Downregulation of DNMT3a expression increases miR-182-induced apoptosis of ovarian cancer through caspase-3 and caspase-9-mediated apoptosis and DNA damage response

From molecular pathogenesis to therapy: Unraveling non-coding RNAs/DNMT3A axis in human cancers

Cancer is a comprehensive classification encompassing more than 100 forms of malignancies that manifest in diverse tissues within the human body. Recent studies have provided evidence that aberrant epigenetic modifications are pivotal indicators of cancer. Epigenetics encapsulates DNA methyltransferases as a crucial class of modifiers. DNMTs, including DNMT3A, assume central roles in DNA methylation processes that orchestrate normal biological functions, such as gene transcription, predominantly in mammals. Typically, deviations in DNMT3A function engender distortions in factors that drive tumor growth and progression, thereby exacerbating the malignant phenotype of tumors. Consequently, such abnormalities pose significant challenges in cancer therapy because they impede treatment efficacy. Non-coding RNAs (ncRNAs) represent a group of RNA molecules that cannot encode functional proteins. Recent investigation attests to the crucial significance of regulatory ncRNAs in epigenetic regulation. Notably, recent reports have illuminated the complex interplay between ncRNA expression and epigenetic regulatory machinery, including DNMT3A, particularly in cancer. Recent findings have demonstrated that miRNAs, namely miR-770-5p, miR-101, and miR-145 exhibit the capability to target DNMT3A directly, and their aberration is implicated in diverse cellular abnormalities that predispose to cancer development. This review aims to articulate the interplay between DNMT3A and the ncRNAs, focusing on its impact on the development and progression of cancer, cancer therapy resistance, cancer stem cells, and prognosis. Importantly, the emergence of such reports that suggest a connection between DNMT3A and ncRNAs in several cancers indicates that this connecting axis offers a valuable target with significant therapeutic potential that might be exploited for cancer management.

The effects of chitosan-loaded JQ1 nanoparticles on OVCAR-3 cell cycle and apoptosis-related gene expression

Background and purpose

Ovarian cancer is the deadliest gynecological cancer. Bromodomain and extra terminal domain (BET) proteins play major roles in the regulation of gene expression at the epigenetic level. Jun Qi (JQ1) is a potent inhibitor of BET proteins. Regarding the short half-life and poor pharmacokinetic profile, JQ1 was loaded into newly developed nano-carriers. Chitosan nanoparticles are one of the best and potential polymers in cancer treatment. The present study aimed to build chitosan-JQl nanoparticles (Ch-J-NPs), treat OVCAR-3 cells with Ch-J-NPs, and evaluate the effects of these nanoparticles on cell cycle and apoptosis-associated genes.

Experimental approach

Ch-J-NPs were synthesized and characterized. The size and morphology of Ch-J-NPs were defined by DLS and FE-SEM techniques. OVCAR-3 cells were cultured and treated with Ch-J-NPs. Then, IC50 was measured using MTT assay. The groups were defined and cells were treated with IC50 concentration of Ch-J-NPs, for 48 h. Finally, cells in different groups were assessed for the expression of genes of interest using quantitative RT-PCR.

Findings/Results

IC50 values for Ch-J-NPs were 5.625 μg/mL. RT-PCR results demonstrated that the expression of genes associated with cell cycle activity (c-MYC, hTERT, CDK1, CDK4, and CDK6) was significantly decreased following treatment of cancer cells with Ch-J-NPs. Conversely, the expression of caspase-3, and caspase-9 significantly increased. BAX (pro-apoptotic) to BCL2 (anti-apoptotic) expression ratio, also increased significantly after treatment of cells with Ch-J-NPs.

Conclusion and implications

Ch-J-NPs showed significant anti-cell cyclic and apoptotic effects on OVCAR-3 cells.

Correlation of DNA methylation of DNMT3A and TET2 with oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the sixth most common malignancy worldwide. Abnormal epigenetic modifications, including DNA methylation, are hallmarks of cancer and implicated in the development of various tumors. DNA methylation is catalyzed by the DNA methyltransferase and ten-eleven translocation dioxygenase families, with DNMT3A and TET2 being the most widely studied members, respectively. The correlation of methylation β values and clinical features was conducted in patients with OSCC in The Cancer Genome Atlas database. DNA methylation and protein expression levels of DNMT3A and TET2 in tissues were analyzed with methylation-specific polymerase chain reaction (MSP) and western blotting. To evaluate the effects of DNMT3A and TET2 on the biological characteristics of OSCC, cell proliferation was assessed with 5-ethynyl-2'-deoxyuridine, and cell migration capacity was quantified with wound healing and transwell assays. A survival analysis was performed with the Kaplan-Meier approach. The correlation between different methylation β values and clinical features was revealed. MSP revealed varying methylation degrees of DNMT3A and TET2 in OSCC tissues. Furthermore, western blotting showed that the protein expression levels were significantly different in cancer and surrounding healthy tissue samples. In vitro experiments demonstrated that DNMT3A knockdown and TET2 overexpression could inhibit the proliferation and migration of OSCC. Survival analysis revealed that patients with high DNMT3A methylation levels showed higher survival rates.

Anti-apoptotic capacity of MALAT1 on hippocampal neurons correlates with CASP3 DNA methylation in a mouse model of autism

Prior evidence has suggested the alleviatory effect of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on neuroinflammation in neurodegenerative diseases. This study primarily investigates the underlying mechanism of how the long non-coding RNA MALAT1 affects neuronal apoptosis in the hippocampus of mice with autism spectrum disorder (ASD). The findings demonstrate that CASP3 is highly expressed while MALAT1 is downregulated in the hippocampal neurons of autistic mice. MALAT1 mainly localizes within the cell nucleus and recruits DNA methyltransferases (including DNMT1, DNMT3a, and DNMT3b) to the promoter region of CASP3, promoting its methylation and further inhibiting its expression. In vitro experiments reveal that reducing MALAT1 expression promotes the expression of CASP3 and Bax while suppressing Bcl-2 expression, thereby enhancing cellular apoptosis. Conversely, increasing MALAT1 expression yields the opposite effect. Consequently, these results further confirm the role of MALAT1 in suppressing neuronal apoptosis in the hippocampus of mice with ASD through the regulation of CASP3 promoter methylation. Thus, this research unveils the significant roles of MALAT1 and CASP3 in the pathogenesis of ASD, offering new possibilities for future therapeutic interventions.

Identifying miRNA biomarkers for breast cancer and ovarian cancer: a text mining perspective

BACKGROUND

microRNA (miRNAs) are small, non-coding RNAs that mediate post-transcriptional gene silencing. Numerous studies have demonstrated the critical role of miRNAs in the development of breast cancer and ovarian cancer. To reduce potential bias from individual studies, a more comprehensive approach of exploring miRNAs in cancer research is essential. This study aims to explore the role of miRNAs in the development of breast cancer and ovarian cancer.

METHODS

Abstracts of the publications were tokenized and the biomedical terms (miRNA, gene, disease, species) were identified and extracted for vectorization. Predictive analyses were conducted with four machine learning models: K-Nearest Neighbors (KNN), Support Vector Machines (SVM), Random Forest (RF), and Naïve Bayes. Both holdout validation and cross-validation were utilized. Feature importance will be identified for miRNA-cancer networks construction.

RESULTS

We found that miR-182 is highly specific to female cancers. miR-182 targets different genes in regulating breast cancer and ovarian cancer. Naïve Bayes provided a promising prediction model for breast cancer and ovarian cancer with miRNAs and genes combination, with an accuracy score greater than 60%. Feature importance identified miR-155 and miR-199 are critical for breast cancer and ovarian cancer prediction, with miR-155 being highly related to breast cancer, whereas miR-199 being more associated with ovarian cancer.

CONCLUSION

Our approach effectively identified potential miRNA biomarkers associated with breast cancer and ovarian cancer, providing a solid foundation for generating novel research hypotheses and guiding future experimental studies.

MicroRNA-182-5p aggravates ulcerative colitis by inactivating the Wnt/β-catenin signaling pathway through DNMT3A-mediated SMARCA5 methylation

This research focused on novel molecular mechanisms underlying microRNA (miR)-182-5p in ulcerative colitis (UC). Colon tissues were obtained from UC patients, and dextrose sodium sulfate (DSS)-induced mouse and interleukin-1β (IL-1β)-induced Caco-2 cell models were generated. Then, miR-182-5p, SMARCA5, and the Wnt/β-catenin signaling pathway were altered in IL-1β-stimulated Caco-2 cells and DSS-treated mice to assess their function. MiR-182-5p and SMARCA5 were upregulated and DNMT3A, β-catenin, and Cyclin D1 were downregulated in UC patients, IL-1β-stimulated Caco-2 cells, and DSS-treated mice. Mechanistically, miR-182-5p targeted DNMT3A to upregulate SMARCA5, thus blocking the Wnt/β-catenin signaling pathway. Moreover, SMARCA5 silencing or Wnt/β-catenin signaling pathway activation repressed apoptosis and augmented proliferation and epithelial barrier function of IL-1β-stimulated Caco-2 cells. SMARCA5 silencing annulled the impacts of miR-182-5p overexpression on IL-1β-stimulated Caco-2 cells. SMARCA5 silencing or miR-182-5p inhibition ameliorated intestinal barrier dysfunction in DSS-treated mice. Collectively, miR-182-5p aggravates UC by inactivating the Wnt/β-catenin signaling pathway through DNMT3A-mediated SMARCA5 methylation.

Deregulated miRNA clusters in ovarian cancer: Imperative implications in personalized medicine

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. OC is usually detected at the advanced stages of the disease, making it highly lethal. miRNAs are single-stranded, small non-coding RNAs with an approximate size ranging around 22 nt. Interestingly, a considerable proportion of miRNAs are organized in clusters with miRNA genes placed adjacent to one another, getting transcribed together to result in miRNA clusters (MCs). MCs comprise two or more miRNAs that follow the same orientation during transcription. Abnormal expression of the miRNA cluster has been identified as one of the key drivers in OC. MC exists both as tumor-suppressive and oncogenic clusters and has a significant role in OC pathogenesis by facilitating cancer cells to acquire various hallmarks. The present review summarizes the regulation and biological function of MCs in OC. The review also highlights the utility of abnormally expressed MCs in the clinical management of OC.

miR-182 targeting reprograms tumor-associated macrophages and limits breast cancer progression

Breast cancer is a major threat of women’s health worldwide. Nontumor cell components play crucial roles in cancer. Macrophages, the cells of the innate immune system that normally exert antitumor activities, can be educated by tumors to an alternatively activated phenotype that is known to promote tumor progression. Understanding the mechanism of macrophage education by tumor cells will help the design of new therapeutic approaches. We find that breast tumor cells induce the expression of a microRNA, miR-182, in macrophages, and miR-182 promotes macrophage alternative activation to drive tumor development. Importantly, using cationized mannan-modified extracellular vesicles to load miR-182 inhibitors and deliver the inhibitors specifically into macrophages can effectively inhibit alternative activation of macrophages and suppress breast tumor development.

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFβ signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFβ/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.

Intronic miR-140-5p contributes to beta-cypermethrin-mediated testosterone decline

Beta-cypermethrin (β-CYP), a widely-used pyrethroid pesticide, is considered to have anti-androgenic effects and could impair male reproduction. To ascertain whether MAPK pathways, DNA methyltransferases (DNMTs), and miRNAs played pleiotropic roles in β-CYP-mediated testicular dysfunction, Sprague-Dawley rats and Leydig cells were employed in this study. Results showed that plasma testosterone levels were declined, testicular histomorphology and ultrastructures were abnormally altered, and Leydig cell functions were damaged after β-CYP exposure. JNK and p38/MAPK pathways were inactivated, accompanied by the decrease in c-Jun and Sp1 expressions. Specific activators/inhibitors of MAPK pathways and Co-IP demonstrated that DNMT3α was synergistically regulated by JNK/p38 pathways. The activity, mRNA and protein expressions of DNMT3α were all reduced by β-CYP. β-CYP induced expressions of intronic miR-140-5p and its host gene Wwp2, and then overexpressed miR-140-5p suppressed steroidogenic StAR, P450scc, and 3β-HSD by directly targeting SF-1. SF-1 silencing/overexpression, ChIP, and qPCR indicated that SF-1 modulated positively StAR, P450scc, and 3β-HSD expressions by directly binding to their promoter regions. Intriguingly, 5α-reductase expressions were downregulated after β-CYP exposure. Collectively, β-CYP has the anti-androgenic feature and the DNMT3α/miR-140-5p/SF-1 cascade co-regulated by JNK/p38 functions critically in β-CYP-caused testosterone declines. The downregulation of 5α-reductases may be a potential compensatory mechanism of the organism.

Downregulation of DNMT3A Attenuates the Warburg Effect, Proliferation, and Invasion via Promoting the Inhibition of miR-603 on HK2 in Ovarian Cancer

Background: Ovarian cancer is a highly malignant gynecological cancer. Aerobic glycolysis is one of the features of cancer cell metabolism. Studying the molecular modulation of the Warburg effect in ovarian cancer is significantly valuable for understanding the progression mechanism of ovarian cancer. Materials and Methods: The expression level and prognostic significance of DNMT3A were analyzed using public databases. DNMT3A was overexpressed by plasmid transfection, and DNMT3A was interfered with specific siRNAs transfection. miR-603 was overexpressed by mimic transfection or inhibited by inhibitor transfection. The expression of the molecules was detected by qPCR or western blotting. CCK-8 and transwell assays were used to determine the cell proliferation, migration, and invasion abilities of ovarian cancer. Results: We found that the DNMT3A protein level was higher in ovarian cancer tissues than in normal ovary tissues, but the mRNA level had no significant difference in ovarian cancer tissues and normal ovary tissues. The higher the RNA level of DNMT3A, the poorer prognosis of patients. DNMT3A knocking down impeded the Warburg effect, cell proliferation, migration, and invasion of ovarian cancer cells. Further investigations discovered that DNMT3A promoted ovarian cancer cell malignancy via silencing miR-603. Conclusion: We found that patients who overexpressed DNMT3A showed a poor prognosis. DNMT3A was found to promote the Warburg effect, cell proliferation, migration, and invasion of ovarian cancer by inhibiting the expression of miR-603. As a result, the research revealed that DNMT3A/miR-603/HK2 axis contributed to the Warburg effect of ovarian cancer and DNMT3A may be a potential therapeutic target for ovarian cancer.

The pattern of alternative splicing in lung adenocarcinoma shows novel events correlated with tumorigenesis and immune microenvironment

Lung adenocarcinoma (LUAD) is the leading cause of cancer deaths worldwide due to the lack of early diagnostic markers and specific drugs. Previous studies have shown the association of LUAD growth with aberrant alternative splicing (AS). Herein, clinical data of 535 tumor tissues and 59 normal tissues were extracted from The Cancer Genome Atlas (TCGA) database. Each sample was analyzed using the ESTIMATE algorithm; a comparison between higher and lower score groups (stromal or immune) was made to determine the overall- and progression-free survival-related differentially expressed AS (DEAS) events. We then performed unsupervised clustering of these DEASs, followed by determining their relationship with survival rate, immune cells, and the tumor microenvironment (TME). Next, two prognostic signatures were developed using bioinformatics tools to explore the prognosis of cases with LUAD. Five OS- and six PFS-associated DEAS events were implemented to establish a prognostic risk score model. When compared to the high-risk group (HRG), the PFS and OS of the low-risk group (LRG) were found to be considerable. Additionally, a better prognosis was found considerably associated with the ESTIMATE score of the patients as well as immune cells infiltration. Our analysis of AS events in LUAD not only helps to clarify the tumorigenesis mechanism of AS but also provides ideas for revealing potential prognostic biomarkers and therapeutic targets.

Peroxiredoxin 6 overexpression regulates adriamycin-induced myocardial injury, oxidative stress and immune response in rats

Background

Adriamycin is an anthracycline drug used to treat a variety of tumors. Adriamycin has a much stronger affinity for myocardial tissue than other body tissues. Cancer patients treated with adriamycin are prone to toxic damage to heart tissue. Peroxiredoxin 6 (PRDX6) is a novel antioxidant enzyme in metabolic diseases, the aim of this study was to investigate the role of PRDX6 in myocardial injury.

Methods

Sixty male specific-pathogen-free Wistar rats were enrolled and divided equally into the control group (control), the Adriamycin group, the Adriamycin + empty vector lentivirus (Adriamycin + LV) group, and the Adriamycin + Peroxiredoxin 6 overexpression (Adriamycin + PRDX6) group. Western blot, reverse transcription-polymerase chain reaction (PCR), enzyme-linked immunosorbent assay, hematoxylin and eosin staining (HE) and immunohistochemistry were used in this research.

Results

The myocardial tissues of the Adriamycin group had significantly lower expression levels of PRDX6 and PRDX6 mRNA than those of the control group, and the myocardial tissues of the Adriamycin + PRDX6 rats had significantly higher expression levels of PRDX6 and PRDX6 mRNA than those of the Adriamycin + LV group. Serum creatine kinase isoenzyme (CK-MB), myoglobin (Mb), cardiac troponin I (cTnI), myocardial injury, positive rate of caspase-3, B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) levels, malondialdehyde (MDA), lactate dehydrogenase (LDH), IL-1β, IL-6, inducible nitric oxide synthase (iNOS), and IL-4 proteins in the adriamycin-induced rats were significantly higher than those in the control group, while superoxide dismutase (SOD) activity was significantly lower than that in the control group. PRDX6 overexpression reversed the above results.

Conclusions

PRDX6 overexpression can alleviate adriamycin-induced myocardial injury in rats, which may be related to oxidative stress regulation and the levels of inflammatory factors.

Exosomes secreted by chronic hepatitis B patients with PNALT and liver inflammation grade ≥ A2 promoted the progression of liver cancer by transferring miR-25-3p to inhibit the co-expression of TCF21 and HHIP

OBJECTIVES

The current study aimed to investigate the mechanism by which exosomes secreted by CHB patients with PNALT and liver inflammation grade (≥A2) affected the development of liver cancer.

MATERIALS AND METHODS

Gene expression was assessed by RT-PCR, Western blotting and immunohistochemistry. CCK-8, colony formation, transwell, scratch-wound and flow cytometry assays were used to detect cell viability, proliferation, apoptosis and metastasis. The interaction of TCF21 and HHIP was assessed by co-immunoprecipitation assay. Luciferase reporter was used to detect the combination of TCF21/HHIP and miR-25-3p. Xenograft studies in nude mice manifested tumour growth ability of miR-25-3p. Bioinformatics analyses were conducted using TargetScan, EVmiRNA, TCGA, GEO, DAVID, COEXPEDIA, UALCAN, UCSC and the Human Protein Atlas databases.

RESULTS

CHB-PNALT-Exo (≥A2) promoted the proliferation and metastasis of HepG2.2.15 cells. miR-25-3p was upregulated in CHB-PNALT-Exo (≥A2). miR-25-3p overexpression promoted cell proliferation and metastasis and was related to poor survival in patients with CHB-PNALT (≥A2). The cell proliferation- and metastasis-promoting functions of CHB-PNALT-Exo (≥A2) were abolished by miR-25-3p inhibitors. TCF21 directly interacted with HHIP. Inhibition of TCF21 or HHIP promoted cell proliferation and metastasis. Knockdown of TCF21 or HHIP counteracted the effects of CHB-PNALT-Exo (≥A2) containing miR-25-3p inhibitor on cell proliferation, metastasis and the expression of Ki67, E-cadherin and caspase-3/-9.

CONCLUSIONS

Transfer of miR-25-3p by CHB-PNALT-Exo promoted the development of liver cancer by inhibiting the co-expression of TCF21 and HHIP.

A novel circular RNA circFN1 enhances cisplatin resistance in gastric cancer via sponging miR-182-5p

Cisplatin (CDDP) is commonly used for gastric cancer (GC) chemotherapy. However, after several CDDP-based treatment cycles, patients always acquire chemotherapy resistance, which limits the overall clinical efficacy of the treatment. Clarification of the mechanisms responsible for CDDP resistance is required to improve therapeutic outcomes for patients. Circular RNAs (circRNAs) are noncoding RNAs involved in the pathogenesis of cancer, although their role in the mechanism underlying CDDP resistance in GC remains unknown. In the present study, we explored the underlying roles of circRNAs in the modulation of CDDP resistance in CDDP-sensitive and CDDP-resistant human GC cells. Using RNA sequencing and quantitative reverse transcription polymerase chain reaction, expression of circFN1 (originating from exons 10, 11, and 12 of the FN1 gene hsa_circ_0058147) was higher in CDDP-resistant GC cells and tissues. CircFN1 upregulation in GC patients treated by CDDP was significantly correlated with aggressive biological behavior. CircFN1 promoted viability and inhibited apoptosis of GC cells exposed to CDDP in vivo and in vitro. Furthermore, circFN1 suppressed GC cell apoptosis by "sponging" miR-182-5p. These findings demonstrate the involvement of circFN1 in CDDP resistance of GC and implicate circFN1 as a therapeutic target for GC patients treated with CDDP. It provides novel evidence of the function of circRNAs as microRNA sponges and highlight a potential therapeutic target for extinguishing CDDP resistance in patients with GC.

Bavachin Protects Human Aortic Smooth Muscle Cells Against β-Glycerophosphate-Mediated Vascular Calcification and Apoptosis via Activation of mTOR-Dependent Autophagy and Suppression of β-Catenin Signaling

Vascular calcification is a major complication of cardiovascular disease and chronic renal failure. Autophagy help to maintain a stable internal and external environment that is important for modulating arteriosclerosis, but its pathogenic mechanism is far from clear. Here, we aimed to identify the bioactive compounds from traditional Chinese medicines (TCM) that exhibit an anti-arteriosclerosis effect. In β-glycerophosphate (β-GP)-stimulated human aortic smooth muscle cells (HASMCs), the calcium level was increased and the expression of the calcification-related proteins OPG, OPN, Runx2, and BMP2 were all up-regulated, followed by autophagy induction and apoptosis. Meanwhile, we further revealed that β-GP induced apoptosis of human osteoblasts and promoted differentiation of osteoblasts through Wnt/β-catenin signaling. Bavachin, a natural compound from Psoralea corylifolia, dose-dependently reduced the level of intracellular calcium and the expression of calcification-related proteins OPG, OPN, Runx2 and BMP2, thus inhibiting cell apoptosis. In addition, bavachin increased LC3-II and beclin1 expression, along with intracellular LC3-II puncta formation, which autophagy induction is Atg7-dependent and is regulated by suppression of mTOR signaling. Furthermore, addition of autophagy inhibitor, wortmannin (WM) attenuated the inhibitory effect of bavachin on β-GP-induced calcification and apoptosis in HASMCs. Collectively, the present study revealed that bavachin protects HASMCs against apoptosis and calcification by activation of the Atg7/mTOR-autophagy pathway and suppression of the β-catenin signaling, our findings provide a potential clinical application for bavachin in the therapy of cardiovascular disease.

miR-30a-3p inhibits the proliferation of liver cancer cells by targeting DNMT3a through the PI3K/AKT signaling pathway

MicroRNAs (miRNAs or miRs) are crucial for normal development and maintenance of homeostasis. Dysregulated miRNA expression contributes to numerous pathological conditions, including cancer tumorigenesis. However, a limited number of studies have examined the regulatory effects of miR-30a-3p in tumorigenesis. Therefore, the present study investigated the mechanistic process of tumorigenesis in liver cancer. The results revealed a high expression of DNA methyltransferase 3a (DNMT3a) and a low expression of miR-30a-3p in HepG2 cells compared with that in the L02 cell line. A luciferase reporter assay demonstrated that DNMT3a is a direct target of miR-30a-3p. In addition, DNMT3a overexpression significantly enhanced cell proliferation, which was reversed by a miR-30a-3p mimic. Similarly, the miR-30a-3p mimic blocked DNMT3a-triggered cell cycle processes and apoptosis by attenuating active p-AKT and p-PI3K in HepG2 cells. In summary, the results of the present study demonstrate that miR-30a-3p is essential for cell proliferation regulation via its association with AKT/PI3K signaling in liver cancer. These results provide insight into the molecular mechanism by which miR-30a-3p inhibits liver cancer cell proliferation and provides a foundation for its clinical development and application.

Prognostic values and prospective pathway signaling of MicroRNA-182 in ovarian cancer: a study based on gene expression omnibus (GEO) and bioinformatics analysis

BACKGROUND

Ovarian carcinoma (OC) is a common cause of death among women with gynecological cancer. MicroRNAs (miRNAs) are believed to have vital roles in tumorigenesis of OC. Although miRNAs are broadly recognized in OC, the role of has-miR-182-5p (miR-182) in OC is still not fully elucidated.

METHODS

We evaluated the significance of miR-182 expression in OC by using analysis of a public dataset from the Gene Expression Omnibus (GEO) database and a literature review. Furthermore, we downloaded three mRNA datasets of OC and normal ovarian tissues (NOTs), GSE14407, GSE18520 and GSE36668, from GEO to identify differentially expressed genes (DEGs). Then the targeted genes of hsa-miR-182-5p (TG_miRNA-182-5p) were predicted using miRWALK3.0. Subsequently, we analyzed the gene overlaps integrated between DEGs in OC and predicted target genes of miR-182 by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. STRING and Cytoscape were used to construct a protein-protein interaction (PPI) network and the prognostic effects of the hub genes were analyzed.

RESULTS

A common pattern of up-regulation for miR-182 in OC was found in our review of the literature. A total of 268 DEGs, both OC-related and miR-182-related, were identified, of which 133 genes were discovered from the PPI network. A number of DEGs were enriched in extracellular matrix organization, pathways in cancer, focal adhesion, and ECM-receptor interaction. Two hub genes, MCM3 and GINS2, were significantly associated with worse overall survival of patients with OC. Furthermore, we identified covert miR-182-related genes that might participate in OC by network analysis, such as DCN, AKT3, and TIMP2. The expressions of these genes were all down-regulated and negatively correlated with miR-182 in OC.

CONCLUSIONS

Our study suggests that miR-182 is essential for the biological progression of OC.

MicroRNA-377 Inhibits Atherosclerosis by Regulating Triglyceride Metabolism Through the DNA Methyltransferase 1 in Apolipoprotein E-Knockout Mice

BACKGROUND

Lipoprotein lipase (LPL) plays an important role in triglyceride metabolism. It is translocated across endothelial cells to reach the luminal surface of capillaries by glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1), where it hydrolyzes triglycerides in lipoproteins. MicroRNA 377 (miR-377) is highly associated with lipid levels. However, how miR-377 regulates triglyceride metabolism and whether it is involved in the development of atherosclerosis remain largely unexplored. Methods and Results: The clinical examination displayed that miR-377 expression was markedly lower in plasma from patients with hypertriglyceridemia compared with non-hypertriglyceridemic subjects. Bioinformatics analyses and a luciferase reporter assay showed that DNA methyltransferase 1 (DNMT1) was a target gene of miR-377. Moreover, miR-377 increased LPL binding to GPIHBP1 by directly targeting DNMT1 in human umbilical vein endothelial cells (HUVECs) and apolipoprotein E (ApoE)-knockout (KO) mice aorta endothelial cells (MAECs). In vivo, hematoxylin-eosin (H&E), Oil Red O and Masson's trichrome staining showed that ApoE-KO mice treated with miR-377 developed less atherosclerotic plaques, accompanied by reduced plasma triglyceride levels.

CONCLUSIONS

It is concluded that miR-377 upregulates GPIHBP1 expression, increases the LPL binding to GPIHBP1, and reduces plasma triglyceride levels, likely through targeting DNMT1, inhibiting atherosclerosis in ApoE-KO mice.

miR-1269 promotes cell survival and proliferation by targeting tp53 and caspase-9 in lung cancer

Background and aim

Lung cancer is the leading cause of cancer death worldwide. In this study, we aim to elucidate the role of miR-1269 in the pathogenesis of lung cancer.

Methods and results

From the results of analyses using The Cancer Genome Atlas (TCGA) database, we noted the expression of miR-1269 was increased in lung cancer tissue. miR-1269 expression was detected in both the normal adjacent lung tissue and in the tumorous lung tissue of lung cancer patients, and miR-1269 was more highly expressed in the tumors. High expression of miR-1269 correlated with patients’ tumor stage and lymph node metastasis. A Cell Counting Kit-8 (CCK8) analysis and a cloning formation assay showed that overexpression of miR-1269 significantly promoted the growth of A549 cells, and that a lower expression of miR-1269 significantly increased cell apoptosis. We used the TargetScan 6.2 Database to predict the potential targets of miR-1269, and a luciferase activity assay was used to determine the direct interaction between miR-1269, tumor protein p53 (TP53), and caspase-9. Results from Western blots and real-time PCR showed that overexpression of miR-1269 significantly inhibited TP53 and caspase-9 expression. In addition, caspase-3 activity was found to decrease in a miR-1269 mimic group. The results showed that gene silencing of TP53 and caspase-9 significantly inhibited A549 cell growth and promoted cell apoptosis. The results also showed that the inhibition of miR-1269 and caspase-9 expression inhibited cell apoptosis. Immunohistochemistry (IHC) results demonstrated that TP53 and caspase-9 were expressed in low levels in tumor tissues, and that an inverse correlation exists between miR-1269 expression levels and TP53 or caspase-9 expression levels.

Conclusion

These results demonstrate that miR-1269 promotes cell survival and proliferation by targeting TP53 and caspase-9 in lung cancer.

Arsenic trioxide-mediated suppression of miR-182-5p is associated with potent anti-oxidant effects through up-regulation of SESN2

Arsenic trioxide (ATO) is a traditional Chinese medicine that can induce oxidative stress for treatment of cancer cells. However, ATO may generate anti-oxidative responses to compromise the cytotoxic effect, but the underlying mechanisms remain unclear. Here we found that ATO could inhibit miR-182-5p expression in patient-derived primary S1 glioblastoma (GBM) cells accompanied by up-regulation of Sestrin-2 (SESN2) mRNA, a known anti-oxidant molecule. This phenomenon was also detected in a U87MG glioma cell line, human lung adenocarcinoma H1299 cell line and A549 cell line. Pretreatment with a free radical scavenger N-acetylcysteine (NAC) reduced the oxidative stress induced by ATO. Concomitantly, ATO mediated suppression of miR-182-5p and enhancement of SESN2 expression were also compromised. The MTT assay further showed that ATO induced cytotoxicity was enhanced by transfection of miR-182-5p mimics. Overexpression of miR-182-5p mimics significantly suppressed the expression of SENS2 and a firefly luciferase reporter gene fused to 3’- untranslated region (UTR) of SESN2 mRNA. Use of ribonucleoprotein immunoprecipitation (RNP-IP), ATO mediated suppression of miR-182-5p led to the stabilization of SESN2 mRNA as a result of Argonaute-2 (AGO2) dependent gene silencing. Furthermore, high expression of miR-182-5p and low expression of SESN2 mRNA tend to be associated with longer survival of glioma or lung cancer patients using public available gene expression datasets and online tools for prediction of clinical outcomes. Taken together, current data suggest that the miR-182-5p/SENS2 pathway is involved in ATO induced anti-oxidant responses, which may be important for the design of novel strategy for cancer treatment.

Autophagy inhibition of immature oocytes during vitrification-warming and in vitro mature activates apoptosis via caspase-9 and -12 pathway

OBJECTIVE

The aim of this study is to determine the role of autophagy in the immature oocytes during vitrification-warming and in vitro maturation (IVM); the correlations among autophagy, apoptosis, and the activities of caspase in the immature oocytes during vitrification-warming and IVM were also explored.

STUDY DESIGN

Immature oocytes from mice were vitrified-warmed and IVM. An autophagy inhibitor (3-methyladenine) was supplemented in cryopreservation solutions and warming solutions. The expression of beclin-1 (an autophagy marker), caspase-3, -8, -9, and -12 were measured. Moreover, the viability of vitrified-warmed immature oocytes and their subsequent developmental competence were measured.

RESULTS

The levels of beclin-1 expression in both mRNA and protein in oocytes experienced vitrification-warming and IVM were significantly higher than that in fresh immature oocytes experienced IVM. The levels of caspase-3, -9, -12 expression in both mRNA and protein in oocytes vitrified with 3-methyladenine were significantly higher than that vitrified without 3-methyladenine. However, the differences in the caspase-8 expression in both mRNA and protein between the oocytes vitrified with 3-methyladenine and that vitrified without 3-methyladenine were not significant.

CONCLUSION

Immature oocyte cryopreservation exhibits autophagic activation. Autophagy inhibition of the immature oocytes during vitrification-warming and IVM activates apoptosis via caspase-9 and -12 pathway.

MiR-143 inhibits cell proliferation and invasion by targeting DNMT3A in gastric cancer

Increasing evidence has suggested that MircroRNAs (miRNAs) dysregulated in pathogenesis and tumorigenicity in human cancers including gastric cancer (GC). MiR-143 had been reported to function as tumor suppressor in GC progression, however, the underlying function of miR-143 in GC still need to be well known. In the study, we revealed that miR-143 was significantly down-regulated in GC cell lines. Upregulation of miR-143 inhibited cell proliferation, invasion, S phase cell proportion and cell cycle related protein levels of Cyclin D1, CDK4 and CDK6 in GC. Furthermore, luciferase reporter assays demonstrated that DNMT3A was a direct target of miR-143 and Upregulation of miR-143 inhibited the DNMT3A mRNA and protein expression levels in GC cells. Moreover, we demonstrated that DNMT3A knockdown rescued the promoting effect of miR-143 inhibitor on cell proliferation in GC. Thus, these results demonstrated that miR-143 targeted DNMT3A in GC cells and inhibit GC tumorigenesis and progression, which may provide a novel therapeutic target of GC.

MicroRNA-mediated drug resistance in ovarian cancer

The development of intrinsic or acquired resistance to chemotherapeutic agents used in the treatment of various human cancers is a major obstacle for the successful abolishment of cancer. The accumulated efforts in the understanding the exact mechanisms of development of multidrug resistance (MDR) have led to the introduction of several unique and common mechanisms. Recent studies demonstrate the regulatory role of small noncoding RNA or miRNA in the several parts of cancer biology. Practically all aspects of cell physiology under normal and disease conditions are reported to be controlled by miRNAs. In this review, we discuss how the miRNA profile is changed upon MDR development and the pivotal regulatory role played by miRNAs in overcoming resistance to chemotherapeutic agents. It is hoped that further studies will support the use of these differentially expressed miRNAs as prognostic and predictive markers, as well as novel therapeutic targets to overcome resistance in ovarian cancer.