Role of miR-497 in VEGF-A-mediated cancer cell growth and invasion in non-small cell lung cancer

Metformin-mediated epigenetic modifications in diabetes and associated conditions: Biological and clinical relevance

An intricate interplay between genetic and environmental factors contributes to the development of type 2 diabetes (T2D) and its complications. Therefore, it is not surprising that the epigenome also plays a crucial role in the pathogenesis of T2D. Hyperglycemia can indeed trigger epigenetic modifications, thereby regulating different gene expression patterns. Such epigenetic changes can persist after normalizing serum glucose concentrations, suggesting the presence of a 'metabolic memory' of previous hyperglycemia which may also be epigenetically regulated. Metformin, a derivative of biguanide known to reduce serum glucose concentrations in patients with T2D, appears to exert additional pleiotropic effects that are mediated by multiple epigenetic modifications. Such modifications have been reported in various organs, tissues, and cellular compartments and appear to account for the effects of metformin on glycemic control as well as local and systemic inflammation, oxidant stress, and fibrosis. This review discusses the emerging evidence regarding the reported metformin-mediated epigenetic modifications, particularly on short and long non-coding RNAs, DNA methylation, and histone proteins post-translational modifications, their biological and clinical significance, potential therapeutic applications, and future research directions.

Extracellular Vesicles as Delivery Shippers for Noncoding RNA-Based Modulation of Angiogenesis: Insights from Ischemic Stroke and Cancer

Ischemic stroke and systemic cancer are two of the leading causes of mortality. Hypoxia is a central pathophysiological component in ischemic stroke and cancer, representing a joint medical function. This function includes angiogenesis regulation. Vascular remodeling coupled with axonal outgrowth following cerebral ischemia is critical in improving poststroke neurological functional recovery. Antiangiogenic strategies can inhibit cancer vascularization and play a vital role in impeding cancer growth, invasion, and metastasis. Although there are significant differences in the cause of angiogenesis across both pathophysiological conditions, emerging evidence states that common signaling structures, such as extracellular vesicles (EVs) and noncoding RNAs (ncRNAs), are involved in this context. EVs, heterogeneous membrane vesicles encapsulating proteomic genetic information from parental cells, act as multifunctional regulators of intercellular communication. Among the multifaceted roles in modulating biological responses, exhaustive evidence shows that ncRNAs are selectively sorted into EVs, modulating common specific aspects of cancer development and stroke prognosis, namely, angiogenesis. This review will discuss recent advancements in the EV-facilitated/inhibited progression of specific elements of angiogenesis with a particular concern about ncRNAs within these vesicles. The review is concluded by underlining the clinical opportunities of EV-derived ncRNAs as diagnostic, prognostic, and therapeutic agents.

miR-451a suppresses papillary thyroid cancer cell proliferation and invasion and facilitates apoptosis through targeting DCBLD2 and AKT1

Papillary thyroid cancer (PTC) is a common malignancy. MicroRNAs (miRNAs) may act as oncogenes or tumor suppressor genes. However, the role of miR-451a in PTC is not fully understood. Hence, the objective of the study was to research the effect and mechanism of miR-451a in PTC. Differentially expressed miRNAs between GSE113629 and GSE103996 databases were assessed by Venn diagram. miR-451a and its downstream target genes were assessed by RT-PCR and Western blot. The proliferation, invasion, and apoptosis were determined by CCK-8, EdU, transwell, and flow cytometry assays. Dual-luciferase reporter assay were used to evaluated the target of miR-451a. Xenografted tumors was used to explore the function of miR-451a in vivo. Pathological changes and related protein expression were measured by HE staining and immunohistochemistry. MiR-451a was downregulated in PTC tissues and blood, and low expression of miR-451a was related to short overall survival, serious lymph node metastasis and high TNM grade in PTC patients. Moreover, increase of miR-451a restrained the proliferation and invasion and accelerated the apoptosis. Furthermore, miR-451a repressed VEGF signaling pathway. Importantly, miR-451a was demonstrated to target DCBLD2 and AKT1. Overexpression of DCBLD2 and AKT1 could restore the effect of miR-451a on PTC cells. In addition, miR-451a reduced the growth of xenografted tumors in vivo. The data suggested that miR-451a attenuated the proliferation, invasion and promoted apoptosis in PTC cells via inhibiting DCBLD2 and AKT1.

Non-coding RNAs in lung cancer: emerging regulators of angiogenesis

Lung cancer is the second cancer and the leading cause of tumor-related mortality worldwide. Angiogenesis is a crucial hallmark of cancer development and a promising target in lung cancer. However, the anti-angiogenic drugs currently used in the clinic do not achieve long-term efficacy and are accompanied by severe adverse reactions. Therefore, the development of novel anti-angiogenic therapeutic approaches for lung cancer is urgently needed. Non-coding RNAs (ncRNAs) participate in multiple biological processes in cancers, including tumor angiogenesis. Many studies have demonstrated that ncRNAs play crucial roles in tumor angiogenesis. This review discusses the regulatory functions of different ncRNAs in lung cancer angiogenesis, focusing on the downstream targets and signaling pathways regulated by these ncRNAs. Additionally, given the recent trend towards utilizing ncRNAs as cancer therapeutics, we also discuss the tremendous potential applications of ncRNAs as biomarkers or novel anti-angiogenic tools in lung cancer.

Metformin and insulin-resistant related diseases: Emphasis on the role of microRNAs

Metformin is one of the most prescribed drugs in type II diabetes (T2DM) which has recently found new applications in the prevention and treatment of various illnesses, from metabolic disorders to cardiovascular and age-related diseases. Metformin improves insulin resistance (IR) by modulating metabolic mechanisms and mitochondrial biogenesis. Alternation of microRNAs (miRs) in the treatment of IR-related illnesses has been observed by metformin therapy. MiRs are small non-coding RNAs that play important roles in RNA silencing, targeting the 3'untranslated region (3'UTR) of most mRNAs and inhibiting the translation of related proteins. As a result, their dysregulation is associated with many diseases. Metformin may alter miRs levels in the treatment of various diseases by AMPK-dependent or AMPK-independent mechanisms. Here, we summarized the therapeutic role of metformin by modifying the aberrant expression of miRs as potential biomarkers or therapeutic targets in diseases in which IR plays a key role.

Long Non-Coding RNA JPX Contributes to Tumorigenesis by Regulating miR-5195-3p/VEGFA in Non-Small Cell Lung Cancer

Background

Lung cancer is the most frequently diagnosed cancer. Of all lung cancers, 80–85% are verified as non-small-cell lung cancer (NSCLC). Just proximal to X-inactive specific transcript (JPX), functions as lncRNA, contributed to tumor progression and suggested a poor prognosis in NSCLC. However, the pathogenesis of JPX involved in NSCLC is still unclear.

Methods

The expressions of JPX, miR-5195-3p, and Vascular endothelial growth factor A (VEGFA) were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Proliferation, colony number, apoptosis, invasion, and migration were analyzed by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, transwell, and wound healing assays, severally. The protein levels of VEGFA, E-cadherin, N-cadherin, and Vimentin were detected by Western blot assay. The interaction between JPX, miR-5195-3p and VEGFA was predicted by starBase, and then verified by the dual-luciferase reporter, RNA Immunoprecipitation (RIP) and RNA pull-down assay. The biological role of JPX on NSCLC tumor growth was assessed by the xenograft tumor model in vivo.

Results

JPX and VEGFA were upregulated, and miR-5195-3p was downregulated in NSCLC. JPX induced proliferation, colony number, invasion, migration, epithelial–mesenchymal transition (EMT), and inhibited apoptosis of NSCLC cells. JPX is directly bound to miR-5195-3p. JPX regulated NSCLC cell proliferation, apoptosis and EMT by modulating miR-5195-3p. miR-5195-3p hindered NSCLC cells proliferation, EMT and accelerated apoptosis by directly targeting VEGFA. JPX silencing hindered the cell growth of NSCLC in vivo.

Conclusion

JPX facilitated proliferation, colony number, invasion, migration, EMT, and repressed apoptosis by miR-5195-3p/VEGFA axis, offering a possible therapeutic strategy for NSCLC.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Simple Summary

Tumor cell invasiveness and metastasis are key processes in cancer progression and are composed of many steps. All of them are regulated by multiple microRNAs that either promote or suppress tumor progression. Multiple studies demonstrated that microRNAs target the mRNAs of multiple genes involved in the regulation of cell motility, local invasion, and metastatic niche formation. Thus, microRNAs are promising biomarkers and therapeutic targets in oncology.

Abstract

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Serum and Glucocorticoid-Inducible Kinase 1 (SGK1) in NSCLC Therapy

Non-small cell lung cancer (NSCLC) remains the most prevalent and one of the deadliest cancers worldwide. Despite recent success, there is still an urgent need for new therapeutic strategies. It is also becoming increasingly evident that combinatorial approaches are more effective than single modality treatments. This review proposes that the serum and glucocorticoid-inducible kinase 1 (SGK1) may represent an attractive target for therapy of NSCLC. Although ubiquitously expressed, SGK1 deletion in mice causes only mild defects of ion physiology. The frequent overexpression of SGK1 in tumors is likely stress-induced and provides a therapeutic window to spare normal tissues. SGK1 appears to promote oncogenic signaling aimed at preserving the survival and fitness of cancer cells. Most importantly, recent investigations have revealed the ability of SGK1 to skew immune-cell differentiation toward pro-tumorigenic phenotypes. Future studies are needed to fully evaluate the potential of SGK1 as a therapeutic target in combinatorial treatments of NSCLC. However, based on what is currently known, SGK1 inactivation can result in anti-oncogenic effects both on tumor cells and on the immune microenvironment. A first generation of small molecules to inactivate SGK1 has already been already produced.

Beyond Conventional: The New Horizon of Anti-Angiogenic microRNAs in Non-Small Cell Lung Cancer Therapy

GLOBOCAN 2018 identified lung cancer as the leading oncological pathology in terms of incidence and mortality rates. Angiogenesis is a key adaptive mechanism of numerous malignancies that promotes metastatic spread in view of the dependency of cancer cells on nutrients and oxygen, favoring invasion. Limitation of the angiogenic process could significantly hamper the disease advancement through starvation of the primary tumor and impairment of metastatic spread. This review explores the basic molecular mechanisms of non-small cell lung cancer (NSCLC) angiogenesis, and discusses the influences of the key proangiogenic factors-the vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (FGF2), several matrix metalloproteinases (MMPs-MMP-2, MMP-7, MMP-9) and hypoxia-and the therapeutic implications of microRNAs (miRNAs, miRs) throughout the entire process, while also providing critical reviews of a number of microRNAs, with a focus on miR-126, miR-182, miR-155, miR-21 and let-7b. Finally, current conventional NSCLC anti-angiogenics-bevacizumab, ramucirumab and nintedanib-are briefly summarized through the lens of evidence-based medicine.

MicroRNAs as regulators of VEGFA and NFE2L2 in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that are involved in post-transcriptional regulation of various genes, and their deregulation can lead to tumorigenesis. They may play the role of oncogenes or tumor suppressors by regulating different genes involved in cellular processes. One of the genes regulated by the miRNAs is the vascular endothelial growth factor A (VEGFA), which is responsible for angiogenesis. Angiogenesis is the process of formation of new blood vessels from pre-existing ones. This process plays an important role in tumor development, since it is responsible for the transport of nutrients required for tumor growth. Several studies have shown an increased expression of VEGFA in various cancers. Another gene regulated by miRNAs, the nuclear factor erythroid 2-like-2 (NFE2L2/NRF2), has a cytoprotective function and regulates cellular defense against oxidative stress. The NFE2L2 is the major regulator of cytoprotective agents and their oxidative damage to cells, which is down-regulated by Kelch-like ECH-associated protein 1 (KEAP1) at the post-transcriptional level. Regulation of the VEGFA and NFE2L2 by miRNAs has been observed in hepatocellular carcinoma and breast, lung, esophageal, endometrial, gastric, and ovarian cancer. This review highlights the role of miRNAs in the regulation of VEGFA and NFE2L2 and their relevance as therapeutic targets in various cancers.

Role of VEGFs/VEGFR-1 Signaling and its Inhibition in Modulating Tumor Invasion: Experimental Evidence in Different Metastatic Cancer Models

The vascular endothelial growth factor (VEGF) family members, VEGF-A, placenta growth factor (PlGF), and to a lesser extent VEGF-B, play an essential role in tumor-associated angiogenesis, tissue infiltration, and metastasis formation. Although VEGF-A can activate both VEGFR-1 and VEGFR-2 membrane receptors, PlGF and VEGF-B exclusively interact with VEGFR-1. Differently from VEGFR-2, which is involved both in physiological and pathological angiogenesis, in the adult VEGFR-1 is required only for pathological angiogenesis. Besides this role in tumor endothelium, ligand-mediated stimulation of VEGFR-1 expressed in tumor cells may directly induce cell chemotaxis and extracellular matrix invasion. Furthermore, VEGFR-1 activation in myeloid progenitors and tumor-associated macrophages favors cancer immune escape through the release of immunosuppressive cytokines. These properties have prompted a number of preclinical and clinical studies to analyze VEGFR-1 involvement in the metastatic process. The aim of the present review is to highlight the contribution of VEGFs/VEGFR-1 signaling in the progression of different tumor types and to provide an overview of the therapeutic approaches targeting VEGFR-1 currently under investigation.

Exosome-mediated microRNA-497 delivery for anti-cancer therapy in a microfluidic 3D lung cancer model

Non-small cell lung cancer (NSCLC) is one of the leading causes of death from cancer worldwide. The delivery and controlled regulation of miRNAs via exosomes is known as a potential therapeutic approach in the treatment of cancer. In this study, human cell-derived exosomes were used as delivery vehicles for miRNAs, and we investigated their anti-tumor and anti-angiogenic effects on NSCLCs that were cultured in 2D and 3D microfluidic devices. We demonstrated that exosomes that contained miRNA-497 (miR-497) effectively suppressed tumor growth and the expression of their associated genes, i.e., yes-associated protein 1 (YAP1), hepatoma-derived growth factor (HDGF), cyclin E1 (CCNE1), and vascular endothelial growth factor-A (VEGF-A), in A549 cells. Also, the level of VEGF-A-mediated angiogenic sprouting was decreased drastically in human umbilical vein endothelial cells (HUVECs) cultured in a microfluidic device. To mimic the in vivo-like tumor microenvironment of NSCLC, A549 cells were co-cultured with HUVECs in a single device, and miR-497-loaded exosomes were delivered to both types of cells. As a result, both the tube formation of endothelial cells and the migration of tumor decreased dramatically compared to the control. This indicated that miR-497 has synergistic inhibitory effects that target tumor growth and angiogenesis, so exosome-mediated miRNA therapeutics combined with the microfluidic technology could be a predictive, cost-efficient translational tool for the development of targeted cancer therapy.

Downregulation of Rab17 promotes cell proliferation and invasion in non-small cell lung cancer through STAT3/HIF-1α/VEGF signaling

BACKGROUND

Rab GTPases play a key role in regulating intercellular vesicle trafficking in both exo- and endocytic pathways. Recent studies have reported that Rab small GTPases and the associated regulatory proteins and effectors are involved in many cancers. The purpose of this study was to investigate the biological role of Rab17 in non-small cell lung cancer (NSCLC) and the relative mechanism.

METHODS

Rab17 expression in human NSCLC cell lines and tissues was evaluated using real-time PCR (RT-PCR), western blot and immunohistochemical (IHC) staining. NSCLC cell lines with RAB17 stable knockdown were generated to explore its function in vitro and in vivo. Additionally, we investigated the potential mechanism of Rab17 by identifying the expression levels of STAT3/HIF-1α/VEGF pathway using western blot analysis.

RESULTS

Decreased Rab17 expression was correlated with poor overall survival in NSCLC patients. The functional assays showed that knockdown of Rab17 could promote tumorigenic properties of NSCLC cells in vitro and in vivo, including enhanced cell proliferation, colony formation, invasion and migration, angiogenesis and tumor xenograft growth, and suppressed apoptosis. Moreover, Rab17 downregulation decreased epithelial marker E-cadherin and increased mesenchymal markers Vimentin and β-catenin, suggesting knockdown of Rab17 induced epithelial-mesenchymal transition (EMT).

CONCLUSION

Downregulation of Rab17 promotes cell invasion and enhances tumorigenicity in part through the STAT3/HIF-1α/VEGF pathway, which may represent a novel potential therapeutic target.

MiR-195 and miR-497 suppress tumorigenesis in lung cancer by inhibiting SMURF2-induced TGF-β receptor I ubiquitination

SMURF2 is a member of the HECT family of E3 ubiquitin ligases that have important roles as a negative regulator of transforming growth factor‐β (TGF‐β) signaling through ubiquitin‐mediated degradation of TGF‐β receptor I. However, the regulatory mechanism of SMURF2 is largely unknown. In this study, we identified that micro(mi)R‐195 and miR‐497 putatively target SMURF2 using several target prediction databases. Both miR‐195 and miR‐497 bind to the 3′‐UTR of the SMURF2 mRNA and inhibit SMURF2 expression. Furthermore, miR‐195 and miR‐497 regulate SMURF2‐dependent TβRI ubiquitination and cause the activation of the TGF‐β signaling pathway in lung cancer cells. Upregulation of miR‐195 and miR‐497 significantly reduced cell viability and colony formation through the activation of TGF‐β signaling. Interestingly, miR‐195 and miR‐497 also reduced the invasion ability of lung cancer cells when cells were treated with TGF‐β1. Subsequent in vivo studies in xenograft nude mice model revealed that miR‐195 and miR‐497 repress tumor growth. These findings demonstrate that miR‐195 and miR‐497 act as a tumor suppressor by suppressing ubiquitination‐mediated degradation of TGF‐β receptors through SMURF2, and suggest that miR‐195 and miR‐497 are potential therapeutic targets for lung cancer.

miR‑497 inhibits the proliferation and migration of A549 non‑small‑cell lung cancer cells by targeting FGFR1

Fibroblast growth factor receptor 1 (FGFR1) signaling has been reported to contribute to the carcinogenic progression of various cancer types. Previous studies have demonstrated that FGFR1 expression is increased in non‑small cell lung cancer (NSCLC) and promotes cancer cell metastasis. However, the molecular mechanisms underlying increased FGFR1 expression in NSCLC remains largely unknown. In the current study, microRNA (miR)‑497 levels were observed to be inversely correlated with FGFR1 expression in tumor samples from patients with NSCLC. In the NSCLC cell line A549, miR‑497 overexpression inhibited cell proliferation and migration. Increased expression of miR‑497 led to a reduction in FGFR1 expression, at the mRNA and protein levels. In addition, transfection of miR‑497 mimics inactivated the protein kinase B (AKT) and c‑Jun N‑terminal kinase (JNK) signaling pathways, as reduced matrix metallopeptidase 26 expression; all of which are regulated by FGFR1. Using TargetScan software, FGFR1 was also identified as a predicted target gene of miR‑497, and a dual luciferase reporter assay confirmed that miR‑497 directly regulated FGFR1. Transfection of a recombinant FGFR1 overexpression vector reversed miR‑497 mimic‑induced arrest of cell growth and migration in A549 cells. In conclusion, the results of the present study identified miR‑497 as a potential tumor suppressor gene in NSCLC that may function via repressing FGFR1 expression, and AKT and JNK signaling.

Prognostic Value of MicroRNA-497 in Various Cancers: A Systematic Review and Meta-Analysis

Background

Some studies showed that microRNA-497 (miR-497) might act as a prognostic biomarker of cancer. However, the conclusion was not consistent. The aim of this study was to investigate the prognostic role of miR-497 in various carcinomas.

Methods

We systematically searched the databases of PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Data to identify relevant studies. Two independent reviewers performed the data extraction and assessed the study quality. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) for overall survival (OS) and disease-free survival/relapse-free survival (DFS/RFS) were used to assess the associations between miR-497 expression and cancer prognosis.

Results

A total of 15 studies involving 1760 participants fulfilled the inclusion criteria. The lower level of miR-497 expression was significantly associated with shorter overall survival (HR = 2.19, 95% CI: 1.84-2.60). No significant association was found between miR-497 expression and DFS/RFS in various carcinomas (HR = 1.17, 95% CI: 0.53-2.57). Subgroup analyses by ethnicity and cancer type showed the consistent results.

Conclusion

Our studies suggested that miR-497 might be a prognostic biomarker in cancers. However, further multicenter prospective clinical researches are needed to confirm the association between miR-497 expression and cancer prognosis.

miR-497 may enhance the sensitivity of non-small cell lung cancer cells to gefitinib through targeting the insulin-like growth factor-1 receptor

Background

Recently, studies have demonstrated that microRNA-497 (miR-497) plays an important role in modulating tumor cell sensitivity to chemotherapeutic drugs; however, its role in cellular resistance to the effects of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in treatment of non-small cell lung cancer (NSCLC) is not fully understood. In this study, we explored the potential of miR-497 in targeting the insulin-like growth factor-1 receptor (IGF-1R) signaling pathways to overcome gefitinib resistance.

Methods

A gefitinib resistant human lung adenocarcinoma A549 cell line (A549/GR) was established by the method of gefitinib mutagenesis culture. Next, the A549/GR cells were transfected with miR-497 mimics to establish an miR-497 overexpression model, designated A549/GR-miR497-mimic. MTT assay was used to assess cell resistance to gefitinib, and western blot assay was employed to evaluate alterations of IGF-1R and the AKT1 signaling pathway.

Results

We found that A549/GR-miR497-mimic cells (IC50 =33.76±0.97 µmol/L) were more sensitive to gefitinib than the control group (P<0.01). In addition, the expression levels of IGF-1R and phosphorylated AKT1 (p-AKT1) in A549/GR-miR497-mimic cells were reduced.

Conclusions

We demonstrated that miR-497 may have the effect of reversing gefitinib resistance and increasing the sensitivity of NSCLC cells to EGFR-TKIs by inhibiting the expression of IGF-1R and reducing activation of the downstream AKT signaling pathway. Thus, miR-497 plays a vital role in the acquired resistance to EGFR-TKIs, and it may represent a potential therapeutic strategy to treat NSCLC exhibiting resistance to EGFR-TKIs.

Prognostic Role of MicroRNA-497 In Cancer Patients: A Meta-analysis

Background: MicroRNA-497(miR-497) has been studied for its irreplaceable role of predicting the prognosis of various cancers, but there has been no systematic study to summarize the data. Consequently, we performed this meta-analysis to reveal the association between the expression level of miR-497 and cancer prognosis systematically.

Materials and Methods: PubMed was searched for appropriate studies and a total of 12 eligible publications with 989 cancer patients were recruited into our analysis to assess the strength of the association. Hazard ratios (HRs) and odds ratios (ORs) were analyzed to finish this work.

Results: The cancer patients who have high expressing level of miR-497 are less possible to have lymph node metastasis (OR = 0.25, 95% CI: 0.16-0.40, P < 0.001) and more likely to have favourable tumor-node-metastasis stage (OR = 0.29, 95% CI: 0.17-0.49, P < 0.001). Also, high miR-497 expression level was notably connected to better overall survival (pooled HR = 0.41, 95% CI: 0.32-0.53, P < 0.001).

Conclusions: High expressing levels of miR-497 might be a potential biomarker which can be used to predict the better prognosis of different cancer types.

miR-497/Wnt3a/c-jun feedback loop regulates growth and epithelial-to-mesenchymal transition phenotype in glioma cells

Glioma is one of the most frequent intracranial malignant tumors. Abnormal expression of microRNAs usually contributes to the development and progression of glioma. In the current study, we explored the role and underlying mechanism of miR-497 in glioma. We revealed that miR-497 expression was significantly down-regulated in glioma tissues and cell lines. Reduced expression of miR-497 was associated with poor disease-free and over-all survival rate. Restoration of miR-497 decreased glioma cell growth and invasion both in vitro and in vivo. The oncogene Wnt3a was identified as a downstream target of miR-497 by using luciferase and western blot assays. Knockdown of Wnt3a mimicked the effect of miR-497 in glioma cells. In summary, our study demonstrated that miR-497 may function as a tumor suppressor in glioma and suggested that miR-497 is a potential therapeutic target for glioma patients.

miR‑140‑5p regulates cell migration and invasion of non‑small cell lung cancer cells through targeting VEGFA

Lung cancer is the most common type of cancer worldwide, the most prevalent form of which is non-small cell lung cancer (NSCLC). MicroRNAs (miRs) are involved in the progression of NSCLC; however, the specific function of miR-140-5p in NSCLC remains unclear. The present study demonstrated that miR-140-5p was downregulated in the tumor tissues of patients with NSCLC, and it was associated with a poor prognosis. Furthermore, miR-140-5p significantly suppressed cell migration and invasion of the NSCLC cell line A549. In addition, the direct regulatory effect of miR-140-5p on vascular endothelial growth factor-A (VEGFA) was predicted by TargetScan and verified using a luciferase reporter gene assay. The present study also hypothesized that miR-140-5p may inhibit the expression of phosphorylated-protein kinase B by targeting VEGFA. In conclusion, miR-140-5p may be a potential target for the development of anti-neoplastic therapies in lung cancer.

Identification of micro-RNA expression profile related to recurrence in women with ESMO low-risk endometrial cancer

Background

Actual European pathological classification of early-stage endometrial cancer (EC) may show insufficient accuracy to precisely stratify recurrence risk, leading to potential over or under treatment. Micro-RNAs are post-transcriptional regulators involved in carcinogenic mechanisms, with some micro-RNA patterns of expression associated with EC characteristics and prognosis. We previously demonstrated that downregulation of micro-RNA-184 was associated with lymph node involvement in low-risk EC (LREC). The aim of this study was to evaluate whether micro-RNA signature in tumor tissues from LREC women can be correlated with the occurrence of recurrences.

Methods

MicroRNA expression was assessed by chip analysis and qRT-PCR in 7 formalin-fixed paraffin-embedded (FFPE) LREC primary tumors from women whose follow up showed recurrences (R+) and in 14 FFPE LREC primary tumors from women whose follow up did not show any recurrence (R−), matched for grade and age. Various statistical analyses, including enrichment analysis and a minimum p-value approach, were performed.

Results

The expression levels of micro-RNAs-184, -497-5p, and -196b-3p were significantly lower in R+ compared to R− women. Women with a micro-RNA-184 fold change < 0.083 were more likely to show recurrence (n = 6; 66%) compared to those with a micro-RNA-184 fold change > 0.083 (n = 1; 8%), p = 0.016. Women with a micro-RNA-196 fold change < 0.56 were more likely to show recurrence (n = 5; 100%) compared to those with a micro-RNA-196 fold change > 0.56 (n = 2; 13%), p = 0.001.

Conclusions

These findings confirm the great interest of micro-RNA-184 as a prognostic tool to improve the management of LREC women.

Co-targeting of IGF1R/mTOR pathway by miR-497 and miR-99a impairs hepatocellular carcinoma development

Persistent activation of IGF1R/mTOR signaling pathway plays crucial role in the development of hepatocellular carcinoma (HCC). Therefore, our goal was to elucidate microRNAs (miRNAs) targeting IGF1R/mTOR and the therapeutic potential of single or dual miRNA on HCC development. In this study, we found that miR-497 and miR-99a that target the 3′-UTR of both IGF1R and mTOR were down-regulated in HCC human tissues and cell lines. Functional assay revealed that ectopic expression of miR-497 or miR-99a in HCC cells resulted in a significant inhibition on tumor growth and invasiveness in vitro and tumor development in vivo via repressing the expression of IGF1R and mTOR. Such inhibitory effect on tumor growth is reversed by application of IGF1 ((IGF1R ligand) or MHY1485 (mTOR agonist) in vitro. Furthermore, we found that simultaneous over-expression of both miR-497 and miR-99a exhibited much stronger inhibitory effects on tumor growth than their individual effect, which is still correlated with significantly stronger repression of IGF1R and mTOR. Overall, our results suggest that miR-497 and miR-99a both function as tumor-suppressive miRNAs by suppressing IGF1R/mTOR signaling pathway. The synergistic actions of these two miRNAs partly correlated with IGF1R and mTOR levels, which may represent new strategies for the molecular treatment of HCC.

MicroRNA-29c inhibits proliferation and promotes apoptosis in non-small cell lung cancer cells by targeting VEGFA

Non-small cell lung cancer (NSCLC) is a primary sub-type of lung cancer with a high incidence rate and poor prognosis. The primary therapeutic treatment for NSCLC is chemotherapy, which is considered to be ineffective and excessively toxic. Novel therapeutic methods, particularly molecular targeted therapy, have attracted considerable attention. MicroRNAs (miRs) are reported to be potential biomarkers and targeted agents with roles in various types of tumors. Herein, the present study presented the observation of aberrant low expression of miR‑29c and associated overexpression of vascular endothelial growth factor A (VEGFA) in NSCLC tumor tissues. The effects of miR‑29c upon NSCLC tumor progression, including cell proliferation and cellular apoptosis, were investigated. The possible regulatory mechanism of action of miR‑29c on its direct target VEGFA and the phosphatidylinositol 3‑kinase (PI3K)/RAC‑α serine/threonine‑protein kinase (Akt) signaling pathway was examined using multiple methods, including reverse transcription-quantitative polymerase chain reaction analysis, dual luciferase assay and western blot analysis. The results demonstrated that miR‑29c expression was downregulated in NSCLC tumor tissues compared with normal tissues. A marked negative correlation in the expression of miR‑29c and VEGFA was observed in clinical NSCLC tissues and cultured NSCLC cells. Overexpression of miR‑29c may inhibit cell proliferation and accelerate the cellular apoptosis rate of NSCLC tumor cells. Furthermore, the overexpression of miR‑29c was demonstrated to be able to downregulate the expression levels of VEGFA and PI3K/Akt signaling pathway‑associated proteins. The results of the present study suggested that miR‑29c might regulate NSCLC tumor progression by targeting VEGFA.

MicroRNAs as regulators of cisplatin-resistance in non-small cell lung carcinomas

With more than 80% of all diagnosed lung cancer cases, non-small cell lung cancer (NSCLC) remains the leading cause of cancer death worldwide. Exact diagnosis is mostly very late and advanced-stage NSCLCs are inoperable at admission. Tailored therapies with tyrosine kinase inhibitors are only available for a minority of patients. Thus, chemotherapy is often the treatment of choice. As first-line chemotherapy for NSCLCs, platinum-based substances (e.g. cisplatin, CDDP) are mainly used. Unfortunately, the positive effects of CDDP are frequently diminished due to development of drug resistance and negative influence of microenvironmental factors like hypoxia. MicroRNAs (miRNAs) are small, non-coding molecules involved in the regulation of gene expression and modification of biological processes like cell proliferation, apoptosis and cell response to chemotherapeutics. Expression of miRNAs is often deregulated in lung cancer compared to corresponding non-malignant tissue. In this review we summarize the present knowledge about the effects of miRNAs on CDDP-resistance in NSCLCs. Further, we focus on miRNAs deregulated by hypoxia, which is an important factor in the development of CDDP-resistance in NSCLCs. This review will contribute to the general understanding of miRNA-regulated biological processes in NSCLC, with special focus on the role of miRNA in CDDP-resistance.

VEGF as a potential target in lung cancer

Introduction The vascular endothelial growth factor A (VEGF) is the main mediator of angiogenesis. In addition, VEGF contributes to cancer growth and metastasis directly targeting tumor cells. VEGF overexpression and/or high VEGF serum levels have been reported in lung cancer. Areas covered We searched Pubmed for relevant preclinical studies with the terms 'lung cancer' 'VEGF' and 'in vivo'. We also searched the Clinicaltrials.gov database, the FDA and the EMA websites for the most recent updates on clinical development of anti-VEGF agents. Expert opinion VEGF plays an important role in sustaining the development and progression of lung cancer and it might represent an attractive target for therapeutic strategies. Nevertheless, clinical trials failed to attend the promising expectations deriving from preclinical studies with anti-VEGF agents. To improve the efficacy of anti-VEGF therapies in lung cancer, potential strategies might be the employment of combinatory therapies with immune checkpoint inhibitors or agents that inhibit signaling pathways and proangiogenic factors activated in response to VEGF blockade, and the identification of novel targets in the VEGF cascade. Finally, the identification of predictive markers might help to select patients who are more likely to respond to anti-angiogenic drugs.

MicroRNA‑497 inhibits cellular proliferation, migration and invasion of papillary thyroid cancer by directly targeting AKT3

Thyroid cancer is the most common tumor of the endocrine organs. Emerging studies have indicated the critical roles of microRNAs (miRs) in papillary thyroid cancer (PTC) formation and progression through function as tumor suppressors or oncogenes. The present study investigated the expression level and biological roles of miR-497 in PTC and its underlying mechanisms. It was demonstrated that the expression level of miR-497 was reduced in both PTC tissues and cell lines. Enforced expression of miR-497 suppressed PTC cell proliferation, migration and invasion. According to bioinformatics analysis, a luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blotting, RAC-γ serine/threonine-protein kinase (AKT3) was demonstrated to be the direct target gene of miR-497. In addition, AKT3 expression increased in PTC tissues and negatively correlated with miR-497 expression. Furthermore, downregulation of AKT3 also suppressed cell proliferation, migration and invasion of PTC, which had similar roles to miR-497 overexpression in PTC cells. Taken together, these results suggested that this newly identified miR-497/AKT3 signaling pathway may contribute to PTC occurrence and progression. These findings provide novel potential therapeutic targets for the therapy of PTC.

VEGFA Involves in the Use of Fluvastatin and Zoledronate Against Breast Cancer

Our study aimed to identify key genes involved in the use of fluvastatin and zoledronate against breast cancer, as well as to investigate the roles of vascular endothelial growth factor A (VEGFA) in the malignant behaviors of breast cancer cells. The expression data GSE33552 was downloaded from Gene Expression Omnibus database, including mocked-, fluvastatin- and zoledronate-treated MDA-MB-231 cells. Differentially expressed genes (DEGs) were identified in fluvastatin- and zoledronate-treated cells using limma package, respectively. Pathway enrichment analysis and protein-protein interaction (PPI) network analysis were then performed. Then we used shRNA specifically targeting VEGFA (shVEGFA) to knock down the expression of VEGFA in MDA-MB-231 cells. Cell viability assay, scratch wound healing assay, Transwell invasion assay and flow cytometry were performed to explore the effects of VEGFA knockdown on the malignant behaviors of breast cancer cells. VEGFA was up-regulated in both fluvastatin- and zoledronate-treated breast cancer cells. Moreover, VEGFA was a hub node in PPI network. In addition, VEGFA was successfully knocked down in MDA-MB-231 cells by shVEGFA. Suppression of VEGFA promoted the migration and invasion of breast cancer MDA-MB-231 cells. Suppression of VEGFA inhibited the apoptosis of MDA-MB-231 cells. Our results indicate that up-regulation of VEGFA may prevent the progression of breast cancer after fluvastatin and zoledronate treatment via inducing cell apoptosis and inhibiting migration and invasion. VEGFA may serve as a potential prognostic indicator for clinical outcome in the management of breast cancer.

Reduced expression of microRNA-497 is associated with greater angiogenesis and poor prognosis in human gliomas

MicroRNA (miR)-497 plays a tumor-suppressive role in several malignancies and is involved in glioma invasiveness and resistance to chemotherapy. To add to the knowledge of the clinical significance of miR-497 in human gliomas, quantitative real-time polymerase chain reaction was performed to detect the expression of miR-497 in 110 pairs of freshly prepared glioma and nonneoplastic brain tissues. Then the associations of miR-497 expression with various clinicopathological characteristics and overall survival of glioma patients were estimated statistically. Gain-of-function assays were also performed to examine the role of miR-497 in glioma angiogenesis. The expression of miR-497 in human glioma tissues was significantly lower than in nonneoplastic brain tissues (P<.001). In addition, low miR-497 expression was significantly associated with advanced World Health Organization grade (P<.001) and low Karnofsky performance scores (P=.02). Moreover, the survival of glioma patients with low miR-497 expression was dramatically shorter than that of patients with high miR-497 expression (P=.001). Forced expression of miR-497 in glioma cells inhibited tube formation by cocultured human brain microvascular endothelial cells. We also found that miR-497 overexpression in glioma cells led to decreased expression of vascular endothelial growth factor. In conclusion, miR-497 may be a favorable prognostic marker in human gliomas, in part by being a negative regulator of angiogenesis, implying its potential as a therapeutic target for this cancer.

miR-497 expression, function and clinical application in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that inhibit gene expression by binding to the 3' untranslated region (3'-UTR) of their target mRNAs. Recent studies show that miR-497 plays an important role in various cancers. Here, we summarize the existing studies of miR-497 as following: (1) miR-497 expression in cancer; (2) regulation mechanisms of miR-497 expression; (3) function of miR-497 in cancer; (4) direct targets of miR-497; (5) Clinical applications of miR-497. Recent analyses verify that miR-497 mainly suppresses tumors; however, it also acts as an oncogene in several cancers. Increasing evidence indicates that miR-497 can serve as a diagnostic and prognostic biomarker and is a promising therapeutic target for future clinical applications.

Identification of miRNAs and differentially expressed genes in early phase non-small cell lung cancer

To explore the potential therapeutic targets of early‑stage non-small cell lung cancer (NSCLC), gene microarray analysis was conducted. The microarray data of NSCLC in stage IA, IB, IIA, and IIB (GSE50081), were downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) in IB vs. IA, IIA vs. IB, IIB vs. IIA were screened out via R. ToppGene Suite was used to get the enriched Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the DEGs. The GeneCoDis3 database and Cytoscape software were used to construct the transcriptional regulatory network. In total, 25, 17 and 14 DEGs were identified in IB vs. IA, IIA vs. IB, IIB vs. IIA of NSCLC, respectively. Some GO terms and pathways (e.g., extracellular space, alveolar lamellar body, bioactivation via cytochrome P450 pathway) were found significantly enriched in DEGs. Genes S100P, ALOX15B, CCL11, NLRP2, SERPINA3, FoxO4 and hsa-miR-491 may play important roles in the development of early-stage NSCLC. Thus, by bioinformatics analysis the key genes and biological processes involving in the development of early-stage NSCLC could be established, providing more potential references for the therapeutic targets.