MicroRNA‐33a‐5p suppresses colorectal cancer cell growth by inhibitingMTHFD2

Targeting SHMTs and MTHFDs in cancer: attractive opportunity for anti-tumor strategy

One-carbon metabolism is a universal metabolic process that mediates the transfer of one-carbon units for purine and thymidine synthesis. One-carbon metabolism has been found to be dysregulated in various cancer types due to its role in production of purine and pyrimidine nucleotides, epigenetic program, and redox homeostasis. One-carbon metabolism is composed a network of one-carbon metabolic enzymes. Disturbing the expression and enzymatic activity of these one-carbon metabolic enzymes could lead to fluctuations of metabolites in the tumor microenvironment. Serine hydroxymethyltransferases (SHMTs) and methylenetetrahydrofolate dehydrogenases (MTHFDs) are gradually recognized as important one-carbon metabolic enzymes for regulating tumor initiation and development, representing potential therapeutic targets for anti-tumor strategies. In the review, we primarily focused on the role of SHMTs and MTHFDs in cancer. Several inhibitors targeting MTHFDs and SHMTs have exert its potential to decrease tumor burden and inhibit tumor proliferation, highlighting the potential of targeting one-carbon metabolic enzymes for anti-cancer strategies.

Targeting MTHFD2 to Exploit Cancer-Specific Metabolism and the DNA Damage Response

The one-carbon folate enzyme methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2 (MTHFD2) is a promising therapeutic target in cancer. MTHFD2 is upregulated across numerous cancer types, promotes growth and metastasis of cancer, and correlates with poorer survival. Recent studies have developed small-molecule inhibitors to the isozymes MTHFD2 and MTHFD1 that show promise as anticancer agents through different mechanisms. This review discusses the current understanding of the function of MTHFD2 in cancer and the status of inhibitors for treating MTHFD2-overexpressing cancers.

Targeting serine-glycine-one-carbon metabolism as a vulnerability in cancers

The serine-glycine-one-carbon (SGOC) metabolic pathway is critical for DNA methylation, histone methylation, and redox homeostasis, in addition to protein, lipid, and nucleotide biosynthesis. The SGOC pathway is a crucial metabolic network in tumorigenesis, wherein the outputs are required for cell survival and proliferation and are particularly likely to be co-opted by aggressive cancers. SGOC metabolism provides an integration point in cell metabolism and is of crucial clinical significance. The mechanism of how this network is regulated is the key to understanding tumor heterogeneity and overcoming the potential mechanism of tumor recurrence. Herein, we review the role of SGOC metabolism in cancer by focusing on key enzymes with tumor-promoting functions and important products with physiological significance in tumorigenesis. In addition, we introduce the ways in which cancer cells acquire and use one-carbon unit, and discuss the recently clarified role of SGOC metabolic enzymes in tumorigenesis and development, as well as their relationship with cancer immunotherapy and ferroptosis. The targeting of SGOC metabolism may be a potential therapeutic strategy to improve clinical outcomes in cancers.

Vaspin accelerates the proliferation, invasion and metastasis of Triple-Negative breast cancer through MiR-33a-5p/ABHD2

OBJECTIVE

To explore the influence and the underlying mechanism of vaspin (visceral adipose tissue-derived serpin) on the development of triple-negative breast malignancy.

METHODS

First, we analyzed medical records and screened out 22 breast cancer patients with different BMI according to inclusion and exclusion criterion, and measured serum vaspin of those patients. Then we studied the effects of vaspin on TNBC cell lines by using EdU assay, colony formation, transwell and wound-healing assay. Later, we used bioinformatics analysis to identify downstream effectors and verify with qRT-PCR, luciferase assay, western blot, etc. RESULTS: We found the vaspin level was positively correlated with BMI in breast malignant patients and vaspin could significantly enhance the proliferation, infiltration and transferring of triple-negative breast cancer cells by restraining the expression of miR-33a-5p. By using bioinformatic analysis and luciferase assay, we identified miR-33a-5p directly regulating ABHD2.

CONCLUSION

Vaspin, as a cancer-promoting cytokine, may inhibit miR-33a-5p thus increasing the level of ABHD2 to promote the development of the triple-negative breast cancer.

ATF4/MYC Regulates MTHFD2 to Promote NSCLC Progression by Mediating Redox Homeostasis

Purpose. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) has been reported to be overexpressed in non-small-cell lung cancer (NSCLC) and to correlate with malignant proliferation. However, the mechanism of high MTHFD2 expression in NSCLC has not been clarified. Methods. qPCR, western blot, and immunofluorescence experiments were used to measure the expression of related mRNAs and proteins. Cell apoptosis was measured by flow cytometry and TUNEL assays. The CCK-8 assay was used to determine cell viability. Flow cytometry was used to analyze the cell cycle. ROS, H2O2, MDA, SOD, and NADPH/NADP+ were evaluated by relevant assay kits. Transfection of siRNA or vectors was used to downregulate or upregulate gene expression. Dual-luciferase reporter gene assays were used to evaluate the regulated relationship between MTHFD2 and ATF4 or MYC. Results. MTHFD2 was highly expressed in NSCLC cells. Knockdown of MTHFD2 inhibited proliferation and increased apoptosis. Furthermore, oxidative factors significantly increased, while antioxidant factors significantly decreased in NSCLC cells with MTHFD2 knockdown, indicating that MTHFD2 was involved in NSCLC progression through the redox pathway. Although MTHFD2 was downregulated with ATF4 silencing, the dual-luciferase reporter assay suggested that ATF4 did not directly mediate MTHFD2 transcription. Further studies revealed that MYC had a transcriptional effect on MTHFD2 and was also regulated by ATF4. PCR, and western blotting experiments with ATF4 knockdown and MYC overexpression as well as ATF4 overexpression and MYC knockdown proved that ATF4 stimulated MTHFD2 through MYC mediation. Conclusions. ATF4 promoted high expression of MTHFD2 in NSCLC dependent on MYC.

LINC00974 sponges miR-33a to facilitate cell proliferation, invasion, and EMT of ovarian cancer through HMGB2 upregulation

The function and mechanism of long intergenic non-protein coding RNA 974 (LINC00974) are rarely reported in ovarian cancer (OC). The study aimed to investigate how LINC00974 affects the progression of OC. The expression levels of LINC00974, microRNA-33a (miR-33a), and high mobility group box 2 (HMGB2) mRNA were detected by qRT-PCR. The LINC00974/miR-33a/HMGB2 axis was confirmed by dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and biotinylated RNA pull-down assays. A series of in vitro experiments were employed to assess the effects of LINC00974/miR-33a/HMGB2 axis on the proliferation, invasion and epithelial mesenchymal transition (EMT) of OC cells. Results showed that LINC00974 and HMGB2 mRNA expression were upregulated in OC cells, while miR-33a expression was downregulated. HMGB2 was a direct target gene of miR-33a. LINC00974 act as a competing endogenous RNA (ceRNA) to directly bind with miR-33a, thereby upregulated HMGB2 expression. Notably, silencing of LINC00974 suppressed cell proliferation, invasion and EMT of OC cells, whereas miR-33a knockdown partially reversed the phenotypes of LINC00974 on OC cells. Overall, our study demonstrated that LINC00974 sponges miR-33a to promote cell proliferation, invasion, and EMT of OC through HMGB2 upregulation. LINC00974/miR-33a/HMGB2 axis may be an important signaling pathway in the progression of OC.

Clinical Value and Potential Mechanism of miRNA-33a-5p in Lung Squamous Cell Carcinoma

This study is aimed at thoroughly exploring the expression status, clinical significance, and underlying molecular mechanism of miRNA-33a-5p in lung squamous cell carcinoma (LUSC). Here, we detected miRNA-33a-5p in 20 samples from patients with LUSCs and 20 matching non-LUSC specimens by in-house quantitative real-time PCR (RT-qPCR). Relationship between miRNA-33a-5p expression and clinicopathological traits was investigated from materials derived from miRNA sequencing and miRNA microarrays. A pool standard mean difference (SMD) and summary receiver operating characteristic curves (SROC) were calculated to evaluate the integrated expression value of miRNA-33a-5p in LUSC. Twelve online platforms were applied to select potential target genes of miRNA-33a-5p. The differentially expressed genes (DEGs) of LUSC and the candidate target genes of miRNA-33a-5p were overlapped to acquire a set of specific genes for further analyses of the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and protein–protein interaction (PPI) network. miRNA-33a-5p overexpressed in LUSC was supported by 706 LUSC and 261 non-LUSC samples gathering from RT-qPCR, miRNA-seq, and public miRNA microarrays. The pooled SMD was 0.56 (95% CI: -0.01-1.05), and the area under the curve (AUC) of the SROC was 0.78 (95% CI: 0.74-0.82). A total of 240 genes were identified as potential target genes of miRNA-33a-5p for functional enrichment analyses; the results suggested that these target genes may participate in several vital biological processes that promote the proliferation and progression of LUSC. miRNA-33a-5p may play an essential role in the occurrence and development of LUSC by targeting hub genes (ETS1, EDNRB, CYR61, and LRRK2) derived from the PPI network. In summary, our results indicated that miRNA-33a-5p may contribute as a prospective therapeutic target in LUSC.

Inhibition of zinc finger protein 367 exerts a tumor suppressive role in colorectal cancer by affecting the activation of oncogenic YAP1 signaling

Zinc finger protein 367 (ZNF367) has been documented as a new cancer-related protein that exerts a pivotal role in the carcinogenesis of multiple cancers. However, whether ZNF367 plays a role in colorectal cancer has not been fully understood. Our data showed that ZNF367 expression was higher in colorectal cancer. Depletion of ZNF367 weakened the proliferative and invasive capabilities of colorectal cancer cells. Up-regulation of ZNF367 enhanced the in vitro malignant features of colorectal cancer cells. Knockdown of ZNF367 impeded the activation of Yes-associated protein (YAP1). Reactivation of YAP1 reversed the ZNF367-knockdown-mediated anticancer effects. Suppression of YAP1 significantly abolished ZNF367-overexpression-induced tumor-promotion effects. Depletion of ZNF367 repressed the tumorigenicity of colorectal cancer cells in vivo. These findings demonstrate that ZNF367 is overexpressed in colorectal cancer and acts as a potential tumor-promoter that contributes to the proliferation and invasion of colorectal cancer by enhancing the activation of YAP1 signaling.

Expression and Prognostic Value Identification of Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2) in Brain Low-Grade Glioma

Objective

This study aimed to reveal the potential function of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and emphasized its importance in brain low-grade glioma (LGG).

Methods

We firstly explored the differential expression of MTHFD2 mRNA in LGG and normal tissues, followed by correlation analysis of MTHFD2 mRNA expression with patient’s clinical characteristics. MTHFD2 protein expression in LGG and subcellular location were also evaluated. Then, survival analysis was performed to reveal the influence of MTHFD2 expression on the overall survival of patients, and Cox regression analysis was applied to predict the prognostic factor for overall survival of LGG. Finally, we performed functional analysis to reveal potential MTHFD2-associated pathways involved in LGG.

Results

We found that MTHFD2 was highly expressed in LGG patients (P<0.05), and MTHFD2 expression was related to patient’s age and IDH mutation status (all P<0.05). MTHFD2 protein was mainly localized to the mitochondria. Survival analysis showed that high expression of MTHFD2 desirably improved the prognosis of LGG patients (P<0.001), especially for those patients with age ≥45 years (P<0.05). But independent prognostic role of MTHFD2 in LGG was not observed. Pathway enrichment analysis indicated that MTHFD2 high expression significantly and positively participated in the pathway of one carbon pool by folate (all P<0.05).

Conclusion

High expression of MTHFD2 was observed in LGG, which was favorable for the overall survival of LGG patients. Our results assumed that MTHFD2 high expression might play a pivotal role in LGG through positively regulating pathway of one carbon pool by folate.

MTHFD2 promotes tumorigenesis and metastasis in lung adenocarcinoma by regulating AKT/GSK-3β/β-catenin signalling

Recent studies have demonstrated that one‐carbon metabolism plays a significant role in cancer development. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme of one‐carbon metabolism, has been reported to be dysregulated in many cancers. However, the specific role and mechanism of MTHFD2 in lung adenocarcinoma (LUAD) still remains unclear. In this study, we evaluated the clinicopathological and prognostic values of MTHFD2 in LUAD patients. We conducted a series of functional experiments in vivo and in vitro to explore novel mechanism of MTHFD2 in LUAD. The results showed that MTHFD2 was significantly up‐regulated in LUAD tissues and predicted poor prognosis of LUAD patients. Knockdown of MTHFD2 dramatically inhibited cell proliferation and migration by blocking the cell cycle and inducing the epithelial‐mesenchymal transition (EMT). In addition, MTHFD2 knockdown suppressed LUAD growth and metastasis in cell‐derived xenografts. Mechanically, we found that MTHFD2 promoted LUAD cell growth and metastasis via AKT/GSK‐3β/β‐catenin signalling. Finally, we identified miR‐30a‐3p as a novel regulator of MTHFD2 in LUAD. Collectively, MTHFD2 plays an oncogenic role in LUAD progression and is a promising target for LUAD diagnosis and therapy.

Tumor suppressive role of miR-33a-5p in pancreatic ductal adenocarcinoma cells by directly targeting RAP2A

Background

The suppressive effects of miR-33a-5p have been reported in colorectal cancer and lung cancer. However, the functional role of miR-33a-5p in pancreatic ductal adenocarcinoma (PDAC) has not yet been elucidated.

Methods

The expression of miR-33a-5p was determined using reverse-transcription quantitative PCR (RT-qPCR) in PDAC tissues and cell lines. The association between miR-33a-5p expression and clinical categorical parameters was analyzed by the chi-square test. Cell proliferation was analyzing by Cell Counting Kit -8 (CCK-8) assay. Transwell assay was utilized to assess cell migration and invasion. The interactions between miR-33a-5p and RAP2A were verified by luciferase reporter assay, RT-qPCR, western blot analysis and RNA immunoprecipitation (RIP) assay.

Results

Here, we observed for the first time that miR-33a-5p expression level was significantly decreased in PDAC tissues and cell lines. There was a significant association between decreased miR-33a-5p expression and TNM stage or lymph node metastasis. Overexpression of miR-33a-5p significantly inhibited SW1990 and PANC-1 cell proliferation, migration and invasion. Knockdown of miR-33a-5p remarkedly promoted cell proliferation, migration and invasion in BxPC-3 and ASPC-1. Mechanistically, RAP2A was confirmed as the target of miR-33a-5p in PDAC cells. Moreover, RAP2A overexpression abolished miR-33a-5p-mediated suppressive effects on SW1990 and PANC-1 cells.

Conclusions

Taken together, these results suggest that miR-33a-5p exerted tumor suppressive effects on PDAC cells by targeting RAP2A, which might provide a new theoretical basis for the clinical treatment of PDAC.

Therapeutic targeting of the mitochondrial one-carbon pathway: perspectives, pitfalls, and potential

Most of the drugs currently prescribed for cancer treatment are riddled with substantial side effects. In order to develop more effective and specific strategies to treat cancer, it is of importance to understand the biology of drug targets, particularly the newly emerging ones. A comprehensive evaluation of these targets will benefit drug development with increased likelihood for success in clinical trials. The folate-mediated one-carbon (1C) metabolism pathway has drawn renewed attention as it is often hyperactivated in cancer and inhibition of this pathway displays promise in developing anticancer treatment with fewer side effects. Here, we systematically review individual enzymes in the 1C pathway and their compartmentalization to mitochondria and cytosol. Based on these insight, we conclude that (1) except the known 1C targets (DHFR, GART, and TYMS), MTHFD2 emerges as good drug target, especially for treating hematopoietic cancers such as CLL, AML, and T-cell lymphoma; (2) SHMT2 and MTHFD1L are potential drug targets; and (3) MTHFD2L and ALDH1L2 should not be considered as drug targets. We highlight MTHFD2 as an excellent therapeutic target and SHMT2 as a complementary target based on structural/biochemical considerations and up-to-date inhibitor development, which underscores the perspectives of their therapeutic potential.

A Review of Small-Molecule Inhibitors of One-Carbon Enzymes: SHMT2 and MTHFD2 in the Spotlight

Metabolic reprogramming is a key hallmark of cancer and shifts cellular metabolism to meet the demands of biomass production necessary for abnormal cell reproduction. One-carbon metabolism (1CM) contributes to many biosynthetic pathways that fuel growth and is comprised of a complex network of enzymes. Methotrexate and 5-fluorouracil were pioneering drugs in this field and are still widely used today as anticancer agents as well as for other diseases such as arthritis. Besides dihydrofolate reductase and thymidylate synthase, two other enzymes of the folate cycle arm of 1CM have not been targeted clinically: serine hydroxymethyltransferase (SHMT) and methylenetetrahydrofolate dehydrogenase (MTHFD). An increasing body of literature suggests that the mitochondrial isoforms of these enzymes (SHMT2 and MTHFD2) are clinically relevant in the context of cancer. In this review, we focused on the 1CM pathway as a target for cancer therapy and, in particular, SHMT2 and MTHFD2. The function, regulation, and clinical relevance of SHMT2 and MTHFD2 are all discussed. We expand on previous clinical studies and evaluate the prognostic significance of these critical enzymes by performing a pan-cancer analysis of patient data from the The Cancer Genome Atlas and a transcriptional coexpression network enrichment analysis. We also provide an overview of preclinical and clinical inhibitors targeting the folate pathway, the methionine cycle, and folate-dependent purine biosynthesis enzymes.

Circ_SATB2 Attenuates the Anti-Tumor Role of Celastrol in Non-Small-Cell Lung Carcinoma Through Targeting miR-33a-5p/E2F7 Axis

Background

Celastrol (Cela) was a natural compound that exerted anti-tumor activity in many cancer cells. Nevertheless, the molecular mechanism behind the anti-tumor role of Cela in non-small-cell lung carcinoma (NSCLC) remains to be clarified.

Methods

Flow cytometry was used to analyze cell cycle progression and apoptosis. Colony formation assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to analyze cell proliferation. Cell migration and invasion abilities were assessed by transwell assays. Quantitative real-time polymerase chain reaction (qRT-PCR) was implemented for the detection of RNA levels. Western blot assay was used for the determination of protein levels. Dual-luciferase reporter assay was conducted to confirm the interaction between microRNA-33a-5p (miR-33a-5p) and circular RNA SATB homeobox 2 (circ_SATB2) or E2F transcription factor 7 (E2F7). Xenograft tumor assay was conducted to test the roles of Cela and circ_SATB2 in NSCLC progression in vivo.

Results

Cela hampered the malignant behaviors of NSCLC cells. Cela down-regulated circ_SATB2 level in NSCLC cells. Cela stimulation-induced suppressive influence in NSCLC progression was alleviated by circ_SATB2 accumulation. E2F7 interference overturned circ_SATB2-mediated effects in Cela-stimulated NSCLC cells. MiR-33a-5p was a target of circ_SATB2, and E2F7 was verified as a target of miR-33a-5p. Circ_SATB2 attenuated Cela-mediated effects through targeting miR-33a-5p in NSCLC cells. Cela-mediated suppressive effect on tumor growth was partly attenuated by the overexpression of circ_SATB2 in vivo.

Conclusion

Cela suppressed NSCLC development through regulating circ_SATB2/miR-33a-5p/E2F7 signaling cascade.

Gambogic Acid Inhibits the Progression of Gastric Cancer via circRNA_ASAP2/miR-33a-5p/CDK7 Axis

Background

Gastric cancer (GC) is a major cancer-related mortality disease. Gambogic acid (GA) has been investigated to inhibit cancer progression. In the present study, the molecular mechanism of GA in regulating GC progression was studied.

Methods

The expression levels of circular RNA ASAP2 (circ_ASAP2), miR-33a-5p and cyclin-dependent kinases 7 (CDK7) were detected by quantitative real-time polymerase reaction (qRT-PCR). CDK7 protein level was evaluated by Western blot. Cell colony formation assay, 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, transwell assay and flow cytometry analysis were employed to reveal the functional effects among circ_ASAP2, miR-33a-5p and CDK7 on GA-induced GC progression. Mechanistically, the binding relationship between miR-33a-5p and circ_ASAP2 or CDK7 was predicted with starBase v3.0 online database and verified by dual-luciferase reporter assay. In vivo tumor formation assay was used to explain the impacts of GA treatment on GC growth in vivo.

Results

Circ_ASAP2 and CDK7 expression were downregulated in GA-induced GC cells compared with GC cells. MiR-33a-5p expression was upregulated in GA-induced GC cells relative to GC cells. The protein expression level of CDK7 was lower in GA-induced GC cells than that in GC cells. Further, circ_ASAP2 overexpression decreased GA-induced inhibition effects on cell proliferation, migration and invasion and GA-induced promotion effect on cell apoptosis in both AGS and HGC-27 cells, whereas this phenomenon was reversed by miR-33a-5p. In addition, circ_ASAP2 functioned as a sponge of miR-33a-5p and miR-33a-5p was associated with CDK7. Furthermore, GA treatment inhibited GC growth in vivo.

Conclusion

Circ_ASAP2 overexpression promoted cell proliferation, migration and invasion, whereas inhibited cell apoptosis by upregulating CDK7 expression through binding to miR-33a-5p in GA-induced GC cells. This study provided a theoretical basis in GC treatment with GA.

MiR-33a-5p targets NOMO1 to modulate human cardiomyocyte progenitor cells proliferation and differentiation and apoptosis

PURPOSE

MicroRNA (miRNA) is known to be involved in the pathological process of congenital heart disease (CHD), and nodal modulator1 (NOMO1) is a critical determinant of heart formation. The present study aims to discover the effect of miR-33a-5p and NOMO1 on CHD.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect expressions of miR-33a-5p mimic or inhibitor and overexpressed NOMO1 plasmid orNOMO1 knockdown. Human cardiomyocyte progenitor cells (hCMPCs) proliferation was measured by cell counting kit-8 (CCK-8) at 24, 48 and 72 h. Flow cytometry was applied to investigate hCMPCs cell cycle progression and apoptosis. Expressions of cell apoptotic proteins Bax, Cleaved(C) caspase-3 and Bcl-2, and expressions of cardiomyocyte differentiation markers GATA4, troponin T (cTnT) and myocyte enhancer factor2C (MEF2C) in hCMPCs were identified by qRT-PCR and western blot. Target genes and potential binding sites of NOMO1 and miR-33a-5p were predicted with Targetscan 7.2, and was confirmed through dual-luciferase reporter assay.

RESULTS

Up-regulation of miR-33a-5p inhibited hCMPCs proliferation, cell cycle G0/S transition but promoted hCMPCs apoptosis, which was partially mitigated by overexpressed NOMO1. NOMO1 was the target gene of miR-33a-5p. Expressions of Bax and C caspase-3 were enhanced but expressions of Bcl-2, GATA4, cTnT and MEF2C were reduced by up-regulation of miR-33a-5p, which was partially mitigated by overexpressed NOMO1.

CONCLUSION

Up-regulation of miR-33a-5p inhibited hCMPCs proliferation, cell cycle G0/S transition and differentiation into cardiomyocytes but promoted apoptosis via targeting NOMO1.

Identification of MTHFD2 as a novel prognosis biomarker in esophageal carcinoma patients based on transcriptomic data and methylation profiling

DNA methylation is an important epigenetic regulatory mechanism in esophageal carcinoma (EC) and is associated with genomic instability and carcinogenesis. In the present study, we aimed to identify tumor biomarkers for predicting prognosis of EC patients.We downloaded mRNA expression profiles and DNA methylation profiles associated with EC from the Gene Expression Omnibus database. Differentially expressed and differentially methylated genes between tumor tissues and adjacent normal tissue samples were identified. Functional enrichment analyses were performed, followed by the construction of protein-protein interaction networks. Data were validated based on methylation profiles from The Cancer Genome Atlas. Candidate genes were further verified according to survival analysis and Cox regression analysis.We uncovered multiple genes with differential expression or methylation in tumor samples compared with normal samples. After taking the intersection of 3 differential gene sets, we obtained a total of 232 overlapping genes. Functional enrichment analysis revealed that these genes are related to pathways such as "glutathione metabolism," "p53 signaling pathway," and "focal adhesion." Furthermore, 8 hub genes with inversed expression and methylation correlation were identified as candidate genes. The abnormal expression levels of MSN, PELI1, and MTHFD2 were correlated with overall survival times in EC patients (P < .05). Only MTHFD2 was significantly associated with a pathologic stage according to univariate analysis (P = .037) and multivariate analysis (P = .043).Our study identified several novel EC biomarkers with prognostic value by integrated analysis of transcriptomic data and methylation profiles. MTHFD2 could serve as an independent biomarker for predicting prognosis and pathological stages of EC.

Silencing long non‑coding RNA NEAT1 suppresses the tumorigenesis of infantile hemangioma by competitively binding miR‑33a‑5p to stimulate HIF1α/NF‑κB pathway

Infantile hemangioma (IH) is one of the most common vascular tumors that occurs during childhood, but its pathogenesis is currently not completely understood. Even though lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) plays vital roles in tumorigenesis of malignant tumors, its roles in IH remain unclear. Therefore, we evaluate the function of lncRNA NEAT1 in IH. Reverse transcription-quantitative PCR indicated that IH tissues exhibited high expression levels of NEAT1 and hypoxia-inducible factor 1α (HIF1α), and low expression levels of the microRNA (miR)-33a-5p. Small interfering RNA-mediated depletion of NEAT1 suppressed hemangioma endothelial cell (HemEC) proliferation, migration and invasion. The data suggested that NEAT1 positively regulated HIF1α expression by sponging miR-33a-5p in HemECs. miR-33a-5p overexpression or HIF1α silencing also acted to suppress HemEC proliferation, migration and invasion. Furthermore, the results indicated that the NEAT1/miR-33a-5p/HIF1α axis regulated the NF-κB signaling pathway. Collectively, the results revealed that depletion of lncRNA NEAT1 suppressed the tumorigenesis of IH by competitively binding miR-33a-5p and thereby stimulating the HIF1α/NF-κB signaling pathway.

Role of microRNA-33a in malignant cells

Cancer causes most of the mortality and morbidity worldwide, with a significant increase in incidence during recent years. MicroRNAs (miRNAs/miRs) are non-coding small RNAs capable of regulating gene expression. They regulate crucial cellular processes, including proliferation, differentiation, metastasis and apoptosis. Therefore, abnormal miRNA expression is associated with multiple diseases, including cancer. There are two types of cancer-associated miRNAs, oncogenic and tumor suppressor miRNAs, depending on their roles and expression patterns in cancer. Accordingly, miRNAs are considered to be targets for cancer prevention and treatment. miR-33a controls cellular cholesterol uptake and synthesis, which are both closely associated with carcinogenesis. The present review thoroughly describes the roles of miR-33a in more than a dozen types of cancer and the underlying mechanisms. Accordingly, the present review may serve as a guide for researchers studying the involvement of miR-33a in diverse cancer settings.

MicroRNA-33a-5p sponges to inhibit pancreatic β-cell function in gestational diabetes mellitus LncRNA DANCR

BACKGROUND

Gestational diabetes mellitus (GDM) is the most common medical complication associated with pregnancy, which may impose risks on both mother and fetus. Micro RNAs (miRNAs) and long noncoding RNAs (lncRNAs) are implied as vital regulators in GDM. A recent paper revealed dysregulation of miR-33a-5p in placental tissues of GDM patients. However, the biological function of miR-33a-5p in GDM remains elusive. This study focused on exploring the function and underlying mechanisms of miR-33a-5p in GDM.

METHODS

12 GDM pregnancies and 12 healthy pregnancies were enrolled in the study. INS-1 cell line was applied in in vitro experiments. The expression levels of miR-33a-5p, lnc-DANCR (Differentiation Antagonizing Non-Protein Coding RNA), and ABCA1 (ATP-binding cassette transporter 1) mRNA were determined by RT-qPCR assay. Glucose and insulin levels were measured by ELISA assay. Luciferase reporter assay and western blot assay were applied to validate the target of miR-33a-5p.

RESULTS

miR-33a-5p was upregulated in the blood samples from GDM, and was positively correlated with blood glucose (p < 0.0001). Overexpression or inhibition of miR-33a-5p significantly inhibited or promoted cell growth and insulin production of INS-1 cells (p < 0.01). Furthermore, ABCA1 is a direct target of miR-33a-5p, and lnc-DANCR functions as a sponge for miR-33a-5p to antagonize the function of miR-33a-5p in INS-1 cells.

CONCLUSION

Our study demonstrated that lnc-DANCR-miR-33a-5p-ABCA1 signaling cascade plays a crucial role in the regulation of the cellular function of INS-1 cells.

miR-205 Promotes Apoptosis of Cervical Cancer Cells and Enhances Drug Sensitivity of Cisplatin by Inhibiting YAP1

Objective: Elevated expression of Yes-associated protein (YAP1) involves in the pathogenesis of cervical cancer. Bioinformatics analysis showed a targeting relationship between miR-205 and the 3'-UTR of YAP1. In this study, we aim to explore the role of miR-205 in the proliferation, apoptosis, or cisplatin (CDDP) resistance of cervical cancer cells. Patients and Methods: The dual luciferase reporter gene assay verified the relationship between miR-205 and YAP1. The CDDP-resistant cell line Hela/CDDP cells were cultured in vitro and divided into miR-NC group, miR-205 mimic group, and miR-205 inhibitor group followed by analysis of the expression of miR-205 and YAP1 mRNA by quantitative real-time polymerase chain reaction (qRT-PCR), and YAP1 protein level by western blot. Results: There was a targeted relationship between miR-205 and YAP1 mRNA. Compared with cervical cell line HCerEpiC cells, miR-205 expression was significantly decreased and YAP1 mRNA and protein expression was significantly increased in Hela cells (p < 0.01). Compared with miR-NC group, YAP1 protein expression in HeLa/CDDP cells was significantly decreased, cell apoptosis was increased, and proliferation was inhibited in miR-205 mimic-transfected Hela/CDDP cells (p < 0.01). Opposite results were obtained in miR-205 inhibitor-transfected Hela/CDDP cells. Conclusions: The expression of miR-205 is related to the CDDP resistance of cervical cancer cells. Increasing the expression of miR-205 can downregulate the expression of YAP1, inhibit the proliferation and promote apoptosis of cervical cancer cells, and enhance the sensitivity to CDDP.

More Than a Metabolic Enzyme: MTHFD2 as a Novel Target for Anticancer Therapy?

The bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase (MTHFD2) is a mitochondrial one-carbon folate metabolic enzyme whose role in cancer was not known until recently. MTHFD2 is highly expressed in embryos and a wide range of tumors but has low or absent expression in most adult differentiated tissues. Elevated MTHFD2 expression is associated with poor prognosis in both hematological and solid malignancy. Its depletion leads to suppression of multiple malignant phenotypes including proliferation, invasion, migration, and induction of cancer cell death. The non-metabolic functions of this enzyme, especially in cancers, have thus generated considerable research interests. This review summarizes current knowledge on both the metabolic functions and non-enzymatic roles of MTHFD2. Its expression, potential functions, and regulatory mechanism in cancers are highlighted. The development of MTHFD2 inhibitors and their implications in pre-clinical models are also discussed.