A randomized controlled trial of inhaled corticosteroids (ICS) on markers of epithelial-mesenchymal transition (EMT) in large airway samples in COPD: an exploratory proof of concept study

Large airway wall vascularity in patients with asthma-COPD overlap: a bronchoscopy study

Large airway wall lamina propria in patients with asthma-COPD overlap is hypovascular with an increase in reticular basement membrane neoangiogenesis, reflecting smoking-related COPD-like pathology and potential epithelial-to-mesenchymal transition https://bit.ly/49DeoFX.

MMPs as potential molecular targets in epithelial-to-mesenchymal transition driven COPD progression

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality globally and the risk of developing lung cancer is six times greater in individuals with COPD who smoke compared to those who do not smoke. Matrix metalloproteinases (MMPs) play a crucial role in the pathophysiology of respiratory diseases by promoting inflammation and tissue degradation. Furthermore, MMPs are involved in key processes like epithelial-to-mesenchymal transition (EMT), metastasis, and invasion in lung cancer. While EMT has traditionally been associated with the progression of lung cancer, recent research highlights its active involvement in individuals with COPD. Current evidence underscores its role in orchestrating airway remodeling, fostering airway fibrosis, and contributing to the potential for malignant transformation in the complex pathophysiology of COPD. The precise regulatory roles of diverse MMPs in steering EMT during COPD progression needs to be elucidated. Additionally, the less-understood aspect involves how these MMPs bi-directionally activate or regulate various EMT-associated signaling cascades during COPD progression. This review article explores recent advancements in understanding MMPs' role in EMT during COPD progression and various pharmacological approaches to target MMPs. It also delves into the limitations of current MMP inhibitors and explores novel, advanced strategies for inhibiting MMPs, potentially offering new avenues for treating respiratory diseases.

Epithelial-mesenchymal transition changes in nonsmall cell lung cancer patients with early COPD

Background

Epithelial-mesenchymal transition (EMT) might be central to lung cancer development in smokers and COPD. We illustrate EMT changes in a broader demographic of patient groups who were diagnosed with nonsmall cell lung cancer (adenocarcinoma and squamous cell carcinoma). These included COPD current and ex-smokers, patients with small airway disease and normal lung function smokers compared to normal controls.

Methods

We had access to surgically resected small airway tissue from 46 subjects and assessed for airway wall thickness and immunohistochemically for the EMT biomarkers E-cadherin, N-cadherin, S100A4, vimentin and epidermal growth factor receptor (EGFR). All tissue analysis was done with a computer and microscope-assisted Image-Pro Plus 7.0 software.

Results

Airway wall thickness significantly increased across all pathological groups (p<0.05) compared to normal controls. Small airway epithelial E-cadherin expression markedly decreased (p<0.01), and increases in N-cadherin, vimentin, S100A4 and EGFR expression were observed in all pathological groups compared to normal controls (p<0.01). Vimentin-positive cells in the reticular basement membrane, lamina propria and adventitia showed a similar trend to epithelium across all pathological groups (p<0.05); however, such changes were only observed in reticular basement membrane for S100A4 (p<0.05). Vimentin was higher in adenocarcinoma versus squamous cell carcinoma; in contrast, S100A4 was higher in the squamous cell carcinoma group. EGFR and N-cadherin expression in both phenotypes was markedly higher than E-cadherin, vimentin and S100A4 (p<0.0001).

Conclusion

EMT is an active process in the small airway of smokers and COPD diagnosed with nonsmall cell lung cancer, contributing to small airway remodelling and cancer development as seen in these patients.

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

cAMP-PDE signaling in COPD: Review of cellular, molecular and clinical features

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among non-contagious diseases in the world. PDE inhibitors are among current medicines prescribed for COPD treatment of which, PDE-4 family is the predominant PDE isoform involved in hydrolyzing cyclic adenosine monophosphate (cAMP) that regulates the inflammatory responses in neutrophils, lymphocytes, macrophages and epithelial cells The aim of this study is to investigate the cellular and molecular mechanisms of cAMP-PDE signaling, as an important pathway in the treatment management of patients with COPD. In this review, a comprehensive literature review was performed about the effect of PDEs in COPD. Generally, PDEs are overexpressed in COPD patients, resulting in cAMP inactivation and decreased cAMP hydrolysis from AMP. At normal amounts, cAMP is one of the essential agents in regulating metabolism and suppressing inflammatory responses. Low amount of cAMP lead to activation of downstream inflammatory signaling pathways. PDE4 and PDE7 mRNA transcript levels were not altered in polymorphonuclear leukocytes and CD8 lymphocytes originating from the peripheral venous blood of stable COPD subjects compared to healthy controls. Therefore, cAMP-PDE signaling pathway is one of the most important signaling pathways involved in COPD. By examining the effects of different drugs in this signaling pathway critical steps can be taken in the treatment of this disease.

The effects of epithelial-mesenchymal transitions in COPD induced by cigarette smoke: an update

Cigarette smoke is a complex aerosol containing a large number of compounds with a variety of toxicity and carcinogenicity. Long-term exposure to cigarette smoke significantly increases the risk of a variety of diseases, including chronic obstructive pulmonary disease (COPD) and lung cancer. Epithelial–mesenchymal transition (EMT) is a unique biological process, that refers to epithelial cells losing their polarity and transforming into mobile mesenchymal cells, playing a crucial role in organ development, fibrosis, and cancer progression. Numerous recent studies have shown that EMT is an important pathophysiological process involved in airway fibrosis, airway remodeling, and malignant transformation of COPD. In this review, we summarized the effects of cigarette smoke on the development and progression of COPD and focus on the specific changes and underlying mechanisms of EMT in COPD induced by cigarette smoke. We spotlighted the signaling pathways involved in EMT induced by cigarette smoke and summarize the current research and treatment approaches for EMT in COPD, aiming to provide ideas for potential new treatment and research directions.

Pathogenesis, clinical features of asthma COPD overlap (ACO), and therapeutic modalities

Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functional abnormalities, with airway obstruction common in both diseases. Asthma COPD overlap (ACO) does not define a single disease but is a descriptive term for clinical use that includes several overlapping clinical phenotypes of chronic airways disease with different underlying mechanisms. This literature review was initiated to describe published studies, identify gaps in knowledge, and propose future research goals regarding the disease pathology of ACO, especially the airway remodelling changes and inflammation aspects. Airway remodelling occurs in asthma and COPD, but there are differences in the structures affected and the prime anatomic site at which they occur. Reticular basement membrane thickening and cellular infiltration with eosinophils and T-helper (CD4+) lymphocytes are prominent features of asthma. Epithelial squamous metaplasia, airway wall fibrosis, emphysema, bronchoalveolar lavage (BAL) neutrophilia and (CD8+) T-cytotoxic lymphocyte infiltrations in the airway wall are features of COPD. There is no universally accepted definition of ACO, nor are there clearly defined pathological characteristics to differentiate from asthma and COPD. Understanding etiological concepts within the purview of inflammation and airway remodelling changes in ACO would allow better management of these patients.

Nanotechnology based advanced therapeutic strategies for targeting interleukins in chronic respiratory diseases

Both communicable and non-communicable chronic respiratory conditions have accorded for suffering of millions of people of all ages and stated to be leading cause of death, morbidity, economic and social pressures, and disability-adjusted life-years (DALYs) worldwide. These illnesses impair patient's health and negatively impacts families and society, particularly in low and middle-income countries. Chronic respiratory diseases (CRDs) affect different organs of respiratory system, involving airways, parenchyma, and pulmonary vasculature. As the number of respiratory diseases are exponentially escalating but still the stakeholders are not paying attention towards its serious complications. Currently, the treatment being used primarily focusses only on alleviating symptoms of these illness rather delivering the therapeutic agent at target site for optimal care and/or prevention. Lately, extensive research is being conducted on airways and systemic inflammation, oxidative stress, airway, or parenchymal rehabilitation. From which macrophages, neutrophils, and T cells, as well as structural cells as fibroblasts, epithelial, endothelial, and smooth muscle cells have been found to be active participants that are involved in these chronic respiratory diseases. The pathogenesis of all these chronic respiratory diseases gets caused differently via mediators and proteins, including cytokines, chemokines, growth factors and oxidants. Presently, the target of prescription therapies is to reduce the inflammation of airways and relieve the airway contraction. In all studies, cytokines have been found to play an imperative role in fostering chronic airway inflammation and remodelling. Owing to the limitations of conventional treatments, the current review aims to summarize the current knowledge about the chronic respiratory disease and discuss further about the various conventional methods that can be used for treating this ailment. Additionally, it also highlights and discusses about the advanced drug delivery system that are being used for targeting the interleukins for the treatment of CRDs.

The Underappreciated Role of Epithelial Mesenchymal Transition in Chronic Obstructive Pulmonary Disease and Its Strong Link to Lung Cancer

The World Health Organisation reported COPD to be the third leading cause of death globally in 2019, and in 2020, the most common cause of cancer death was lung cancer; when these linked conditions are added together they come near the top of the leading causes of mortality. The cell-biological program termed epithelial-to-mesenchymal transition (EMT) plays an important role in organ development, fibrosis and cancer progression. Over the past decade there has emerged a substantial literature that also links EMT specifically to the pathophysiology of chronic obstructive pulmonary disease (COPD) as primarily an airway fibrosis disease; COPD is a recognised strong independent risk factor for the development of lung cancer, over and above the risks associated with smoking. In this review, our primary focus is to highlight these linkages and alert both the COPD and lung cancer fields to these complex interactions. We emphasise the need for inter-disciplinary attention and research focused on the likely crucial roles of EMT (and potential for its inhibition) with recognition of its strategic place mechanistically in both COPD and lung cancer. As part of this we discuss the future potential directions for novel therapeutic opportunities, including evidence-based strategic repurposing of currently used familiar/approved medications.

Fully integrating pathophysiological insights in COPD: an updated working disease model to broaden therapeutic vision

Our starting point is that relatively new findings into the pathogenesis and pathophysiology of airway disease in smokers that lead to chronic obstructive pulmonary disease (COPD) need to be reassessed as a whole and integrated into "mainstream" thinking along with traditional concepts which have stood the test of time. Such a refining of the accepted disease paradigm is urgently needed as thinking on therapeutic targets is currently under active reconsideration. We feel that generalised airway wall "inflammation" is unduly over-emphasised, and highlight the patchy and variable nature of the pathology (with the core being airway remodelling). In addition, we present evidence for airway wall disease in smokers/COPD as including a hypocellular, hypovascular, destructive, fibrotic pathology, with a likely spectrum of epithelial-mesenchymal transition states as significant drivers of this remodelling. Furthermore, we present data from a number of research modalities and integrate this with the aetiology of lung cancer, the role of chronic airway luminal colonisation/infection by a specific group of "respiratory" bacteria in smokers (which results in luminal inflammation) and the central role for oxidative stress on the epithelium. We suggest translation of these insights into more focus on asymptomatic smokers and early COPD, with the potential for fresh preventive and therapeutic approaches.

Increased myofibroblasts in the small airways, and relationship to remodelling and functional changes in smokers and COPD patients: potential role of epithelial-mesenchymal transition

Introduction

Previous reports have shown epithelial-mesenchymal transition (EMT) as an active process that contributes to small airway fibrotic pathology. Myofibroblasts are highly active pro-fibrotic cells that secrete excessive and altered extracellular matrix (ECM). Here we relate small airway myofibroblast presence with airway remodelling, physiology and EMT activity in smokers and COPD patients.

Methods

Lung resections from nonsmoker controls, normal lung function smokers and COPD current and ex-smokers were stained with anti-human α-smooth muscle actin (SMA), collagen 1 and fibronectin. αSMA⁺ cells were computed in reticular basement membrane (Rbm), lamina propria and adventitia and presented per mm of Rbm and mm² of lamina propria. Collagen-1 and fibronectin are presented as a percentage change from normal. All analyses including airway thickness were measured using Image-pro-plus 7.0.

Results

We found an increase in subepithelial lamina propria (especially) and adventitia thickness in all pathological groups compared to nonsmoker controls. Increases in αSMA⁺ myofibroblasts were observed in subepithelial Rbm, lamina propria and adventitia in both the smoker and COPD groups compared to nonsmoker controls. Furthermore, the increase in the myofibroblast population in the lamina propria was strongly associated with decrease in lung function, lamina propria thickening, increase in ECM protein deposition, and finally EMT activity in epithelial cells.

Conclusions

This is the first systematic characterisation of small airway myofibroblasts in COPD based on their localisation, with statistically significant correlations between them and other pan-airway structural, lung function and ECM protein changes. Finally, we suggest that EMT may be involved in such changes.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Inhaled corticosteroids and risk of lung cancer among chronic obstructive pulmonary disease patients: a comprehensive analysis of nine prospective cohorts

BACKGROUND

It remains uncertain whether there is a protective effect of inhaled corticosteroids (ICs) against lung cancer in chronic obstructive pulmonary disease (COPD) patients.

METHODS

Databases including PubMed, Web of Science, EMBASE, and Medline were comprehensively searched. Random-effects model meta-analysis was conducted to calculate the hazard ratios (HRs) for lung cancer incidence among ICs users versus non-ICs users in patients with COPD. Stratified analysis was performed based on region and age of each study. This review was registered on PROSPERO (registration number CRD42020159082).

RESULTS

Based on data from 181,859 COPD patients with a total follow-up duration of 1,109,339.9 person-years, we identified that the use of ICs in COPD patients was associated with a decreased risk of lung cancer [HR: 0.73, 95% confidence interval (CI): 0.62-0.86; P<0.001]. The region-specific HRs for lung cancer incidence were 0.62 (95% CI: 0.62-0.86; P=0.004), 0.77 (95% CI: 0.60-0.97; P=0.028) and 0.81 (95% CI: 0.61-1.08; P=0.155) among European, Asian and North American COPD patients, respectively. Additionally, we found the consistent outcome among age groups (≥70 years old: HR: 0.73, 95% CI: 0.65-0.99, P=0.043; <70 years old: HR: 0.74, 95% CI: 0.56-0.99, P=0.040).

CONCLUSIONS

This study demonstrates that ICs have a protective effect against lung cancer in COPD patients. It could provide guidance for clinicians in the prevention of lung cancer among patients with COPD.

Inhaled corticosteroids and risk of lung cancer: A systematic review and meta-analysis

INTRODUCTION

Current studies investigating the association between inhaled corticosteroid (ICS) use and risk of lung cancer have yielded inconsistent findings. The aim of this systematic review and meta-analysis was to pool all currently available data to estimate this association.

METHODS

We systematically searched MEDLINE (1946 to July 2020), EMBASE (1974 to July 2020) and the Cochrane Library (June 2020) via Ovid to identify relevant articles investigating the association between the ICS use and the risk of lung cancer. Random-effects analysis was used to calculate pooled relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Ten articles including 234 920 patients were analysed. ICS use was identified to have a decreased risk of lung cancer in chronic obstructive pulmonary disease (8 studies, 1806 patients; RR = 0.73, 95% CI: 0.61-0.87, P < .01; I²  = 60.0 %), asthma (1 study, 41 438 patients; RR = 0.44, 95% CI: 0.34-0.57, P < .01) and mixed (1 study, 46 225 patients; RR = 0.79, 95% CI: 0.69-0.90, P < .01) patients. The findings of reduced risk of lung cancer were consistent in all subgroup analyses except for the short-term follow-up (≤5 years) (RR = 0.94, 95% CI: 0.81-1.07, P = .34) and free of immortal time bias (RR = 0.94, 95% CI: 0.82-1.08, P = .38) subgroups.

CONCLUSIONS

The present study suggested that ICS use was associated with decreased risk of lung cancer. However, our findings should be interpreted with caution because most original studies were judged to be at high risk of immortal time bias.

Aesculetin Attenuates Alveolar Injury and Fibrosis Induced by Close Contact of Alveolar Epithelial Cells with Blood-Derived Macrophages via IL-8 Signaling

Pulmonary fibrosis is a disease in which lung tissues become fibrous and thereby causes severe respiratory disturbances. Various stimuli induce infiltration of macrophages to the respiratory tract, secreting inflammatory cytokines, which subsequently leads to the development of pulmonary fibrosis. Aesculetin, a major component of the sancho tree and chicory, is known to biologically have antioxidant and anti-inflammatory effects. Human alveolar epithelial A549 cells were cultured for 24 h in conditioned media of THP-1 monocyte-derived macrophages (mCM) with 1–20 μM aesculetin. Micromolar aesculetin attenuated the cytotoxicity of mCM containing inflammatory tumor necrosis factor-α (TNF)-α and interleukin (IL)-8 as major cytokines. Aesculetin inhibited alveolar epithelial induction of the mesenchymal markers in mCM-exposed/IL-8-loaded A549 cells (≈47–51% inhibition), while epithelial markers were induced in aesculetin-treated cells subject to mCM/IL-8 (≈1.5–2.3-fold induction). Aesculetin added to mCM-stimulated A549 cells abrogated the collagen production and alveolar epithelial CXC-chemokine receptor 2 (CXCR2) induction. The production of matrix metalloproteinase (MMP) proteins in mCM-loaded A549 cells was reduced by aesculetin (≈52% reduction), in parallel with its increase in tissue inhibitor of metalloproteinases (TIMP) proteins (≈1.8-fold increase). In addition, aesculetin enhanced epithelial induction of tight junction proteins in mCM-/IL-8-exposed cells (≈2.3–2.5-fold induction). The inhalation of polyhexamethylene guanidine (PHMG) in mice accompanied neutrophil predominance in bronchoalveolar lavage fluid (BALF) and macrophage infiltration in alveoli, which was inhibited by orally administrating aesculetin to mice. Treating aesculetin to mice alleviated PHMG-induced IL-8-mediated subepithelial fibrosis and airway barrier disruption. Taken together, aesculetin may antagonize pulmonary fibrosis and alveolar epithelial barrier disruption stimulated by the infiltration of monocyte-derived macrophages, which is typical of PHMG toxicity, involving interaction of IL-8 and CXCR2. Aesculetin maybe a promising agent counteracting macrophage-mediated inflammation-associated pulmonary disorders.

Shp2 positively regulates cigarette smoke-induced epithelial mesenchymal transition by mediating MMP-9 production

Cigarette smoke (CS) is a major risk factor for the development of lung cancer and chronic obstructive pulmonary disease (COPD). Epithelial-mesenchymal transition (EMT) commonly coexists in lung cancer and COPD. CS triggers many factors including matrix metalloproteinases (MMPs) production, contributing to EMT progression in the lungs. Here, how Shp2 signaling regulates the CS-induced MMP-9 production and EMT progression were investigated in mouse lungs and in pulmonary epithelial cell cultures (NCI-H292) found CS induced MMP-9 production, EMT progression (increased vimentin and α-SMA; decreased E-cadherin) and collagen deposition in lung tissues; cigarette smoke extract (CSE) induced MMP-9 production and EMT-related phenotypes in NCI-H292 cells, which were partially prevented by Shp2 KO/KD or Shp2 inhibition. The CSE exposure induced EMT phenotypes were suppressed by MMP-9 inhibition. Recombinant MMP-9 induced EMT, which was prevented by MMP-9 inhibition or Shp2 KD/inhibition. Mechanistically, CS and CSE exposure resulted in ERK1/2, JNK and Smad2/3 phosphorylation, which were suppressed by Shp2 KO/KD/inhibition. Consequentially, the CSE exposure-induced MMP-9 production and EMT progression were suppressed by ERK1/2, JNK and Smad2/3 inhibitors. Thus, CS induced MMP-9 production and EMT resulted from activation of Shp2/ERK1/2/JNK/Smad2/3 signaling pathways. Our study contributes to the underlying mechanisms of pulmonary epithelial structural changes in response to CS, which may provide novel therapeutic solutions for treating associated diseases, such as COPD and lung cancer.

Association between COPD exacerbations and lung function decline during maintenance therapy

BACKGROUND

Little is known about the impact of exacerbations on COPD progression or whether inhaled corticosteroid (ICS) use and blood eosinophil count (BEC) affect progression. We aimed to assess this in a prospective observational study.

METHODS

The study population included patients with mild to moderate COPD, aged ≥35 years, with a smoking history, who were followed up for ≥3 years from first to last spirometry recording using two large UK electronic medical record databases: Clinical Practice Research Datalink (CPRD) and Optimum Patient Care Research Database (OPCRD). Multilevel mixed-effects linear regression models were used to determine the relationship between annual exacerbation rate following initiation of therapy (ICS vs non-ICS) and FEV₁ decline. Effect modification by blood eosinophils was studied through interaction terms.

RESULTS

Of 12178 patients included (mean age 66 years; 48% female), 8981 (74%) received ICS. In patients with BEC ≥350 cells/µL not on ICS, each exacerbation was associated with subsequent acceleration of FEV₁ decline of 19.4 mL/year (95% CI 12.0 to 26.7, p<0.0001). This excess decline was reduced by 15.1 mL/year (6.6 to 23.6) to 4.3 mL/year (1.9 to 6.7, p<0.0001) in those with BEC ≥350 cells/µL treated with ICS.

CONCLUSION

Exacerbations are associated with a more rapid loss of lung function among COPD patients with elevated blood eosinophils, defined as ≥350 cells/µL, not treated with ICS. More aggressive prevention of exacerbations using ICS in such patients may prevent excess loss of lung function.

How Do Innate Immune Cells Contribute to Airway Remodeling in COPD Progression?

Recently, the therapeutic potential of immune-modulation during the progression of chronic obstructive pulmonary disease (COPD) has been attracting increasing interest. However, chronic inflammatory response has been over-simplified in descriptions of the mechanism of COPD progression. As a form of first-line airway defense, epithelial cells exhibit phenotypic alteration, and participate in epithelial layer disorganization, mucus hypersecretion, and extracellular matrix deposition. Dendritic cells (DCs) exhibit attenuated antigen-presenting capacity in patients with advanced COPD. Immature DCs migrate into small airways, where they promote a pro-inflammatory microenvironment and bacterial colonization. In response to damage-associated molecular patterns (DAMPs) in lung tissue affected by COPD, neutrophils are excessively recruited and activated, where they promote a proteolytic microenvironment and fibrotic repair in small airways. Macrophages exhibit decreased phagocytosis in the large airways, while they demonstrate high pro-inflammatory potential in the small airways, and mediate alveolar destruction and chronic airway inflammation. Natural killer T (NKT) cells, eosinophils, and mast cells also play supplementary roles in COPD progression; however, their cellular activities are not yet entirely clear. Overall, during COPD progression, “exhausted” innate immune responses can be observed in the large airways. On the other hand, the innate immune response is enhanced in the small airways. Approaches that inhibit the inflammatory cascade, chemotaxis, or the activation of inflammatory cells could possibly delay the progression of airway remodeling in COPD, and may thus have potential clinical significance.

Advances in Molecular Mechanisms and Immunotherapy Involving the Immune Cell-Promoted Epithelial-to-Mesenchymal Transition in Lung Cancer

Immunotherapy has offered a new opportunity for the treatment of many malignancies. In patients with lung cancer, immune checkpoint inhibitors have significantly improved survival. However, little is known about predictive factors or primary and acquired resistance mechanisms. Epithelial-to-mesenchymal transition (EMT) is a complex of phenotypic changes involved in carcinogenesis and resistance to cancer treatments. Specifically, immune cells in the tumor microenvironment can promote EMT, and mesenchymal phenotype acquisition negatively regulates the anticancer immune response. EMT is associated with higher expression of PD-L1 and other immune checkpoints. In this review, we focused on the role of EMT in the interplay between tumor cells and the immune system, with particular emphasis on lung cancer. On the basis of our findings, we hypothesize that the effects of EMT on immune cells could be overcome in this disease by a new combination of immune checkpoint inhibitors.

Chronic Obstructive Pulmonary Disease and Lung Cancer: Underlying Pathophysiology and New Therapeutic Modalities

Chronic obstructive pulmonary disease (COPD) and lung cancer are major lung diseases affecting millions worldwide. Both diseases have links to cigarette smoking and exert a considerable societal burden. People suffering from COPD are at higher risk of developing lung cancer than those without, and are more susceptible to poor outcomes after diagnosis and treatment. Lung cancer and COPD are closely associated, possibly sharing common traits such as an underlying genetic predisposition, epithelial and endothelial cell plasticity, dysfunctional inflammatory mechanisms including the deposition of excessive extracellular matrix, angiogenesis, susceptibility to DNA damage and cellular mutagenesis. In fact, COPD could be the driving factor for lung cancer, providing a conducive environment that propagates its evolution. In the early stages of smoking, body defences provide a combative immune/oxidative response and DNA repair mechanisms are likely to subdue these changes to a certain extent; however, in patients with COPD with lung cancer the consequences could be devastating, potentially contributing to slower postoperative recovery after lung resection and increased resistance to radiotherapy and chemotherapy. Vital to the development of new-targeted therapies is an in-depth understanding of various molecular mechanisms that are associated with both pathologies. In this comprehensive review, we provide a detailed overview of possible underlying factors that link COPD and lung cancer, and current therapeutic advances from both human and preclinical animal models that can effectively mitigate this unholy relationship.

Epithelial-mesenchymal transition is driven by transcriptional and post transcriptional modulations in COPD: implications for disease progression and new therapeutics

COPD is a common and highly destructive disease with huge impacts on people and health services throughout the world. It is mainly caused by cigarette smoking though environmental pollution is also significant. There are no current treatments that affect the overall course of COPD; current drugs focus on symptomatic relief and to some extent reducing exacerbation rates. There is an urgent need for in-depth studies of the fundamental pathogenic mechanisms that underpin COPD. This is vital, given the fact that nearly 40%-60% of the small airway and alveolar damage occurs in COPD well before the first measurable changes in lung function are detected. These individuals are also at a high risk of lung cancer. Current COPD research is mostly centered around late disease and/or innate immune activation within the airway lumen, but the actual damage to the airway wall has early onset. COPD is the end result of complex mechanisms, possibly triggered through initial epithelial activation. To change the disease trajectory, it is crucial to understand the mechanisms in the epithelium that are switched on early in smokers. One such mechanism we believe is the process of epithelial to mesenchymal transition. This article highlights the importance of this profound epithelial cell plasticity in COPD and also its regulation. We consider that understanding early changes in COPD will open new windows for therapy.

Heparin-binding epidermal growth factor (HB-EGF) drives EMT in patients with COPD: implications for disease pathogenesis and novel therapies

Chronic obstructive pulmonary disease (COPD) is a progressive and devastating chronic lung condition that has a significant global burden, both medically and financially. Currently there are no medications that can alter the course of disease. At best, the drugs in clinical practice provide symptomatic relief to suffering patients by alleviating acute exacerbations. Most of current clinical research activities are in late severe disease with lesser attention given to early disease manifestations. There is as yet, a lack of understanding of the underlying mechanisms of disease progression and the molecular switches that are involved in their manifestation. Small airway fibrosis and obliteration are known to cause fixed airflow obstruction in COPD, and the consequential damage to the lung has an early onset. So far, there is little evidence of the mechanisms that underlie this aspect of pathology. However, emerging research confirms that airway epithelial reprogramming or epithelial to mesenchymal transition (EMT) is a key mechanism that drives fibrotic remodelling changes in smokers and patients with COPD. A recent study by Lai et al. further highlights the importance of EMT in smoking-related COPD pathology. The authors identify HB-EGF, an EGFR ligand, as a key driver of EMT and a potential new therapeutic target for the amelioration of EMT and airway remodelling. There are also wider implications in lung cancer prophylaxis, which is another major comorbidity associated with COPD. We consider that improved molecular understanding of the intricate pathways associated with epithelial cell plasticity in smokers and patients with COPD will have major therapeutic implications.

Heparin-binding epidermal growth factor contributes to COPD disease severity by modulating airway fibrosis and pulmonary epithelial-mesenchymal transition

Although airway fibrosis and epithelial-mesenchymal transition (EMT) contribute to airway remodeling in chronic obstructive pulmonary disease (COPD), the mechanisms underlying their development have not been fully elucidated. In the present study, we aimed to assess heparin-binding epidermal growth factor (HB-EGF) expression in the airways of patients with COPD and to elucidate the possible role of HB-EGF in the pathology of COPD. Sputum and lung tissue HB-EGF expression was evaluated in control subjects and patients with COPD. The relationships between HB-EGF expression, disease severity, collagen deposition (fibrosis), and EMT were investigated. In vitro, human bronchial epithelial (HBE) cells and lung fibroblast cells exposed to the recombinant HB-EGF, collagen deposition and EMT were assessed. We found that sputum HB-EGF expression was significantly increased in patients with COPD compared with non-smokers and smokers without COPD. There was a significant positive correlation between sputum HB-EGF and COPD assessment test (CAT) score. HB-EGF expression was significantly increased in the lung tissue samples of patients with COPD and associated with collagen deposition and N- and E-cadherin, and vimentin expression. In vitro, HB-EGF promoted collagen production in lung fibroblasts. Moreover, HB-EGF induced the EMT process through induction of N-and E-cadherin, and vimentin expression in HBE cells. Collectively, HB-EGF induces airway remodeling by modulating airway fibrosis and pulmonary EMT, and contributes to the COPD severity. The current data may provide insight into the underlying pathogenesis of COPD, in which HB-EGF has an important pathogenic role.

Epithelial mesenchymal transition (EMT): a universal process in lung diseases with implications for cystic fibrosis pathophysiology

Cystic Fibrosis (CF) is a genetic disorder that arises due to mutations in the Cystic Fibrosis Transmembrane Conductance Regulator gene, which encodes for a protein responsible for ion transport out of epithelial cells. This leads to a disruption in transepithelial Cl-, Na + and HCO₃− ion transport and the subsequent dehydration of the airway epithelium, resulting in infection, inflammation and development of fibrotic tissue. Unlike in CF, fibrosis in other lung diseases including asthma, chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis has been well characterised. One of the driving forces behind fibrosis is Epithelial Mesenchymal Transition (EMT), a process where epithelial cells lose epithelial proteins including E-Cadherin, which is responsible for tight junctions. The cell moves to a more mesenchymal phenotype as it gains mesenchymal markers such as N-Cadherin (providing the cells with migration potential), Vimentin and Fibronectin (proteins excreted to help form the extracellular matrix), and the fibroblast proliferation transcription factors Snail, Slug and Twist. This review paper explores the EMT process in a range of lung diseases, details the common links that these have to cystic fibrosis, and explores how understanding EMT in cystic fibrosis may open up novel methods of treating patients with cystic fibrosis.

Factors associated with lung cancer in COPD patients

Background

The risk of dying of lung cancer is up to eightfold higher in patients with COPD than in age- and gender-matched controls. The aim of this study was to investigate the factors associated with lung cancer in a large cohort of COPD patients from primary care centers.

Methods

To analyze whether age, gender, socioeconomic factors, comorbidity, and medication affect the risk of lung cancer in COPD, we used a COPD cohort of primary care patients. Data from primary care medical records and mandatory Swedish national registers were collected and linked in this population-based, retrospective observational registry study (NCT01146392).

Results

Of the total cohort, 19,894 patients were included in the study. Five hundred and ninety-four lung cancer cases were diagnosed, corresponding to 3.0% of the studied population. In a multivariate analysis, the risk of lung cancer was lower if the COPD patients had a concurrent asthma diagnosis (HR: 0.54, CI: 0.41–0.71), while the risk of lung cancer increased with increasing age. A decreased lung cancer risk was observed in an exposure-dependent manner in patients who were prescribed inhaled corticosteroids (HR: 0.52, CI: 0.37–0.73), while the opposite was found for the use of acetylsalicylic acid (HR: 1.58, CI: 1.15–2.16).

Conclusion

In this large population-based cohort, a concurrent asthma diagnosis and use of inhaled corticosteroids were independently related to decreased risk of lung cancer in COPD patients, while the use of acetylsalicylic acid was associated with an increased risk. The findings of the present study should be seen as hypothesis generating and need to be confirmed in prospective studies.

Human antigen R enhances the epithelial-mesenchymal transition via regulation of ZEB-1 in the human airway epithelium

BACKGROUND

Increasing evidence suggests that human antigen R (HuR) is involved in the epithelial-mesenchymal transition (EMT) process of several diseases. However, the role of HuR in EMT in the airway epithelial cells of patients with COPD remains unclear.

METHODS

BEAS-2B cells were cultured and treated with 3%CSE. Western blotting, RT-PCR and immunofluoresence were used to detect the expression of HuR, ZEB-1. RNAi was used to suppress HuR expression. Then knockdown of HuR, RT-PCR and Western blotting showed that with siHuR-1 and siHuR-3, clear suppression of HuR expression was confirmed. We chose siHuR-3, the most effective one, to proceed with subsequent experiments. Immunofluorescence analysis, western blotting were used to detect the expression of E-cadherin, vimentin, ZEB-1 and HuR.

RESULTS

We show that more HuR expression is enhanced in the airways epithelium of smokers with or without COPD than controls (nonsmoker non-COPD patients). However, there was no definite correlation between HuR expression and FEV1%. Further study reveals that knockdown of HuR significantly increases the apoptosis of BEAS-2B cells and down-regulates ZEB-1 expression.

CONCLUSIONS

EMT is partially enhanced through the HuR-binding proteins and its post-transcriptional regulation role in airway epithelium in COPD.

Epithelial-to-mesenchymal transition in the context of epidermal growth factor receptor inhibition in non-small-cell lung cancer

The identification of oncogenic driver mutations in non-small-cell lung cancer (NSCLC) has led to the development of targeted drugs. Tyrosine kinase inhibitors (TKIs) directed against the epidermal growth factor receptor (EGFR) target lung tumours bearing EGFR-activating mutations. This new therapeutic strategy has greatly improved tumour response rates. However, drug resistance invariably occurs during TKI-based treatment. Epithelial-to-mesenchymal transition (EMT) is one of the resistance mechanisms identified in EGFR-mutated NSCLC treated with TKIs. In this review we gather together the most important findings on this phenomenon in relation to cancer stem cells and cancer epigenetics. We also outline the correlation between the effects of stromal factors from the microenvironment, the transcription factors activated, the epigenetic changes in chromatin, and the evolution of cellular behaviour. Notably, EMT has already been shown to be the link between benign lung diseases such as chronic obstructive pulmonary disease and lung carcinogenesis. The various mechanisms of acquired resistance to EGFR-TKIs are also briefly described to provide background information on EMT. Our extensive review of the scientific literature serves to highlight the cellular and molecular events that lead to the onset of EMT in NSCLC cells treated with EGFR-TKIs. Finally, we put forward a hypothesis to explain why, in some cases, EMT rather than other known mechanisms is involved in resistance to TKIs.

Airway Epithelium Dysfunction in Cystic Fibrosis and COPD

Cystic fibrosis is a genetic disease caused by mutations in the CFTR gene, whereas chronic obstructive pulmonary disease (COPD) is mainly caused by environmental factors (mostly cigarette smoking) on a genetically susceptible background. Although the etiology and pathogenesis of these diseases are different, both are associated with progressive airflow obstruction, airway neutrophilic inflammation, and recurrent exacerbations, suggesting common mechanisms. The airway epithelium plays a crucial role in maintaining normal airway functions. Major molecular and morphologic changes occur in the airway epithelium in both CF and COPD, and growing evidence suggests that airway epithelial dysfunction is involved in disease initiation and progression in both diseases. Structural and functional abnormalities in both airway and alveolar epithelium have a relevant impact on alteration of host defences, immune/inflammatory response, and the repair process leading to progressive lung damage and impaired lung function. In this review, we address the evidence for a critical role of dysfunctional airway epithelial cells in chronic airway inflammation and remodelling in CF and COPD, highlighting the common mechanisms involved in the epithelial dysfunction as well as the similarities and differences of the two diseases.

Airway epithelial barrier dysfunction in the pathogenesis and prognosis of respiratory tract diseases in childhood and adulthood

The lungs are in direct contact with the environment through the tubular structure that constitutes the airway. Starting from the nasal orifice, the airway is exposed to foreign particles including infectious agents, allergens, and other substances that can damage the airways. Therefore, the airway must have a functional epithelial barrier both in the upper and lower airways to protect against these threats. As with the skin, it is likely that the pathogenesis of respiratory diseases is a consequence of epithelial barrier defects in these airways. The characteristics of this system, starting from the beginning of life and extending into maturing and aging, determine the prognosis of respiratory diseases. In this article, we discuss the pathogenesis, clinical phenotype, and prognosis of respiratory diseases from newborns to adulthood in the context of epithelial barrier function and dysfunction.

β-catenin, Twist and Snail: Transcriptional regulation of EMT in smokers and COPD, and relation to airflow obstruction

COPD is characterised by poorly reversible airflow obstruction usually due to cigarette smoking. The transcription factor clusters of β-catenin/Snail1/Twist has been implicated in the process of epithelial mesenchymal transition (EMT), an intermediate between smoking and airway fibrosis, and indeed lung cancer. We have investigated expression of these transcription factors and their "cellular localization" in bronchoscopic airway biopsies from patients with COPD, and in smoking and non-smoking controls. An immune-histochemical study compared cellular protein expression of β-catenin, Snail1 and Twist, in these subject groups in 3 large airways compartment: epithelium (basal region), reticular basement membrane (Rbm) and underlying lamina propria (LP). β-catenin and Snail1 expression was generally high in all subjects throughout the airway wall with marked cytoplasmic to nuclear shift in COPD (P < 0.01). Twist expression was generalised in the epithelium in normal but become more basal and nuclear with smoking (P < 0.05). In addition, β-catenin and Snail1 expression, and to lesser extent of Twist, was related to airflow obstruction and to expression of a canonical EMT biomarker (S100A4). The β-catenin-Snail1-Twist transcription factor cluster is up-regulated and nuclear translocated in smokers and COPD, and their expression is closely related to both EMT activity and airway obstruction.

Airway inflammation in chronic obstructive pulmonary disease (COPD): a true paradox

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is primarily an airway condition, which mainly affects cigarette smokers and presents with shortness of breath that is progressive and poorly reversible. In COPD research, there has been a long held belief that airway disease progression is due to inflammation. Although this may be true in the airway lumen with innate immunity activated by the effect of smoke or secondary to infection, the accurate picture of inflammatory cells in the airway wall, where the pathophysiological COPD remodeling occurs, is uncertain and debatable. Areas covered: The current review provides a comprehensive literature survey of the changes in the main inflammatory cells in human COPD patients and focuses on contrarian views that affect the prevailing dogma on inflammation. The review also delves into the role of oxidative stress and inflammasomes in modulating the immune response in COPD. Further, the effects of inflammation in affecting the epithelium, fibroblasts, and airway remodeling are discussed. Expert commentary: Inflammation as a driving force for airway wall damage and remodelling in early COPD is at the very least 'oversimplified' and is likely to be misleading. This has serious implications for rational thinking about the illness, including pathogenesis and designing therapy.

Roflumilast treatment inhibits lung carcinogenesis in benzo(a)pyrene-induced murine lung cancer model

Roflumilast, a potent and selective inhibitor of phosphodiesterase-4 (PDE4), has been used in treatment of COPD. PDE4 inhibitor is associated with inhibition of chronic airway inflammation, oxidative stress, and mesenchymal markers in B(a)P-induced lung tumors. The aim of this study was to assess whether roflumilast alone or added to inhaled budesonide might have dose-dependent inhibition on lung carcinogenesis induced by carcinogen B(a)P in mice. Female A/J mice were given a single dose of benzo(a)pyrene. Administration of roflumilast (1mg/kg or 5mg/kg) via oral gavage and aerosolized budesonide (2.25mg/ml) began 2 weeks post-carcinogen treatment and continued for 26 weeks. Tumor load was determined by averaging the total tumor volume in each group. Benzo(a)pyrene induced an average tumor size of 9.38 ± 1.75 tumors per mouse, with an average tumor load of 19.53 ± 3.81mm³. Roflumilast 5mg/kg treatment decreased (P < 0.05) tumor load per mouse compared to the B(a)P group. Roflumilast 5mg/kg treatment significantly increased the levels of cAMP in tumors with adjacent lung tissues (P < 0.05). The expression level of PDE4D gene was decreased by roflumilast 5mg/kg treatment, significantly (P < 0.05). Compared to the B(a)P exposure group, expression levels of HIF-1α and VEGFA were attenuated by roflumilast 5mg/kg treatment (P < 0.05). High-dose roflumilast can attenuate lung carcinogenesis in B(a)P-induced murine lung cancer model. The chemopreventive effect of roflumilast might be associated with inhibition of increased cAMP-mediated inflammatory process and markers of angiogenesis in tumor tissues.

Glucocorticoids ameliorate TGF-β1-mediated epithelial-to-mesenchymal transition of airway epithelium through MAPK and Snail/Slug signaling pathways

Chronic rhinosinusitis with nasal polyps (CRSwNP) is closely associated with tissue remodeling. Epithelial-to-mesenchymal transition (EMT), a process of tissue remodeling, can be a therapeutic target of CRSwNP. Glucocorticoids are a type of steroid hormone that is used primarily in medical therapy for patients with CRSwNP; however, their effects on EMT in the airway epithelium remain unknown. To investigate the effects of dexamethasone and fluticasone propionate, a class of glucocorticoids, on transforming growth factor-β1 (TGF-β1) -induced EMT, we used A549 cells, human primary nasal epithelial cells (hPNECs) and ex vivo organ culture of the inferior turbinate. TGF-β1 induced changes in cell morphology, suppressed the expression of E-cadherin and enhanced the expression of a-smooth muscle actin, vimentin and fibronectin in A549 cells. However, glucocorticoids inhibited EMT, migration and invasion enhancement by TGF-β1. We found that the induction of phosphorylated ERK, p38 and the activity of Snail and Slug transcription factors by TGF-β1 were suppressed by glucocorticoids. Glucocorticoids also had a similar effect in hPNECs and ex vivo organ cultures of the inferior turbinate. These findings suggest that glucocorticoids might be a useful therapy for preventing tissue remodeling by blocking the EMT initiated by TGF-β1-induced MAPK and Snail/Slug signaling pathways in CRSwNP.

Epithelial and endothelial cell plasticity in chronic obstructive pulmonary disease (COPD)

Chronic Obstructive Pulmonary Disease (COPD) is mainly caused by smoking and presents with shortness of breath that is progressive and irreversible. It is a worldwide health problem and the fourth most common cause of chronic disability and mortality (even in developed countries). It is a complex disease involving both the airway and lung parenchyma. Small-airway fibrosis is the main contributor to physiological airway dysfunction in COPD. One potential mechanism contributing to small-airway fibrosis is epithelial mesenchymal transition (EMT). When associated with angiogenesis (EMT-type-3), EMT may well also be linked to the development of airway epithelial cancer, which is closely associated with COPD and predominantly observed in large airways. Vascular remodeling has also been widely reported in smokers and patients with COPD but the mechanisms behind it are poorly understood. It is quite possible that the process of endothelial to mesenchymal transition (EndMT) is also active in COPD lungs, in addition to EMT. Understanding these pathological mechanisms will greatly enhance our knowledge of the immunopathology of smoking-related lung disease. Only by understanding these processes can new therapies be developed.