MiR-199a-5p-HIF-1α-STAT3 Positive Feedback Loop Contributes to the Progression of Non-Small Cell Lung Cancer

Non-coding RNAs as potential mediators of resistance to lung cancer immunotherapy and chemotherapy

Lung cancer is a common cause of cancer-related death globally. The majority of lung cancer patients initially benefit from chemotherapy and immunotherapy. However, as the treatment cycle progresses and the disease evolves, the emergence of acquired resistance leads to treatment failure. Many researches have shown that non-coding RNAs (ncRNAs) not only influence lung cancer progression but also act as potential mediators of immunotherapy and chemotherapy resistance in lung cancer, mediating drug resistance by regulating multiple targets and pathways. In addition, the regulation of immune response by ncRNAs is dualistic, forming a microenvironment for inhibits/promotes immune escape through changes in the expression of immune checkpoints. The aim of this review is to understand the effects of ncRNAs on the occurrence and development of lung cancer, focusing on the role of ncRNAs in regulating drug resistance of lung cancer.

AAV-mediated combination gene therapy of inducible Caspase 9 and miR-199a-5p is therapeutic in hepatocellular carcinoma

Advanced-stage hepatocellular carcinoma (HCC) remains an untreatable disease with an overall survival of less than one year. One of the critical molecular mediators contributing to increased resistance to therapy and relapse, is increased hypoxia-inducible factor 1α (HIF-1α) levels, leading to metastasis of tumor cells. Several microRNAs are known to be dysregulated and impact HIF-1α expression in HCC. An in silico analysis demonstrated that hsa-miR-199a-5p is downregulated at various stages of HCC and is known to repress HIF-1α expression. Based on this analysis, we developed a combinatorial suicide gene therapy by employing hepatotropic Adeno-associated virus-based vectors encoding an inducible caspase 9 (iCasp9) and miR-199a. The overexpression of miR-199a-5p alone significantly decreased ( ~ 2-fold vs. Mock treated cells, p < 0.05) HIF-1α mRNA levels, with a concomitant increase in cancer cell cytotoxicity in Huh7 cells in vitro and in xenograft models in vivo. To further enhance the efficacy of gene therapy, we evaluated the synergistic therapeutic effect of AAV8-miR-199a and AAV6-iCasp9 in a xenograft model of HCC. Our data revealed that mice receiving combination suicide gene therapy exhibited reduced expression of HIF-1α ( ~ 4-fold vs. Mock, p < 0.001), with a significant reduction in tumor growth when compared to mock-treated animals. These findings underscore the therapeutic potential of downregulating HIF-1α during suicide gene therapy for HCC.

Analysis of the correlation between the levels of HIF-1α and miR-199a in lesions and the psoriasis severity index

Introduction

The pathogenesis of psoriasis is complex. Previous bioinformatics studies have found differential expression of HIF-1α and miR-199 in psoriasis, but the correlation between miR-199a and HIF-1α and the severity of psoriasis is still unclear. This study found differential expression of HIF-1α and miR-199a levels in the skin lesions of patients with different degrees of psoriasis. HIF-1α mRNA and miR-199a are PASI influencing factors, and the levels of HIF-1 α and miR-199a in the skin lesions can serve as potential indicators for evaluating the severity index of psoriasis.

Aim

To examine the relationships between the levels of HIF-1α and miR-199a and psoriasis severity.

Material and methods

Sixty-five patients with psoriasis vulgaris treated from January 2023 to May 2024 were divided into a mild group (n = 16), a moderate group (n = 23), and a severe group (n = 26) according to the lesion area and severity index (PASI) score, and 40 healthy people were included in the control group (group A). The expression of HIF-1a and miR-199a in psoriatic lesions and normal skin tissues was detected by fluorescence quantitative PCR.

Results

The level of miR-199a in lesions in the observation group (group B) was lower than that in group A, but the level of HIF-1αmRNA in group B was greater than that in group A. The level of miR-199a in moderate and severe psoriasis patients was lower than that in mild psoriasis patients, and that in severe psoriasis patients was lower than that in moderate psoriasis patients. HIF-1α mRNA in lesions was positively associated with the PASI in psoriasis patients, and the miR-199a level in lesions was positively associated with the PASI in psoriasis patients. Furthermore, taking the PASI as the dependent variable and HIF-1αmRNA and miR-199a with a linear relationship with the dependent variable as the independent variables, multiple stepwise regression analysis showed that HIF-1α mRNA and miR-199a influenced the PASI.

Conclusions

HIF-1α and miR-199a are differentially expressed in the lesions of patients with different severities of psoriasis. The HIF-1α and miR-199a levels in lesions can be used as potential indices to evaluate the severity of psoriasis.

miR-199a-5p targets DUSP14 to regulate cell proliferation, invasion and stemness in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) shows the highest morbidity among malignant tumors worldwide. Despite improvements of diagnosis and treatment, patient prognosis remains unfavorable. Therefore, there is a need to discover a novel treatment strategy for NSCLC. DUSP14 is related to various cancers as the regulatory factor for cellular processes. However, its specific roles in NSCLC and the upstream modulator remain largely unclear.

Methods

DUSP14 expression patterns within the lung cancer patient cohort from TCGA database were analyzed using UALCAN online tool. Different databases including miRDB, starbase, and Targetscan were employed to screen the upstream regulator of DUSP14. DUSP14 and miR-199a-5p expression was determined by qRT-PCR and Western blot techniques. To confirm binding interaction of DUSP14 with miR-199a-5p, we conducted a dual-luciferase reporter assay. Cell viability, migration, and stemness properties were assessed using CCK-8, EdU (5-ethynyl-2'-deoxyuridine) incorporation, transwell invasion, and sphere formation assays. The effect of DUSP14 silencing on tumorigenesis was assessed with the NSCLC cell xenograft mouse model.

Results

Our study discovered that DUSP14 exhibited high expression within NSCLC tumor samples, which is related to the dismal prognostic outcome in NSCLC patients. Silencing DUSP14 impaired NSCLC cell proliferation, migration, and tumor sphere formation. Besides, we identified miR-199a-5p as the upstream regulatory factor for DUSP14, and its expression was negatively related to DUSP14 level within NSCLC tissues. Introducing miR-199a-5p recapitulated the function of DUSP14 silencing in NSCLC cell aggressiveness and stemness. Moreover, knocking down DUSP14 efficiently inhibited tumor formation in NSCLC cells of the xenograft model.

Conclusions

Our study suggests that DUSP14 is negatively regulated by miR-199a-5p within NSCLC, whose overexpression is required for sustaining NSCLC cell proliferation, invasion and stemness.

Functional impact of multi-omic interactions in lung cancer

Lung tumors are a leading cause of cancer-related death worldwide. Lung cancers are highly heterogeneous on their phenotypes, both at the cellular and molecular levels. Efforts to better understand the biological origins and outcomes of lung cancer in terms of this enormous variability often require of high-throughput experimental techniques paired with advanced data analytics. Anticipated advancements in multi-omic methodologies hold potential to reveal a broader molecular perspective of these tumors. This study introduces a theoretical and computational framework for generating network models depicting regulatory constraints on biological functions in a semi-automated way. The approach successfully identifies enriched functions in analyzed omics data, focusing on Adenocarcinoma (LUAD) and Squamous cell carcinoma (LUSC, a type of NSCLC) in the lung. Valuable information about novel regulatory characteristics, supported by robust biological reasoning, is illustrated, for instance by considering the role of genes, miRNAs and CpG sites associated with NSCLC, both novel and previously reported. Utilizing multi-omic regulatory networks, we constructed robust models elucidating omics data interconnectedness, enabling systematic generation of mechanistic hypotheses. These findings offer insights into complex regulatory mechanisms underlying these cancer types, paving the way for further exploring their molecular complexity.

Advances in Predictive Biomarkers for Anti-Angiogenic Therapy in Non-Small Cell Lung Cancer

This study aimed to explore advances in biomarkers related to anti-angiogenic therapy in patients with non-small cell lung cancer (NSCLC), thereby enhancing treatment selection, advancing personalized and precision medicine to improve treatment outcomes and patient survival rates. This article reviews key discoveries in predictive biomarkers for anti-angiogenic therapy in NSCLC in recent years, such as (1) liquid biopsy predictive biomarkers: studies have identified activated circulating endothelial cells (aCECs) via liquid biopsy as potential predictive biomarkers for the efficacy of anti-angiogenic therapy; (2) imaging biomarkers: advanced imaging technologies, such as dynamic contrast-enhanced integrated magnetic resonance positron emission tomography (MR-PET), are used to assess tumor angiogenesis in patients with NSCLC and evaluate the clinical efficacy of anti-angiogenic drugs; (3) genetic predictive biomarkers: research has explored polymorphisms of Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1) and vascular endothelial growth factor-A (VEGF-A), as well as how plasma levels of VEGF-A can predict the outcomes and prognosis of patients with non-squamous NSCLC undergoing chemotherapy combined with bevacizumab. Despite progress in identifying biomarkers related to anti-angiogenic therapy, several challenges remain, including limitations in clinical trials, heterogeneity in NSCLC, and technical hurdles. Future research will require extensive clinical validation and in-depth mechanistic studies to fully exploit the potential of these biomarkers for personalized treatment.

Exosomal hsa-miR-151a-3p and hsa-miR-877-5p are potential novel biomarkers for predicting bone metastasis in lung cancer

Exosomal miRNAs (exo-miRNAs) have arisen as novel diagnostic biomarkers for various cancers. However, few reports on exo-miRNAs related to bone metastasis (BM) in lung cancer exist. This study aims to screen out key exo-miRNAs and estimate their prognostic values for predicting BM in lung cancer. The differentially expressed exo-miRNAs between the highly-metastatic (95D) and lowly-metastatic (A549) human lung cancer cell lines were comprehensively analyzed using high-throughput sequencing followed by bioinformatic analyses. 29 candidate exo-miRNAs were identified, and 101 BM-related target genes were predicted. Enrichment analysis revealed that these target genes were mainly involved in regulating transcription and pathways in cancer. An exosomal miRNA-mRNA regulatory network consisting of 7 key miRNAs and 10 hub genes was constructed. Further function analysis indicated that these 10 hub genes were mainly enriched in regulating cancer's apoptosis and central carbon metabolism. The survival analysis indicated that 7 of 10 hub genes were closely related to prognosis. Mutation analysis showed that lung cancer patients presented certain genetic alterations in the 7 real hub genes. GSEA for a single hub gene suggested that 6 of 7 real hub genes had close associations with lung cancer development. Finally, ROC analysis revealed that hsa-miR-151a-3p and hsa-miR-877-5p provided high diagnostic accuracy in discriminating patients with bone metastasis (BM+) from patients without bone metastasis (BM-). These findings provided a comprehensive analysis of exo-miRNAs and target genes in the regulatory network of BM in lung cancer. In particular, hsa-miR-151a-3p and hsa-miR-877-5p may be novel biomarkers for predicting BM in lung cancer.

miR-199a/214 cluster enhances prostate cancer sensitiveness to nimotuzumab via targeting TBL1XR1

Prostate cancer (PCa) is a significant health concern affecting men worldwide. Previous studies have shown that nimotuzumab, a drug targeting the epidermal growth factor receptor (EGFR), can effectively inhibit cancer progression. Here, we aimed to explore the role of miR-199a/214 cluster in mediating the inhibitory effect of nimotuzumab on the development of PCa. In this study, we conducted an MTT assay to assess cell proliferation and utilized flow cytometry to evaluate cell apoptosis and cell cycle arrest. To investigate the molecular mechanisms underlying the effects of nimotuzumab on prostate cancer development, we focused on the miR-199a-5p and miR-214-3p miRNA clusters. The TargetScan Human database was used to predict the binding sites between miR-199a-5p or miR-214-3p and the 3'-UTR of the transducin (β)-like 1 X-linked receptor 1 (TBL1XR1) mRNA. To confirm the direct interaction and binding between miR-199a-5p or miR-214-3p and the 3'-UTR of TBL1XR1 mRNA, we performed luciferase reporter assays. Our findings demonstrated that nimotuzumab exerted a significant dosage-dependent suppression of PCa cell proliferation and facilitated PCa cell apoptosis and cell cycle arrest. Concurrently, nimotuzumab obviously impeded the activity of Wnt/β-catenin and EGFR signaling pathways in PCa cells. We also observed downregulation of miR-199a-5p and miR-214-3p in PCa cells. Overexpression of miR-199a/214 cluster inhibited PCa cell viability and enhanced cell apoptosis. Furthermore, we found that miR-199a/214 cluster augmented the inhibitory effect of nimotuzumab on PCa cell proliferation and promoted its ability to induce apoptosis and cell cycle arrest. This effect was reversed upon TBL1XR1 overexpression, indicating that TBL1XR1 is involved in the regulatory pathway of miR-199a/214 and nimotuzumab in PCa cells. We further revealed that TBL1XR1 was overexpressed in PCa and was identified as a downstream target of the miR-199a/214 cluster. In nimotuzumab-treated PCa cells, the overexpression of miR-199a/214 markedly inhibited Wnt/β-catenin and EGFR signaling, and this effect was also rescued by TBL1XR1 overexpression. In summary, our data indicated that miR-199a/214 cluster play a crucial role in enhancing the inhibitory effect of nimotuzumab on PCa development by downregulating TBL1XR1 and modulating Wnt/β-catenin and EGFR signaling pathways. These findings offer a novel therapeutic approach for the treatment of prostate cancer.

The Importance of the Immune System and Molecular Cell Signaling Pathways in the Pathogenesis and Progression of Lung Cancer

Lung cancer is a disease that in recent years has become one of the greatest threats to modern society. Every year there are more and more new cases and the percentage of deaths caused by this type of cancer increases. Despite many studies, scientists are still looking for answers regarding the mechanisms of lung cancer development and progression, with particular emphasis on the role of the immune system. The aim of this literature review was to present the importance of disorders of the immune system and the accompanying changes at the level of cell signaling in the pathogenesis of lung cancer. The collected results showed that in the process of immunopathogenesis of almost all subtypes of lung cancer, changes in the tumor microenvironment, deregulation of immune checkpoints and abnormalities in cell signaling pathways are involved, which contribute to the multistage and multifaceted carcinogenesis of this type of cancer. We, therefore, suggest that in future studies, researchers should focus on a detailed analysis of tumor microenvironmental immune checkpoints, and to validate their validity, perform genetic polymorphism analyses in a wide range of patients and healthy individuals to determine the genetic susceptibility to lung cancer development. In addition, further research related to the analysis of the tumor microenvironment; immune system disorders, with a particular emphasis on immunological checkpoints and genetic differences may contribute to the development of new personalized therapies that improve the prognosis of patients.

Matched Analyses of Brain Metastases versus Primary Non-Small Cell Lung Cancer Reveal a Unique microRNA Signature

Distant spreading of tumor cells to the central nervous system in non-small cell lung cancer (NSCLC) occurs frequently and poses major clinical issues due to limited treatment options. RNAs displaying differential expression in brain metastasis versus primary NSCLC may explain distant tumor growth and may potentially be used as therapeutic targets. In this study, we conducted systematic microRNA expression profiling from tissue biopsies of primary NSCLC and brain metastases from 25 patients. RNA analysis was performed using the nCounter Human v3 miRNA Expression Assay, NanoString technologies, followed by differential expression analysis and in silico target gene pathway analysis. We uncovered a panel of 11 microRNAs with differential expression and excellent diagnostic performance in brain metastasis versus primary NSCLC. Five microRNAs were upregulated in brain metastasis (miR-129-2-3p, miR-124-3p, miR-219a-2-3p, miR-219a-5p, and miR-9-5p) and six microRNAs were downregulated in brain metastasis (miR-142-3p, miR-150-5p, miR-199b-5p, miR-199a-3p, miR-199b-5p, and miR-199a-5p). The differentially expressed microRNAs were predicted to converge on distinct target gene networks originating from five to twelve core target genes. In conclusion, we uncovered a unique microRNA profile linked to two target gene networks. Our results highlight the potential of specific microRNAs as biomarkers for brain metastasis in NSCLC and indicate plausible mechanistic connections.

Cancer Stem Cells and the Tumor Microenvironment: Targeting the Critical Crosstalk through Nanocarrier Systems

The physiological state of the tumor microenvironment (TME) plays a central role in cancer development due to multiple universal features that transcend heterogeneity and niche specifications, like promoting cancer progression and metastasis. As a result of their preponderant involvement in tumor growth and maintenance through several microsystemic alterations, including hypoxia, oxidative stress, and acidosis, TMEs make for ideal targets in both diagnostic and therapeutic ventures. Correspondingly, methodologies to target TMEs have been investigated this past decade as stratagems of significant potential in the genre of focused cancer treatment. Within targeted oncotherapy, nanomedical derivates-nanocarriers (NCs) especially-have emerged to present notable prospects in enhancing targeting specificity. Yet, one major issue in the application of NCs in microenvironmental directed therapy is that TMEs are too broad a spectrum of targeting possibilities for these carriers to be effectively employed. However, cancer stem cells (CSCs) might portend a solution to the above conundrum: aside from being quite heavily invested in tumorigenesis and therapeutic resistance, CSCs also show self-renewal and fluid clonogenic properties that often define specific TME niches. Further scrutiny of the relationship between CSCs and TMEs also points towards mechanisms that underly tumoral characteristics of metastasis, malignancy, and even resistance. This review summarizes recent advances in NC-enabled targeting of CSCs for more holistic strikes against TMEs and discusses both the current challenges that hinder the clinical application of these strategies as well as the avenues that can further CSC-targeting initiatives. Central role of CSCs in regulation of cellular components within the TME.

Collagen Remodeling along Cancer Progression Providing a Novel Opportunity for Cancer Diagnosis and Treatment

The extracellular matrix (ECM) is a significant factor in cancer progression. Collagens, as the main component of the ECM, are greatly remodeled alongside cancer development. More and more studies have confirmed that collagens changed from a barrier to providing assistance in cancer development. In this course, collagens cause remodeling alongside cancer progression, which in turn, promotes cancer development. The interaction between collagens and tumor cells is complex with biochemical and mechanical signals intervention through activating diverse signal pathways. As the mechanism gradually clears, it becomes a new target to find opportunities to diagnose and treat cancer. In this review, we investigated the process of collagen remodeling in cancer progression and discussed the interaction between collagens and cancer cells. Several typical effects associated with collagens were highlighted in the review, such as fibrillation in precancerous lesions, enhancing ECM stiffness, promoting angiogenesis, and guiding invasion. Then, the values of cancer diagnosis and prognosis were focused on. It is worth noting that several generated fragments in serum were reported to be able to be biomarkers for cancer diagnosis and prognosis, which is beneficial for clinic detection. At a glance, a variety of reported biomarkers were summarized. Many collagen-associated targets and drugs have been reported for cancer treatment in recent years. The new targets and related drugs were discussed in the review. The mass data were collected and classified by mechanism. Overall, the interaction of collagens and tumor cells is complicated, in which the mechanisms are not completely clear. A lot of collagen-associated biomarkers are excavated for cancer diagnosis. However, new therapeutic targets and related drugs are almost in clinical trials, with merely a few in clinical applications. So, more efforts are needed in collagens-associated studies and drug development for cancer research and treatment.

miR-199a: A Tumor Suppressor with Noncoding RNA Network and Therapeutic Candidate in Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. miR-199a, which has two mature molecules: miR-199a-3p and miR-199a-5p, plays an important biological role in the genesis and development of tumors. We collected recent research results on lung cancer and miR-199a from Google Scholar and PubMed databases. The biological functions of miR-199a in lung cancer are reviewed in detail, and its potential roles in lung cancer diagnosis and treatment are discussed. With miR-199a as the core point and a divergence outward, the interplay between miR-199a and other ncRNAs is reviewed, and a regulatory network covering various cancers is depicted, which can help us to better understand the mechanism of cancer occurrence and provide a means for developing novel therapeutic strategies. In addition, the current methods of diagnosis and treatment of lung cancer are reviewed. Finally, a conclusion was drawn: miR-199a inhibits the development of lung cancer, especially by inhibiting the proliferation, infiltration, and migration of lung cancer cells, inhibiting tumor angiogenesis, increasing the apoptosis of lung cancer cells, and affecting the drug resistance of lung cancer cells. This review aims to provide new insights into lung cancer therapy and prevention.

A Description of the Hemolytic Component in Sickle Leg Ulcer: The Role of Circulating miR-199a-5p, miR-144, and miR-126

Sickle leg ulcers (SLU) are malleoli lesions with exuberant hemolytic pathophysiology. The microRNAs are potential genetic biomarkers for several pathologies. Thereby, we aimed to assess the expression of circulating miR-199a-5p, miR-144, and miR-126 in association with hemolytic biomarkers in SLU. This cross-sectional study included 69 patients with sickle cell disease, 52 patients without SLU (SLU-) and 17 patients with active SLU or previous history (SLU+). The results demonstrated elevated expression of circulating miR-199a-5p and miR-144 in SLU+ patients while miR-126 expression was reduced. Circulating miR-199a-5p and miR-144 were associated with hemolytic biomarkers such as LDH, indirect bilirubin, AST, GGT, iron, ferritin, RBC, hemoglobin, and NOm, in addition to association with impaired clinical profile of SLU. Furthermore, in silico analyses indicated interactions of miR-199a-5p with HIF1A, Ets-1, and TGFB2 genes, which are associated with vasculopathy and reduced NO. In contrast, miR-126 was associated with an attenuating clinical profile of SLU, in addition to not characterizing hemolysis. In summary, this study demonstrates, for the first time, that hemolytic mechanism in SLU can be characterized by circulating miR-199a-5p and miR-144. The circulating miR-126 may play a protective role in SLU. Thus, these microRNAs can support to establish prognosis and therapeutic strategy in SLU.

miR-199a Downregulation as a Driver of the NOX4/HIF-1α/VEGF-A Pathway in Thyroid and Orbital Adipose Tissues from Graves′ Patients

Graves’ disease (GD) is an autoimmune thyroiditis often associated with Graves’ orbitopathy (GO). GD thyroid and GO orbital fat share high oxidative stress (OS) and hypervascularization. We investigated the metabolic pathways leading to OS and angiogenesis, aiming to further decipher the link between local and systemic GD manifestations. Plasma and thyroid samples were obtained from patients operated on for multinodular goiters (controls) or GD. Orbital fats were from GO or control patients. The NADPH-oxidase-4 (NOX4)/HIF-1α/VEGF-A signaling pathway was investigated by Western blotting and immunostaining. miR-199a family expression was evaluated following quantitative real-time PCR and/or in situ hybridization. In GD thyroids and GO orbital fats, NOX4 was upregulated and correlated with HIF-1α stabilization and VEGF-A overexpression. The biotin assay identified NOX4, HIF-1α and VEGF-A as direct targets of miR-199a-5p in cultured thyrocytes. Interestingly, GD thyroids, GD plasmas and GO orbital fats showed a downregulation of miR-199a-3p/-5p. Our results also highlighted an activation of STAT-3 signaling in GD thyroids and GO orbital fats, a transcription factor known to negatively regulate miR-199a expression. We identified NOX4/HIF-1α/VEGF-A as critical actors in GD and GO. STAT-3-dependent regulation of miR-199a is proposed as a common driver leading to these events in GD thyroids and GO orbital fats.

Multicellular Effects of STAT3 in Non-small Cell Lung Cancer: Mechanistic Insights and Therapeutic Opportunities

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and accounts for 85% of lung cancer cases. Aberrant activation of the Signal Transducer and Activator of Transcription 3 (STAT3) is frequently observed in NSCLC and is associated with a poor prognosis. Pre-clinical studies have revealed an unequivocal role for tumor cell-intrinsic and extrinsic STAT3 signaling in NSCLC by promoting angiogenesis, cell survival, cancer cell stemness, drug resistance, and evasion of anti-tumor immunity. Several STAT3-targeting strategies have also been investigated in pre-clinical models, and include preventing upstream receptor/ligand interactions, promoting the degradation of STAT3 mRNA, and interfering with STAT3 DNA binding. In this review, we discuss the molecular and immunological mechanisms by which persistent STAT3 activation promotes NSCLC development, and the utility of STAT3 as a prognostic and predictive biomarker in NSCLC. We also provide a comprehensive update of STAT3-targeting therapies that are currently undergoing clinical evaluation, and discuss the challenges associated with these treatment modalities in human patients.

Regulation of Hypoxic Signaling and Oxidative Stress via the MicroRNA-SIRT2 Axis and Its Relationship with Aging-Related Diseases

The sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylase and ADP-ribosyl transferases plays key roles in aging, metabolism, stress response, and aging-related diseases. SIRT2 is a unique sirtuin that is expressed in the cytosol and is abundant in neuronal cells. Various microRNAs were recently reported to regulate SIRT2 expression via its 3'-untranslated region (UTR), and single nucleotide polymorphisms in the miRNA-binding sites of SIRT2 3'-UTR were identified in patients with neurodegenerative diseases. The present review highlights recent studies into SIRT2-mediated regulation of the stress response, posttranscriptional regulation of SIRT2 by microRNAs, and the implications of the SIRT2-miRNA axis in aging-related diseases.

mmu-miR-199a-5p regulates CYP2B10 through repression of E4BP4 in mouse AML-12 hepatocytes

miR-199a-5p is an important regulator of many biological processes. However, whether and how CYP enzymes are regulated by miR-199a-5p are unknown. Here, we aimed to investigate a potential role of mmu-miR-199a-5p in regulating CYP2 enzymes.Regulatory effects of mmu-miR-199a-5p on CYP expression were assessed in mouse AML-12 hepatocytes. Metabolic activity of CYP2B10 was probed using cyclophosphamide (CPA) as a specific substrate. Regulatory mechanism was investigated using combined luciferase reporter assays and chromatin immunoprecipitation.Of several important drug-metabolizing CYPs, mmu-miR-199a-5p significantly increased the mRNA levels of Cyp2a10, Cyp2c29 and Cyp2j5 in AML-12 cells with Cyp2a10 altered the most. Consistently, mmu-miR-199a-5p enhanced the expression of CYP2B10 protein and cellular metabolism of CPA. Based on database analysis, Cyp2b10 was not a direct target gene of mmu-miR-199a-5p. Thus, a mediator is necessary for the miRNA regulation of CYP2B10. We found that E4BP4 repressed Cyp2b10 transcription and expression through specific binding to a D-box element in the gene promoter. Moreover, mmu-miR-199a-5p inhibited the expression of E4bp4 at the posttranscriptional level by directly targeting the 59-65 nt segment in its 3'UTR.In conclusion, mmu-miR-199a-5p positively regulates CYP2B10 expression through inhibiting its repressor E4BP4. Our findings may provide increased understanding of the complex regulatory pathways for CYP2B10.