MicroRNA-451 induces epithelial–mesenchymal transition in docetaxel-resistant lung adenocarcinoma cells by targeting proto-oncogene c-Myc

Advances in the study of epithelial mesenchymal transition in cancer progression: Role of miRNAs

Epithelial-mesenchymal transition (EMT) has been extensively studied for its roles in tumor metastasis, the generation and maintenance of cancer stem cells and treatment resistance. Epithelial mesenchymal plasticity allows cells to switch between various states within the epithelial-mesenchymal spectrum, resulting in a mixed epithelial/mesenchymal phenotypic profile. This plasticity underlies the acquisition of multiple malignant features during cancer progression and poses challenges for EMT in tumors. MicroRNAs (miRNAs) in the microenvironment affect numerous signaling processes through diverse mechanisms, influencing physiological activities. This paper reviews recent advances in EMT, the role of different hybrid states in tumor progression, and the important role of miRNAs in EMT. Furthermore, it explores the relationship between miRNA-based EMT therapies and their implications for clinical practice, discussing how ongoing developments may enhance therapeutic outcomes.

Role of microRNAs in lung oncogenesis: Diagnostic implications, resistance mechanisms, and therapeutic strategies

Lung cancer continues to pose a significant global health concern, presenting a formidable challenge on a worldwide scale, necessitating a deeper understanding of molecular mechanisms underlying its pathogenesis and treatment responses. microRNA (miRNA) modulation in the context of lung cancer therapeutics aims to unravel the complexities of miRNA-mediated regulatory networks. This comprehensive review elucidates microRNA's diverse roles in lung cancer, encompassing their involvement in key signaling pathways, cellular processes, the regulation of oncogenic or tumor-suppressive targets, and drug sensitivity. Moreover, this review critically examines the potential of miRNAs as diagnostic and prognostic biomarkers and their implications in therapeutic interventions for lung cancer. microRNAs are effective in making lung cancer therapy more efficient. They can make tumor cells more responsive to chemotherapy, radiation, and targeted therapies. microRNAs can target the drug efflux mechanism, increasing the effectiveness of chemotherapy agents and decreasing resistance. Furthermore, microRNAs play a crucial role in developing and inhibiting the resistance mechanisms against conventional treatments; improving the dysregulated expression of microRNAs enhances the therapeutic efficacy of existing therapies. By compiling knowledge on miRNA-mediated processes related to lung cancer, this review offers a comprehensive resource for researchers to understand and address the complexities of oncogenesis, diagnostics, resistance mechanisms, and therapeutic strategies.

Non-small cell lung cancer map and analysis: exploring interconnected oncogenic signal integrators

Non-Small Cell lung cancer (NSCLC) is known for its fast progression, metastatic potency, and a leading cause of mortality globally. At diagnosis, approximately 30-40% of NSCLC patients already present with metastasis. Epithelial to mesenchymal transition (EMT) is a developmental program implicated in cancer progression and metastasis. Transforming Growth Factor-β (TGFβ) and its signalling plays a prominent role in orchestrating the process of EMT and cancer metastasis. In present study, a comprehensive molecular interaction map of TGFβ induced EMT in NSCLC was developed through an extensive literature survey. The map encompasses 394 species interconnected through 554 reactions, representing the relationship and complex interplay between TGFβ induced SMAD dependent and independent signalling pathways (PI3K/Akt, Wnt, EGFR, JAK/STAT, p38 MAPK, NOTCH, Hypoxia). The map, built using Cell Designer and compliant with SBGN and SBML standards, was subsequently translated into a logical modelling framework using CaSQ and dynamically analysed with Cell Collective. These analyses illustrated the complex regulatory dynamics, capturing the known experimental outcomes of TGFβ induced EMT in NSCLC including the co-existence of hybrid EM phenotype during transition. Hybrid EM phenotype is known to contribute for the phenotypic plasticity during metastasis. Network-based analysis identified the crucial network level properties and hub regulators, while the transcriptome-based analysis cross validated the prognostic significance and clinical relevance of key regulators. Overall, the map developed and the subsequent analyses offer deeper understanding of the complex regulatory network governing the process of EMT in NSCLC.

Extracellular Vesicles Derived From Lipopolysaccharide-Challenged Gingival Fibroblast Reveal Distinct miRNA Expression Patterns Associated With Reduced Cancer Survival

OBJECTIVES

Periodontitis is a prevalent inflammatory disease with established systemic implications. Extracellular vesicles (EVs) have emerged as key mediators of intercellular communication, potentially linking periodontitis to systemic diseases. However, the molecular cargo of EVs from inflamed periodontal cells remains poorly characterized. This study investigates the EV cargo of human gingival fibroblasts (hGF-hTERT) following lipopolysaccharide (LPS) stimulation and explores their potential role in cancer progression.

MATERIALS AND METHODS

EVs were isolated from LPS-treated and untreated fibroblasts via ultracentrifugation. Dynamic light scattering and scanning electron microscopy characterized EV size and morphology. RNA sequencing identified differentially expressed miRNAs, validated by qPCR. Functional pathway enrichment and in-silico analyses using The Cancer Genome Atlas (TCGA) were performed to assess EV-associated miRNA impact on tumorigenesis.

RESULTS

EV size and concentration remained unchanged after LPS stimulation. However, LPS-derived EVs exhibited a 2.6-fold increase in miRNA content, with three significantly upregulated miRNAs: miR-146a-5p, miR-486-5p, and miR-451a. Functional enrichment analysis revealed their involvement in inflammation, immune modulation, and cancer pathways. In vitro, LPS-derived EVs significantly enhanced prostate cancer (LnCap) cell proliferation. TCGA analysis linked the upregulated miRNAs to poor cancer prognosis.

CONCLUSIONS

LPS stimulation alters the miRNA cargo of gingival fibroblast-derived EVs, enhancing pathways associated with inflammation and cancer progression. These findings suggest a mechanistic role for periodontal EVs in systemic disease pathogenesis, warranting further investigation into their diagnostic and therapeutic potential.

Identification of miR-451 target genes as prognostic markers in diffuse large B-cell lymphoma

BACKGROUND

B-cell lymphoma, a diverse malignancy, is intricately regulated by multiple factors. MicroRNAs (miRNAs) have been demonstrated to be important regulators of the initiation and progression of human B-cell lymphoma, but their functions need to be further explored.

RESEARCH DESIGN AND METHODS

Two B-cell lymphoma cell lines, Romas and HBL-1, were engineered to overexpress miR-451, with cell proliferation assessed via cell counting assays. Flow cytometry was used to study the effects of miR-451 on cell cycle and apoptosis. Bioinformatics analyses were performed using GEO datasets (GSE181063, GSE32918, GSE56315) to identify DEGs, and potential miR-451 target genes were predicted using tools like ENCORI, TargetScan, and R packages. A risk model for DLBCL prognosis was developed using Cox and LASSO regression. qRT-PCR validated the expression of these target genes.

RESULTS

This study revealed that miR-451 inhibited cell proliferation, arrested the cell cycle, and induced apoptosis in human DLBCL cell lines. Bioinformatics analysis identified 9 target genes (MMP9, AQP9, RIN2, EOMES, LCP2, SELPLG, MAL, SOCS5, S1PR3) significantly associated with DLBCL prognosis, suggesting a potential mechanism by which miR-451 suppresses DLBCL development.

CONCLUSIONS

Our study indicates that a specific set of miR-451 target genes may significantly influence DLBCL patient outcomes.

GSK-3: An "Ace" Among Kinases

Background: Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase known to participate in the regulation of β-catenin signaling (Wnt signaling). This aids in the establishment of a multicomponent destruction complex that stimulates phosphorylation, leading to the destruction of β-catenin. Evidence about the role of increasingly active β-catenin signaling is involved in many forms of human cancer. The understanding of GSK-3 remains elusive as recent research aims to focus on developing potent GSK-3 inhibitors to target this kinase. Objective: This short review aims to highlight the regulation of GSK-3 with emphasis on Wnt signaling while highlighting its interaction with miRNAs corresponding to pluripotency and epithelial mesenchymal transition substantiating this kinase as an "Ace" among kinases in regulation of cellular processes. Result: Significant findings of miRNA regulation by GSK-3 exemplify the underpinnings of kinase-mediated transcriptional regulation in cancers. Conclusion: The review provides evidence on the role of GSK-3 as a possible master regulator of proteins and noncoding RNA, thereby implicating the fate of a cell.

Suppression of N-Glycosylation of Zinc Finger Protein 471 Affects Proliferation, Invasion, and Docetaxel Sensitivity of Tongue Squamous Cell Carcinoma via Regulation of c-Myc

Zinc finger protein 471 (ZNF471) is a member of the Krüppel-related domain zinc finger protein family, and has recently attracted attention because of its anti-cancer effects. N-glycosylation regulates expression and functions of the protein. This study aimed to investigate the effects of ZNF471 N-glycosylation on the proliferation, invasion, and docetaxel sensitivity of tongue squamous cell carcinoma (TSCC). It analyzed the expression, function, and prognostic significance of ZNF471 in TSCC using bioinformatics techniques such as gene differential expression analysis, univariate Cox regression analysis, functional enrichment analysis, and gene set enrichment analysis. Using site-specific mutagenesis, this study generated three mutant sites for ZNF471 N-glycosylation to determine the effect of N-glycosylation on ZNF471 protein levels and function. Quantitative real-time PCR, Western blot analysis, and immunohistochemistry tests confirmed the down-regulation of ZNF471 expression in TSCC. Low expression of ZNF471 is associated with poor prognosis of patients with TSCC. Overexpression of ZNF471 in vitro retarded the proliferation of TSCC cells and suppressed cell invasion and migration ability. Asparagine 358 was identified as a N-glycosylation site of ZNF471. Suppressing N-glycosylation of ZNF471 enhanced the protein stability and promoted the translocation of protein to the cell nucleus. ZNF471 binding to c-Myc gene promoter suppressed oncogene c-Myc expression, thereby playing the anti-cancer effect and enhancing TSCC sensitivity to docetaxel. In all, N-glycosylation of ZNF471 affects the proliferation, invasion, and docetaxel sensitivity of TSCC via regulation of c-Myc.

MicroRNA-451a inhibits gemcitabine-refractory biliary tract cancer progression by suppressing the MIF-mediated PI3K/AKT pathway

Gemcitabine is an effective chemotherapeutic agent for biliary tract cancers (BTCs), including gallbladder cancer (GBC) and cholangiocarcinoma (CCA). However, few other effective agents are currently available, particularly for GEM-refractory BTCs. We previously identified microRNA-451a (miR-451a) as a potential therapeutic target in GBC. To elucidate the antineoplastic effects of miR-451a and its underlying mechanisms, we transfected miR-451a into GBC, gemcitabine-resistant GBC (GR-GBC), and gemcitabine-resistant CCA (GR-CCA) cell lines. Furthermore, mimicking in vivo conditions, tumorigenic GBC organoids and three-dimensional (3D) cell culture systems were employed to investigate the anti-proliferative effects of miR-451a on BTCs, and its effect on stem cell properties. We found that miR-451a significantly inhibited cell proliferation, induced apoptosis, and reduced chemoresistant phenotypes, such as epithelial-mesenchymal transition, in both GBC and GR-GBC. The principal mechanism is probably the negative regulation of the phosphatidylinositol 3-kinase/AKT pathway, partially accomplished by directly downregulating macrophage migration inhibitory factor. The Gene Expression Omnibus database revealed that miR-451a was the most significantly downregulated microRNA in CCA tissues. The introduction of miR-451a resulted in similar antineoplastic effects in GR-CCA. Furthermore, miR-451a reduced cell viability in 3D spheroid models and tumorigenic GBC organoids. These findings suggest that the supplementation of miR-451a is a potential treatment strategy for GEM-refractory BTCs.

The Role of MicroRNA in the Regulation of Tumor Epithelial–Mesenchymal Transition

Consistently, the high metastasis of cancer cells is the bottleneck in the process of tumor treatment. In this process of metastasis, a pivotal role is executed by epithelial–mesenchymal transition (EMT). The epithelial-to-mesenchymal transformation was first proposed to occur during embryonic development. Later, its important role in explaining embryonic developmental processes was widely reported. Recently, EMT and its intermediate state were also identified as crucial drivers in tumor progression with the gradual deepening of research. To gain insights into the potential mechanism, increasing attention has been focused on the EMT-related transcription factors. Correspondingly, miRNAs target transcription factors to control the EMT process of tumor cells in different types of cancers, while there are still many exciting and challenging questions about the phenomenon of microRNA regulation of cancer EMT. We describe the relevant mechanisms of miRNAs regulating EMT, and trace the regulatory roles and functions of major EMT-related transcription factors, including Snail, Twist, zinc finger E-box-binding homeobox (ZEB), and other families. In addition, on the basis of the complex regulatory network, we hope that the exploration of the regulatory relationship of non-transcription factors will provide a better understanding of EMT and cancer metastasis. The identification of the mechanism leading to the activation of EMT programs during diverse disease processes also provides a new protocol for the plasticity of distinct cellular phenotypes and possible therapeutic interventions. Here, we summarize the recent progress in this direction, with a promising path for further insight into this fast-moving field.

Loss of PFKFB4 induces cell cycle arrest and glucose metabolism inhibition by inactivating MEK/ERK/c-Myc pathway in cervical cancer cells

6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 (PFKFB4) was reported to be necessary for tumour growth in several cancers. However, the function of PFKFB4 in cervical cancer has not been clearly elucidated. Bioinformatics analysis was applied to detect the expression of PFKFB4 in cervical cancer and the association with survival prognosis. The effect of PFKFB4 on cervical cancer cells growth, cycle, invasion, migration and glucose metabolism was investigated by loss-of-function approaches in vitro. The association between PFKFB4 and MEK/ERK/c-Myc pathway was identified by western blot assay. We found that PFKFB4 was highly expressed in cervical cancer samples and its overexpression led to a poor prognosis of cervical cancer patients. Knock down of PFKFB4 reduced cell growth, blocked cell cycle, inhibited cell invasion and migration, and blocked glucose metabolism in cervical cancer cells. Our findings afforded a theoretical basis for further research on the treatment of cervical cancer based on the control of PFKFB4 expression. Impact StatementWhat is already known on this subject? PFKFB4 was overexpressed in several kinds of cancers and its requirement for tumour growth has been confirmed in cancers such as glioma and breast cancer. However, the function of PFKFB4 in cervical cancer cells has not been clearly elucidated. A bioinformatics study showed that PFKFB4 was a member of a six-gene signature associated with glycolysis to predict the prognosis of patients with cervical cancer. However, the relationship between PFKFB4 and glucose metabolism in cervical cancer has not been revealed.What do the results of this study add? Our results showed that PFKFB4 was highly expressed in cervical cancer samples and its overexpression led to a poor prognosis of cervical cancer patients. Moreover, the administration of si-PFKFB4 significantly reduced cell growth ability, blocked cell cycle, restrained the mobility and suppressed the glucose metabolism in cervical cancer cells partially by inactivating MEK/ERK/c-Myc pathway.What are the implications of these findings for clinical practice and/or further research? Our findings afforded a theoretical basis for further research on the treatment of cervical cancer based on the control of PFKFB4 expression.

An Overview on the Role of miR-451 in Lung Cancer: Diagnosis, Therapy, and Prognosis

MicroRNAs (miRNAs) are highly conserved non-coding RNAs involved in many physiological processes such as cell proliferation, inhibition, development of apoptosis, differentiation, suppresses tumorigenicity, and regulating cell growth. The description of the alterations of miRNA expression patterns in cancers will be helpful to recognize biomarkers for early detection and possible therapeutic intervention in the treatment of cancers. Recent studies have shown that miR-451 is broadly dysregulated in lung cancer and is a crucial agent in lung tumor progression. This review summarizes recent advances of the potential role of miR-451 in lung cancer diagnosis, prognosis, and treatment and provides an insight into the potential use of miR-451 for the development of advanced therapeutic methods in lung cancer.

Overview on the Role of E-Cadherin in Gastric Cancer: Dysregulation and Clinical Implications

Gastric cancer is the fifth most common cancer and the third most common cause of cancer death all over the world. E-cadherin encoded by human CDH1 gene plays important roles in tumorigenesis as well as in tumor progression, invasion and metastasis. Full-length E-cadhrin tethered on the cell membrane mainly mediates adherens junctions between cells and is involved in maintaining the normal structure of epithelial tissues. After proteolysis, the extracellular fragment of the full-length E-cadhein is released into the extracellular environment and the blood, which is called soluble E-cadherin (sE-cadherin). sE-cadherin promots invasion and metastasis as a paracrine/autocrine signaling molecule in the progression of various types of cancer including gastric cancer. This review mainly summarizes the dysregulation of E-cadherin and the regulatory roles in the progression, invasion, metastasis, and drug-resistance, as well as its clinical applications in diagnosis, prognosis, and therapeutics of gastric cancer.

The Role of Non-Coding RNAs in the Regulation of the Proto-Oncogene MYC in Different Types of Cancer

Alterations in the expression level of the MYC gene are often found in the cells of various malignant tumors. Overexpressed MYC has been shown to stimulate the main processes of oncogenesis: uncontrolled growth, unlimited cell divisions, avoidance of apoptosis and immune response, changes in cellular metabolism, genomic instability, metastasis, and angiogenesis. Thus, controlling the expression of MYC is considered as an approach for targeted cancer treatment. Since c-Myc is also a crucial regulator of many cellular processes in healthy cells, it is necessary to find ways for selective regulation of MYC expression in tumor cells. Many recent studies have demonstrated that non-coding RNAs play an important role in the regulation of the transcription and translation of this gene and some RNAs directly interact with the c-Myc protein, affecting its stability. In this review, we summarize current data on the regulation of MYC by various non-coding RNAs that can potentially be targeted in specific tumor types.

New insight towards development of paclitaxel and docetaxel resistance in cancer cells: EMT as a novel molecular mechanism and therapeutic possibilities

Epithelial-to-mesenchymal transition (EMT) mechanism is responsible for metastasis and migration of cancer cells to neighboring cells and tissues. Morphologically, epithelial cells are transformed to mesenchymal cells, and at molecular level, E-cadherin undergoes down-regulation, while an increase occurs in N-cadherin and vimentin levels. Increasing evidence demonstrates role of EMT in mediating drug resistance of cancer cells. On the other hand, paclitaxel (PTX) and docetaxel (DTX) are two chemotherapeutic agents belonging to taxene family, capable of inducing cell cycle arrest in cancer cells via preventing microtubule depolymerization. Aggressive behavior of cancer cells resulted from EMT-mediated metastasis can lead to PTX and DTX resistance. Upstream mediators of EMT such as ZEB1/2, TGF-β, microRNAs, and so on are involved in regulating response of cancer cells to PTX and DTX. Tumor-suppressing factors inhibit EMT to promote PTX and DTX sensitivity of cancer cells. Furthermore, three different strategies including using anti-tumor compounds, gene therapy and delivery systems have been developed for suppressing EMT, and enhancing cytotoxicity of PTX and DTX against cancer cells that are mechanistically discussed in the current review.

The Role of MicroRNAs in Lung Cancer Metabolism

MicroRNAs (miRNAs) are short-strand non-coding RNAs that are responsible for post-transcriptional regulation of many biological processes. Their differential expression is important in supporting tumorigenesis by causing dysregulation in normal biological functions including cell proliferation, apoptosis, metastasis and invasion and cellular metabolism. Cellular metabolic processes are a tightly regulated mechanism. However, cancer cells have adapted features to circumvent these regulations, recognizing metabolic reprogramming as an important hallmark of cancer. The miRNA expression profile may differ between localized lung cancers, advanced lung cancers and solid tumors, which lead to a varying extent of metabolic deregulation. Emerging evidence has shown the relationship between the differential expression of miRNAs with lung cancer metabolic reprogramming in perpetuating tumorigenesis. This review provides an insight into the role of different miRNAs in lung cancer metabolic reprogramming by targeting key enzymes, transporter proteins or regulatory components alongside metabolic signaling pathways. These discussions would allow a deeper understanding of the importance of miRNAs in tumor progression therefore providing new avenues for diagnostic, therapeutic and disease management applications.

Targeting a novel LncRNA SNHG15/miR-451/c-Myc signaling cascade is effective to hamper the pathogenesis of breast cancer (BC) in vitro and in vivo

BACKGROUND

To our knowledge, LncRNA SNHG15 exerted its tumor-promoting effects to facilitate the development of breast cancer (BC), but there still needed more data to elucidate the potential underlying mechanisms.

METHODS

We examined genes expression status by performing Real-Time qPCR and Western Blot analysis, and cellular functions, including cell proliferation, viability, apoptosis, mobility, were measured by using the CCK-8 assay, colony formation assay, trypan blue staining assay, flow cytometer (FCM), transwell assay and wound scratch assay, respectively. The predicted targeting sites in LncRNA SNHG15, miR-451 and c-Myc 3'UTR were validated by dual-luciferase reporter gene system assay. Finally, we established the tumor-bearing mice models, and the expression status, including its enrichment and cellular localization were examined by immunohistochemistry (IHC) assay.

RESULTS

Our data indicated LncRNA SNHG15 upregulated c-Myc to facilitate BC progression by sponging miR-451 in a competing endogenous RNA (ceRNA)-dependent manner in vitro and in vivo. Specifically, LncRNA SNHG15 and c-Myc were upregulated, while miR-451 was downregulated in BC cells and clinical tissues, compared to their normal counterparts. In addition, miR-451 negatively correlated with LncRNA SNHG15 and c-Myc, and LncRNA SNHG15 was positively relevant to c-Myc in BC tissues. Next, we validated that LncRNA SNHG15 sponged miR-451 to upregulate c-Myc in BC cells. Further gain- and loss-of-function experiments evidenced that LncRNA SNHG15 promoted, while miR-451 inhibited malignant phenotypes, including cell proliferation, viability, migration, invasion and epithelial-mesenchymal transition (EMT) in BC cells. Interestingly, the inhibiting effects of LncRNA SNHG15 ablation on BC progression were abrogated by both silencing miR-451 and overexpressing c-Myc.

CONCLUSIONS

We concluded that targeting the LncRNA SNHG15/miR-451/c-Myc signaling cascade was novel to hamper BC progression, which broadened our knowledge in this field, and provided potential biomarkers for BC diagnosis and treatment.

Serum Exosomes and Their miRNA Load-A Potential Biomarker of Lung Cancer

Early detection of lung cancer in screening programs is a rational way to reduce mortality associated with this malignancy. Low-dose computed tomography, a diagnostic tool used in lung cancer screening, generates a relatively large number of false-positive results, and its complementation with molecular biomarkers would greatly improve the effectiveness of such programs. Several biomarkers of lung cancer based on different components of blood, including miRNA signatures, were proposed. However, only a few of them have been positively validated in the context of early cancer detection yet, which imposes a constant need for new biomarker candidates. An emerging source of cancer biomarkers are exosomes and other types of extracellular vesicles circulating in body fluids. Hence, different molecular components of serum/plasma-derived exosomes were tested and showed different levels in lung cancer patients and healthy individuals. Several studies focused on the miRNA component of these vesicles. Proposed signatures of exosome miRNA had promising diagnostic value, though none of them have yet been clinically validated. These signatures involved a few dozen miRNA species overall, including a few species that recurred in different signatures. It is worth noting that all these miRNA species have cancer-related functions and have been associated with lung cancer progression. Moreover, a few of them, including known oncomirs miR-17, miR-19, miR-21, and miR-221, appeared in multiple miRNA signatures of lung cancer based on both the whole serum/plasma and serum/plasma-derived exosomes.

EMT-associated microRNAs and their roles in cancer stemness and drug resistance

Epithelial‐to‐mesenchymal transition (EMT) is implicated in a wide array of malignant behaviors of cancers, including proliferation, invasion, and metastasis. Most notably, previou studies have indicated that both cancer stem‐like properties and drug resistance were associated with EMT. Furthermore, microRNAs (miRNAs) play a pivotal role in the regulation of EMT phenotype, as a result, some miRNAs impact cancer stemness and drug resistance. Therefore, understanding the relationship between EMT‐associated miRNAs and cancer stemness/drug resistance is beneficial to both basic research and clinical treatment. In this review, we preliminarily looked into the various roles that the EMT‐associated miRNAs play in the stem‐like nature of malignant cells. Then, we reviewed the interaction between EMT‐associated miRNAs and the drug‐resistant complex signaling pathways of multiple cancers including lung cancer, gastric cancer, gynecologic cancer, breast cancer, liver cancer, colorectal cancer, pancreatic cancer, esophageal cancer, and nasopharyngeal cancer. We finally discussed the relationship between EMT, cancer stemness, and drug resistance, as well as looked forward to the potential applications of miRNA therapy for malignant tumors.

Clinical Impact of the Epithelial-Mesenchymal Transition in Lung Cancer as a Biomarker Assisting in Therapeutic Decisions

Lung cancer is one of the most common solid cancers and represents the leading cause of cancer death worldwide. Over the last decade, research on the epithelial-mesenchymal transition (EMT) in lung cancer has gained increasing attention. Here, we review clinical and histological features of non-small-cell lung cancer associated with EMT. We then aimed to establish potential clinical implications of EMT in current therapeutic options, including surgery, radiation, targeted therapy against oncogenic drivers, and immunotherapy.

LncRNA SNHG15 regulates EGFR-TKI acquired resistance in lung adenocarcinoma through sponging miR-451 to upregulate MDR-1

Lung adenocarcinoma (LUAD) is the main component of non-small-cell lung cancer (NSCLC) and causes a great health concern globally. The top priority of LUAD treatment is to deal with gefitinib resistance. Long non-coding RNAs are certified to modify gefitinib resistance in the course of tumor aggravation. The study focuses on addressing the function of small nucleolar RNA host gene 15 (SNHG15) on modifying gefitinib resistance in LUAD. Previously, NOTCH pathway is implicated in LUAD chemo-resistance. SNHG15 level was boosted following the depletion of NOTCH-1 in A549/GR and H1975/GR cells. Functional studies indicated that SNHG15 and multidrug resistance protein 1 (MDR-1) were overexpressed and possess tumor-promoting functions in gefitinib-resistant LUAD cells while miR-451 was downregulated and possess tumor-suppressive behaviors in gefitinib-resistant LUAD cells. Mechanically, the SNHG15 was cytoplasmically distributed in GR LUAD cells. In addition, SNHG15 released MDR-1 from the suppression of miR-451, leading to MDR-1 promotion. In addition, the elevation of SNHG15 could be attributed to ZEB1. Rescue assays highlighted that downstream molecules MDR-1 and miR-451 could reverse the effects of SNHG15 downregulation on gefitinib-resistant LUAD cells. SNHG15 could alter chemo-resistance of LUAD cells to Gefitinib via regulating miR-451/MDR-1, which could be inspiring findings for the advancement of chemo-therapies for LUAD.

MiRNA-451a inhibits airway remodeling by targeting Cadherin 11 in an allergic asthma model of neonatal mice

Airway remodeling happens in childhood asthma, in parallel with, but not necessarily subsequent to, airway inflammation. The differentiation of airway epithelial cells into myofibroblasts via epithelial-mesenchymal-transition (EMT) is one of the mechanisms underlying airway remodeling. This study aimed at identifying novel molecules involved in pediatric asthma-associated airway remodeling. Asthma model was established by challenging C57BL/6 mouse pups with ovalbumin (OVA). We found that the expression of Cadherin 11 (CDH11), a type II cadherin, was increased by OVA treatments in the airway epithelium. Our earlier microarray data suggested miRNA-451a-5p (miRNA-451a) as a potential regulator of CDH11. In contrast to CDH11, miRNA-451a expression decreased in the asthmatic lung. MiRNA-451a was then packaged into a lentivirus vector and systematically given to the asthmatic pups. Our data indicated that OVA-induced infiltration of inflammatory cells, including eosnophils, neutrophils, macrophages and lymphocytes, was reduced by miRNA-451a over-expression. EMT was initiated in asthmatic mice as demonstrated by increased alpha-smooth muscle actin (α-SMA) positive cells present in airway epithelium, which was inhibited by miRNA-451a. CDH11 elevation in vivo was also inhibited by miRNA-451a. Dual-Luciferase analysis further showed CDH11 as a novel valid target of miRNA-451a. Additionally, in vitro, EMT was triggered in human 16HBE airway epithelial cells by pro-fibrotic transforming growth factor β (TGF-β). Corresponding to the anti-EMT effects observed in vivo, miRNA-451a also inhibited TGF-β-induced collagen deposition in cultured airway epithelial cells by targeting in CDH11. In summary, our study demonstrates that the deregulated miRNA-451a-CDH11 axis contributes to airway remodeling in childhood asthma.

Screening for Potential Biomarkers in Peripheral Blood From Miners Exposed to Radon Radiation

In this cohort study of 144 miners, 72 miners worked underground (the study group) and 72 miners worked aboveground (the control group). Based on questionnaire data and of radon concentration measurements, the cumulative radon exposure dose was calculated for each miner using the parameters recommended in International Commission on Radiological Protection Publication 137. Hematological parameters such as lymphocyte count (LYM) and neutrophil count (NE) were assessed, cell cycle phases and regulatory proteins were detected by flow cytometry, and microRNA (miRNA) microarray screening and real-time polymerase chain reaction (PCR) were used to detect miRNAs in plasma. The interrelationships between various potential biomarkers were analyzed using bioinformatics and statistical methods. The mean cumulative exposure dose of underground miners and controls was 982 and 48 mSv, respectively. Hematological parameters (such as LYM and NE) were significantly lower in the underground group. Cyclin-dependent kinase (CDK)-2, CDK4, CDK6, CyclinA2, CyclinD1, and CyclinE1 were significantly higher in the underground group. MicroRNA microarray screening showed that 5 miRNAs were downregulated (fold-change >2) in the underground group. The real-time PCR detection results of miR-19a, miR-30e, miR-335, and miR-451a were consistent with the screening results. LYM, NE, CDK2, CDK4, CDK6, Cyclin A2, Cyclin D1, Cyclin E1, miR-19a, miR-30e, miR-335, and miR451a are potential biomarkers of radon radiation damage.

Non-coding RNAs in Lung Cancer Chemoresistance

Background:

Lung cancer is the leading cause of cancer-associated death worldwide with limited treatment options. The major available treatment options are surgery, radiotherapy, chemotherapy and combinations of these treatments. In chemotherapy, tyrosine kinase inhibitors and taxol are the first lines of chemotherapeutics used for the treatment of lung cancer. Often drug resistance in the clinical settings hinders the efficiency of the treatment and intrigues the tumor relapse. Drug-resistance is triggered either by intrinsic factors or due to the prolonged cycles of chemotherapy as an acquired-resistance. There is an emerging role of non-coding RNAs (ncRNAs), including notorious microRNAs (miRNAs), proposed to be actively involved in the regulations of various tumor-suppressor genes and oncogenes.

Result:

The altered gene expression by miRNA is largely mediated either by the degradation or by interfering with the translation of targeted mRNA. Unlike miRNA, other type of ncRNAs, such as long non-coding RNAs (lncRNAs), can target the transcriptional activator or the repressor, RNA polymerase, and even DNA-duplex to regulate the gene expressions. Many studies have confirmed the crucial role of ncRNAs in lung adenocarcinoma progression and importantly, in the acquisition of chemoresistance. Recently, ncRNAs have become early biomarkers and therapeutic targets for lung cancer.

Conclusion:

Targeting ncRNAs could be an effective approach for the development of novel therapeutics against lung cancer and to overcome the chemoresistance.

miR-451: A Novel Biomarker and Potential Therapeutic Target for Cancer

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded small RNAs involved in a variety of cellular processes, including ontogeny, cell proliferation, differentiation, and apoptosis. They can also function as oncogenes or tumor suppressor genes. Recent studies have revealed that miRNA-451 (miR-451) is involved in the regulation of various human physiological and pathological processes. Furthermore, it has been shown that miR-451 not only directly affects the biological functions of tumor cells but also indirectly affects tumor cell invasion and metastasis upon secretion into the tumor microenvironment via exosomes. Thus, miR-451 also influences the progression of tumorigenesis and drug resistance. This review summarizes the expression of miR-451 in various cancer types and the relationship between miR-451 and the diagnosis, treatment, and drug resistance of solid tumors. In addition, we address possible mechanisms of action of miR-451 and its potential application as a biomarker in the diagnosis and treatment of human cancers.

Exosomal Transfer Of Cisplatin-Induced miR-425-3p Confers Cisplatin Resistance In NSCLC Through Activating Autophagy

Introduction

Exosomes are important mediators of intercellular communication. Previously, we characterized circulating exosomal miR-425-3p as a non-invasive prognostic marker for predicting clinical response to platinum-based chemotherapy in patients with non-small cell lung cancer (NSCLC).

Methods

Circulating exosomal miR-425-3p was validated by qRT-PCR in paired serum samples from NSCLC patients during the course of platinum-based chemotherapy. Cell coculture was performed to examine the effects of exosomal miR-425-3p on the sensitivity of recipient A549 cells to cisplatin. Using bioinformatics, ChIP and luciferase reporter assays, the transcription factor essential for miR-425-3p expression was identified. Autophagic activity in the recipient cells was determined by Western blot and fluorescence microscopy.

Results

Higher levels of exosomal miR-425-3p were found in serum samples from the patients in tolerance versus those at baseline. An upward trend in the expression of circulating exosomal miR-425-3p was revealed during chemotherapy. Furthermore, the expression of exosomal miR-425-3p could be induced by cisplatin in NSCLC cells. Exosomes isolated from either cisplatin-treated or cisplatin-resistant NSCLC cells conferred chemoresistance to sensitive A549 cells in a miR-425-3p-dependent manner. Cisplatin-induced c-Myc was found to directly bind the miR-425-3p promoter and transactivated its expression. Exosomal miR-425-3p facilitated autophagic activation in the recipient cells by targeting AKT1, eventually leading to chemoresistance.

Discussion

Our results suggest that apart from a prognostic marker of treatment response, exosomal miR-425-3p might be a potential dynamic biomarker to tailor cisplatin resistance in NSCLC patients during the treatment and represent a promising therapeutic target for therapy-resistant NSCLC.

A comprehensive review on miR-451: A promising cancer biomarker with therapeutic potential

MicroRNAs (miRNAs) are proposed as a family of short noncoding molecules able to manage and control the expression of the gene targets at the posttranscriptional level. They contribute in several fundamental physiological mechanisms as well as a verity of human and animal diseases such as cancer progression. Among these tiny RNAs, miR-451 placed on chromosome 17 at 17q11.2 presents an essential role in many biological processes in health condition and also in pathogenesis of different diseases. Besides, it has been recently considered as a valuable biomarker for cancer detection, prognosis and treatment. Therefore, this review will provide the critical functions of miR-451 on biological mechanisms including cell cycle and proliferation, cell survival and apoptosis, differentiation and development as well as disease initiation and progression such as tumor formation, migration, invasion, and metastasis.

FOX-A1 contributes to acquisition of chemoresistance in human lung adenocarcinoma via transactivation of SOX5

Background

Chemoresistance is a major obstacle for the effective treatment of lung adenocarcinoma (LAD). Forkhead box (FOX) proteins have been demonstrated to play critical roles in promoting epithelial-mesenchymal transition (EMT) and chemoresistance. However, whether FOX proteins contribute to the acquisition of EMT and chemoresistance in LAD remains largely unknown.

Methods

FOX-A1 expression was measured in LAD cells and tissues by qRT-PCR. The expression levels of EMT markers were detected by western blotting and immunofluorescence assay. The interaction between Sex determining region Y-box protein 5 (SOX5) and FOX-A1 was validated by chromatin immunoprecipitation sequence (ChIP-seq) and Chromatin immunoprecipitation (ChIP) assay. Kaplan-Meier analysis and multivariate Cox regression analysis were performed to analyze the significance of FOX-A1 and SOX5 expression in the prognosis of LAD patients.

Findings

FOX-A1 was upregulated in docetaxel-resistant LAD cells. High FOX-A1 expression was closely associated with a worse prognosis. Upregulation of FOX-A1 in LAD samples indicated short progression-free survival (PFS) and overall survival (OS). SOX5 is a new and direct target of FOX-A1 and was positively regulated by FOX-A1 in LAD cell lines. Knockdown of FOX-A1 or SOX5 reversed the chemoresistance of docetaxel-resistant LAD cells by suppressing cell proliferation, migration and EMT progress.

Interpretation

These data elucidated an original FOX-A1/SOX5 pathway that represents a promising therapeutic target for chemosensitizing LAD and provides predictive biomarkers for evaluating the efficacy of chemotherapies.

The tumour suppressor effects and regulation of cancer stem cells by macrophage migration inhibitory factor targeted miR-451 in colon cancer

BACKGROUND

This study aimed to investigate the impact of miR-451 on the biological behaviours of colon cancer cells along with its targets interactions.

METHOD

The levels of miR-451 were tested in colon cancer cell lines (SW480 and SW48). Multiple functional and immunological assays were performed to analyse miR-451 induced growth changes in-vitro and downstream effects on target proteins.

RESULTS

Overexpression of miR-451 in colon cancer cells led to reduced cell proliferation, increased apoptosis and decrease accumulation of the cells at the G0/G1 phase of the cell cycle. In addition, a significant increase in the number of the cells was noted in the G2-M phase of cell cycle. Moreover, miR-451 reduced the expression of Oct-4, Sox-2 and Snail indicating its role in stem cell and epithelial-mesenchymal transition (EMT) regulation. An inverse correlation between miR-451 and macrophage migration inhibitory protein (MIF) protein expression occurred in colon cancer cells. Furthermore, restoration the level of miR-451 in colon cancer cells inhibits tumour spheres formation.

CONCLUSION

miR-451 has tumour suppressor effects in vitro, which can inhibit the cancer-related signalling pathways in colon cancer.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

Delta-tocotrienol inhibits non-small-cell lung cancer cell invasion via the inhibition of NF-κB, uPA activator, and MMP-9

Background

Delta-tocotrienol (δT), an isomer of vitamin E, exhibits anticancer properties in different cancer types including non-small-cell lung cancer (NSCLC). Yet, anti-invasive effects of δT and its underlying cellular mechanism in NSCLC have not been fully explored. Matrix metalloproteinase 9 (MMP-9)-based cell migration and invasion are critical cellular mechanisms in cancer development. The current evidence indicates that MMP-9 is upregulated in most patients, and the inhibition of MMPs is involved in decreasing invasion and metastasis in NSCLC. Therefore, its suppression is a promising strategy for attenuating cell invasion and metastasis processes in NSCLC.

Purpose

The aim of this study was to evaluate the possibility of MMP-9 inhibition as the underlying mechanism behind the antimetastatic properties of δT on NSCLC cells.

Methods

The effects of δT on cell proliferation, migration, invasion, adhesion, and aggregation capabilities were investigated using different cell-based assays. An inhibitory effect of MMP-9 enzyme activity with δT was also identified using gel zymography. Using real-time PCR and Western blot analysis, a number of cellular proteins, regulatory genes, and miRNA involved in the Notch-1 and urokinase-type plasminogen activator (uPA)-mediated MMP-9 pathways were examined.

Results

The study found that δT inhibited cell proliferation, cell migration, invasion, aggregation, and adhesion in a concentration-dependent manner and reduced MMP-9 activities. Real-time PCR and Western blot analysis data revealed that δT increased miR-451 expressions and downregulated Notch-1-mediated nuclear factor-κB (NF-κB), which led to the repressed expression of MMP-9 and uPA proteins.

Conclusion

δT attenuated tumor invasion and metastasis by the repression of MMP-9/uPA via downregulation of Notch-1 and NF-κB pathways and upregulation of miR-451. The data suggest that δT may have potential therapeutic benefit against NSCLC metastasis.

Drug Resistance in Non-Small Cell Lung Cancer: A Potential for NOTCH Targeting?

Drug resistance is a major cause for therapeutic failure in non-small cell lung cancer (NSCLC) leading to tumor recurrence and disease progression. Cell intrinsic mechanisms of resistance include changes in the expression of drug transporters, activation of pro-survival, and anti-apoptotic pathways, as well as non-intrinsic influences of the tumor microenvironment. It has become evident that tumors are composed of a heterogeneous population of cells with different genetic, epigenetic, and phenotypic characteristics that result in diverse responses to therapy, and underlies the emergence of resistant clones. This tumor heterogeneity is driven by subpopulations of tumor cells termed cancer stem cells (CSCs) that have tumor-initiating capabilities, are highly self-renewing, and retain the ability for multi-lineage differentiation. CSCs have been identified in NSCLC and have been associated with chemo- and radiotherapy resistance. Stem cell pathways are frequently deregulated in cancer and are implicated in recurrence after treatment. Here, we focus on the NOTCH signaling pathway, which has a role in stem cell maintenance in non-squamous non-small lung cancer, and we critically assess the potential for targeting the NOTCH pathway to overcome resistance to chemotherapeutic and targeted agents using both preclinical and clinical evidence.

HDAC3-mediated silencing of miR-451 decreases chemosensitivity of patients with metastatic castration-resistant prostate cancer by targeting NEDD9

Background:

Treatment of metastatic castration-resistant prostate cancer (mCRPC) with docetaxel often fails due to the emergence of chemoresistance. Thus, restoring chemosensitivity to docetaxel-based therapies remains a challenge in mCRPC treatment.

Methods:

microRNA (miR)-451 expression was measured in docetaxel-treated prostate cancer cells and tumor tissues by quantitative reverse-transcription polymerase chain reaction . Cell-counting kit 8 assay was performed to determine docetaxel chemoresistance. Neural-precursor-cell-expressed developmentally downregulated protein 9 (NEDD9) was identified as a novel target of miR-451 by dual-luciferase reporter system. Chromatin immunoprecipitation and co-immunoprecipitation assay were performed to confirm that histone deacetylase 3 (HDAC3)/Sp1 (a highly evolutionarily conserved transcription factor) interacted with the Sp1 binding sites in miR-451 promoter.

Results:

miR-451 was found to be silenced in docetaxel-treated prostate cancer cells and mCRPC tissues. Low miR-451 expression was closely associated with a high Gleason score, high Eastern Cooperative Oncology Group performance status score, visceral metastasis and poor prognosis. Low expression of miR-451 was significantly correlated with short progression-free survival (PFS) and overall survival (OS) according to Kaplan–Meier analysis, and miR-451 was determined to be an independent poor prognostic factor for PFS and OS in mCRPC patients by univariate and multivariate Cox regression analyses. NEDD9 was identified as a new and functional target of miR-451. Restoration of NEDD9 partially reversed the effects of miR-451 on enhancing chemosensitivity of prostate cancer cells. HDAC3 was confirmed to be involved in silencing of miR-451 expression in prostate cancer cells.

Conclusions:

The current data revealed a new HDAC3/Sp1/miR-451/NEDD9 signaling axis that regulates the chemosensitivity of prostate cancer cells and represents a novel therapeutic target for chemosensitizing mCRPC.

Methylation-associated silencing of microRNA-129-3p promotes epithelial-mesenchymal transition, invasion and metastasis of hepatocelluar cancer by targeting Aurora-A

Metastasis and recurrence has become one major obstacle for further improving the survival of hepatocelluar cancer (HCC) patients. Therefore, it is critical to elucidate the mechanisms involved in HCC metastasis. This study aimed to investigate the roles of microRNA (miR)-129-3p in HCC metastasis and its possible molecular mechanisms. By using microarray analysis to compare levels of different miRNAs in HCC tissues with or without lymph node metastasis (LNM), we showed that HCC tissues with LNM had reduced levels of miR-129-3p, which was related to its promoter hypermethylation and correlated with tumor metastasis, recurrence and poor prognosis. Gain - and loss - of - function assays indicated that re-expression of miR-129-3p could reverse epithelial-mesenchymal transition (EMT), and reduce in vitro invasion and in vivo metastasis of HCC cells. Aurora-A, a serine/threonine protein kinase, was identified as a direct target of miR-129-3p. Knockdown of Aurora-A phenocopied the effect of miR-129-3p overexpression on HCC metastasis. In addition, Aurora-A upregulation could partially rescue the effect of miR-129-3p. We further demonstrated that activation of PI3K/Akt and p38-MAPK signalings were involved in miR-129-3p-mediated HCC metastasis. These findings suggest that methylation-mediated miR-129-3p downregulation promotes EMT, in vitro invasion and in vivo metastasis of HCC cells via activation of PI3K/Akt and p38-MAPK signalings partially by targeting Aurora-A. Therefore, miR-129-3p may be a novel prognostic biomarker and potential therapeutic target for HCC.

Long noncoding RNA ROR regulates chemoresistance in docetaxel-resistant lung adenocarcinoma cells via epithelial mesenchymal transition pathway

Emerging evidence indicates that the dysregulation of long non-coding RNAs (lncRNAs) contributes to the development and progression of lung adenocarcinoma (LAD), however the underlying mechanism of action of lncRNAs remains unclear. It is well known that the effective treatment of cancers has been hindered by drug resistance in the clinical setting. Epithelial-mesenchymal transition (EMT) has been recognized to be involved in acquiring drug resistance, cell migration and invasion properties in several types of cancer. Docetaxel-resistant LAD cells established previously in our lab present chemoresistant and mesenchymal features. Long intergenic non-protein coding RNA, regulator of reprogramming (linc-ROR), was first discovered in induced pluripotent stem cells (iPSCs) and was upregulated in docetaxel-resistant LAD cells. In this study, we tried to make clarification of lincRNA-related mechanisms underlying EMT followed by acquired resistance to chemotherapy in LAD. In order to hit the mark, we made use of multiple methods including microarray analysis, qRT-PCR, western blotting analysis, loss/gain-of-function analysis, luciferase assays, drug sensitivity assays, wound-healing assay and invasion assay. We found that decreased expression of linc-ROR effectively reversed EMT in docetaxel-resistant LAD cells and sensitized them to chemotherapy. The function of linc-ROR exerted in LAD cells depended on the sponging of miR-145, therefore, releasing the miR-145 target FSCN1, and thus contributing to the acquisition of chemoresistance and EMT phenotypes of docetaxel-resistant LAD cells. Our findings revealed that linc-ROR might act as potential therapeutic target to overcome chemotherapy resistance in LAD.

MicroRNA-595 sensitizes ovarian cancer cells to cisplatin by targeting ABCB1

Ovarian cancer is among the leading cause of cancer-related deaths in females. In this study, we demonstrated that miR-595 expression was downregulated in the ovarian cancer tissues and cell lines. miR-595 expression was lower in the lymph node metastases tissues than in the primary ovarian cancer tissues and normal tissues. Furthermore, miR-595 overexpression suppressed the ovarian cancer cell proliferation, colony formation and invasion and promoted the sensitivity of ovarian cancer cell to cisplatin. We identified ABCB1 as a direct target gene of miR-595 in the ovarian cancer cell. ABCB1 expression was upregulated in the ovarian cancer tissues and cell lines. Morevoer, the expression level of ABCB1 was inversely correlated with miR-595 in the ovarian cancer tissues. In addition, overexpression of ABCB1 decreased the miR-595-overexpressing HO8910PM and SKOV-3 cell sensitivity to cisplatin. Ectopic expression of ABCB1 promoted the miR-595-overexpressing HO8910PM and SKOV-3 cell proliferation, colony formation and invasion. These data suggested that miR-595 acted a tumor suppressor role in ovarian cancer development and increased the sensitivity of ovarian cancer to cisplatin.

miR-296-3p Negatively Regulated by Nicotine Stimulates Cytoplasmic Translocation of c-Myc via MK2 to Suppress Chemotherapy Resistance

This study aimed to identify mechanisms by which microRNA 296-3p (miR-296-3p) functions as a tumor suppressor to restrain nasopharyngeal carcinoma (NPC) cell growth, metastasis, and chemoresistance. Mechanistic studies revealed that miR-296-3p negatively regulated by nicotine directly targets the oncogenic protein mitogen-activated protein kinase-activated protein kinase-2 (Mapkapk2) (MK2). Suppression of MK2 downregulated Ras/Braf/Erk/Mek/c-Myc and phosphoinositide-3-kinase (PI3K)/Akt/c-Myc signaling and promoted cytoplasmic translocation of c-Myc, which activated miR-296-3p expression by a feedback loop. This ultimately inhibited cell cycle progression, epithelial-to-mesenchymal transition (EMT), and chemoresistance of NPC. In addition, nicotine as a key component of tobacco was observed to suppress miR-296-3p and thus elevate MK2 expression by inducing PI3K/Akt/c-Myc signaling. In clinical samples, reduced miR-296-3p as an unfavorable factor was inversely correlated with MK2 and c-Myc expression. These results reveal a novel mechanism by which miR-296-3p negatively regulated by nicotine directly targets MK2-induced Ras/Braf/Erk/Mek/c-Myc or PI3K/AKT/c-Myc signaling to stimulate its own expression and suppress NPC cell proliferation and metastasis. miR-296-3p may thus serve as a therapeutic target to reverse chemotherapy resistance of NPC.

Downregulation of miR-101 contributes to epithelial-mesenchymal transition in cisplatin resistance of NSCLC cells by targeting ROCK2

Chemoresistance and epithelial-mesenchymal transition (EMT) in cancer are linked phenomena. EMT contributes to chemoresistance, however, little is known about whether chemotherapy can induce EMT in cancer cells. Here, we found that miR-101 expression was downregulated in cisplatin-resistant non-small cell lung cancer (NSCLC) cells. Restoration of miR-101 expression inhibited EMT and increased the sensitivity of cisplatin-resistant NSCLC cells to cisplatin in vitro by targeting ROCK2. Furthermore, ROCK2 protein level was inversely correlated with miR-101 level in NSCLC tissue samples. Kaplan-Meier analysis revealed that low miR-101 expression in NSCLC was correlated with poor survival time. In summary, our results provide novel mechanistic insights into the role of miR-101/ROCK2 signaling in the cisplatin resistance of NSCLC cells. Targeting of miR-101 is a potential therapeutic approach for NSCLC.

MicroRNA-421 regulated by HIF-1α promotes metastasis, inhibits apoptosis, and induces cisplatin resistance by targeting E-cadherin and caspase-3 in gastric cancer

Hypoxia and dysregulation of microRNAs (miRNAs) have been identified as crucial factors in carcinogenesis. However, the potential mechanisms of HIF-1α and miR-421 in gastric cancer have not been well elucidated. In this study, we found that miR-421 was up-regulated by HIF-1α. Overexpression of miR-421 promoted metastasis, inhibited apoptosis, and induced cisplatin resistance in gastric cancer in vivo and in vitro. E-cadherin and caspase-3 were identified as targets of miR-421. Besides, relative mRNA expression of miR-421 was significantly increased in gastric cancer tumor tissues compared with non-tumor tissues in a cohort of gastric cancer specimens (n=107). The expression of miR-421 was higher in advanced gastric cancers compared with localized ones. Moreover, Kaplan–Meier analysis illustrated that those patients with low levels of miR-421 had a significant longer overall survival (p = 0.006) and time to relapse (p = 0.007). Therefore, miR-421 could serve as an important prognostic marker and a potential molecular target for therapy in gastric cancer.

MiR-216b inhibits cell proliferation by targeting FOXM1 in cervical cancer cells and is associated with better prognosis

Background

Our previous study showed FOXM1 expression was significantly up-regulated in cervical cancer, and was associated with poor prognosis. To clarify miRNAs-FOXM1 modulation pathways, in this study, we investigated the relationships between miR-216b and FOXM1 and the role of miR-216b in cell proliferation and prognosis of cervical cancer patients.

Methods

Western blotting and qPCR were used to determine expression of FOXM1, cell cycle related factors and miR-216b level. MiR-216b overexpression and inhibited cell models were constructed, and siRNA was used for FOXM1 silencing. Cell proliferation was analyzed by MTT and colony formation assay. Dual luciferase reporter assay system was used to clarify the relationships between miR-216b and FOXM1. Kaplan-Meier survival analysis was used to evaluate prognosis.

Results

MiR-216b was down-regulated in cervical cancer cells and tissues, and its ectopic expression could decrease cell proliferation. Western blotting analysis showed miR-216b can inhibit cell proliferation by regulating FOXM1-related cell cycle factors, suppressing cyclinD1, c-myc, LEF1 and p-Rb and enhancing p21 expression. Repressing of miR-216b stimulated cervical cancer cell proliferation, whereas silencing FOXM1 expression could reverse this effect. Western blotting and luciferase assay results proved FOXM1 is a direct target of miR-216b. Survival analysis showed higher level of miR-216b was associated with better prognosis in cervical cancer patients.

Conclusions

FOXM1 expression could be suppressed by miR-216b via direct binding to FOXM1 3′-UTR and miR-216b could inhibit cell proliferation by regulating FOXM1 related Wnt/β-catenin signal pathway. MiR-216b level is related to prognosis in cervical cancer patients and may serve as a potential prognostic marker.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3650-5) contains supplementary material, which is available to authorized users.

A regulatory circuit HP1γ/miR-451a/c-Myc promotes prostate cancer progression

Heterochromatin protein 1γ (HP1γ) has been implicated in carcinogenesis of various cancer types. However, the role of HP1γ in prostate cancer (PCa) progression and the underlying molecular mechanisms remain largely unknown. We found that HP1γ is upregulated in PCa and elevated levels of HP1γ in PCa predict poor outcome. In addition, depletion of HP1γ in PCa cells not only repressed proliferation and induced apoptosis but also impaired tumorigenicity. We also found that c-Myc was capable of upregulating HP1γ by directly binding to the E-box element in the first intron of HP1γ gene, and the upregulated HP1γ, in turn, repressed the expression of miR-451a by enhancing H3K9 methylation at the promoter region of miR-451a. Furthermore, reduction of miR-451a significantly reversed HP1γ loss-induced PCa cell apoptosis, whereas miR-451a overexpression repressed cell survival by targeting and downregulating c-Myc. The association among c-Myc, HP1γ and miR-451a was further confirmed in human clinical samples. Therefore, we propose that an HP1γ/miR-451a/c-Myc regulatory circuitry exists in PCa cells and this circuit has a crucial role in PCa progression.

Roles of GSK-3 and microRNAs on epithelial mesenchymal transition and cancer stem cells

Various signaling pathways exert critical roles in the epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). The Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, hedgehog (Hh), Notch and TP53 pathways elicit essential regulatory influences on cancer initiation, EMT and progression. A common kinase involved in all these pathways is moon-lighting kinase glycogen synthase kinase-3 (GSK-3). These pathways are also regulated by micro-RNAs (miRs). TP53 and components of these pathways can regulate the expression of miRs. Targeting members of these pathways may improve cancer therapy in those malignancies that display their abnormal regulation. This review will discuss the interactions of the multi-functional GSK-3 enzyme in the Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, Hh, Notch and TP53 pathways. The regulation of these pathways by miRs and their effects on CSC generation, EMT, invasion and metastasis will be discussed.

The low expression of miR-451 predicts a worse prognosis in non-small cell lung cancer cases

PURPOSE

miR-451 is a tumor suppressive microRNA with several target genes, including Macrophage migration inhibitory factor (MIF). As little is known about the expression and clinicopathological significance of mir-451 in NSCLC, we performed a clinicopathological study of 370 NSCLC cases to clarify them. Cell biological experiments were also performed on NSCLC cell lines to confirm the tumor-suppressive role of miR-451 and whether or not MIF is targeted by miR-451.

METHODS

We analyzed 370 NSCLC cases for the miR-451 expression by quantitative real-time polymerase chain reaction and the MIF expression by immunohistochemistry. Eighty-four background lung tissue samples were also evaluated for the miR-451 expression. The clinicopathological and genetic factors surveyed were the disease-free survival, smoking status, histological type, disease stage, EGFR gene mutations and ALK rearrangements. In 286 adenocarcinoma cases, the invasive status (adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma) was also evaluated. Five NSCLC cell lines (H23, H441, H522, H1703, and H1975) were cultured and evaluated for their miR-451 and MIF expression. The cell lines with lower miR-451 and higher MIF expressions were then selected and transfected with miR-451-mimic to observe its effects on MIF expression, Akt and Erk status, cell proliferation, and cell migration.

RESULTS

The miR-451 expression was down-regulated in cancer tissues compared with background lung tissues (P<0.0001). Factors such as advanced disease stage, positive pleural invasion and nodal status and being a smoker were significantly correlated with a lower expression of miR-451 (P<0.05 each), while EGFR gene mutations and ALK rearrangements were not. In adenocarcinoma, invasive and minimally invasive adenocarcinoma showed lower expression of miR-451 than adenocarcinoma in situ (P<0.0005, respectively). A survival analysis showed that a lower expression of miR-451 was an independent predictor of a poor prognosis for NSCLC (P<0.05). The MIF expression was inversely correlated with the miR-451 expression. Out of 5 NSCLC cell lines examined, H441 and H1975 showed higher MIF and lower miR-451 expressions. After the transfection of miR-451-mimic, the MIF expression and phosphorylated Akt expression of these cell lines was suppressed, as were cell proliferation and cell migration.

CONCLUSION

This clinicopathological study of 370 NSCLC cases and the cell biological studies of NSCLC cell lines clarified the tumor-suppressive role of miR-451 and its prognostic value. We also validated MIF as a target of miR-451 in NSCLC.

Recent progress on the effects of microRNAs and natural products on tumor epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) is a biological process of phenotypic transition of epithelial cells that can promote physiological development as well as tissue healing and repair. In recent years, cancer researchers have noted that EMT is closely related to the occurrence and development of tumors. When tumor cells undergo EMT, they can develop enhanced migration and local tissue invasion abilities, which can lead to metastatic growth. Nevertheless, two researches in NATURE deny its necessity in specific tumors and that is discussed in this review. The degree of EMT and the detection of EMT-associated marker molecules can also be used to judge the risk of metastasis and to evaluate patients’ prognosis. MicroRNAs (miRNAs) are noncoding small RNAs, which can inhibit gene expression and protein translation through specific binding with the 3′ untranslated region of mRNA. In this review, we summarize the miRNAs that are reported to influence EMT through transcription factors such as ZEB, SNAIL, and TWIST, as well as some natural products that regulate EMT in tumors. Moreover, mutual inhibition occurs between some transcription factors and miRNAs, and these effects appear to occur in a complex regulatory network. Thus, understanding the role of miRNAs in EMT and tumor growth may lead to new treatments for malignancies. Natural products can also be combined with conventional chemotherapy to enhance curative effects.

TCRP1 transcriptionally regulated by c-Myc confers cancer chemoresistance in tongue and lung cancer

Previously, we cloned a new gene termed ‘tongue cancer resistance-associated protein 1’ (TCRP1), which modulates tumorigenesis, enhances cisplatin (cDDP) resistance in cancers, and may be a potential target for reversing drug resistance. However, the mechanisms for regulating TCRP1 expression remain unclear. Herein, we combined bioinformatics analysis with luciferase reporter assay and ChIP assay to determine that c-Myc could directly bind to TCRP1 promoter to upregulate its expression. TCRP1 upregulation in multidrug resistant tongue cancer cells (Tca8113/PYM) and cisplatin-resistant A549 lung cancer cells (A549/DDP) was accompanied by c-Myc upregulation, compared to respective parental cells. In tongue and lung cancer cells, siRNA-mediated knockdown of c-Myc led to decrease TCRP1 expression, whereas overexpression c-Myc did the opposite. Moreover, TCRP1 knockdown attenuated chemoresistance resulting from c-Myc overexpression, but TCRP1 overexpression impaired the effect of c-Myc knockdown on chemosensitivity. Additionally, in both human tongue and lung cancer tissues, c-Myc protein expression positively correlated with TCRP1 protein expression and these protein levels were associated with worse prognosis for patients. Combined, these findings suggest that c-Myc could transcriptionally regulate TCRP1 in cell lines and clinical samples and identified the c-Myc-TCRP1 axis as a negative biomarker of prognosis in tongue and lung cancers.

MicroRNA-451 regulates chemoresistance in renal cell carcinoma by targeting ATF-2 gene

Renal cell carcinoma (RCC) is a malignant tumor, which severely threatens human's life, moreover, the multi-drug resistance (MDR) under RCC undoubtedly strengthen the difficulties in the treatment. MiR-451 has been considered to play an important role in regulation of MDR in several cancers, but the role of it in MDR of RCC has not been explored. This study aims to explore the mechanism of miR-451 as a target to regulate chemotherapy resistance, which is crucial for further exploring novel therapy for RCC. Two human cell lines (ACHN and GRC-1) were performed in this study and adriamycin (ADM) was used to construct MDR cell lines. qRT-PCR was used to determine the mRNA expression of miR-451 and ATF-2. Weston blot was used to determine protein expression. MTT assay and flow cytometry were used for assessing cell viability and apoptosis, individually. Luciferase reporter assay was used to detect the targeting of miR-451 and ATF-2. Results presented that the expression of miR-451 was higher in low MDR cell line (ACHN) comparing with the high MDR cell line (GRC-1), while the expression of ATF-2 revealed an opposite results. MiR-451 targeted ATF-2 and regulated its expression. Overexpression of miR-451 strengthened drug resistance, decreased cell viability, and increased cell apoptosis of GRC-1 pretreated by ADM, while overexpressed ATF-2 reversed the effect induced by miR-451 overexpression. Then miR-451 knockdown improved drug susceptibility, decreased cell apoptosis, and increased cell viability of ACHN induced by ADM, however, ATF-2 suppression reversed the low rate of cell apoptosis and high rate of cell viability induced by miR-451 knockdown. Our results revealed that miR-451 regulates the drug resistance of RCC by targeting ATF-2 gene, which might be critical for overcoming MDR in RCC patients. Impact statement This is the first study to emphasize the expression of miR-451 on regulating multi-drug resistance (MDR) in renal cell carcinoma (RCC). Our study found that miR-451 regulates the drug resistance of RCC by targeting ATF-2, which might be critical for overcoming MDR in RCC patients. This study not only provides solid theory foundation for the clinical therapy, but also offers unique insights for the further RCC research. Furthermore, the study helps us to understand the mechanism of MDR, which was crucial for identifying the chemoresistance on several related tumors.

MicroRNA-7 functions as a tumor-suppressor gene by regulating ILF2 in pancreatic carcinoma

Interleukin enhancer binding factor 2 (ILF2) has been found to be markedly upregulated in pancreatic carcinoma and is involved in the pathogenesis of pancreatic carcinoma. Thus, ILF2 may be a potential target for therapy. Yet, the regulatory mechanisms of ILF2 in pancreatic carcinoma remain largely elusive. In the present study, we demonstrated that ILF2 functioned as an oncogene and regulated epithelial-mesenchymal transition (EMT)-associated genes in pancreatic carcinoma PANC-1 cells. MicroRNA-7 (miR-7) suppressed ILF2 mRNA expression and the protein level in PANC-1 cells. Contrary to ILF2, miRNA-7 functioned as a tumor-suppressor gene and negatively regulated EMT-associated genes in the PANC-1 cells. Curcumin, a polyphenol natural product isolated from the rhizome of the plant Curcuma longa, has emerged as a promising anticancer therapeutic agent. We found that treatment with curcumin increased miR-7 expression and suppressed ILF2 protein in the PANC-1 cells. Thus, we identified ILF2 as a new downstream target gene of curcumin. The results revealed that ILF2 is regulated by miR-7 and suggest that downregulation of miR-7 may be an important factor for the ILF2 overexpression in pancreatic carcinoma.

Influence of microRNAs and Long Non-Coding RNAs in Cancer Chemoresistance

Innate and acquired chemoresistance exhibited by most tumours exposed to conventional chemotherapeutic agents account for the majority of relapse cases in cancer patients. Such chemoresistance phenotypes are of a multi-factorial nature from multiple key molecular players. The discovery of the RNA interference pathway in 1998 and the widespread gene regulatory influences exerted by microRNAs (miRNAs) and other non-coding RNAs have certainly expanded the level of intricacy present for the development of any single physiological phenotype, including cancer chemoresistance. This review article focuses on the latest research efforts in identifying and validating specific key molecular players from the two main families of non-coding RNAs, namely miRNAs and long non-coding RNAs (lncRNAs), having direct or indirect influences in the development of cancer drug resistance properties and how such knowledge can be utilised for novel theranostics in oncology.

MiR-206 inhibits HGF-induced epithelial-mesenchymal transition and angiogenesis in non-small cell lung cancer via c-Met /PI3k/Akt/mTOR pathway

MiR-206 is low expression in lung cancers and associated with cancer metastasis. However, the roles of miR-206 in epithelial-mesenchymal transition (EMT) and angiogenesis in lung cancer remain unknown. In this study, we find that hepatocyte growth factor (HGF) induces EMT, invasion and migration in A549 and 95D lung cancer cells, and these processes could be markedly inhibited by miR-206 overexpression. Moreover, we demonstrate that miR-206 directly targets c-Met and inhibits its downstream PI3k/Akt/mTOR signaling pathway. In contrast, miR-206 inhibitors promote the expression of c-Met and activate the PI3k/Akt/mTOR signaling, and this effect could be attenuated by the PI3K inhibitor. Moreover, c-Met overexpression assay further confirms the significant inhibitory effect of miR-206 on HGF-induced EMT, cell migration and invasion. Notably, we also find that miR-206 effectively inhibits HGF-induced tube formation and migration of human umbilical vein endothelial cells (HUVECs), and the mechanism is also related to inhibition of PI3k/Akt/mTOR signaling. Finally, we reveal the inhibitory effect of miR-206 on EMT and angiogenesis in xenograft tumor mice model. Taken together, miR-206 inhibits HGF-induced EMT and angiogenesis in lung cancer by suppressing c-Met/PI3k/Akt/mTOR signaling. Therefore, miR-206 might be a potential target for the therapeutic strategy against EMT and angiogenesis of lung cancer.