Molecular basis of asbestos-induced lung disease

What rationale for treatment of occupational interstitial lung diseases with the drugs approved for idiopathic pulmonary fibrosis?

PURPOSE OF REVIEW

To critically discuss the rationale for the use of drugs approved for idiopathic pulmonary fibrosis (IPF) to treat occupational interstitial lung diseases (OILDs).

RECENT FINDINGS

Although IPF and OILDs share several clinical, radiological and probably pathogenetic features, currently, OILDs do not have a standard of care. In recent years, our knowledge and understanding of ILDs has improved substantially. Recently, the progressive pulmonary fibrosis (PPF) phenotype, which refers to non-IPF fibrotic ILDs that progress despite appropriate treatment, has been defined. OILDs may also be progressive. Nintedanib, initially approved for treatment of IPF, is also approved in patients with PPF. On the other hand, pirfenidone is approved in IPF but not in PPF, due to the lack of robust evidence of efficacy in this patient subset.

SUMMARY

OILDs are a large and highly heterogeneous group of conditions without a proper standard of care. Nintedanib may slow functional decline and disease progression in progressive OILDs, and new clinical trials are ongoing.

Assessing potentially toxic elements (PTEs) content in asbestos and related groundwater: A review of the levels detected

This article provides a review of published literature on the concentration levels of potentially toxic elements (PTEs) in asbestos minerals like chrysotile, actinolite, amosite (asbestiform grunerite), anthophyllite, crocidolite (asbestiform riebeckite) and tremolite and their potential to release PTEs into groundwaters worldwide. A large number of PTEs, such as Fe, Cr, Ni, Mn, Co and Zn, may be hosted by asbestos minerals, and their release in the lung environment can cause different health problems as well as their intake via drinking water. The review highlights that amosite is the phase with the highest PTEs content, followed by crocidolite, actinolite, anthophyllite, tremolite and chrysotile. Chrysotile, tremolite, and anthophyllite contain higher levels of Cr, Ni, and Co, while Fe and Mn are more enriched in amosite and crocidolite. Actinolite contains a high concentration of all considered PTEs. High levels of Cr, Fe, Zn, Mn, and Ni were also detected in groundwater interacting with ophiolite rocks containing asbestos minerals. The three main recognized hydro-geochemical facies (Mg-HCO3, Ca-HCO3 and Ca-OH), characterizing the ophiolite aquifers, show high levels of Cr and Ni, with values sometimes above the World health Organization (WHO) thresholds for drinking waters, which can cause adverse health effects in short and long term. The knowledge emerging from this work is a significant contribution to the already wide frame of understanding asbestos-related diseases and provide a strong scientific basis for further mineralogical and geochemical studies.

Severe and post-COVID-19 are associated with high expression of vimentin and reduced expression of N-cadherin

SARS-CoV-2 penetrates human cells via its spike protein, which mainly interacts with ACE2 receptors, triggering viral replication and an exacerbated immune response characterized by a cytokine storm. Vimentin III, an intermediate filament protein predominantly found in mesenchymal cells, has garnered considerable attention in recent research due to its multifaceted biological roles and significance in the endothelial-mesenchymal transition (EndMT) during various fibrotic processes. However, the pathophysiological mechanisms linking vimentin to SARS-CoV-2 remain incompletely elucidated. In this study, we determined the expression profiles of vimentin in three cohorts: patients admitted to the intensive care unit with SARS-CoV-2 infection, individuals in the 6-12 month convalescent phase post-infection and COVID-19 negative controls. Our objective was to assess the association between peripheral blood biomarkers implicated in endothelial dysfunction and genes related to fibrosis. Serum levels of vimentin and N-cadherin were determined by ELISA, while vimentin gene expression was determined by qRT-PCR. In addition, we examined the correlation between clinical parameters and serum levels of vimentin and N-cadherin in severe COVID-19 patients and healthy counterparts. Our findings revealed elevated serum vimentin levels and increased gene expression in severe COVID-19 patients compared to healthy controls. Conversely, serum N-cadherin levels were diminished in both acute and convalescent stages of severe COVID-19 relative to healthy individuals. Notably, associations were observed between C-reactive protein, lactate dehydrogenase, lymphocyte count and vimentin levels in severe COVID-19 patients, indicative of endothelial dysfunction. Furthermore, our study identified vimentin and N-cadherin as potential diagnostic markers via ROC analysis. Overall, delineating the dysregulation of vimentin and N-cadherin due to SARS-CoV-2 infection in disease pathogenesis and tissue homeostasis offers novel insights for clinical management and targeted therapeutic interventions.

DNA damage-inducing endogenous and exogenous factors and research progress

The substances that cause abnormal DNA structures are known as DNA damage-inducing factors, and their resulting DNA damage has been extensively studied and proven to be closely related to cancer, neurodegenerative diseases, and aging. Prolonged exposure to DNA damage-inducing factors can lead to a variety of difficult-to-treat diseases, yet these factors have not been well summarized. It is crucial to use a combination of environmental science and life science to gain a deep understanding of the environmental sources and biological consequences of DNA damage-inducing factors for mechanistic research and prevention of diseases such as cancer. This article selected 14 representative carcinogenic exogenous DNA damage-inducing factors and summarized them through a literature search, including both exogenous and endogenous DNA damage factors, and explored the types of DNA damage caused by the relevant damage factors.

OGG1: An emerging multifunctional therapeutic target for the treatment of diseases caused by oxidative DNA damage

Oxidative DNA damage-related diseases, such as incurable inflammation, malignant tumors, and age-related disorders, present significant challenges in modern medicine due to their complex molecular mechanisms and limitations in identifying effective treatment targets. Recently, 8-oxoguanine DNA glycosylase 1 (OGG1) has emerged as a promising multifunctional therapeutic target for the treatment of these challenging diseases. In this review, we systematically summarize the multiple functions and mechanisms of OGG1, including pro-inflammatory, tumorigenic, and aging regulatory mechanisms. We also highlight the potential of OGG1 inhibitors and activators as potent therapeutic agents for the aforementioned life-limiting diseases. We conclude that OGG1 serves as a multifunctional hub; the inhibition of OGG1 may provide a novel approach for preventing and treating inflammation and cancer, and the activation of OGG1 could be a strategy for preventing age-related disorders. Furthermore, we provide an extensive overview of successful applications of OGG1 regulation in treating inflammatory, cancerous, and aging-related diseases. Finally, we discuss the current challenges and future directions of OGG1 as an emerging multifunctional therapeutic marker for the aforementioned challenging diseases. The aim of this review is to provide a robust reference for scientific researchers and clinical drug developers in the development of novel clinical targeted drugs for life-limiting diseases, especially for incurable inflammation, malignant tumors, and age-related disorders.

Ferritin adsorption onto chrysotile asbestos fibers influences the protein secondary structure

Asbestos fiber exposure triggers chronic inflammation and cancer. Asbestos fibers can adsorb different types of proteins. The mechanism of this adsorption, not yet completely understood, has been studied in detail mainly with serum albumin and was shown to induce structural changes in the bound protein. The findings of these works regarded mainly the changes of the protein structure, independently of any relation with asbestos-related diseases. For the first time, we have focused our attention to the consequences of the interaction between asbestos fibers and ferritin, a protein involved in iron metabolism, which is strongly modified in asbestos-related diseases. Even if it is known that ferritin can be adsorbed by asbestos fibers, the results of this interaction for the ferritin secondary structure has not previously been studied. One consequence of asbestos-ferritin interaction, is the formation of the so-called ferruginous/asbestos bodies (ABs). In the AB-coating material, the secondary structure of ferritin is modified, and at present, it is unclear whether or not this modification is a direct consequence of the asbestos interaction. In the present study, chrysotile asbestos, more than other asbestos fiber types tested, was found to rapidly bind holo-ferritin, and the presence of iron seemed to play a key role in this process, since iron-free apo-ferritin was adsorbed at a lower level, and iron-saturated chrysotile lost its ferritin-adsorbing capacity. To directly study the details of ferritin adsorption on asbestos fibers, High Resolution Transmission Electron Microscopy (HR-TEM) was employed together with FTIR microspectroscopy and Infrared nanoscopy, which to the best of our knowledge, have not previously been used for this purpose. Chrysotile-bound apo-ferritin underwent a significant change in secondary structure, showing a shift from a prevalent α-helix to a β-sheet conformation. Conversely, the adsorbed holo-ferritin structure appeared to be only weakly modified. These findings add a new potential mechanism to the toxic activities of asbestos: the fibers can modify the structure, and very likely, the function of adsorbed proteins. This, in relation to ferritin, could be a key mechanism in cell iron homeostasis alteration, typically reported in asbestos-related diseases.

Synthetic silica fibers of different length, diameter and shape: synthesis and interaction with rat (NR8383) and human (THP-1) macrophages in vitro, including chemotaxis and gene expression profile

BACKGROUND

Inhalation of biopersistent fibers like asbestos can cause strong chronic inflammatory effects, often resulting in fibrosis or even cancer. The interplay between fiber shape, fiber size and the resulting biological effects is still poorly understood due to the lack of reference materials.

RESULTS

We investigated how length, diameter, aspect ratio, and shape of synthetic silica fibers influence inflammatory effects at doses up to 250 µg cm-2. Silica nanofibers were prepared with different diameter and shape. Straight (length ca. 6 to 8 µm, thickness ca. 0.25 to 0.35 µm, aspect ratio ca. 17:1 to 32:1) and curly fibers (length ca. 9 µm, thickness ca. 0.13 µm, radius of curvature ca. 0.5 µm, aspect ratio ca. 70:1) were dispersed in water with no apparent change in the fiber shape during up to 28 days. Upon immersion in aqueous saline (DPBS), the fibers released about 5 wt% silica after 7 days irrespectively of their shape. The uptake of the fibers by macrophages (human THP-1 and rat NR8383) was studied by scanning electron microscopy and confocal laser scanning microscopy. Some fibers were completely taken up whereas others were only partially internalized, leading to visual damage of the cell wall. The biological effects were assessed by determining cell toxicity, particle-induced chemotaxis, and the induction of gene expression of inflammatory mediators.

CONCLUSIONS

Straight fibers were only slightly cytotoxic and caused weak cell migration, regardless of their thickness, while the curly fibers were more toxic and caused significantly stronger chemotaxis. Curly fibers also had the strongest effect on the expression of cytokines and chemokines. This may be due to the different aspect ratio or its twisted shape.

Artificial Intelligence-based Quantification of Pleural Plaque Volume and Association With Lung Function in Asbestos-exposed Patients

PURPOSE

Pleural plaques (PPs) are morphologic manifestations of long-term asbestos exposure. The relationship between PP and lung function is not well understood, whereas the time-consuming nature of PP delineation to obtain volume impedes research. To automate the laborious task of delineation, we aimed to develop automatic artificial intelligence (AI)-driven segmentation of PP. Moreover, we aimed to explore the relationship between pleural plaque volume (PPV) and pulmonary function tests.

MATERIALS AND METHODS

Radiologists manually delineated PPs retrospectively in computed tomography (CT) images of patients with occupational exposure to asbestos (May 2014 to November 2019). We trained an AI model with a no-new-UNet architecture. The Dice Similarity Coefficient quantified the overlap between AI and radiologists. The Spearman correlation coefficient ( r ) was used for the correlation between PPV and pulmonary function test metrics. When recorded, these were vital capacity (VC), forced vital capacity (FVC), and diffusing capacity for carbon monoxide (DLCO).

RESULTS

We trained the AI system on 422 CT scans in 5 folds, each time with a different fold (n = 84 to 85) as a test set. On these independent test sets combined, the correlation between the predicted volumes and the ground truth was r = 0.90, and the median overlap was 0.71 Dice Similarity Coefficient. We found weak to moderate correlations with PPV for VC (n = 80, r = -0.40) and FVC (n = 82, r = -0.38), but no correlation for DLCO (n = 84, r = -0.09). When the cohort was split on the median PPV, we observed statistically significantly lower VC ( P = 0.001) and FVC ( P = 0.04) values for the higher PPV patients, but not for DLCO ( P = 0.19).

CONCLUSION

We successfully developed an AI algorithm to automatically segment PP in CT images to enable fast volume extraction. Moreover, we have observed that PPV is associated with loss in VC and FVC.

Adjuvant Novel Nanocarrier-Based Targeted Therapy for Lung Cancer

Lung cancer has the lowest survival rate due to its late-stage diagnosis, poor prognosis, and intra-tumoral heterogeneity. These factors decrease the effectiveness of treatment. They release chemokines and cytokines from the tumor microenvironment (TME). To improve the effectiveness of treatment, researchers emphasize personalized adjuvant therapies along with conventional ones. Targeted chemotherapeutic drug delivery systems and specific pathway-blocking agents using nanocarriers are a few of them. This study explored the nanocarrier roles and strategies to improve the treatment profile's effectiveness by striving for TME. A biofunctionalized nanocarrier stimulates biosystem interaction, cellular uptake, immune system escape, and vascular changes for penetration into the TME. Inorganic metal compounds scavenge reactive oxygen species (ROS) through their photothermal effect. Stroma, hypoxia, pH, and immunity-modulating agents conjugated or modified nanocarriers co-administered with pathway-blocking or condition-modulating agents can regulate extracellular matrix (ECM), Cancer-associated fibroblasts (CAF),Tyro3, Axl, and Mertk receptors (TAM) regulation, regulatory T-cell (Treg) inhibition, and myeloid-derived suppressor cells (MDSC) inhibition. Again, biomimetic conjugation or the surface modification of nanocarriers using ligands can enhance active targeting efficacy by bypassing the TME. A carrier system with biofunctionalized inorganic metal compounds and organic compound complex-loaded drugs is convenient for NSCLC-targeted therapy.

Occupational respiratory disorders in Iran: a review of prevalence and inducers

The link between occupational respiratory diseases (ORD) and exposure to harmful factors that are present in the workplace has been well shown. Factors such as physical activity, age and duration of occupational exposure playing important roles in ORD severity, should be identified in the workplace, their effects on workers health should be studied, and ultimately, exposure to them must be minimized. We carried out a literature review by searching PubMed, Scopus, and Web of Science databases to retrieve studies published from 1999 until the end of April 2023 reporting the prevalence and inducers of ORD in Iran. In Iranian workers, several ORD such as interstitial lung disease, silicosis, occupational asthma, pulmonary inflammatory diseases, chronic obstructive pulmonary diseases, and lung cancers have been reported. It was indicated that ORD mainly occur due to repeated and prolonged exposure to noxious agents in the workplace. We also extracted the prevalence of ORD in different regions of Iran from the retrieved reports. Based on our literature review, the prevalence of ORD among Iranian workers highlights the importance of regular assessment of the risk of exposure to noxious agents in the workplace to develop measures for preventing potential adverse effects.

Environmental Causes of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF), the most common and severe of the idiopathic interstitial pneumonias, is a chronic and relentlessly progressive disease, which occurs mostly in middle-aged and elderly males. Although IPF is by definition "idiopathic", multiple factors have been reported to increase disease risk, aging being the most prominent one. Several occupational and environmental exposures, including metal dust, wood dust and air pollution, as well as various lifestyle variables, including smoking and diet, have also been associated with an increased risk of IPF, probably through interaction with genetic factors. Many of the predisposing factors appear to act also as trigger for acute exacerbations of the disease, which herald a poor prognosis. The more recent literature on inhalation injuries has focused on the first responders in the World Trade Center attacks and military exposure. In this review, we present an overview of the environmental and occupational causes of IPF and its pathogenesis. While our list is not comprehensive, we have selected specific exposures to highlight based on their overall disease burden.

Dissolution Reaction and Surface Modification of UICC Amosite in Mimicked Gamble's Solution: A Step towards Filling the Gap between Asbestos Toxicity and Its Crystal Chemical Features

This study focuses on the dissolution process and surface characterization of amosite fibres following interaction with a mimicked Gamble's solution at a pH of 4.5 and T = 37 °C, up to 720 h. To achieve this, a multi-analytical approach was adopted, and the results were compared to those previously obtained on a sample of asbestos tremolite and UICC crocidolite, which were investigated under the same experimental conditions. Combining surface chemical data obtained by XPS with cation release quantified by ICP-OES, an incongruent behaviour of the fibre dissolution was highlighted for amosite fibres, similarly to asbestos tremolite and UICC crocidolite. In particular, a preferential release of Mg and Ca from the amphibole structure was observed, in agreement with their Madelung site energies. Notably, no Fe release from amosite fibres was detected in our experimental conditions (pH of 4.5 and atmospheric pO2), despite the occurrence of Fe(II) at the M(4) site of the amphibole structure, where cations are expected to be rapidly leached out during mineral dissolution. Moreover, the oxidation of both the Fe centres initially present on the fibre surface and those promoted from the bulk, because of the erosion of the outmost layers, was observed. Since biodurability (i.e., the resistance to dissolution) is one of the most important toxicity parameters, the knowledge of the surface alteration of asbestos possibly occurring in vivo may help to understand the mechanisms at the basis of its long-term toxicity.

Asbestos exposure and small cell lung cancer: Systematic review and meta-analysis

Asbestos is a mineral that is carcinogenic to humans. Its use has been banned in many occidental countries yet it is still produced in the United States, and materials that contain asbestos remain in many occupational settings and indoor environments. Even though asbestos carcinogenicity is well known, there is scant literature on its specific effects regarding small cell lung cancer (SCLC). We therefore conducted a systematic review and meta-analysis to determine SCLC risk among workers exposed to asbestos. A systematic search of the literature was conducted to identify studies which reported occupational exposure to asbestos and SCLC-related deaths and/or incidence. We identified seven case-control studies that included 3,231 SCLC cases; four studies reported smoking-adjusted risks. A significantly increased risk of SCLC (pooled OR 1.89; 95% CI, 1.25-2.86) was observed on pooling studies on men (six studies) that displayed moderate heterogeneity (I2 = 46.0%). Overall, our synthesis suggests that occupational exposure to asbestos significantly increases the risk of SCLC on men.

HMGB1 released by mesothelial cells drives the development of asbestos-induced mesothelioma

Asbestos is the main cause of malignant mesothelioma. Previous studies have linked asbestos-induced mesothelioma to the release of HMGB1 from the nucleus to the cytoplasm, and from the cytoplasm to the extracellular space. In the cytoplasm, HMGB1 induces autophagy impairing asbestos-induced cell death. Extracellularly, HMGB1 stimulates the secretion of TNFα. Jointly, these two cytokines kick-start a chronic inflammatory process that over time promotes mesothelioma development. Whether the main source of extracellular HMGB1 were the mesothelial cells, the inflammatory cells, or both was unsolved. This information is critical to identify the targets and design preventive/therapeutic strategies to interfere with asbestos-induced mesothelioma. To address this issue, we developed the conditional mesothelial HMGB1-knockout (Hmgb1ΔpMeso) and the conditional myelomonocytic-lineage HMGB1-knockout (Hmgb1ΔMylc) mouse models. We establish here that HMGB1 is mainly produced and released by the mesothelial cells during the early phases of inflammation following asbestos exposure. The release of HMGB1 from mesothelial cells leads to atypical mesothelial hyperplasia, and in some animals, this evolves over the years into mesothelioma. We found that Hmgb1ΔpMeso, whose mesothelial cells cannot produce HMGB1, show a greatly reduced inflammatory response to asbestos, and their mesothelial cells express and secrete significantly reduced levels of TNFα. Moreover, the tissue microenvironment in areas of asbestos deposits displays an increased fraction of M1-polarized macrophages compared to M2 macrophages. Supporting the biological significance of these findings, Hmgb1ΔpMeso mice showed a delayed and reduced incidence of mesothelioma and an increased mesothelioma-specific survival. Altogether, our study provides a biological explanation for HMGB1 as a driver of asbestos-induced mesothelioma.

Vaping, Environmental Toxicants Exposure, and Lung Cancer Risk

Lung cancer (LC) is the second-most prevalent tumor worldwide. According to the most recent GLOBOCAN data, over 2.2 million LC cases were reported in 2020, with an estimated new death incident of 1,796,144 lung cancer cases. Genetic, lifestyle, and environmental exposure play an important role as risk factors for LC. E-cigarette, or vaping, products (EVPs) use has been dramatically increasing world-wide. There is growing concern that EVPs consumption may increase the risk of LC because EVPs contain several proven carcinogenic compounds. However, the relationship between EVPs and LC is not well established. E-cigarette contains nicotine derivatives (e.g., nitrosnornicotine, nitrosamine ketone), heavy metals (including organometal compounds), polycyclic aromatic hydrocarbons, and flavorings (aldehydes and complex organics). Several environmental toxicants have been proven to contribute to LC. Proven and plausible environmental carcinogens could be physical (ionizing and non-ionizing radiation), chemicals (such as asbestos, formaldehyde, and dioxins), and heavy metals (such as cobalt, arsenic, cadmium, chromium, and nickel). Air pollution, especially particulate matter (PM) emitted from vehicles and industrial exhausts, is linked with LC. Although extensive environmental exposure prevention policies and smoking reduction strategies have been adopted globally, the dangers remain. Combined, both EVPs and toxic environmental exposures may demonstrate significant synergistic oncogenicity. This review aims to analyze the current publications on the importance of the relationship between EVPs consumption and environmental toxicants in the pathogenesis of LC.

Oxidative Stress and Lung Fibrosis: Towards an Adverse Outcome Pathway

Lung fibrosis is a progressive fatal disease in which deregulated wound healing of lung epithelial cells drives progressive fibrotic changes. Persistent lung injury due to oxidative stress and chronic inflammation are central features of lung fibrosis. Chronic cigarette smoking causes oxidative stress and is a major risk factor for lung fibrosis. The objective of this manuscript is to develop an adverse outcome pathway (AOP) that serves as a framework for investigation of the mechanisms of lung fibrosis due to lung injury caused by inhaled toxicants, including cigarette smoke. Based on the weight of evidence, oxidative stress is proposed as a molecular initiating event (MIE) which leads to increased secretion of proinflammatory and profibrotic mediators (key event 1 (KE1)). At the cellular level, these proinflammatory signals induce the recruitment of inflammatory cells (KE2), which in turn, increase fibroblast proliferation and myofibroblast differentiation (KE3). At the tissue level, an increase in extracellular matrix deposition (KE4) subsequently culminates in lung fibrosis, the adverse outcome. We have also defined a new KE relationship between the MIE and KE3. This AOP provides a mechanistic platform to understand and evaluate how persistent oxidative stress from lung injury may develop into lung fibrosis.

Cytotoxicity of fibrous antigorite from New Caledonia

Exposure to asbestos and asbestos-like minerals has been related to the development of severe lung diseases, including cancer and malignant mesothelioma (MM). A high incidence of non-occupational MM was observed in New Caledonia (France) in people living in proximity of serpentinite outcrops, containing chrysotile and fibrous antigorite. Antigorite is a magnesium silicate, which shares with chrysotile asbestos the chemical formula. To achieve information on antigorite toxicity, we investigated the physico-minero-chemical features relevant for toxicity and cellular effects elicited on murine macrophages (MH-S) and alveolar epithelial cells (A549) of three fibrous antigorites (f-Atg) collected in a Caledonian nickel lateritic ore and subjected to supergene alteration. Field Atg were milled to obtain samples suitable for toxicological studies with a similar particle size distribution. UICC chrysotile (Ctl) and a non-fibrous antigorite (nf-Atg) were used as reference minerals. A high variability in toxicity was observed depending on shape, chemical alteration, and surface reactivity. The antigorites shared with Ctl a similar surface area (16.3, 12.1, 20.3, 13.4, and 15.6 m²/g for f-Atg1, 2, 3, nf-Atg, and Ctl). f-Atg showed different level of pedogenetic weathering (Ni depletion f-Atg1 ≪ f-Atg2 and 3) and contained about 50% of elongated mineral particles, some of which exhibited high aspect ratios (AR > 10 μm, 20%, 26%, 31% for f-Atg1, 2, and 3, respectively). The minerals differed in bio-accessible iron at pH 4.5 (f-Atg1 ≪ f-Atg3, < f-Atg2, nf-Atg < Ctl), and surface reactivity (ROS release in solution, f-Atg1 ≪ f-Atg2, 3, nf-Atg, and Ctl). f-Atg2 and f-Atg3 induced oxidative stress and pro-inflammatory responses, while the less altered, poorly reactive sample (f-Atg1) induced negligible effects, as well nf-Atg. The slow dissolution kinetics observed in simulated body fluids may signal a high biopersistence. Overall, our work revealed a significative cellular toxicity of f-Atg that correlates with fibrous habit and surface reactivity.

Stromal inflammation, fibrosis and cancer: An old intuition with promising potential

It is now well established that the biology of cancer is influenced by not only malignant cells but also other components of the tumour microenvironment. Chronic inflammation and fibrosis have long been postulated to be involved in carcinogenesis. Chronic inflammation can promote tumorigenesis via growth factor/cytokine-mediated cellular proliferation, apoptotic resistance, immunosuppression; and free-radical-induced oxidative deoxyribonucleic acid damage. Fibrosis could cause a perturbation in the dynamics of the tumour microenvironment, potentially damaging the genome surveillance machinery of normal epithelial cells. In this review, we will provide an in-depth discussion of various diseases characterised by inflammation and fibrosis that have been associated with an increased risk of malignancy. In particular, we will present a comprehensive overview of the impact of alterations in stromal composition on tumorigenesis, induced as a consequence of inflammation and/or fibrosis. Strategies including the application of various therapeutic agents with stromal manipulation potential and targeted cancer screening for certain inflammatory diseases which can reduce the risk of cancer will also be discussed.

What role for asbestos in idiopathic pulmonary fibrosis? Findings from the IPF job exposures case-control study

BACKGROUND

Asbestos has been hypothesised as the cause of the recent global increase in the incidence of 'idiopathic' pulmonary fibrosis (IPF). Establishing this has important diagnostic and therapeutic implications. The association between occupational asbestos exposure and IPF, and interaction with a common (minor allele frequency of 9% in European populations) genetic variant associated with IPF, MUC5B rs35705950, is unknown.

METHODS

Multicentre, incident case-control study. Cases (n=494) were men diagnosed with IPF at 21 UK hospitals. Controls (n=466) were age-matched men who attended a hospital clinic in the same period. Asbestos exposure was assessed at interview using a validated job exposure matrix and a source-receptor model. The primary outcome was the association between asbestos exposure and IPF, estimated using logistic regression adjusted for age, smoking and centre. Interaction with MUC5B rs35705950 was investigated using a genetic dominant model.

RESULTS

327 (66%) cases and 293 (63%) controls ever had a high or medium asbestos exposure risk job; 8% of both cases and controls had cumulative exposure estimates ≥25 fibre ml⁻¹ years. Occupational asbestos exposure was not associated with IPF, adjusted OR 1.1 (95% CI 0.8 to 1.4; p=0.6) and there was no gene-environment interaction (p=0.3). Ever smoking was associated with IPF, OR 1.4 (95% CI 1 to 1.9; p=0.04) and interacted with occupational asbestos exposure, OR 1.9 (95% CI 1 to 3.6; p=0.04). In a further non-specified analysis, when stratifying for genotype there was significant interaction between smoking and work in an exposed job (p<0.01) for carriers of the minor allele of MUC5B rs35705950.

CONCLUSION

Occupational asbestos exposure alone, or through interaction with MUC5B rs35705950 genotype, was not associated with IPF. Exposure to asbestos and smoking interact to increase IPF risk in carriers of a common genetic variant, the minor allele of MUC5B rs35705950.

TRIAL REGISTRATION NUMBER

NCT03211507.

Asbestos Fibers Enhance the TMEM16A Channel Activity in Xenopus Oocytes

BACKGROUND

The interaction of asbestos fibers with target cell membranes is still poorly investigated. Here, we detected and characterized an enhancement of chloride conductance in Xenopus oocyte cell membranes induced by exposure to crocidolite (Croc) asbestos fibers.

METHODS

A two-microelectrode voltage clamp technique was used to test the effect of Croc fiber suspensions on outward chloride currents evoked by step membrane depolarization. Calcium imaging experiments were also performed to investigate the variation of 'resting' oocyte [Ca2+]i following asbestos exposure.

RESULTS

The increase in chloride current after asbestos treatment, was sensitive to [Ca2+]e, and to specific blockers of TMEM16A Ca2+-activated chloride channels, MONNA and Ani9. Furthermore, asbestos treatment elevated the 'resting' [Ca2+]i likelihood by increasing the cell membrane permeability to Ca2 in favor of a tonic activation of TMEME16A channels. Western blot analysis confirmed that TMEME16A protein was endogenously present in the oocyte cell membrane and absorbed by Croc.

CONCLUSION

the TMEM16A channels endogenously expressed by Xenopus oocytes are targets for asbestos fibers and represent a powerful tool for asbestos-membrane interaction studies. Interestingly, TMEM16A channels are highly expressed in many types of tumors, including some asbestos-related cancers, suggesting them, for the first time, as a possible early target of crocidolite-mediated tumorigenic effects on target cell membranes.

Asbestos fibers promote iron oxidation and compete with apoferritin enzymatic activity

Asbestos fibers interact with many different proteins and may affect either their structure or functions. The aim of this study was to determine whether ferritin absorbed onto fibers might modify its ferroxidase activity. By measuring apo-ferritin ferroxidase activity, data demonstrated that ferritin in the presence of fibers did not significantly modify this enzymatic activity. However, fibers in the absence of ferritin promoted ferrous iron oxidation. Evidence suggests that asbestos fibers may promote iron oxidation and subsequently affect cellular iron homeostatic mechanisms.

Identification of Highly Sensitive Pleural Effusion Protein Biomarkers for Malignant Pleural Mesothelioma by Affinity-Based Quantitative Proteomics

Malignant pleural mesothelioma (MPM) is an asbestos-associated, highly aggressive cancer characterized by late-stage diagnosis and poor prognosis. Gold standards for diagnosis are pleural biopsy and cytology of pleural effusion (PE), both of which are limited by low sensitivity and markedly inter-observer variations. Therefore, the assessment of PE biomarkers is considered a viable and objective diagnostic tool for MPM diagnosis. We applied a novel affinity-enrichment mass spectrometry-based proteomics method for explorative analysis of pleural effusions from a prospective cohort of 84 patients referred for thoracoscopy due to clinical suspicion of MPM. Protein biomarkers with a high capability to discriminate MPM from non-MPM patients were identified, and a Random Forest algorithm was applied for building classification models. Immunohistology of pleural biopsies confirmed MPM in 40 patients and ruled out MPM in 44 patients. Proteomic analysis of pleural effusions identified panels of proteins with excellent diagnostic properties (90-100% sensitivities, 89-98% specificities, and AUC 0.97-0.99) depending on the specific protein combination. Diagnostic proteins associated with cancer growth included galactin-3 binding protein, testican-2, haptoglobin, Beta ig-h3, and protein AMBP. Moreover, we also confirmed previously reported diagnostic accuracies of the MPM markers fibulin-3 and mesothelin measured by two complementary mass spectrometry-based methods. In conclusion, a novel affinity-enrichment mass spectrometry-based proteomics identified panels of proteins in pleural effusion with extraordinary diagnostic accuracies, which are described here for the first time as biomarkers for MPM.

The Role of DNA Damage and Repair in Idiopathic Pulmonary Fibrosis

The mortality rate of idiopathic pulmonary fibrosis (IPF) increases yearly due to ineffective treatment. Given that the lung is exposed to the external environment, it is likely that oxidative stress, especially the stimulation of DNA, would be of particular importance in pulmonary fibrosis. DNA damage is known to play an important role in idiopathic pulmonary fibrosis initiation, so DNA repair systems targeting damage are also crucial for the survival of lung cells. Although many contemporary reports have summarized the role of individual DNA damage and repair pathways in their hypotheses, they have not focused on idiopathic pulmonary fibrosis. This review, therefore, aims to provide a concise overview for researchers to understand the pathways of DNA damage and repair and their roles in IPF.

Primary Peritoneal Mesothelioma: Diagnostic Challenges of This Lethal Imposter

Primary Peritoneal Mesothelioma is a rapidly aggressive and rare neoplasm that arises from the lining of mesothelial cells of the peritoneum and spreads extensively within the confines of the abdominal cavity. The pathogenesis of all forms of mesothelioma is strongly associated with industrial pollutants, of which asbestos is the principal carcinogen. Characteristically, asbestos exposure has a strong relationship with mesothelioma of the pleura, but the peritoneal cavity is the second most commonly affected site. Additionally, in contrast to pleural mesothelioma, which has a male predominance (male-female ratio of between four and five to one), women comprise approximately one-half of all cases of malignant peritoneal mesothelioma. A thorough history of occupational/paraoccupational exposure along with histopathology is the key to timely diagnosis and treatment.

Lipidomics Profiles and Lipid Metabolite Biomarkers in Serum of Coal Workers' Pneumoconiosis

As a serious occupational pulmonary fibrosis disease, pneumoconiosis still lacks effective biomarkers. Previous studies suggest that pneumoconiosis may affect the body's lipid metabolism. The purpose of this study was to explore lipidomics profiles and lipid metabolite biomarkers in the serum of coal workers' pneumoconiosis (CWP) by a population case-control study. A total of 150 CWP cases and 120 healthy controls from Beijing, China were included. Blood lipids were detected in serum biochemistry. Lipidomics was performed in serum samples for high-throughput detection of lipophilic metabolites. Serum high density lipoprotein cholesterol (HDL-C) decreased significantly in CWP cases. Lipidomics data found 131 differential lipid metabolites between the CWP case and control groups. Further, the top eight most important differential lipid metabolites were screened. They all belonged to differential metabolites of CWP at different stages. However, adjusting for potential confounding factors, only three of them were significantly related to CWP, including acylhexosylceramide (AHEXCER 43:5), diacylglycerol (DG 34:8) and dimethyl-phosphatidylethanolamine (DMPE 36:0|DMPE 18:0_18:0), of which good sensitivity and specificity were proven. The present study demonstrated that lipidomics profiles could change significantly in the serum of CWP patients and that the lipid metabolites represented by AHEXCER, DG and DMPE may be good biomarkers of CWP.

Serum vimentin predicts mortality in pediatric severe sepsis: A prospective observational study

OBJECTIVES

Vascular hyperpermeability by loss of endothelial barrier integrity is a hallmark of sepsis. Vimentin is involved in the regulation of the endothelial function and inflammatory response. However, the serum level of vimentin and its clinical relevance in pediatric severe sepsis (PSS) remain unknown.

METHODS

We conducted a prospective study of PSS cases who were admitted to the pediatric intensive care unit (PICU) from January 2018 to December 2020.

RESULTS

A total of 108 patients with PSS with a median age of 19.5 month were enrolled. The hospital mortality rate was 19.44% (21/108). Comparing with healthy controls, serum vimentin levels on PICU admission were significantly higher in patients with PSS (P < 0.001). The area under the ROC curve for vimentin to predict the hospital mortality was 0.712 (95% CI: 0.578-846) with a sensitivity of 71.43% and a specificity of 70.11%. Moreover, hospital mortality was significantly higher in patients with vimentin level over the cutoff value of 24.53 ng/ml than in patients with vimentin level below 24.53 ng/ml (P < 0.001).

CONCLUSIONS

Serum vimentin level as an indicator of endothelial injury is associated with the prognosis of PSS, and serum vimentin level ≥24.53 ng/ml on PICU admission predicts high risk for hospital mortality in PSS.

Nanoscale transformations of amphiboles within human alveolar epithelial cells

Amphibole asbestos is related to lung fibrosis and several types of lung tumors. The disease-triggering mechanisms still challenge our diagnostic capabilities and are still far from being fully understood. The literature focuses primarily on the role and formation of asbestos bodies in lung tissues, but there is a distinct lack of studies on amphibole particles that have been internalized by alveolar epithelial cells (AECs). These internalized particles may directly interact with the cell nucleus and the organelles, exerting a synergistic action with asbestos bodies (AB) from a different location. Here we document the near-atomic- to nano-scale transformations induced by, and taking place within, AECs of three distinct amphiboles (anthophyllite, grunerite, "amosite") with different Fe-content and morphologic features. We show that: (i) an Fe-rich layer is formed on the internalized particles, (ii) particle grain boundaries are transformed abiotically by the internal chemical environment of AECs and/or by a biologically induced mineralization mechanism, (iii) the Fe-rich material produced on the particle surface does not contain large amounts of P, in stark contrast to extracellular ABs, and (iv) the iron in the Fe-rich layer is derived from the particle itself. Internalized particles and ABs follow two distinct formation mechanisms reaching different physicochemical end-states.

The Significance of Short Latency in Mesothelioma for Attribution of Causation: Report of a Case with Predisposing Germline Mutations and Review of the Literature

Malignant mesothelioma is a tumour of the serosal membranes, related to asbestos exposure. Median latency is in the order of 40 years in various registries, but small numbers of cases with shorter latencies have long been reported and often dismissed as unrelated to asbestos exposure. However, emerging data regarding the significance of inherited mutations leading to a predisposition to mesothelioma suggest that the causative effect of asbestos may be associated with shorter latencies in a subset of patients. Here, we describe a male patient with germline mutations in RAD51 and p53 who developed peritoneal mesothelioma 8.5 years after well-documented asbestos exposure and discuss the current literature on the subject. Mesothelioma in situ is now a WHO-accepted diagnosis, but preliminary data reveal a potential lead time of 5 or more years to invasive disease, and this is also a factor which may affect the recording of latency (and potentially survival) in the future.

Pectin/chitosan/tripolyphosphate encapsulation protects the rat lung from fibrosis and apoptosis induced by paraquat inhalation

BACKGROUND

Paraquat poisoning leads to lung injury and pulmonary fibrosis. The effect of paraquat encapsulation by previously described Pectin/Chitosan/Tripolyphosphate nanoparticles on its pulmonary toxicity was investigated in present study in a rat model of poison inhalation.

MATERIAL AND METHOD

The rats inhaled nebulized different formulation of paraquat (n = 5) for 30 min in various experimental groups. Lung injury and fibrosis scores, Lung tissue enzymatic activities, apoptosis markers were determined compared among groups.

RESULTS

Encapsulation of paraquat significantly rescued both lung injury and fibrosis scores. Lung MDA level was reduced by encapsulation. Paraquat poisoning led to lung tissue apoptosis as was evidenced by higher Caspase-3 and Bax/Bcl2 expressions in rats subjected to paraquat inhalation instead of normal saline or free nanoparticles. Again, nanoencapsulation reduced these apoptosis markers significantly. Alpha-SMA expression was also reduced by encapsulation. Nanoparticles per se have no or little toxicity as was evidenced by inflammatory and apoptotic markers and histological scores.

CONCLUSION

In a rat model of inhalation toxicity of paraquat, loading of this herbicide on PEC/CS/TPP nanoparticles reduced acute lung injury and fibrosis. The encapsulation also led to lower apoptosis, oxidative stress and alpha-SMA expression in the lung tissue.

Hazardous Elements in Asbestos Tremolite from the Basilicata Region, Southern Italy: A First Step

In this paper, we report the quantification of potentially toxic elements (PTEs) hosted into two tremolite asbestos from Episcopia and San Severino Lucano villages (Basilicata region, Southern Italy). Micro X-ray fluorescence and Inductively Coupled Plasma spectroscopy with Optical Emission Spectrometry techniques were used to quantify the concentration of major, minor (Si, Mg, Ca, Al, Fe, Mn) and trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Sb, Sn Sr, Ti, Te, V, W, Zn, Zr), with the aim of providing available data useful for the determination of the asbestos fibers toxicity. Results show that in the two studied samples there exist high concentrations of Fe, Mn, Cr and Ni which could lead to the high toxicity of the mineral fibers. By considering the pseudo-total PTEs amounts in each tremolite asbestos, it is possible to affirm that one of the samples is more enriched in toxic elements than the other one (3572 ppm versus 1384 ppm). These PTEs can represent a source of risk to human health since they may be transported away from the geological outcrops, through asbestos in the air, water and soils and thus encountering the human body.

SIRT3 Overexpression Ameliorates Asbestos-Induced Pulmonary Fibrosis, mt-DNA Damage, and Lung Fibrogenic Monocyte Recruitment

Alveolar epithelial cell (AEC) mitochondrial (mt) DNA damage and fibrotic monocyte-derived alveolar macrophages (Mo-AMs) are implicated in the pathobiology of pulmonary fibrosis. We showed that sirtuin 3 (SIRT3), a mitochondrial protein regulating cell fate and aging, is deficient in the AECs of idiopathic pulmonary fibrosis (IPF) patients and that asbestos- and bleomycin-induced lung fibrosis is augmented in Sirt3 knockout (Sirt3-/-) mice associated with AEC mtDNA damage and intrinsic apoptosis. We determined whether whole body transgenic SIRT3 overexpression (Sirt3Tg) protects mice from asbestos-induced pulmonary fibrosis by mitigating lung mtDNA damage and Mo-AM recruitment. Crocidolite asbestos (100 µg/50 µL) or control was instilled intratracheally in C57Bl6 (Wild-Type) mice or Sirt3Tg mice, and at 21 d lung fibrosis (histology, fibrosis score, Sircol assay) and lung Mo-AMs (flow cytometry) were assessed. Compared to controls, Sirt3Tg mice were protected from asbestos-induced pulmonary fibrosis and had diminished lung mtDNA damage and Mo-AM recruitment. Further, pharmacologic SIRT3 inducers (i.e., resveratrol, viniferin, and honokiol) each diminish oxidant-induced AEC mtDNA damage in vitro and, in the case of honokiol, protection occurs in a SIRT3-dependent manner. We reason that SIRT3 preservation of AEC mtDNA is a novel therapeutic focus for managing patients with IPF and other types of pulmonary fibrosis.

Loss of Nitric Oxide Induces Fibrogenic Response in Organotypic 3D Co-Culture of Mammary Epithelia and Fibroblasts-An Indicator for Breast Carcinogenesis

Simple Summary

Fibrosis, which is often caused by chronic diseases and environmental substances, is closely associated with cancer. Thus, the development of a robust method allowing for deep studies of the linkage between fibrosis and cancer is essential. Here, we tested whether our novel three-dimensional (3D) co-culture of breast epithelia and fibroblasts would be a suitable model for that purpose. We compared the phenotypic effects of L-NAME, an inhibitor of nitric oxide (NO) production, on 3D mono- and co-cultures. We previously reported that prolonged NO depletion with L-NAME caused fibrosis and tumorigenesis in mouse mammary glands. Such in vivo effects of L-NAME were well recapitulated in 3D co-cultures, but not in 3D mono-cultures of epithelia and fibroblasts. These results support not only the essential roles of the presence of the stroma in cancer development, but also the utility of this co-culture in studying the causal relationship between fibrosis and cancer.

Abstract

Excessive myofibroblast activation, which leads to dysregulated collagen deposition and the stiffening of the extracellular matrix (ECM), plays pivotal roles in cancer initiation and progression. Cumulative evidence attests to the cancer-causing effects of a number of fibrogenic factors found in the environment, diseases and drugs. While identifying such factors largely depends on epidemiological studies, it would be of great importance to develop a robust in vitro method to demonstrate the causal relationship between fibrosis and cancer. Here, we tested whether our recently developed organotypic three-dimensional (3D) co-culture would be suitable for that purpose. This co-culture system utilizes the discontinuous ECM to separately culture mammary epithelia and fibroblasts in the discrete matrices to model the complexity of the mammary gland. We observed that pharmaceutical deprivation of nitric oxide (NO) in 3D co-cultures induced myofibroblast differentiation of the stroma as well as the occurrence of epithelial–mesenchymal transition (EMT) of the parenchyma. Such in vitro response to NO deprivation was unique to co-cultures and closely mimicked the phenotype of NO-depleted mammary glands exhibiting stromal desmoplasia and precancerous lesions undergoing EMT. These results suggest that this novel 3D co-culture system could be utilized in the deep mechanistic studies of the linkage between fibrosis and cancer.

The role of macrophage polarization and function in environmental toxicant-induced cancers

Macrophages are a critical member of the innate immune system and can intensify tumor invasiveness and assist the growth of neoplastic cells. Moreover, they have the capability to reinforce immunosuppression and angiogenesis. Various investigations suggest that health-related issues, including inflammatory disorders and neoplastic diseases may be caused by environmental toxicant exposure. However, it is still unclear what role these environmental toxicants play in causing carcinogenesis by disturbing the mechanisms of migration, polarization, differentiation, and immune-stimulatory functions of macrophages. Accordingly, in this article, we will explore the interaction between environmental chemicals and inflammatory macrophage processes at the molecular level and their association with tumor progression and carcinogenesis.

Leflunomide Induces Dose-Dependent Lung Injury in Mice via Stimulating Vimentin and NLRP3 Inflammasome Production

Recently, the therapeutic importance of the anti-rheumatic drug, leflunomide, has been increased after the involvement of leflunomide in treating other autoimmune diseases and its promising role in retarding human malignancies. Few studies have focused on the safety in human or animals without clear outlining of the pathologic features on target organs. One clinical study related leflunomide with significant pulmonary complications in predisposed individuals. The current study examined the dose-dependent lung injury produced by leflunomide in healthy mice. Albino mice were allocated into four different groups. Group (1): Vehicle control group, Group (2–4): mice received leflunomide (2.5, 5 or 10 mg/kg), respectively, for 8 weeks and then lungs were dissected from the mice for histopathological examination and fibrosis evaluation (Masson’s trichrome staining and α-smooth muscle actin immunohistochemistry). Enzyme linked immunosorbent assay was used to assess the vimentin and other inflammatory factors in the lung homogenate whereas Western blot analysis was employed to assess α-smooth muscle actin, vimentin and collagen 1. Results indicated that leflunomide induced dose-dependent pulmonary injury and the high dose and increased the vimentin, inflammatory markers (NLRP3 and interlukin-1β). Histologic examination showed distorted architecture, marked inflammatory cells infiltrate and increase collagen content. The findings were supported by Western blotting and the immunohistochemical study which showed greater pulmonary α-smooth muscle actin and vimentin content. In conclusion, the current results highlighted that leflunomide produced dose-dependent pulmonary toxicities that requires further investigation of the nature of injury.

Preoperative Diagnosis Failure for a Rare Gastric Collision Tumor: A Case Report

Gastrointestinal stromal tumors (GISTs) are common mesenchymal tumors of the gastrointestinal tract (GIT), usually occur as a solitary neoplasm. Inflammatory florid polyp (IFP) is a solitary rare benign lesion of the gastrointestinal tract, mainly occur in the gastric antrum, whose atypical presentation can mimic GISTs or other malignant tumors, therefore the synchronous occurrence of GISTs and IFP is extremely rare. We had a case of a 58-year-old man that was presented with recurrent epigastric pain and recurrent melena. Upper endoscopic examination revealed a large polypoid antrum polyp measured 7 cm at greatest dimension with focal ulceration. Clinical and radiological features did not reach the definite diagnosis until histopathological evaluation with immunohistochemical analysis was performed. Surgical intervention is recommended and partial gastrectomy was done with wide resection margins. Histological examination revealed two distinct GISTs and IFP parts presenting a collision tumor that showed spindle and epitheloid cells consistent with GISTs with histological features of florid polyp showed a characteristic perivascular onion-skin arrangement of spindle cells with dense chronic inflammatory infiltrate including eosinophils and lymphocytes. Immunohistochemical studies have been done and revealed an association between GISTs and IFP. To the best of our knowledge, this is the first case of a collision tumor consisting of a GIST and an IFP arising in the stomach. In conclusion, the gastrointestinal stromal tumor is the comments mesenchymal tumor of GIT and IFP is a rare benign lesion of GIT therefore association between GIST and IFP as a collision tumor is extremely rare.

Smoking, occupational exposures, and idiopathic pulmonary fibrosis among Swedish construction workers

BACKGROUND

Cigarette smoking and occupational exposures each have been reported to increase the risk of idiopathic pulmonary fibrosis (IPF), a disease previously considered of unknown origin. We investigated the risk of IPF mortality associated with combined smoking and occupational exposures.

METHODS

A registry study of Swedish construction workers (N = 389,132), linked baseline smoking and occupational data with registry data on cause of death and hospital care diagnoses. Occupation was classified by the likelihood of exposure to vapors, gases, dusts, or fumes using a job-exposure matrix. Those likely exposed to asbestos or silica were excluded from the analysis. Age-adjusted relative risks [RRs] were calculated using Poisson regression. Follow-up observation began at age 40 and ended at age 89.

RESULTS

Heavy smokers at baseline who were exposed to inorganic dusts during their working life had an increased risk of IPF mortality (RR 1.70; 95% confidence interval [CI] 1.11-2.60), while there was no statistically increased risk in the other exposure groups. There were dose-response relationships between smoking at baseline and IPF mortality among both unexposed and dust exposed workers, with similar risk for dust exposed and unexposed, except among baseline heavy smokers, where workers exposed to inorganic dust manifested the highest risk (RR 4.22; 95% CI 2.69-6.60). Excluding workers with chronic obstructive pulmonary disease or emphysema did not affect the results substantively.

CONCLUSION

A clear dose-response relationship was seen between smoking at baseline and IPF, supporting a causal relationship. Occupational exposure to inorganic dusts, excluding silica and asbestos, was associated with increased risk of IPF in baseline heavy current smokers.

Role of microRNAs in Lung Carcinogenesis Induced by Asbestos

MicroRNAs are a class of small noncoding endogenous RNAs 19–25 nucleotides long, which play an important role in the post-transcriptional regulation of gene expression by targeting mRNA targets with subsequent repression of translation. MicroRNAs are involved in the pathogenesis of numerous diseases, including cancer. Lung cancer is the leading cause of cancer death in the world. Lung cancer is usually associated with tobacco smoking. However, about 25% of lung cancer cases occur in people who have never smoked. According to the International Agency for Research on Cancer, asbestos has been classified as one of the cancerogenic factors for lung cancer. The mechanism of malignant transformation under the influence of asbestos is associated with the genotoxic effect of reactive oxygen species, which initiate the processes of DNA damage in the cell. However, epigenetic mechanisms such as changes in the microRNA expression profile may also be implicated in the pathogenesis of asbestos-induced lung cancer. Numerous studies have shown that microRNAs can serve as a biomarker of the effects of various adverse environmental factors on the human body. This review examines the role of microRNAs, the expression profile of which changes upon exposure to asbestos, in key processes of carcinogenesis, such as proliferation, cell survival, metastasis, neo-angiogenesis, and immune response avoidance.

The Dark Side of the Force: When the Immune System Is the Fuel of Tumor Onset

Nowadays, it is well accepted that inflammation is a critical player in cancer, being, in most cases, the main character of the process. Different types of tumor arise from sites of infection or chronic inflammation. This non-resolving inflammation is responsible for tumor development at different levels: it promotes tumor initiation, as well as tumor progression, stimulating both tumor growth and metastasis. Environmental factors, lifestyle and infections are the three main triggers of chronic immune activation that promote or increase the risk of many different cancers. In this review, we focus our attention on tumor onset; in particular, we summarize the knowledge about the cause and the mechanisms behind the inflammation-driven cancer development.

Hazardous minerals mining: Challenges and solutions

Minerals are valuable resources gifted to man from the Mother Earth and quite often they need to be dug out from deep down with much effort to utilize them in many of our anthropogenic activities. The fascinating nature, colours as well as the physicochemical properties of minerals has extended their prospective value in the synthesis of various household and industrial products. However, knowledge of the mostly explored minerals, associated products, and their hazardous nature becomes relevant to its prevalence in our daily life. The harmful effects of some minerals are mostly evident from its site of occurrence, process of mining, post mining wastes left over and even in finished products. The current review focuses to evaluate the hazardous nature of minerals, cautions associated with its mining, drastic effects on human health, and ecosystem as an eye-opener to us. Finally, the effective remedies that could be implemented in the exploration of minerals are also discussed to the best of our knowledge. Bioleaching methods of rare earth elements and copper have been discussed briefly to explain the pros and cons of biological methods over conventional chemical leaching methods.

Perspective: The Lung, Particles, Fibers, Nanomaterials, and Autoimmunity

Studies have shown that a wide range of factors including drugs, chemicals, microbes, and other environmental agents can induce pre-clinical autoimmunity. However, only a few have been confidently linked to autoimmune diseases. Among these are exposures to inhaled particulates that are known to be associated with autoimmune diseases such as lupus and rheumatoid arthritis. In this article, the potential of particle, fiber, and nanomaterial exposures to induce autoimmunity is discussed. It is hypothesized that inhalation of particulate material known to be associated with human autoimmune diseases, such as cigarette smoke and crystalline silica, results in a complex interplay of a number of pathological processes, including, toxicity, oxidative stress, cell and tissue damage, chronic inflammation, post-translational modification of self-antigens, and the formation of lymphoid follicles that provide a milieu for the accumulation of autoreactive B and T cells necessary for the development and persistence of autoimmune responses, leading to disease. Although experimental studies show nanomaterials are capable of inducing several of the above features, there is no evidence that this matures to autoimmune disease. The procession of events hypothesized here provides a foundation from which to pursue experimental studies to determine the potential of other environmental exposures to induce autoimmunity and autoimmune disease.

Pulmonary toxicants and fibrosis: innate and adaptive immune mechanisms

Pulmonary fibrosis is characterized by destruction and remodeling of the lung due to an accumulation of collagen and other extracellular matrix components in the tissue. This results in progressive irreversible decreases in lung capacity, impaired gas exchange and eventually, hypoxemia. A number of inhaled and systemic toxicants including bleomycin, silica, asbestos, nanoparticles, mustard vesicants, nitrofurantoin, amiodarone, and ionizing radiation have been identified. In this article, we review the role of innate and adaptive immune cells and mediators they release in the pathogenesis of fibrotic pathologies induced by pulmonary toxicants. A better understanding of the pathogenic mechanisms underlying fibrogenesis may lead to the development of new therapeutic approaches for patients with these debilitating and largely irreversible chronic diseases.

A Review of Asbestos Bioweathering by Siderophore-Producing Pseudomonas: A Potential Strategy of Bioremediation

Asbestos, silicate minerals present in soil and used for building constructions for many years, are highly toxic due primarily to the presence of high concentrations of the transition metal iron. Microbial weathering of asbestos occurs through various alteration mechanisms. Siderophores, complex agents specialized in metal chelation, are common mechanisms described in mineral alteration. Solubilized metals from the fiber can serve as micronutrients for telluric microorganisms. The review focuses on the bioweathering of asbestos fibers, found in soil or manufactured by humans with gypsum (asbestos flocking) or cement, by siderophore-producing Pseudomonas. A better understanding of the interactions between asbestos and bacteria will give a perspective of a detoxification process inhibiting asbestos toxicity.

Thermal inertization of amphibole asbestos modulates Fe topochemistry and surface reactivity

This study discloses the morphological and chemical-structural modifications that occur during thermal degradation of amphibole asbestos. Low-iron tremolite and iron-rich crocidolite were heated at temperatures ranging from r.t. to 1200 °C. Heating promoted a complex sequence of iron oxidation, migration and/or clustering and, finally, the formation of brittle fibrous pseudomorphs consisting of newly formed minerals and amorphous nanophases. The effects of the thermal modifications on toxicologically relevant asbestos reactivity were evaluated by quantifying carbon- and oxygen-centred, namely hydroxyl (OH), radicals. Heating did not alter carbon radicals, but largely affected oxygen-centred radical yields. At low temperature, reactivity of both amphiboles decreased. At 1200 °C, tremolite structural breakdown was achieved and the reactivity was further reduced by migration of reactive iron ions into the more stable TO₄ tetrahedra of the newly formed pyroxene(s). Differently, crocidolite breakdown at 1000 °C induced the formation of hematite, Fe-rich pyroxene, cristobalite, and abundant amorphous material and restored radical reactivity. Our finding suggests that thermally treated asbestos and its breakdown products still share some toxicologically relevant properties with pristine fibre. Asbestos inertization studies should consider morphology and surface reactivity, beyond crystallinity, when proving that a thermally inactivated asbestos-containing material is safe.

Update of in vitro, in vivo and ex vivo fluoro-edenite effects on malignant mesothelioma: A systematic review (Review)

Fluoro-edenite (FE), asbestiform fiber found in Biancavilla (Sicily, Italy), presents various characteristics similar to the asbestos group, in particular two fibrous phases tremolite and actinolite. Indeed, epidemiological studies have shown that FE fibers have similar effects to those of asbestos fibers. Such studies have reported a high incidence of malignant mesothelioma (MM), an aggressive neoplasm of the serosal membranes lining the pleural cavity, in individuals residing there due to FE exposure in Biancavilla related to environmental contamination. Evidence has led to the classification of FE as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC). The aim of this systematic review is to compare the results achieved in in vitro, in vivo and ex vivo experimental studies involving FE in order to update the current knowledge on the pathogenesis and molecular mechanisms responsible for FE-mediated MM development as well as the availability of effective biomarkers for MM prevention and diagnosis. This review is focused on the pathophysiological mechanisms mediated by inflammation induced by FE fiber exposure and which are responsible for MM development. This review also discusses the discovery of new diagnostic and prognostic biomarkers for the management of this pathology. It is known that the risk of cancer development increases with chronic inflammation, arising from enhanced reactive oxygen species (ROS) and NO^• production stimulated by the body to remove exogenous agents, causing DNA damage and enhanced signal transduction that may lead to activation of oncogenes. Studies concerning MM biomarker discovery indicate that several biomarkers have been proposed for MM, but mesothelin is the only Food and Drug Administration (FDA)-approved biomarker for MM, with limitations. In recent studies, in silico analysis to identify selected miRNAs highly deregulated in cancer samples when compared with normal control have been developed. This in silico approach could represent an effort in the field of biomarker discovery for MM.

Targeting Tumor-Associated Macrophages in Anti-Cancer Therapies: Convincing the Traitors to Do the Right Thing

In the last decade, it has been well-established that tumor-infiltrating myeloid cells fuel not only the process of carcinogenesis through cancer-related inflammation mechanisms, but also tumor progression, invasion, and metastasis. In particular, tumor-associated macrophages (TAMs) are the most abundant leucocyte subset in many cancers and play a major role in the creation of a protective niche for tumor cells. Their ability to generate an immune-suppressive environment is crucial to escape the immune system and to allow the tumor to proliferate and metastasize to distant sites. Conventional therapies, including chemotherapy and radiotherapy, are often not able to limit cancer growth due to the presence of pro-tumoral TAMs; these are also responsible for the failure of novel immunotherapies based on immune-checkpoint inhibition. Several novel therapeutic strategies have been implemented to deplete TAMs; however, more recent approaches aim to use TAMs themselves as weapons to fight cancer. Exploiting their functional plasticity, the reprogramming of TAMs aims to convert immunosuppressive and pro-tumoral macrophages into immunostimulatory and anti-tumor cytotoxic effector cells. This shift eventually leads to the reconstitution of a reactive immune landscape able to destroy the tumor. In this review, we summarize the current knowledge on strategies able to reprogram TAMs with single as well as combination therapies.

Mechanisms of Environment-Induced Autoimmunity

Although numerous environmental exposures have been suggested as triggers for preclinical autoimmunity, only a few have been confidently linked to autoimmune diseases. For disease-associated exposures, the lung is a common site where chronic exposure results in cellular toxicity, tissue damage, inflammation, and fibrosis. These features are exacerbated by exposures to particulate material, which hampers clearance and degradation, thus facilitating persistent inflammation. Coincident with exposure and resulting pathological processes is the posttranslational modification of self-antigens, which, in concert with the formation of tertiary lymphoid structures containing abundant B cells, is thought to promote the generation of autoantibodies that in some instances demonstrate major histocompatibility complex restriction. Under appropriate gene-environment interactions, these responses can have diagnostic specificity. Greater insight into the molecular and cellular requirements governing this process, especially those that distinguish preclinical autoimmunity from clinical autoimmunedisease, may facilitate determination of the significance of environmental exposures in human autoimmune disease.

8-Oxoguanine DNA glycosylase modulates the cell transformation process in pulmonary fibrosis by inhibiting Smad2/3 and interacting with Smad7

The DNA repair enzyme 8-oxoguanine DNA glycosylase-1 (OGG1) is involved in early embryonic development, as well as in multiple conditions, including cardiac fibrosis, diabetes, and neurodegenerative diseases. But, function of OGG1 in pulmonary fibrosis was not entirely clear. In this study, we identified a novel function of OGG1 in the cell transformation process in pulmonary fibrosis. We demonstrated that OGG1 and Smad7 co-localize and interact in A549 cells. Bleomycin-induced pulmonary fibrosis was established in wild-type (WT) and Ogg1^-/- mice. Upon treatment with transforming growth factor (TGF)-β1, increased OGG1 expression was observed in WT mice with pulmonary fibrosis as well as in A549 cells, MRC-5 cells, and primary rat type II alveolar epithelial cells. The increased expression of OGG1 promoted cell migration, while OGG1 depletion decreased migration ability. Expression of the transformation-associated markers vimentin and alpha-smooth muscle actin were also affected by OGG1. We also observed that OGG1 promoted TGF-β1-induced cell transformation and activated Smad2/3 by interacting with Smad7. The interaction between OGG1 and the TGF-β/Smad axis modulates the cell transformation process in lung epithelial cells and fibroblasts. Moreover, we demonstrated that Ogg1 deficiency relieved pulmonary fibrosis in bleomycin-treated mice. Ogg1 knockout decreased the bleomycin-induced expression of Smad7 and phosphorylation of Smad2/3 in mice. These findings suggest that OGG1 has multiple biological functions in the pathogenesis of pulmonary fibrosis.

The Sphingosine Kinase 1 Inhibitor, PF543, Mitigates Pulmonary Fibrosis by Reducing Lung Epithelial Cell mtDNA Damage and Recruitment of Fibrogenic Monocytes

Idiopathic pulmonary fibrosis (IPF) is a chronic disease for which novel approaches are urgently required. We reported increased sphingosine kinase 1 (SPHK1) in IPF lungs and that SPHK1 inhibition using genetic and pharmacologic approaches reduces murine bleomycin-induced pulmonary fibrosis. We determined whether PF543, a specific SPHK1 inhibitor post bleomycin or asbestos challenge mitigates lung fibrosis by reducing mitochondrial (mt) DNA damage and pro-fibrotic monocyte recruitment—both are implicated in the pathobiology of pulmonary fibrosis. Bleomycin (1.5 U/kg), crocidolite asbestos (100 µg/50 µL) or controls was intratracheally instilled in Wild-Type (C57Bl6) mice. PF543 (1 mg/kg) or vehicle was intraperitoneally injected once every two days from day 7−21 following bleomycin and day 14−21 or day 30−60 following asbestos. PF543 reduced bleomycin- and asbestos-induced pulmonary fibrosis at both time points as well as lung expression of profibrotic markers, lung mtDNA damage, and fibrogenic monocyte recruitment. In contrast to human lung fibroblasts, asbestos augmented lung epithelial cell (MLE) mtDNA damage and PF543 was protective. Post-exposure PF543 mitigates pulmonary fibrosis in part by reducing lung epithelial cell mtDNA damage and monocyte recruitment. We reason that SPHK1 signaling may be an innovative therapeutic target for managing patients with IPF and other forms of lung fibrosis.