The IL-6/STAT3 pathway via miR-21 is involved in the neoplastic and metastatic properties of arsenite-transformed human keratinocytes

Expression of Selected miRNAs in Normal and Cancer-Associated Fibroblasts and in BxPc3 and MIA PaCa-2 Cell Lines of Pancreatic Ductal Adenocarcinoma

Therapy for pancreatic ductal adenocarcinoma remains challenging, and the chances of a complete cure are very limited. As in other types of cancer, the expression and role of miRNAs in controlling the biological properties of this type of tumor have been extensively studied. A better insight into miRNA biology seems critical to refining diagnostics and improving their therapeutic potential. In this study, we focused on the expression of miR-21, -96, -196a, -210, and -217 in normal fibroblasts, cancer-associated fibroblasts prepared from a ductal adenocarcinoma of the pancreas, and pancreatic carcinoma cell lines. We compared these data with miRNAs in homogenates of paraffin-embedded sections from normal pancreatic tissues. In cancer-associated fibroblasts and cancer cell lines, miRNAs differed significantly from the normal tissue. In detail, miR-21 and -210 were significantly upregulated, while miR-217 was downregulated. Similar transcription profiles were earlier reported in cancer-associated fibroblasts exposed to hypoxia. However, the cells in our study were cultured under normoxic conditions. We also noted a relation to IL-6 production. In conclusion, cultured cancer-associated fibroblasts and carcinoma cells reflect miR-21 and -210 expression similarly to the cancer tissue samples harvested from the patients.

Arsenic and Diabetes Mellitus: A Putative Role for the Immune System

Diabetes mellitus (DM) is an enormous public health issue worldwide. Recent data suggest that chronic arsenic exposure is linked to the risk of developing type 1 and type 2 DM, albeit the underlying mechanisms are unclear. This review discusses the role of the immune system as a link to possibly explain some of the mechanisms of developing T1DM or T2DM associated with arsenic exposure in humans, animal models, and in vitro studies. The rationale for the hypothesis includes: (1) Arsenic is a well-recognized modulator of the immune system; (2) arsenic exposures are associated with increased risk of DM; and (3) dysregulation of the immune system is one of the hallmarks in the pathogenesis of both T1DM and T2DM. A better understanding of DM in association with immune dysregulation and arsenic exposures may help to understand how environmental exposures modulate the immune system and how these effects may impact the manifestation of disease.

Involvement of METTL3 in arsenite-induced skin lesions by targeting the SOCS3/STAT3/Krt signaling pathway

Arsenic is a common environmental pollutant, typically affecting the skin most severely. Recent studies have shown that arsenic's toxicity may be linked to N6-methyladenosine (m⁶A), an abundant and dynamic epigenetic RNA modification. However, it is not completely understood how m⁶A contributes to arsenite-induced skin lesions. Herein, it is shown that methyltransferase-like 3 (METTL3) plays a crucial role in the involvement of arsenite-induced skin lesions in an m⁶A-dependent manner. Using bioinformatic analysis and experimental approaches, we demonstrate that arsenite induces METTL3 upregulation, represses suppressors of cytokine signaling 3 (SOCS3) expression in an m⁶A- YTH m⁶A RNA binding protein 2 (YTHDF2)-dependent manner, and leads to the aberrant activation of the Janus kinase (JAK)2/signal transducer and activator of transcription 3(STAT3) signaling pathway. We further found that the activated transcription factor STAT3 binds to the promoter regions of Krt1 and Krt10, promoting their transcription, which ultimately leads to arsenite-induced skin lesions. In conclusion, our study reveals the role of m⁶A in arsenite-induced skin lesions through the activation of the JAK2/STAT3/Krt signaling axis. The findings provide new insight into the potential molecular mechanisms underlying arsenic toxicity regulation through m⁶A modification.

miRNAs and arsenic-induced carcinogenesis

Arsenic-induced carcinogenesis is a worldwide health problem. Identifying the molecular mechanisms responsible for the induction of arsenic-induced cancers is important for developing treatment strategies. MicroRNA (miRNA) dysregulation is known to affect development and progression of human cancer. Several studies have identified an association between altered miRNA expression in cancers from individuals chronically exposed to arsenic and in cell models for arsenic-induced carcinogenesis. This chapter provides a comprehensive review for miRNA dysregulation in arsenic-induced cancer.

MiR-21 and Tocilizumab interactions improve COVID-19 myocarditis outcomes

BACKGROUND

Myocarditis is now one of the most fatal and morbid complications of COVID-19. Many scientists have recently concentrated on this problem.

OBJECTIVES

This study assessed the effects of Remdesivir (RMS) and Tocilizumab (TCZ) in COVID-19 myocarditis.

DESIGN

Observational, cohort study.

METHODS

Patients with COVID-19 myocarditis were enrolled in the study and divided into three groups, TCZ-treated, RMS-treated, and Dexamethasone-treated patients. After 7 days of treatment, patients were reassessed for improvement.

RESULTS

TCZ significantly improved patients' ejection fraction in 7 days, but it had limited efficacy. RMS improved inflammatory characteristics of the disease, but RMS-treated patients showed exacerbated cardiac function over 7 days, and the mortality rate with RMS was higher than TCZ. TCZ protects the heart by decreasing the miR-21 expression rate.

CONCLUSION

Using Tocilizumab in early diagnosed COVID-19 myocarditis patients can save their cardiac function after hospitalization and decrease the mortality rate. miR-21 level determines the outcome and responsiveness of COVID-19 myocarditis to treatment.

MicroRNA-Gene Interactions Impacted by Toxic Metal(oid)s during EMT and Carcinogenesis

Chronic environmental exposure to toxic metal(loid)s significantly contributes to human cancer development and progression. It is estimated that approximately 90% of cancer deaths are a result of metastasis of malignant cells, which is initiated by epithelial-mesenchymal transition (EMT) during early carcinogenesis. EMT is regulated by many families of genes and microRNAs (miRNAs) that control signaling pathways for cell survival, death, and/or differentiation. Recent mechanistic studies have shown that toxic metal(loid)s alter the expression of miRNAs responsible for regulating the expression of genes involved in EMT. Altered miRNA expressions have the potential to be biomarkers for predicting survival and responses to treatment in cancers. Significantly, miRNAs can be developed as therapeutic targets for cancer patients in the clinic. In this mini review, we summarize key findings from recent studies that highlight chemical-miRNA-gene interactions leading to the perturbation of EMT after exposure to toxic metal(loid)s including arsenic, cadmium, nickel, and chromium.

JAK2/STAT3 in role of arsenic-induced cell proliferation: a systematic review and meta-analysis

OBJECTIVES

Malignant cell proliferation is one of the important mechanisms of arsenic poisoning. A large number of studies have shown that STAT3 plays an important role in cell malignant proliferation, but there are still many contradictions in the effect of arsenic on JAK2/STAT3. This study aims to explore the role of JAK2/STAT3 in arsenic-induced cell proliferation.

METHODS

By taking normal cells as the research object and using Standard Mean Difference (SMD) as the effect size, meta-analysis was used to explore the effect of arsenic on JAK2/STAT3. Then, the dose-effect Meta was used to further clarify the dose-effect relationship of arsenic on JAK2/STAT3.

RESULTS

Through meta-analysis, this study found that arsenic could promote the phosphorylation of STAT3 (SMD=4.21, 95%CI [1.05, 7.37]), and increase IL-6 and p-JAK2, Vimentin, VEGF expression levels, thereby inducing malignant cell proliferation. In addition, this study also found that arsenic exposure dose (<5 μmol m^-3), time(<24 h) and cell type were important sources of heterogeneity in the process of exploring the effects of arsenic on p-STAT3, IL-6 and p-JAK2. Dose-effect relationship meta-analysis results showed that arsenic exposure significantly increased the expression level of IL-6. When the arsenic exposure concentration was less than 7 μmol m^-3, the expression level of p-JAK2 upregulated significantly as the arsenic exposure concentration gradually increasing. Moreover, the expression level of p-STAT3 elevated significantly with the gradual increase of the arsenic concentration under 5 μmol m^-3 of arsenic exposure, but the expression level of p-STAT3 gradually decreases when the concentration is greater than 5 μmol m^-3.

CONCLUSIONS

Exposure to low dose of arsenic could promote the expression of JAK2/STAT3 and induce the malignant proliferation of cells through upregulating IL-6, and there was dose-effect relationship among them.

Toxic metals in the regulation of epithelial-mesenchymal plasticity: demons or angels?

Epithelial cells can trans-differentiate into motile mesenchymal cells through a dynamic process known as epithelial-mesenchymal transition (EMT). EMT is crucial in embryonic development and wound healing but also contributes to human diseases such as organ fibrosis and cancer progression. Heavy metals are environmental pollutants that can affect human health in various ways, including causing cancers. The cytotoxicity and carcinogenicity of heavy metals are complex, and studies have demonstrated that some of these metals can affect the progress of EMT. Here, we focus on reviewing the roles of six environmentally common toxic metals concerning EMT: arsenic (AS), cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and copper (Cu). Noteworthily, the effects of these elements on EMT may vary according to the form, dose, and exposure time; the dual role of heavy metals (e.g., AS, Cd, and Cu) on EMT is also observed, in which, sometimes they can promote while sometimes inhibit the EMT process. Given the vast number of toxicologically relevant metals that exist in nature, we believe a comprehensive understanding of their effects on EMT is required to dictate in what circumstances these metals act more likely as demons or angels.

Noncoding RNAs as sensors of tumor microenvironmental stress

The tumor microenvironment (TME) has been demonstrated to modulate the biological behavior of tumors intensively. Multiple stress conditions are widely observed in the TME of many cancer types, such as hypoxia, inflammation, and nutrient deprivation. Recently, accumulating evidence demonstrates that the expression levels of noncoding RNAs (ncRNAs) are dramatically altered by TME stress, and the dysregulated ncRNAs can in turn regulate tumor cell proliferation, metastasis, and drug resistance. In this review, we elaborate on the signal transduction pathways or epigenetic pathways by which hypoxia-inducible factors (HIFs), inflammatory factors, and nutrient deprivation in TME regulate ncRNAs, and highlight the pivotal roles of TME stress-related ncRNAs in tumors. This helps to clarify the molecular regulatory networks between TME and ncRNAs, which may provide potential targets for cancer therapy.

Tanshinone IIA-regulation of IL-6 antagonizes PM2 .5 -induced proliferation of human bronchial epithelial cells via a STAT3/miR-21 reciprocal loop

Particulate matter 2.5 (PM_2.5 ), a component of atmospheric particulate matter, leads to changes in gene expression and cellular functions. Epidemiological evidence confirms that PM_2.5 has a positive correlation with lung injury. However, the molecular mechanisms involved remain poorly understood, and preventive methods are needed. In the present study, with human bronchial epithelial (HBE) cells in culture, we showed that low concentrations of PM_2.5 resulted in acceleration of the G1/S transition and cell proliferation. Consistent with these effects, expression of the pro-inflammatory factor interleukin-6 (IL-6) was elevated in HBE cells exposed to PM_2.5 . Accordingly, signal transducer and activator of transcription 3 (STAT3) was activated, which down-regulated expression of cyclin D1. In addition, PM_2.5 exposure led to higher levels of miR-21, and there was a reciprocal loop between miR-21 and STAT3. For HBE cells, tanshinone IIA (Tan IIA) reversed the PM_2.5 -induced cell cycle alteration and cell proliferation, and reduced the expression of cytokines (IL-6, STAT3, and miR-21). These results show that, for HBE cells, Tan IIA attenuates the PM_2.5 -induced G1/S alteration and cell proliferation, and indicate that it has potential clinical application for PM_2.5 -induced respiratory injuries.

A tEMTing target? Clinical and experimental evidence for epithelial-mesenchymal transition in the progression of cutaneous squamous cell carcinoma (a scoping systematic review)

Cutaneous squamous cell carcinoma (cSCC) is a disease with globally rising incidence and poor prognosis for patients with advanced or metastatic disease. Epithelial-mesenchymal transition (EMT) is a driver of metastasis in many carcinomas, and cSCC is no exception. We aimed to provide a systematic overview of the clinical and experimental evidence for EMT in cSCC, with critical appraisal of type and quality of the methodology used. We then used this information as rationale for potential drug targets against advanced and metastatic cSCC. All primary literature encompassing clinical and cell-based or xenograft experimental studies reporting on the role of EMT markers or related signalling pathways in the progression of cSCC were considered. A screen of 3443 search results yielded 86 eligible studies comprising 44 experimental studies, 22 clinical studies, and 20 studies integrating both. From the clinical studies a timeline illustrating the alteration of EMT markers and related signalling was evident based on clinical progression of the disease. The experimental studies reveal connections of EMT with a multitude of factors such as genetic disorders, cancer-associated fibroblasts, and matrix remodelling via matrix metalloproteinases and urokinase plasminogen activator. Additionally, EMT was found to be closely tied to environmental factors as well as to stemness in cSCC via NFκB and β-catenin. We conclude that the canonical EGFR, canonical TGF-βR, PI3K/AKT and NFκB signalling are the four signalling pillars that induce EMT in cSCC and could be valuable therapeutic targets. Despite the complexity, EMT markers and pathways are desirable biomarkers and drug targets for the treatment of advanced or metastatic cSCC.

Keeping It Local in Metabolic Disease: Adipose Tissue Paracrine Signaling and Insulin Resistance

Alterations in adipose tissue composition and function are associated with obesity and contribute to the development of type 2 diabetes. While the significance of this relationship has been cemented, our understanding of the multifaceted role of adipose tissue in metabolic heath and disease continues to evolve and expand. Heterogenous populations of cells that make up adipose tissue throughout the body generate diverse secretomes containing a mosaic of bioactive compounds with vast structural and signaling capabilities. While there are many reports highlighting the important role of adipose tissue endocrine signaling in insulin resistance and type 2 diabetes, the direct, local, paracrine effect of adipose tissue has received less attention. Recent studies have begun to underscore the importance of considering anatomically discrete adipose depots for their specific impact on local microenvironments and metabolic function in neighboring tissues as well as regulation of whole-body physiology. This article highlights the important role of adipose tissue paracrine signaling on metabolic function and insulin sensitivity in nearby tissues and organs, specifically focusing on visceral, pancreatic, subcutaneous, intermuscular, and perivascular adipose tissue depots.

Crosstalk between Environmental Inflammatory Stimuli and Non-Coding RNA in Cancer Occurrence and Development

Simple Summary

Increasing evidence has indicated that chronic inflammatory processes have an influence on tumor occurrence and all stages of tumor development. A dramatic increase of studies into non-coding RNAs (ncRNAs) biology has shown that ncRNAs act as oncogenic drivers and tumor suppressors in various inflammation-induced cancers. Thus, this complex network of inflammation-associated cancers and ncRNAs offers targets for prevention from the malignant transformation from inflammation and treatment of malignant diseases.

Abstract

There is a clear relationship between inflammatory response and different stages of tumor development. Common inflammation-related carcinogens include viruses, bacteria, and environmental mutagens, such as air pollutants, toxic metals, and ultraviolet light. The expression pattern of ncRNA changes in a variety of disease conditions, including inflammation and cancer. Non-coding RNAs (ncRNAs) have a causative role in enhancing inflammatory stimulation and evading immune responses, which are particularly important in persistent pathogen infection and inflammation-to-cancer transformation. In this review, we investigated the mechanism of ncRNA expression imbalance in inflammation-related cancers. A better understanding of the function of inflammation-associated ncRNAs may help to reveal the potential of ncRNAs as a new therapeutic strategy.

ATF3 inhibits arsenic-induced malignant transformation of human bronchial epithelial cells by attenuating inflammation

Arsenic is a naturally occurring metalloid strongly associated with the incidence of lung cancer. Understanding the mechanisms of arsenic-induced carcinogenesis favors the development of effective interventions to reduce the incidence and mortality of lung cancer. In this study, we investigated the role of activating transcription factor 3 (ATF3) in arsenic-induced transformation of human bronchial epithelial cells. ATF3 was upregulated during chronic exposure to 0.25 μM arsenic, and loss of ATF3 promoted arsenic-induced transformation. Moreover, arsenic-transformed ATF3 knockout (ATF3 KO-AsT) cells exhibited more aggressive characteristics, including acceleration in proliferation, resistance to chemotherapy and increase in migratory capacity. RNA-seq revealed that pathways involved in inflammation, cell cycle, EMT and oncogenesis were affected due to ATF3 deficiency during chronic arsenic exposure. Further experiments confirmed the overproduction of IL-6, IL-8 and TNFα as well as enhanced phosphorylation of AKT and STAT3 in ATF3 KO-AsT cells. Our results demonstrate that ATF3 upregulated by chronic low-dose arsenic exposure represses cell transformation and acquisition of malignant characteristics through inhibiting the production of proinflammatory cytokines and activation of downstream proteins AKT and STAT3, providing a new strategy for the prevention of carcinogen-induced lung cancer.

MicroRNA-21 Deficiency Promotes the Early Th1 Immune Response and Resistance toward Visceral Leishmaniasis

MicroRNA-21 (miR-21) inhibits IL-12 expression and impairs the Th1 response necessary for control of Leishmania infection. Recent studies have shown that Leishmania infection induces miR-21 expression in dendritic cells and macrophages, and inhibition of miR-21 restores IL-12 expression. Because miR-21 is known to be expressed due to inflammatory stimuli in a wide range of hematopoietic cells, we investigated the role of miR-21 in regulating immune responses during visceral leishmaniasis (VL) caused by Leishmania donovani infection. We found that miR-21 expression was significantly elevated in dendritic cells, macrophages, inflammatory monocytes, polymorphonuclear neutrophils, and in the spleen and liver tissues after L. donovani infection, concomitant with an increased expression of disease exacerbating IL-6 and STAT3. Bone marrow dendritic cells from miR-21 knockout (miR-21KO) mice showed increased IL-12 production and decreased production of IL-10. On L. donovani infection, miR-21KO mice exhibited significantly greater numbers of IFN-γ- and TNF-α-producing CD4⁺ and CD8⁺ T cells in their organs that was associated with increased production of Th1-associated IFN-γ, TNF-α, and NO from the splenocytes. Finally, miR-21KO mice displayed significantly more developing and mature hepatic granulomas leading to reduction in organ parasitic loads compared with wild type counterparts. Similar results were noted in L. donovani-infected wild type mice after transient miR-21 depletion. These observations indicate that miR-21 plays a critical role in pathogenesis of VL by suppressing IL-12- and Th1-associated IFN-γ and also inducing disease-promoting induction of the IL-6 and STAT-3 signaling pathway. miR-21 could therefore be used as a potential target for developing host-directed treatment for VL.

miR-21-regulated M2 polarization of macrophage is involved in arsenicosis-induced hepatic fibrosis through the activation of hepatic stellate cells

Arsenicosis induced by chronic exposure to arsenic is recognized as one of the main damaging effects on public health. Exposure to arsenic can cause hepatic fibrosis, but the molecular mechanisms by which this occurs are complex and elusive. It is not known if miRNAs are involved in arsenic-induced liver fibrosis. We found that in the livers of mice exposed to arsenite, there were elevated levels of microRNA-21 (miR-21), phosphorylated mammalian target of rapamycin (p-mTOR), and arginase 1 (Arg1); low levels of phosphatase and tensin homolog (PTEN); and more extensive liver fibrosis. For cultured cells, arsenite-induced miR-21, p-mTOR, and Arg1; decreased PTEN; and promoted M2 polarization of macrophages derived from THP-1 monocytes (THP-M), which caused secretion of fibrogenic cytokines, including transforming growth factor-β1. Coculture of arsenite-treated, THP-M with LX-2 cells induced α-SMA and collagen I in the LX-2 cells and resulted in the activation of these cells. Downregulation of miR-21 in THP-M inhibited arsenite-induced M2 polarization and activation of LX-2 cells, but cotransfection with PTEN siRNA or a miR-21 inhibitor reversed this inhibition. Moreover, knockout of miR-21 in mice attenuated liver fibrosis and M2 polarization compared with WT mice exposed to arsenite. Additionally, LN, PCIII, and HA levels were higher in patients with higher hair arsenic levels, and levels of miR-21 were higher than controls and positively correlated with PCIII, LN, and HA levels. Thus, arsenite induces the M2 polarization of macrophages via miR-21 regulation of PTEN, which is involved in the activation of hepatic stellate cells and hepatic fibrosis. The results establish a previously unknown mechanism for arsenicosis-induced fibrosis.

Long Non-Coding RNAs (lncRNAs) Tumor-Suppressive Role of lncRNA on Chromosome 8p12 (TSLNC8) Inhibits Tumor Metastasis and Promotes Apoptosis by Regulating Interleukin 6 (IL-6)/Signal Transducer and Activator of Transcription 3 (STAT3)/Hypoxia-Inducible Factor 1-alpha (HIF-1α) Signaling Pathway in Non-Small Cell Lung Cancer

BACKGROUND Long non-coding RNAs (lncRNAs) exert various functions in human cancers. However, the biological functions of lncRNAs in non-small cell lung cancer (NSCLC) are unknown. In the present study we investigated the tumor-suppressive role of lncRNA on chromosome 8p12 (TSLNC8) in the pathogenesis and progression of NSCLC. MATERIAL AND METHODS qRT-PCR was carried out to evaluate the expression of TSLNC8 in lung cancer cell lines. The effects of TSLNC8 on A549 cells proliferation, migration, and invasion were analyzed using CCK-8 assay, wound healing assay, Transwell assay, and Western blot analysis. We used flow cytometry to assess cell apoptosis, and cell autophagy was assessed by Western blot analysis and immunofluorescence staining. Levels of proteins in the IL-6/STAT3/HIF-1alpha pathway were measured by Western blot analysis. RESULTS The results revealed that TSLNC8 was significantly downregulated in lung cancer cells compared to normal bronchial epithelial cells. Further experiments showed that overexpression of TSLNC8 in A549 cells significantly inhibited proliferation in a time-dependent manner and promoted cell apoptosis. We found that TSLNC8 overexpression suppressed cell migration and invasion, and upregulation of TSLNC8 regulated the protein levels of Beclin-1, p62, ATG14, and LC3-II and inhibited the IL-6/STAT3/HIF-1alpha signaling pathway. CONCLUSIONS lncRNA TSLNC8 remarkably inhibited the proliferation and migration and accelerated apoptosis of lung cancer cells by targeting the IL-6/STAT3/HIF-1alpha signaling pathway. TSLNC8 may be a potential therapeutic target for the diagnosis and treatment of NSCLC.

A case-control study on the relationship between miRNAs single nucleotide polymorphisms and sepsis risk

MicroRNAs (miRNAs) play an important role in the pathogenesis of sepsis, but the association of miRNAs single nucleotide polymorphisms (SNPs) and sepsis risk is not clear. We analyzed plasma levels of miR-187, miR-21, and miR-145 in 180 patients with sepsis and 180 healthy controls were analyzed, and the SNPs: rs12605436, rs13137, and rs353291 were detected by sequencing. Plasma levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured in all subjects by enzyme-linked immunosorbent assay (ELISA). The results showed that the levels of TNF-α and IL-6 in the plasma of patients with sepsis were significantly higher than those in patients of the control group (P < .0001). Plasma levels of miR-187 in patients with sepsis were significantly lower than those in the control group, while those of miR-21 and miR-145 were significantly higher than those in the control group (P < .0001). Plasma levels of miR-187 in sepsis patients were inversely correlated with those of TNF-α and IL-6 (r = -0.2841, -0.2163), and plasma levels of miR-21 and miR-145 were positively correlated with those of TNF-α and IL-6 (r = 0.615, 0.3057, 0.4465, 0.2734). The T allele of the miR-187 SNP rs12605436 was found to be a risk factor for sepsis (OR = 1.403, 95% CI = 1.205-1.612, P < .001). The T allele of the miR-21 SNP rs13137 and the T allele of the miR-145 SNP rs353291 (OR = 0.685, 95% CI = 0.566-0.820, P < .001) were found to be a protective factor for sepsis (OR = 0.755, 95% CI = 0.632-0.896, P < .001). From our results, we can see that the plasma levels of miRNAs containing the SNPs rs12605436, rs13137, and rs353291 are associated with the occurrence of sepsis.

Mechanistic evidence that benzo[a]pyrene promotes an inflammatory microenvironment that drives the metastatic potential of human mammary cells

Benzo[a]pyrene (B(a)P) is a major cancer-causing contaminant present in food such as cooked meats and cereals, and is ubiquitous in the environment in smoke derived from the combustion of organic material. Exposure to B(a)P is epidemiologically linked with the incidence of breast cancer. Although B(a)P is recognized as a complete genotoxic carcinogen, thought to act primarily via CYP-mediated metabolic activation to DNA-damaging species, there is also evidence that B(a)P exposure elicits other biological responses that promote development of the cancer phenotype. Here in mechanistic studies using human mammary cells MCF-7 and MDA-MB-231, we have explored mechanisms whereby B(a)P (10^- 8 to 10^- 5M) promotes inflammation pathways via TNF-α and NFκB leading to IL-6 upregulation, microRNA (Let7a, miR21 and miR29b) dysregulation and activation of VEGF. The miRNA dysregulation is associated with altered expression of inflammation mediators and increased migration and invasive potential of human mammary cancer cells. Our data suggest that mammary cell exposure to B(a)P results in perturbation of inflammation mediators and dysregulation of tumorigenic miRNAs, leading to an inflammation microenvironment that facilitates migration and invasion of mammary epithelial cells. These properties of B(a)P, together with its well-established metabolic activation to DNA-damaging species, offer mechanistic insights into its carcinogenic mode of action.

Identification of serum inflammatory markers as classifiers of lung cancer mortality for stage I adenocarcinoma

BACKGROUND

Lung cancer is the leading cause of cancer-related mortality worldwide. Low-dose CT (LDCT) imaging is now recommended to screen high-risk lung cancer individuals in the USA. LDCT has resulted in increased detection of stage I lung cancer for which the current standard of care is surgery alone. However, approximately 30% of these patients develop recurrence and therefore are in need of further treatment upon diagnosis. This study aims to explore blood-based inflammatory biomarkers to identify patients at high-risk of mortality for which additional treatment modalities can be offered at time of diagnosis.

PATIENTS AND METHODS

Recent work on a small panel of circulating cytokines identified elevated levels of IL-6, a pro-inflammatory cytokine, as an indicator of poor survival for lung cancer patients. To reflect the broader role of inflammation in lung cancer, we examined a large panel of 33 inflammatory proteins in the sera of 129 lung cancer patients selected from the National Cancer Institute-Maryland case-control study. To reduce heterogeneity, we specifically focused our study on stage I lung adenocarcinoma patients.

RESULTS

We replicated the previous observations that IL-6 is associated with prognosis of lung cancer and extended its utility to prognosis in this highly-selected population of stage I lung adenocarcinoma patients. In addition, we developed a multi-marker, combined prognostic classifier that includes the pro-inflammatory Th-17 cell effector cytokine, IL-17. Patients with high levels of IL-6 and IL-17A had a significantly adverse survival compared with patients with low levels (P for trend <0.0001). Patients in the high risk group, with high levels of both proteins had a 5-year survival rate of 46% in comparison to 93% for those with low levels of both markers. Furthermore, we validated the same trends for the IL-6 and IL-17A prognostic signature in an independent data set.

CONCLUSIONS

The results identified here justify further investigation of this novel, combined cytokine prognostic classifier for the identification of high-risk stage I lung adenocarcinoma patients. This classifier has the much-needed potential to identify patients at high risk of recurrence and thus prospectively identify the subset of patients requiring more aggressive treatment regimens at the time of diagnosis.

IL-37 inhibits invasion and metastasis in non-small cell lung cancer by suppressing the IL-6/STAT3 signaling pathway

Background

IL‐37 has been identified as a fundamental inhibitor of inflammatory and immunity responses. It plays a crucial protective role in several cancers, but its anti‐tumor activity and the potential regulatory mechanism of IL‐37 in non‐small cell lung cancer (NSCLC) is largely unclear.

Methods

Enzyme‐linked immunosorbent assay was used to detect plasma IL‐37 expression in NSCLC patients and healthy controls. The NSCLC cell line A549 was cultured with recombinant human IL‐37 or recombinant human IL‐6 protein. A549 invasion and metastasis were detected using Transwell invasion and scratch wound healing assays, respectively. Protein expression of STAT3, pSTAT3, E‐cadherin, vimentin, and N‐cadherin were detected using Western blotting, and messenger RNA expression of STAT3, E‐cadherin, vimentin, and N‐cadherin was assessed in each group using real time PCR.

Results

IL‐37 plasma expression was decreased in NSCLC patients, and the downregulation of IL‐37 was correlated with tumor stage. In vitro, IL‐37 inhibited invasion and migration in A549 cells, while IL‐6 promoted invasion and migration in A549 cells. pSTAT3, vimentin, and N‐cadherin expression was increased. E‐cadherin expression was lower in the IL‐6 group than in the control group; however, the opposite pattern was observed in the IL‐37 + IL‐6 group.

Conclusion

Our results showed that IL‐37 plays an inhibitory role in NSCLC progression, possibly by suppressing STAT3 activation and decreasing epithelial‐to‐mesenchymal transition by inhibiting IL‐6 expression. IL‐37 could serve as a potential novel tumor suppressor in NSCLC.

Circ008913,viamiR-889 regulation of DAB2IP/ZEB1, is involved in the arsenite-induced acquisition of CSC-like properties by human keratinocytes in carcinogenesis

Circ008913,viamiR-889 regulation of DAB2IP/ZEB1, is involved in the arsenite-induced acquisition of CSC-like properties and the neoplastic transformation.

Down regulation of miR-143 promotes radiation - Induced thymic lymphoma by targeting B7H1

MicroRNA-143 has been implicated in tumor metastasis by directly targeting Bcl-2, and microRNA-143 expression is decreased in several human tumors. However, the expression and targets of miR-143 in radiation carcinogenesis remain unclear. We found that the expression of miR-143 is down-regulated and the expression of B7H1 (Pdcd1) is up-regulated in radiation-induced thymic lymphoma model in BALB/c mice. Additionally, overexpression of miR-143 strongly inhibited cell proliferation and increased cell apoptosis and its down-regulation promoted cell proliferation and reduced cell apoptosis. We also determined that there is an inverse correlation between miR-143 expression and B7H1 protein expression in radiation-induced thymic lymphoma samples, and miR-143 targets B7H1 in a 3'UTR-dependent manner. In addition, we found that adenovirus over-expression of pre-miR-143 reduced tumorigenesis in vivo. Finally, we conclude that down-regulated expression of miR-143 and up-regulation of its direct target B7H1 may indicate a novel therapeutic method for radiation-induced thymic lymphoma by increased expression of miR-143 or inhibition of B7H1.

Mechanism of microRNA-146a-mediated IL-6/STAT3 signaling in lumbar intervertebral disc degeneration

The aim of the study was to investigate the mechanism of microRNA (miR)-146a-mediated activation of interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) in lumbar intervertebral disc degeneration. To obtain intervertebral tissue, we recruited 5 patients with lumbar intervertebral disc herniation (experimental group) and 5 patients with lumbar burst fracture (control group). Nucleus pulposus tissue was extracted by surgery and cultured. miR-146a empty vector, mimic, and inhibitor were transfected into the two groups of cells for 24 h and the levels of IL-6, type II collagen (Col II), aggrecan, STAT3, matrix metalloproteinase (MMP)-3, and a disintegrin and metalloproteinase with thrombospondin type I motifs (ADAMTS) were detected. We found no differences in the levels of IL-6, Col II, aggrecan, STAT3, MMP-3, and ADAMTS before and after treatment in the control group. However, the levels of miR-146a, IL-6, STAT3, MMP-3, and ADAMTS were significantly elevated, whereas Col II and aggrecan levels were lower in the experimental group before treatment. The levels of IL-6, STAT3, MMP-3, and ADAMTS were elevated after treatment with miR-146a mimic when compared with the miR-146a empty vector in the experimental group, and Col II and aggrecan levels were decreased. However, the cells treated with miR-146a inhibitor had the opposite result. Thus, the IL-6/STAT3 signaling pathway can be mediated by a high expression of miR-146a to regulate the occurrence of lumbar intervertebral disc degeneration.

miR-21 Promotes Fibrogenesis in Peritoneal Dialysis

Peritoneal dialysis (PD) is a life-saving form of renal replacement therapy for those with end-stage kidney disease. Mesothelial cells (MCs) line the peritoneal cavity and help define peritoneal response to treatment-associated injury, a major reason for treatment failure. miRNAs are important regulators, but their roles in peritoneal fibrosis are largely unknown. In this study, miR-21 was one of the most abundant miRNAs in primary MCs, and was up-regulated by the profibrotic cytokine transforming growth factor-β1 and in PD effluent-derived MCs exhibiting mesenchymal phenotypic change. Increased miR-21 was found in peritoneal membrane biopsy specimens from PD patients compared to healthy controls (PD biocompatible, 5.86×, P = 0.0001; PD conventional, 7.09×, P < 0.0001, n = 11 per group). In PD effluent from a cohort of 230 patients, miR-21 was higher in those receiving the therapy long-term compared to new starters (n = 230, miR-21 3.26×, P = 0.001) and associated with icodextrin use (R = 0.52; 95% CI, 0.20-0.84), peritonitis count (R = 0.16; 95% CI, 0.03-0.29), and dialysate cytokines. miR-21 down-regulated programmed cell death 4 and programmed cell death 4 protein was decreased in peritoneal membrane biopsy specimens from PD patients compared to healthy controls. New miR-21 targets were identified that may be important during PD fibrogenesis. These data identify miR-21 as an important effector of fibrosis in the peritoneal membrane, and a promising biomarker in the dialysis effluent for membrane change in patients receiving PD.

Low-level arsenic causes chronic inflammation and suppresses expression of phagocytic receptors

The impact of chronic low-level groundwater arsenic (As) exposure [in the range above the WHO-recommended limit of 10 μg/L but ≤50 μg/L (permissible limit of As for many Asian countries)] was investigated for cross talk of inflammatory changes and expression of phagocytic receptors of exposed rural women (N, 45) from districts of 24 Parganas (south) and in matched control groups (N, 43) [As ≤10 μg/L] from the same district. Systemic inflammation was evident from the upregulated levels of pro-inflammatory mediators like tumor necrosis factor-α (TNF-α); interleukins (ILs) like IL-6, IL-8, and IL-12; and C-reactive protein (CRP) in the sera and upregulated expression of protein kinase B phosphorylated at ser473 (pAKTser473)/nuclear factor-κB (NF-κB)/TNF-α axis in the leukocytes of exposed women with respect to control. We found that low-dose As exposure apart from inflicting inflammation altered the expression of phagocytic receptors-Fcγ receptors (FcγRs) and complement receptors (CRs). The leukocytes of the low-As-exposed women exhibited suppression of CD64, CD35, and CD11b and increased expression of CD16 with respect to control. Groundwater As showed a negative correlation with CD64 expression on monocytes [Pearson's r, -0.8205; 95% confidence interval (CI), -0.8789 to -0.7379] and granulocytes [r, -0.7635; 95% CI, -0.8388 to -0.6595] and a positive correlation with CD16 on granulocytes [r, 0.8363; 95% CI, 0.7599 to 0.8899]. A negative correlation of groundwater As was also observed with expression of CD35 on granulocytes [r, -0.8780; 95% CI, -0.9185 to -0.8192] and monocytes [r, -0.7778; 95% CI, -0.8490 to -0.6790] and CD11b on monocytes [r, -0.6035; 95% CI, -0.7218 to -0.4511]. Therefore, it may be indicated that chronic low-level As exposure (11-50 μg/L) not only evoked chronic inflammatory changes but also suppressed the expression of FcγRs and CRs in the exposed women. This, in turn, may lead to susceptibility towards pathogenic infections or in long run may even contribute towards chronic inflammatory diseases including cancer.

Hepatitis B virus X protein increases microRNA‑21 expression and accelerates the development of hepatoma via the phosphatase and tensin homolog/phosphoinositide 3‑kinase/protein kinase B signaling pathway

Hepatitis B virus (HBV) X protein (HBx) is a key regulatory protein that is involved in HBV infection, replication and carcinogenesis of hepatocellular carcinoma (HCC). The aim of the present study was to investigate the role of HBx in the progression and metastasis of liver cancer cells and to determine the underlying molecular mechanism of HBx in metastatic liver cancer cells. HBx protein expression was detected by western blot analysis, and microRNA (miR)‑21 levels were determined by reverse transcription‑quantitative polymerase chain reaction in the highly metastatic MHCC‑97H low metastatic MHCC‑97L and SMMC‑7721 liver cancer cell lines. The results demonstrated that the levels of HBx and miR‑21 were significantly increased in MHCC‑97H cells compared with MHCC‑97L and SMMC‑7721 cells. In addition, three pairs of small interfering (si)RNA specific to HBx were designed and synthesized to interfere with endogenous HBx in liver cancer cells, and the results demonstrated that knockdown HBx was associated with a corresponding decrease in miR‑21 expression. The MTT assay results demonstrated that cell viability significantly decreased in HBx‑siRNA cells compared with scramble siRNA‑transfected cells. In addition, transfection with an miR‑21 inhibitor inhibited MHCC‑97H cell proliferation. Furthermore, Transwell assay results revealed that downregulation of HBx and treatment with miR‑21 inhibitors contributed to the inhibition of MHCC‑97H cell invasion and metastasis. Western blot analysis demonstrated that miR‑21 inhibitors and HBx‑siRNA treatment led to the upregulation of phosphatase and tensin homolog (PTEN), and decreased levels of phosphoinositide 3‑kinase (PI3K), phosphorylated protein kinase B (Akt) and matrix metalloproteinase (MMP)‑2. The results of the present study indicated that HBx was positively associated with miR‑21 expression, and downregulation of miR‑21 and HBx suppressed MMP‑2 activity via the PTEN/PI3K/Akt signaling pathway. Therefore, HBx and miR‑21 may represent novel therapeutic targets for the treatment of HCC.

MicroRNA expression profiles and networks in CXCL12‑stimulated human endometrial stromal cells

The chemokine stromal cell-derived factor-1 (C-X-C motif chemokine ligand 12; CXCL12) is important in the recruitment of leukocytes to the peritoneal cavity and the regulation of endometriotic tissue growth in endometriosis patients. However, the alterations in microRNA (miRNA) expression induced by CXCL12 remain to be fully elucidated. The present study evaluated key miRNAs in CXCL12‑stimulated endometrial stromal cells (ESCs), and investigated the underlying cellular regulatory mechanisms of CXCL12 in endometriosis by building networks between miRNAs, genes and gene ontologies (GOs). Differential expression of miRNAs and mRNAs induced by CXCL12 stimulation in ESCs was measured using miRNA and gene chips, and it was observed that 35 miRNAs and 1,671 mRNAs were differentially expressed. Using potential target genes of the 35 miRNAs, intersections of these genes were examined and 63 intersection genes were identified. A total of 39 GOs were obtained for these intersection genes, based on information from GO databases, including immune cell chemoattractants, inflammatory and immune responses, and pathological processes of endometriotic lesions in endometriosis. In addition, miRNA‑gene networks were built according to the GO and Kyoto Encyclopedia of Genes and Genomes databases. The present study, to the best of our knowledge, provides the most complete miRNAome and mRNAome profiles, and the most detailed investigation of the underlying cellular regulatory mechanisms, of the effects of CXCL12 in endometriosis. These results may facilitate the complete elucidation of the role of CXCL12 in endometriosis, and its underlying epigenetic mechanisms.

Induction of the mesenchymal to epithelial transition by demethylation-activated microRNA-125b is involved in the anti-migration/invasion effects of arsenic trioxide on human chondrosarcoma

Background

In addition to treating acute promyelocytic leukemia, arsenic trioxide (ATO) suppresses other solid tumors, including chondrosarcoma. However, the effects of ATO on metastasis in chondrosarcoma cells, and the underlying molecular mechanisms remain unclear.

Methods

The effects of ATO on the migratory and invasive capacities of chondrosarcoma cells were investigated by Wound healing, Transwell and EMT assays. The expression of miR-125b in human chondrosarcoma tissues and cell lines was detected by real-time PCR analysis. Bisulfite sequencing analysis (BSP) was used to detect the effects of ATO on the expression of miR-125b. The gain-of-function and loss-of-function experiments were performed on chondrosarcoma cell lines to investigate the effects of miR-125b on chondrosarcoma invasion, and to determine whether signal transducer and activator of transcription 3(Stat3) mediates these effects. Dual-luciferase reporter assay was used to identify whether Stat3 is a direct target of miR-125b.

Results

MiR-125b was significantly downregulated in human metastatic chondrosarcoma tissues and cell lines but not in non-metastatic chondrosarcoma tissues. ATO up-regulates the expression of miR-125b by the demethylation of DNA. ATO induces MET and attenuates the invasive capacities of chondrosarcoma cells through miR-125b. Stat3 was verified as a direct target of miR-125b, which is involved in ATO regulating EMT-associated traits.

Conclusions

These findings, for the first time, provides evidence that the miR-125b-mediated inhibition of Stat3 is involved in the ATO-induced attenuation of metastasis in chondrosarcoma cells.

Hexavalent chromium induces malignant transformation of human lung bronchial epithelial cells via ROS-dependent activation of miR-21-PDCD4 signaling

Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with an increased risk of lung cancer. However, the mechanisms underlying Cr(VI)-induced carcinogenesis remain unclear. MicroRNA-21 (miR-21) is a key regulator of oncogenic processes. Studies have shown that miR-21 exerts its oncogenic activity by targeting the tumor suppressor gene programmed cell death 4 (PDCD4). The present study examined the role of miR-21-PDCD4 signaling in Cr(VI)-induced cell transformation and tumorigenesis. Results showed that Cr(VI) induces ROS generation in human bronchial epithelial (BEAS-2B) cells. Chronic exposure to Cr(VI) is able to cause malignant transformation in BEAS-2B cells. Cr(VI) caused a significant increase of miR-21 expression associated with an inhibition of PDCD4 expression. Notably, STAT3 transcriptional activation by IL-6 is crucial for the Cr(VI)-induced miR-21 elevation. Stable knockdown of miR-21 or overexpression of PDCD4 in BEAS-2B cells significantly reduced the Cr(VI)-induced cell transformation. Furthermore, the Cr(VI) induced inhibition of PDCD4 suppressed downstream E-cadherin protein expression, but promoted β-catenin/TCF-dependent transcription of uPAR and c-Myc. We also found an increased miR-21 level and decreased PDCD4 expression in xenograft tumors generated with chronic Cr(VI)-exposed BEAS-2B cells. In addition, stable knockdown of miR-21 and overexpression of PDCD4 reduced the tumorogenicity of chronic Cr(VI)-exposed BEAS-2B cells in nude mice. Taken together, these results demonstrate that the miR-21-PDCD4 signaling axis plays an important role in Cr(VI)-induced carcinogenesis.

Oxymatrine attenuates CCl4-induced hepatic fibrosis via modulation of TLR4-dependent inflammatory and TGF-β1 signaling pathways

Oxymatrine (OMT) is able to effectively protect against hepatic fibrosis because of its anti-inflammatory property, while the underlying mechanism remains incompletely understood. In this study, forty rats were randomly divided into five groups: control group, model group (carbon tetrachloride, CCl4) and three OMT treatment groups (30, 60, 120mg/kg). After CCl4 alone, the fibrosis score was 20.2±0.8, and the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hydroxyproline content, and collagen I expression was elevated, but OMT blunted these parameters. Treatment with OMT prevented CCl4-induced increases in expression of pro-inflammatory and pro-fibrotic cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α, meanwhile OMT promoted the expression of anti-inflammatory and anti-fibrotic factors such as interleukin (IL)-10 and bone morphogenetic protein and activin membrane-bound inhibitor (Bambi). Moreover, lipopolysaccharides (LPS) and high mobility group box-1 (HMGB1), which activates Toll-like receptor 4 (TLR4) and modulate hepatic fibrogenesis through hepatic stellate cells (HSCs) or Kupffer cells, were significantly decreased by OMT treatment. These results were further supported by in vitro data. First, OMT suppressed the expression of TLR4 and its downstream pro-inflammatory cytokines, lowered the level of HMGB1, TGF-β1 in macrophages. Then, OMT promoted Bambi expression and thereby inhibited activation of HSCs mediated by transforming growth factor (TGF)-β1. In conclusion, this study showed that OMT could effectively attenuate the CCl4-induced hepatic fibrosis, and this effect may be due to modulation of TLR4-dependent inflammatory and TGF-β1 signaling pathways.

MicroRNA-21 activation of Akt via PTEN is involved in the epithelial-mesenchymal transition and malignant transformation of human keratinocytes induced by arsenite

MicroRNAs are involved in the epithelial-mesenchymal transition (EMT) and malignant transformation of cells. However, the molecular mechanisms remain unclear. In seeking new biomarkers of chemical exposure in the risk assessment of arsenite-induced skin cancer, the function of microRNA-21 (miR-21) in the regulation of serine/threonine kinase (Akt) activation was investigated. Akt suppresses phosphatase and tensin homolog (PTEN) and is involved in neoplastic and metastatic properties of arsenite-transformed human keratinocyte (T-HaCaT) cells. In HaCaT cells, arsenite caused an increase of miR-21 levels and a decrease of PTEN, which activated Akt signaling and induced the EMT. On inhibiting miR-21, the levels of PTEN were increased, and activation of Akt was blocked. Knock-down of PTEN by siRNA enhanced the activation of Akt. The effects of an miR-21 inhibitor on Akt activation were antagonized by PTEN siRNA. In T-HaCaT cells, blocking the activation of Akt by LY294002 inhibited the EMT. Moreover, the effects of an miR-21 mimic on the EMT and the neoplastic capacity, invasion, and metastasis of T-HaCaT cells were antagonized by LY294002. T-HaCaT transfected with PTEN plasmids showed decreased Akt activation and E-cadherin expression and increased vimentin levels. Thus, activation of Akt, controlled by miR-21/PTEN, is involved in the EMT, and thereby affects the neoplastic, invasion, and migratory capacities of T-HaCaT cells. The results point to the potential use of miR-21 as a biomarker for skin cancer and as a target for cancer prevention and treatment.

MicroRNA-21 activation of ERK signaling via PTEN is involved in arsenite-induced autophagy in human hepatic L-02 cells

Autophagy, an evolutionarily conserved cellular process, has diverse physiological and pathological roles in biological functions. Whether autophagy is induced by arsenite, a well-established human carcinogen, and the molecular mechanisms involved, remain to be established. Further, microRNAs (miRNAs) act as regulators in various cancers, but how miRNAs regulate autophagy remains largely unexplored. We have found that, in human hepatic epithelial (L-02) cells, arsenite increases levels of autophagy-related proteins in a concentration- and time-dependent manner and elevates the number of autophagic vacuoles (AVs). Arsenite also activates the ERK pathway in a dose- and time-dependent manner. In L-02 cells exposed to arsenite, microRNA-21 (miRNA-21) is over-expressed, and its target proteins, PTEN, PDCD4, and Spry1, are decreased. Moreover, inhibition of miR-21 increases levels of PTEN, and reduces levels of Beclin 1 and LC3 II/I, indicating that miR-21 is involved in arsenite-induced autophagy. In addition, ectopic expression of PTEN blocks the effect of miR-21 on the arsenite-induced autophagy and decreases p-ERK levels. Also, ERK promotes the autophagy induced by arsenite. In sum, upon exposure of cells to arsenite, over-expression of miR-21 activates ERK through PTEN, factors that participate in arsenite-induced autophagy. This link, mediated through miRNAs, establishes a mechanism for the development of autophagy that is associated with arsenic toxicity. Such information contributes to an understanding of the liver toxicity caused by arsenite.