 in TC. The differentially expressed circRNAs in TC tissues were identified using GSE18105 from gene expression omnibus (GEO) database. CircUBAP2 and miR-370-3p expression was analyzed using qRT-PCR. The stability of circUBAP2 was confirmed by actinomycin D and RNase R. The subcellular localization of circUBAP2 was detected using cell fractionation assay. Cell proliferation, apoptosis, and invasion were evaluated using MTT, flow cytometry analysis, and Transwell invasion assay, respectively. The interaction between circUBAP2 and miR-370-3p was predicted using bioinformatics analysis and validated by luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation. CircUBAP2 was upregulated and miR-370-3p was downregulated in TC tissues and cells. CircUBAP2 was highly stable, resistant to RNase R digestion, and predominantly localized in the cytoplasm. CircUBAP2 knockdown inhibited cell proliferation and invasion and triggered apoptosis in TC cells. Bioinformatics analysis showed that circUBAP2 contained putative binding sites of miR-370-3p. CircUBAP2 acted as a sponge to inhibit miR-370-3p expression. Mechanistically, miR-370-3p inhibition abolished the effects of circUBAP2 on proliferation, apoptosis, and invasion in TC cells. Taken together, CircUBAP2 knockdown impeded the proliferation and invasion and induced apoptosis in TC cells via sponging miR-370-3p.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

Non-coding RNAs rewire cancer metabolism networks

Non-coding RNAs (ncRNAs) are functional RNAs with limited or no protein-coding ability. These interact with their target molecules and participate in the precise regulation of disease development. Metabolic reprogramming is a hallmark in cancer, and is considered essential in meeting increased macromolecular biosynthesis and energy generation of tumors. Recent studies have revealed the involvement of ncRNAs in several metabolic regulations of cancer through direct modulation of metabolic enzyme activities or participation of metabolism-related signaling pathways. Elucidation of how ncRNAs regulate metabolic reprogramming of cancers has opened up a novel intention to understand the mechanism of metabolic rewiring and also the opportunities of utilizing ncRNA-based therapeutics for targeting the metabolism in cancer treatment.

Long noncoding RNA FGF14-AS2 inhibits breast cancer metastasis by regulating the miR-370-3p/FGF14 axis

Long noncoding RNAs (lncRNAs) have emerged as important regulators in cancers, including breast cancer. However, the overall biological roles and clinical significance of most lncRNAs are not fully understood. This study aimed to elucidate the potential role of a novel lncRNA FGF14-AS2 and the mechanisms underlying metastasis in breast cancer. The lncRNA FGF14-AS2 was significantly downregulated in breast cancer tissues; patients with lower FGF14-AS2 expression had advanced clinical stage. In vitro and in vivo assays of FGF14-AS2 alterations revealed a complex integrated phenotype affecting breast cancer cell migration, invasion, and tumor metastasis. Mechanistically, FGF14-AS2 functioned as a competing endogenous RNA of miR-370-3p, thereby leading to the activation of its coding counterpart, FGF14. Clinically, we observed increased miR-370-3p expression in breast cancer tissues, whereas FGF14 expression was decreased in breast cancer tissues compared to the adjacent normal breast tissues. FGF14-AS2 expression was significantly negatively correlated with miR-370-3p expression, and correlated positively to FGF14 expression. Collectively, our findings support a model in which the FGF14-AS2/miR-370-3p/FGF14 axis is a critical regulator in breast cancer metastasis, suggesting a new therapeutic direction in breast cancer.

Regulation of Glycolysis by Non-coding RNAs in Cancer: Switching on the Warburg Effect

The “Warburg effect” describes the reprogramming of glucose metabolism away from oxidative phosphorylation toward aerobic glycolysis, and it is one of the hallmarks of cancer cells. Several factors can be involved in this process, but in this review, the roles of non-coding RNAs (ncRNAs) are highlighted in several types of human cancer. ncRNAs, including microRNAs, long non-coding RNAs, and circular RNAs, can all affect metabolic enzymes and transcription factors to promote glycolysis and modulate glucose metabolism to enhance the progression of tumors. In particular, the 5′-AMP-activated protein kinase (AMPK) and the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathways are associated with alterations in ncRNAs. A better understanding of the roles of ncRNAs in the Warburg effect could ultimately lead to new therapeutic approaches for suppressing cancer.

Circular RNA CircITGA7 Promotes Tumorigenesis of Osteosarcoma via miR-370/PIM1 Axis

Many studies have shown that there are many circular RNA (circRNA) expression abnormalities in osteosarcoma (OS), and this abnormality is related to the development of osteosarcoma. But at present, it is unclear as to what circITGA7 has in the OS and what it does. In this study, qRT-PCR was used to detect the expression of circITGA7, miR-370, and PIM1 mRNA in OS tissues and cells. The CCK-8 assay was used to detect the effect of circITGA7 on cell proliferation. Later, the transwell assay was used to detect cell migration and invasion. The dual-luciferase reporter assay confirmed the existence of the targeting relationship between circITGA7 and miR-370, and miR-370 and PIM1. We found that circITGA7 was upregulated in OS tissues and cell lines. Knockdown of circITGA7 weakened the cell's ability to proliferate and metastasize. Furthermore, we observed that miR-370 was negatively regulated by circITGA7, while PIM1 was positively regulated by it. A functional assay validated that circITGA7 promoted OS progression via suppressing miR-370 and miR-370 affected OS proliferation and migration via PIM6 in OS. In summary, this study shows that circITGA7 promotes OS proliferation and metastasis via miR-370/PIM1.

Rescue of TCA Cycle Dysfunction for Cancer Therapy

Mitochondrion, a maternally hereditary, subcellular organelle, is the site of the tricarboxylic acid (TCA) cycle, electron transport chain (ETC), and oxidative phosphorylation (OXPHOS)—the basic processes of ATP production. Mitochondrial function plays a pivotal role in the development and pathology of different cancers. Disruption in its activity, like mutations in its TCA cycle enzymes, leads to physiological imbalances and metabolic shifts of the cell, which contributes to the progression of cancer. In this review, we explored the different significant mutations in the mitochondrial enzymes participating in the TCA cycle and the diseases, especially cancer types, that these malfunctions are closely associated with. In addition, this paper also discussed the different therapeutic approaches which are currently being developed to address these diseases caused by mitochondrial enzyme malfunction.

Glutamate metabotropic receptor 4 (GRM4) inhibits cell proliferation, migration and invasion in breast cancer and is regulated by miR-328-3p and miR-370-3p

Background

Glutamate metabotropic receptors (GRM) play a variety of roles in neuronal cells. However, their clinical significance and biological functions in breast cancer remain unknown.

Methods

RNA sequencing data of breast cancer was obtained from the TCGA dataset (v2) and mined for the expression profiles of GRM family according to cancer subtypes. mRNA expression of GRM family in breast cancer tissues and para-cancerous tissue samples as well as breast cancer cell lines were measured by qPCR. The effects of over- and under-expression of GRM4 on cell capabilities to survive, migrate and invade were determined by colony formation, transwell migration and invasion assays. To explore the upstream regulation pattern of GRM4, miRNAs that target GRM4 were predicted and validated by dual luciferase reporter assay. In addition, the mRNA and protein expression of GRM4 regulated by these miRNAs were further measured by qPCR and western blot assay.

Results

GRM4 was the only GRM member that expressed in breast cancer tissues. Ectopic expression of GRM4 was correlated with better prognosis of breast cancer patients. Overexpression of GRM4 could significantly inhibit cell proliferation, migration and invasion capacity in MDA-MB-231, while knockdown of GRM4 could promote these processes. miR-328-3p and miR-370-3p were predicted to regulate the expression of GRM4 and dual luciferase reporter assay demonstrated that miR-328-3p and miR-370-3p directly bound to the 3′ UTR of GRM4 and mutations on the binding regions on GRM4 significantly decreased the luciferase activity. qPCR demonstrated that expression of miR-328-3p and miR-370-3p was significantly decreased in breast cancer tissues and cells compared with that in control samples. However, there were no correlations between the expression of miR-328-3p and GRM4, as well as the expression of miR-370-3p and GRM4. Moreover, overexpression of miR-328-3p and miR-370-3p counteracted the inhibitory effect of GRM4-induced cell proliferation, migration and invasion.

Conclusions

Our results suggest that GRM4 might be a tumor suppressor gene in breast cancer under the direct regulation of miR-328-3p and miR-370-3p.

miR-140-5p is negatively correlated with proliferation, invasion, and tumorigenesis in malignant melanoma by targeting SOX4 via the Wnt/β-catenin and NF-κB cascades

MicroRNAs (miRNAs) have been validated as critical regulators in the development of melanoma. miR-140 was abnormally downregulated in uveal melanoma samples. However, the expression level and roles of miR-140-5p remain unclear in melanoma for now. We speculate that miR-140-5p is abnormally expressed and may play an important role in melanoma. The expressions of miR-140-5p and SOX4 messenger RNA were determined by quantitative real-time polymerase chain reaction assays. Western blot assays were employed to detect the expression levels of SOX4, Ki67, MMP-2, MMP-7, p-β-catenin, c-Myc, cyclin D1, p65, and IκBα. Luciferase reporter assays were employed to elucidate the interaction between SOX4 and miR-140-5p. MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) and transwell invasion assays were applied to evaluate capabilities of cell proliferation and invasion, respectively. Xenograft models of melanoma were established to verify the role and molecular basis of miR-140-5p. Immunohistochemical (IHC) assays were employed to measure the Ki67 and SOX4 at the protein level in xenografted melanoma tissues. Herein, these observations showed that, miR-140-5p was abnormally downregulated in melanoma tissues and cells, while SOX4 was upregulated. miR-140-5p directly targeted SOX4 and inhibited its expression in melanoma cells. miR-140-5p overexpression repressed melanoma cell proliferation and invasion and its effects were partially restored SOX4 overexpression. Moreover, miR-140-5p hindered melanoma growth in vivo by downregulating SOX4. Mechanistically, miR-140-5p suppressed activation of the Wnt/β-catenin and NF-κB pathways by targeting SOX4. Our study concluded that miR-140-5p hindered cell proliferation, invasion, and tumorigenesis by targeting SOX4 via inactivation of the Wnt/β-catenin and NF-κB signaling pathways in malignant melanoma, which provides an underlying molecular mechanism for the treatment for melanoma with miRNAs.

miR-145-5p inhibits tumor occurrence and metastasis through the NF-κB signaling pathway by targeting TLR4 in malignant melanoma

Compelling evidence shows that deregulated microRNAs (miRNAs) are important regulators in the progression of melanoma. miR-145-5p has been suggested to exhibit antitumorigenic activity in melanoma. However, the molecular mechanism underlying the biological activity of miR-145-5p in melanoma remains to be further understood. Herein, quantitative real-time polymerase chain reaction was used to examine the miR-145-5p expression in malignant melanoma tissues and cells. The interaction between miR-145-5p and toll-like receptor 4 (TLR4) was explored by bioinformatics analyses, luciferase reporter assay, and Western blot. The effects of miR-145-5p or combined with TLR4 on cell proliferation, colony formation, migration, and invasion abilities were investigated by (4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, colony formation, wound healing, and transwell assays, respectively. The melanoma xenograft tumor models were established to determine the biological activity of miR-145-5p in melanoma in vivo. In addition, the changes of the nuclear factor kappa B (NF-κB) pathway were analyzed by detecting the NF-κB activity and the NF-κB p65 protein level. We observed that the miR-145-5p expression was underexpressed in melanoma tissues and cells. miR-145-5p suppressed the TLR4 expression by binding to its 3'untranslated region in melanoma cells. Moreover, TLR4 overexpression abolished the inhibition of cell proliferation, colony formation, migration, and invasion abilities induced by miR-145-5p in melanoma cells. Meanwhile, miR-145-5p was confirmed to restrain melanoma tumor growth in vivo by targeting TLR4. Furthermore, miR-145-5p overexpression inactivated the NF-κB pathway in melanoma in vitro and in vivo, which was reversed by TLR4 overexpression. We concluded that miR-145-5p hindered the occurrence and metastasis of melanoma cells in vitro and in vivo by targeting TLR4 via inactivation of the NF-κB pathway.

Emergence of MicroRNAs as Key Players in Cancer Cell Metabolism

BACKGROUND

Metabolic reprogramming is a hallmark of cancer. MicroRNAs (miRNAs) have been found to regulate cancer metabolism by regulating genes involved in metabolic pathways. Understanding this layer of complexity could lead to the development of novel therapeutic approaches.

CONTENT

miRNAs are noncoding RNAs that have been implicated as master regulators of gene expression. Studies have revealed the role of miRNAs in the metabolic reprogramming of tumor cells, with several miRNAs both positively and negatively regulating multiple metabolic genes. The tricarboxylic acid (TCA) cycle, aerobic glycolysis, de novo fatty acid synthesis, and altered autophagy allow tumor cells to survive under adverse conditions. In addition, major signaling molecules, hypoxia-inducible factor, phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin/phosphatase and tensin homolog, and insulin signaling pathways facilitate metabolic adaptation in tumor cells and are all regulated by miRNAs. Accumulating evidence suggests that miRNA mimics or inhibitors could be used to modulate the activity of miRNAs that drive tumor progression via altering their metabolism. Currently, several clinical trials investigating the role of miRNA-based therapy for cancer have been launched that may lead to novel therapeutic interventions in the future.

SUMMARY

In this review, we summarize cancer-related metabolic pathways, including glycolysis, TCA cycle, pentose phosphate pathway, fatty acid metabolism, amino acid metabolism, and other metabolism-related oncogenic signaling pathways, and their regulation by miRNAs that are known to lead to tumorigenesis. Further, we discuss the current state of miRNA therapeutics in the clinic and their future potential.

CXCL12-regulated miR-370-3p functions as a tumor suppressor gene by targeting HMGA2 in nonfunctional pituitary adenomas

Silencing of noncoding genes within the imprinted DLK1-MEG3 locus is exclusive to human nonfunctional pituitary adenomas (NFPAs), but the exact mechanism is still unclear. This study was designed to demonstrate the impact of CXCL12 on the expression of miRNAs within this locus and phenotypic alterations of NFPAs. Human NFPA samples were collected for screening differentially expressed miRNAs by CXCL12. Target mRNAs of the miRNAs were predicted and verified in vitro. Tumor phenotypic alterations were also tested. Another 51 NFPA samples were enrolled to examine the correlation and clinical features. The expression of miR-370 was decreased by CXCL12 treatment in NFPAs. miR-370-3p was predicted and verified to target HMGA2 as a tumor suppressor gene. Overexpression of HMGA2 inhibited its antitumor function. miR-370-3p was downregulated and HMGA2 was upregulated significantly in High grade NFPAs. In conclusion, the CXCL12/miR-370-3p/HMGA2 signaling pathway is involved in tumor growth and invasiveness of NFPAs.

miR-625-5p/PKM2 negatively regulates melanoma glycolysis state

PKM2 plays an important role in cancer glycolysis, however, the link of PKM2 and microRNAs (miRNAs) in melanoma is still unclear. The study will investigate the role of miRNAs in regulating PKM2 mediated melanoma cell glycolysis. We found that high PKM2 expression in melanoma tissues and cell lines was positively associated with glycolysis. Further study indicated that miR-625-5p regulated PKM2 expression on mRNA and protein levels in melanoma cells. There was a negative relationship between miR-625-5p and PKM2 expression in the clinical melanoma samples. These findings provide an evidence that miR-625-5p/PKM2 plays a role in melanoma cell glucose metabolism.

Reduced Levels of miR-28 and miR-200a Act as Predictor Biomarkers of Aggressive Clinicopathological Characteristics in Gastric Cancer Patients

Background:

MicroRNAs (miRNAs) play critical roles in different pathological processes including cancer development and progression. To find novel molecular diagnostic and prognostic markers and promising therapeutic tools for gastric cancer (GC), we aimed to investigate the relationship of the expression levels of miR–28–5p or miR–200a–3p with the clinicopathological criteria and to explore their impacts on the progression of human GC.

Materials and Methods:

Quantitative RT–PCR was performed to analyze miR–28 and miR–200a expression in 60 GC and 60 non–GC tissue samples.

Result:

Our results revealed that the expressions of miR–200a and miR–28 were significantly downregulated in GC in comparison with non– GC tissues. Tumors with low miR–28 expression had larger tumor size, more advanced histological grade, and a higher incidence of lymph node and distal metastasis than the tumors with high miR–28 expressions. Furthermore, receiver operating characteristic (ROC) analyses demonstrate that the expression of miR–28 is a predictive biomarker allows predicting the histological grade, tumor size, and occurrence of nodal and distal metastases. We also found a significant inverse association between miR–200a expression and the rate of lymph node metastasis (p = 0.010, r = –0.334).

Conclusion:

Our findings suggest that the miR–28 and miR–200a have tumor–suppressor functions and may be considered as potential biomarkers for gastric cancer diagnosis and prognosis.

miR-370-3p Is a Therapeutic Tool in Anti-glioblastoma Therapy but Is Not an Intratumoral or Cell-free Circulating Biomarker

In the last decade, microRNAs (miRs) have been described as biomarkers and therapeutic agents. Based on this finding, our aim here is to know if (1) miRNA-370-3p can be used as a biomarker associated with a favorable survival and if (2) miRNA-370-3p can be used as a therapeutic tool that increases the efficiency of standard anti-GBM treatment. A first approach using the data available on the “Prognostic miRNA Database” indicated that the expression level of miRNA-370-3p in GBM (T-miR-370-3p) is not associated with a prognosis value for survival. A second approach quantifying the expression level of cell-free circulating miRNA-370-3p (cfc-miR-370-3p) also indicated that cfc-miR-370-3p is not associated with a prognosis value for survival. To investigate whether miR-370-3p can be used in vivo to increase the anti-GBM effect of TMZ, we then used the model of LN18-induced GBMs in mice. Our data indicated that the miRNA-370-3p/TMZ treatment was two times more efficient than the TMZ treatment for decreasing the tumor volume. In addition, our study correlated the decrease of tumor volume induced by the miRNA-370-3p/TMZ treatment with the decrease in FOXM1 and MGMT (i.e., two targets of miR-370-3p).

Our data thus support the idea that miR-370-3p could be used as therapeutic tool for anti-glioblastoma therapy, but not as a biomarker.

Amentoflavone induces apoptosis and suppresses glycolysis in glioma cells by targeting miR-124-3p

Malignant glioma is the most common type of brain tumor with poor clinical outcome and survival. Therefore, it is imperative to develop novel therapeutic agents for managing glioma. The aim of this study was to investigate the role of amentoflavone (AF), an active flavonoid component in Selaginella tamariscina Spring, in glioma cells and the underlying mechanism of its action. Our results showed that miR-124-3p expression was significantly down-regulated in glioma tissues relative to normal brain tissues. AF decreased cell viability and triggered apoptosis in both glioma cell lines in a dose-dependent manner. AF induced apoptosis and inhibited glycolysis in the glioma cells by upregulating miR-124-3p. Furthermore, AF upregulated miR-124-3p by repressing DNMT1 through Sp1, which in turn was caused by the activation of ROS/AMPK signaling pathway by AF. In conclusion, AF could induce apoptosis and inhibited glycolysis in glioma cells via miR-124-3p. Our findings provide preliminary experimental data that support further investigation on the therapeutic efficacy of AF in glioma.

MicroRNA-370 inhibits the proliferation, invasion and EMT of gastric cancer cells by directly targeting PAQR4

It has been reported that PAQR4 (Progestin and AdipoQ Receptor 4) expression is closely associated with progression of many cancers and microRNA (miRNA) processing. However, the effects and its precise mechanisms of PAQR4 in gastric cancer (GC) have not been well clarified. Our study aimed to explore the interaction between PAQR4 and miR-370 in GC. In our study, we found that the miR-370 level was significantly down-regulated in GC tissues and cell lines, and the expression of PAQR4 was dramatically increased. Interestingly, the low miR-370 level was closely associated with up-regulated PAQR4 expression in GC tissues. Moreover, introduction of miR-370 dramatically suppressed proliferation, invasion and EMT of GC cells. Whereas, miR-370 knockdown increased the proliferation, invasion and EMT in GC cells. We demonstrated that miR-370 could directly target PAQR4 by using both bioinformatics analysis and luciferase reporter assay. In addition, PAQR4 silencing had the similar effects with miR-370 overexpression on GC cells. Overexpression of PAQR4 in GC cells partially reversed the inhibitory effects of miR-370 mimic. miR-370 inhibited cell proliferation, invasion and EMT of GC cells by directly down-regulating PAQR4 expression, and miR-370 targeting PAQR4 was responsible for inhibition of the proliferation, invasion and EMT of GC cells.

Euxanthone inhibits glycolysis and triggers mitochondria-mediated apoptosis by targeting hexokinase 2 in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is one of the most prevalent gynaecological cancers. Euxanthone, an active ingredient of the medicinal plant Polygala caudata, exhibits a selective cytotoxic effect in tumour cells. The present study was aimed to determine whether euxanthone could suppress ovarian tumour growth, and to study the relevant mechanism. Two EOC cell lines, SKOV3 and A2780, were used as the in vitro model and treated with euxanthone. Cell viability and apoptosis were assayed using Cell Counting Kit-8 (CCK-8) and Annexin-V FITC/PI staining, respectively. Commercially available kits were used to measure the glucose consumption, lactate production, and intracellular ATP levels. Western blots assay was conducted to examine the level of apoptotic markers. To examine the roles of HK2 and STAT3 in the anti-tumour effect of euxanthone, cells were transfected with vectors overexpressing HK2 or STAT3, and assayed as above. Finally, SKOV3 cells were injected to mice models to appreciate the anti-neoplastic effect of euxanthone in vivo. We found that euxanthone impaired the cell viability and induced apoptosis via the intrinsic pathway in a concentration-dependent fashion in both SKOV3 and A2780 cells. Euxanthone also caused inhibition of glycolysis. Apoptosis and glycolysis inhibition was mediated by the downregulation of HK2, which in turn was a result of STAT3 inactivation. In vivo experiments also supported that euxanthone could exert anti-cancer activities without general toxicity. In conclusion, euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells.

SIGNIFICANCE OF THE STUDY

Euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells. Our findings provide preliminary experimental data that support further studies on the potential therapeutic role of euxanthone in ovarian cancer.

MiR-370 inhibits vascular inflammation and oxidative stress triggered by oxidized low-density lipoprotein through targeting TLR4

Atherosclerosis, as a chronic cardiovascular disease, still remains a serious threat to human health. Inflammation and oxidative stress are commonly involved in various stages of atherosclerosis development. MicroRNAs are reported to play important roles in macrophages, which can respond to inflammation and oxidative stress. In our current study, we focused on the biological roles of miR-370 in atherosclerosis. According to the previously research, miR-370 was downregulated in AS mice models. Oxidized low-density lipoprotein (Ox-LDL) is regarded as a crucial regulator of atherosclerosis and we observed that miR-370 was decreased by ox-LDL dose-dependently and time-dependently in THP-1 cells. Then, it was found that miR-370 overexpression was able to inhibit inflammation molecules including IL-6 and IL-1β. Meanwhile, ROS levels, and malondialdehyde (MDA) were also restrained by miR-370 mimics in vitro. Toll-like receptor 4 (TLR4) has been implicated in many inflammation diseases. It can serve as a target of miR-370 and TLR4 expression was greatly increased in ox-LDL-incubated THP-1 cells in a time and dose dependent manner. The negative correlation was validated using a dual-luciferase reporter assay in our study. In conclusion, our present study revealed that miR-370 can reduce inflammatory reaction and inhibit the ROS production by targeting TLR4 in THP-1 cells.