Exposing a deadly alliance: Novel insights into the biological links between COPD and lung cancer

Chronic obstructive pulmonary disease (COPD) affects more than 200 million people worldwide and is expected to become the third leading cause of death in 2020. COPD is characterized by progressive airflow limitation, due to a combination of chronic inflammation and remodeling of the small airways (bronchiolitis) and loss of elastic recoil caused by destruction of the alveolar walls (emphysema). Lung cancer is the most important cause of cancer-related death in the world. (Cigarette) smoking is the principal culprit causing both COPD and lung cancer; in addition, exposure to environmental tobacco smoke, biomass fuel smoke, coal smoke and outdoor air pollution have also been associated with an increased incidence of both diseases. Importantly, smokers with COPD – defined as either not fully reversible airflow limitation or emphysema – have a two- to four-fold increased risk to develop lung cancer. In this review, we highlight several of the genetic, epigenetic and inflammatory mechanisms, which link COPD and carcinogenesis in the lungs. Elucidating the biological pathways and networks, which underlie the increased susceptibility of lung cancer in patients with COPD, has important implications for screening, prevention, diagnosis and treatment of these two devastating pulmonary diseases.     

Recent advances in the assessment and management of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a syndrome of progressive airflow limitation caused by an abnormal inflammatory reaction of the airways and lung parenchyma. It stems from chronic tobacco smoking, and indoor air pollution, and bronchospasm is the predominant cause of the symptoms. The condition is the result of environmental insult and host reaction that is likely to be genetically predetermined. Chronic obstructive pulmonary disease exhibits expiratory airflow limitation due to abnormalities in the airways and/or lung parenchyma. The disease begins with an asymptomatic phase and onset of the symptomatic phase develops with a fall in forced expiratory volume in one second (FEV1) below 70% of the predicted value. There is reduction in diffusing capacity, hypoxaemia and alveolar hypoventilation. However, it is intriguing why only a fraction of smokers develop clinically relevant COPD.     

氧化应激在慢性阻塞性肺疾病发生中的作用及防治策略

COPD 特征是慢性气道炎症、细小支气管重塑及肺实质破坏。研究表明,香烟烟雾等有害气体所引起的氧化应激在 COPD 发展过程起到了至关重要的作用。吸烟增强氧化应激,使氧化/抗氧化比例失衡,直接损伤肺组织,加重气道炎症反应,引起自身免疫反应,最终导致气流受限。因此,对抗氧化应激、提高宿主抗氧化能力,是 COPD 防治的最新着重点。     

Epidemiologie und Bedeutung tabakassoziierter Lungenkrankheiten

Nearly all lung diseases are related to tobacco smoking. This can be explained by the multitude of irritative, toxic, mutagenic, and carcinogenic substances inhaled with cigarette smoke. For two diseases with high prevalence and mortality, i.e., chronic obstructive pulmonary disease (COPD) and lung cancer, cigarette smoke is the single main risk factor. However, nearly all other lung diseases are also caused or aggravated by smoking, e.g., asthma, influenza, pneumonia, tuberculosis, acute respiratory distress syndrome (ARDS), pulmonary hypertension, and interstitial lung disease. Furthermore, second-hand smoke is similarly related to COPD, asthma, lung cancer, pneumonia, tuberculosis, ARDS, and labor-related disease. Smoke-free legislation and uncomplicated access to smoking cessation services are, therefore, of high priority to the health system.     

细胞凋亡与慢性阻塞性肺疾病

慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)定义为气道的慢性炎症、肺实质进行性的破坏.大部分由抽烟引起.涉及到以下几个机制:气道的慢性炎症、蛋白酶/抗蛋白酶失衡、氧化应激.最近的文献提及COPD第4个重要的机制肺内结构细胞的凋亡,血管内皮生长因子在其中起重要作用.凋亡的途径:如caspase-3、神经酰胺等,可以作为预防凋亡和肺气肿发生的靶途径.本篇综述就COPD凋亡机制的相关文献进行讨论.为COPD和肺气肿的凋亡机制提供一些新的文献.     

Pathogenesis of COPD. Part III. Inflammation in COPD.

Chronic obstructive pulmonary disease (COPD) is mostly caused by cigarette smoking and affects up to 25% of smokers. Air pollution and occupational exposure to dust and fumes can also induce COPD. COPD is characterised by airflow limitation that is not fully reversible and chronic inflammation of the lung. Most patients with COPD also have evidence of tissue remodelling in the smaller airways. How the different pathological features are linked remains unknown. The inflammation of the COPD lung is initially caused by cigarette smoke and the increased infiltration of immune cells into the lung, but it is not clear why the inflammation persists after smoking cessation, while other pathologies partly reverse. Furthermore, anti-inflammatory treatments are not very successful and only control the symptoms but do not cure the disease. Animal models suggest that the imbalance of proteases and antiproteases is central to the major pathologies in the COPD lung. However, this hypothesis was never fully confirmed in humans and may only explain the degenerative stage of the disease, emphysema. The role of tissue-forming cells in the pathogenesis of COPD has not been adequately studied and indicates a deregulated synthesis of growth factors and cytokines in COPD. Finally, recent studies indicate that alpha-1-antitrypsin activity plays a role in all forms of COPD.     

化学趋化因子在慢性阻塞性肺疾病中的作用

慢性阻塞性肺疾病(chronic obstructive pulmonary diseases,COPD)是一组以气流受限,且不完全可逆为特征的肺部疾病,认为与肺部对有害气体或有毒颗粒的异常炎症反应有关.目前仍缺乏有效的治疗手段.其诱发慢性炎症的具体细胞分子学机制仍不清楚.然而,越来越多的证据表明香烟诱导的炎症细胞的募集取决于趋化因子及其配体的调节.这里主要探讨CXC-和CC-家族与各种炎性细胞的相互调节,通过阻断趋化因子而减少COPD患者的炎性细胞浸润及实质破坏可能为一种有效的抗炎策略.     

Chronic obstructive pulmonary disease and lung cancer: new molecular insights

Both chronic obstructive pulmonary disease (COPD) and lung cancer are major causes of death worldwide. In most cases this reflects cigarette smoke exposure which is able to induce an inflammatory response in the airways of smokers. Indeed, COPD is characterized by lower airway inflammation, and importantly, the presence of COPD is by far the greatest risk factor for lung cancer amongst smokers. Cigarette smoke induces the release of many inflammatory mediators and growth factors including TGF-β, EGFR, IL-1, IL-8 and G-CSF through oxidative stress pathways and this inflammation may persist for decades after smoking cessation. Mucus production is also increased by these inflammatory mediators, further linking airway inflammation to an important mechanism of lung cancer. A greater understanding of the molecular and cellular pathobiology that distinguishes smokers with lung cancer from smokers with and without COPD is needed to unravel the complex molecular interactions between COPD and lung cancer. By understanding the common signalling pathways involved in COPD and lung cancer the hope is that treatments will be developed that not only treat the underlying disease process in COPD, but also reduce the currently high risk of developing lung cancer in these patients.     

Chronic obstructive pulmonary disease: histopathology, inflammation and potential therapies

Chronic obstructive pulmonary disease (COPD) is a major worldwide health burden with increasing morbidity, mortality and health care cost. It is a slowly progressive chronic inflammatory condition that affects the conducting airways (both large and small) and lung parenchyma. In COPD, inflammation is evident early on even in mild disease and increases with disease severity. Recent advances in our knowledge demonstrate, by comparison with asthma, the distinctive, "abnormal" or exaggerated inflammatory processes involved in the pathogenesis of COPD and thus identify novel therapeutic targets that could potentially impact on disease progression. The present review will focus on what is known of the abnormal inflammatory response of COPD in different regions of the conducting airways and lung. Novel, potentially promising approaches to therapy are presented.     

Functional significance of apoptosis in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a highly prevalent airway disease characterized by an abnormal inflammatory response of the lungs to noxious particles and gases. Cigarette smoking remains a major risk factor in COPD development. Accumulating evidence suggests that apoptosis, a regulated form of cell death, may play an important role in COPD pathogenesis. Increased numbers of apoptotic cells can be detected in lung tissue and airways of human subjects with COPD, relative to normal lungs or those from smokers without COPD. Alveolar wall destruction associated with emphysema development, may involve increased apoptosis of alveolar structural cells. Several intervention-induced apoptotic models (e.g., cigarette smoke, vascular-endothelial growth factor inhibition, and interferon-gamma) cause emphysematous changes in vitro and in vivo. Increased apoptosis in COPD can also imply defects in the normal physiological clearance of apoptotic cells. Additional factors that relate to perpetuation of the pathogenesis of COPD, including protease/antiprotease imbalance, inflammation and oxidative stress, may mutually promote apoptosis or contribute to impaired clearance of apoptotic cells. Given that cigarette smoking is the most common cause of COPD, identification of the pathways of cigarette smoke-induced apoptosis may further the understanding of COPD pathogenesis. However, apoptosis rate is not diminished after cessation of cigarette smoking, indicating that other mechanisms perpetuate apoptosis in COPD. Therefore, understanding functional relationships between apoptosis and protease/antiprotease imbalance, inflammation, oxidative stress and other factors potentially involved in COPD pathogenesis may uncover crucial therapeutic targets.     

Genetic epidemiology of cigarette smoke-induced lung disease

Chronic obstructive pulmonary disease (COPD) and lung cancer represent two diseases that share a strong risk factor in smoking, and COPD increases risk of lung cancer even after adjusting for the effects of smoking. These diseases not only occur jointly within an individual but also there is evidence of shared occurrence within families. Understanding the genetic contributions to these diseases, both individually and jointly, is needed to identify the highest risk group for screening and targeted prevention, as well as aiding in the development of targeted treatments. The chromosomal regions that have been identified as being associated either jointly or independently with lung cancer, COPD, nicotine addiction, and lung function are presented. Studies jointly measuring genetic variation in lung cancer and COPD have been limited by the lack of detailed COPD diagnosis and severity data in lung cancer populations, the lack of lung cancer-specific phenotypes (histology and tumor markers) in COPD populations, and the lack of inclusion of minorities. African Americans, who smoke fewer cigarettes per day and have different linkage disequilibrium and disease patterns than whites, and Asians, also with different patterns of exposure to lung carcinogens and linkage patterns, will provide invaluable information to better understand shared and independent genetic contributions to lung cancer and COPD to more fully define the highest risk group of individuals who will most benefit from screening and to develop molecular signatures to aid in targeted treatment and prevention efforts.     

Role of chronic obstructive pulmonary disease in lung cancer pathogenesis

Chronic obstructive pulmonary disease (COPD) and lung cancer are two important smoking related conditions. However, COPD has been shown to be an independent risk factor for lung cancer regardless of smoking history, suggesting that COPD and lung cancer may share a common pathogenesis. This review summarizes the epidemiology of lung cancer and COPD briefly, as well as discussing the potential for shared genetic risk, and shared genomic mechanisms, such as epigenetic changes or DNA damage induced by smoking. How key areas of COPD pathogenesis, such as inflammation, oxidative stress and protease imbalance may contribute to subsequent development of cancer will also be covered. Finally the possibility that consequences of COPD, such as hypoxia, influence carcinogenesis will be reviewed. By understanding the pathogenesis of COPD and lung cancer in detail it is possible that new treatments may be developed and the risk of lung cancer in COPD may be reduced.     

COPD合并肺癌的发病机制与治疗进展

COPD是老年人呼吸系统多发疾病,与吸烟有着密切关系。近年来,COPD 的发病率仍在不断地上升,现已位居全球人口死亡原因的第4位,据 WHO 预测,到2030年将升至第3位。肺癌是危害人类健康的常见恶性肿瘤之一,是癌症死亡的首位原因,其发病率与病死率也逐年上升,目前已占全球癌症的12%以上。多年来,人们将COPD和肺癌作为2个独立的疾病进行研究。已有研究显示,在原有COPD基础上肺癌发病率比一般人群高2.76倍,COPD被视为独立于吸烟之外可以导致肺癌的另一项危险因素。本文将对两者的发病机制和治疗进展作一简要综述。     

Similar gene expression profiles in smokers and patients with moderate COPD

Chronic obstructive pulmonary disease (COPD) is characterized by multiple cellular and structural changes affecting the airways, lung parenchyma and vasculature, some of which are also identified in smokers without COPD. The molecular mechanisms underlying these changes remain poorly understood. With the aim of identifying mediators potentially implicated in the pathogenic processes that occur in COPD and their potential relationship with cigarette smoking, we evaluated the mRNA expression of genes involved in inflammation, tissue remodeling and vessel maintenance. Lung tissue samples were obtained from 60 patients who underwent lung resection (nonsmokers, n=12; smokers, n=12; and moderate COPD, n=21) or lung transplant (severe-to-very severe COPD, n=15). PCR arrays containing 42 genes coding for growth factors/receptors, cytokines, metalloproteinases, adhesion molecules, and vessel maintenance mediators were used. Smoking-induced changes include the up-regulation of inflammatory genes (IL-1β, IL-6, IL-8, CCL2, and CCL8) and the decreased expression of growth factor/receptor genes (BMPR2, CTGF, FGF1, KDR and TEK) and genes coding for vessel maintenance factors (EDNRB). All these genes exhibited a similar profile in moderate COPD patients. The up-regulation of MMP1 and MMP9 was the main change associated with COPD. Inflammatory genes as well as the endothelial selectin gene (SELE) were down-regulated in patients with more severe COPD. Clustering analysis revealed a closer relationship between moderate COPD and smokers than between both subsets of COPD patients for this selected set of genes. The study reveals striking similarities between smokers and COPD patients with moderate disease emphasizing the crucial role of cigarette smoking in the genesis of these changes, and provides additional evidence of the involvement of the matrix metalloproteinase's in the remodeling process of the lung in COPD.     

Non‐pharmacological treatments for COPD

Chronic obstructive pulmonary disease (COPD) affects roughly 10% of the global population and is growing in prevalence annually. COPD is characterized by progressive non‐reversible narrowing of airways mainly due to cigarette smoking. Therapeutic interventions aimed at altering this progressive disease course can largely be grouped into pharmacological or non‐pharmacological therapies. The focus of this paper is on the non‐pharmacological aspects of COPD management, reviewing the current literature to provide an evidence‐based management approach. Non‐pharmacological therapies reviewed in this article include the implementation of comprehensive care models utilizing a coordinated multidisciplinary team, tele‐monitoring and patient‐centred approach to optimize COPD care and improve compliance. Preventing progression of COPD via smoking cessation remains of paramount importance, and newer therapeutic options including electronic cigarettes show promise in small studies as cessation aids. COPD has systemic manifestations that can be ameliorated with the enrollment in pulmonary rehabilitation programmes, which focus on exercise endurance to improve dyspnoea and quality of life. Advanced therapeutics for COPD includes lung volume reduction surgery for a pre‐specified cohort and minimally invasive bronchoscopic valves that in recent reviews show promise. Lastly, patients on maximal COPD therapy with progressive disease can be referred for lung transplantation; however, this often requires a highly selected and motivated patient and care team. Survival rates for lung transplantation are improving; thus, this procedure remains a viable option as more expertise and experience are gained.     

State of the art. Chronic obstructive pulmonary disease, inflammation, and lung cancer

Both lung cancer and chronic obstructive pulmonary disease (COPD) are associated with cigarette smoking, which, by generating reactive oxidant species, induces a chronic inflammatory state in the lung. Activation, particularly of nuclear factor-kappaB, occurs in both cancer and COPD, and expression of a number of genes is altered in both diseases. In lung cancer, DNA damage, lack of DNA repair, and genomic instability predominate, whereas matrix degradation, lack of repair, and an intense immune response predominate in COPD. The reasons for the different responses to a common inflammatory response induced by smoking remain to be determined, but likely lie in genetic polymorphisms in genes that regulate genome integrity in cancer and that regulate the immune response to tissue destruction in COPD.     

Chronic obstructive pulmonary disease in women: exploring gender differences

PURPOSE OF REVIEW: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality throughout the world. This major public health threat is ranked twelfth as a worldwide burden of disease and is projected to rank fifth by the year 2020 as a cause of lost quantity and quality of life. The impact of this disease in women is significantly understudied but the evidence that does exist reveals potentially substantial gender differences in the susceptibility to, severity of, and response to management of COPD. RECENT FINDINGS: The best known risk factor for the development of COPD is tobacco smoking. While smoking rates in women have largely stabilized in developed countries, the rates are continuing to climb in developing countries. While it is not clear whether women are more susceptible to the toxic effects of cigarette smoke than men, it is known that the incidence and prevalence of COPD will continue to climb as more women smoke. Other known risk factors for the development of COPD include air pollution, infections, occupational exposures, and genetic factors. Air pollution, particularly fine particulate indoor air pollution from biomass fuels disproportionately affects women. Infections such as human immunodeficiency virus (HIV) and tuberculosis (TB) disproportionately affect vulnerable populations such as poor women and occupational exposures to various dusts and toxins are often gender specific. Genetic factors are still being explored but there seems a preponderance of women who are affected by early-onset and non-smoking related COPD. Women with COPD also seem to be underdiagnosed by physicians and may have different responses to medical treatment, smoking cessation interventions, and pulmonary rehabilitation programs. SUMMARY: Chronic obstructive pulmonary disease in women is an understudied subject but is gaining attention as a significant public health threat. In developed countries, efforts at preventing the initiation of tobacco smoking and targeting smoking cessation programs in women are needed. In developing countries, efforts to promote cleaner fuels, improved stoves, better home ventilation, reduce toxic dust and fume exposures, combat infectious diseases such as TB and HIV, and improve nutrition are all ways in which the lung health of women can be improved.     

Prevalence of undiagnosed and undertreated chronic obstructive pulmonary disease in lung cancer population

Background and objective: Chronic obstructive pulmonary disease (COPD) is a risk factor and important coexisting disease for lung cancer; however, the current status of management of COPD in lung cancer patients is not fully described. This study addressed this issue in a general teaching hospital in China. Methods: Medical records of hospitalized lung cancer patients in Zhongshan Hospital, Fudan University, between January 2006 and December 2010 were reviewed. The definition of COPD was according to the spirometric criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) document. The diagnostic rate (COPD recorded as a discharge diagnosis/spirometry‐defined percentage) and conformity to GOLD treatment guidelines were investigated. The factors influencing diagnosis were analysed. Results: During the study period, the prevalence of spirometry‐defined COPD in hospitalized lung cancer patients was 21.6% (705/3263). The overall diagnostic rate of COPD was 7.1%, and the treatment conformity for stable and acute exacerbation of COPD was 27.1% and 46.8%, respectively. Respiratory physicians had a higher diagnostic rate than non‐respiratory doctors (34.8% vs 2.9%, P < 0.001) and a better treatment conformity for acute exacerbation of COPD (63.6% vs 37.5%, P = 0.048). Patients with COPD as a discharge diagnosis had more chance to receive guideline‐consistent treatment. The diagnostic rate of COPD was higher among patients with a history of smoking, respiratory diseases or symptoms. Conclusions: COPD is substantially underdiagnosed and undertreated in a hospitalized lung cancer population. History of smoking, respiratory diseases and symptoms promotes diagnosis. Education of COPD knowledge among patients and doctors is urgently required in this special population.     

Budesonide inhibits interleukin-32 expression in a rat model of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disorder of the lung, and is the fifth leading cause of morbidity worldwide. A novel proinflammatory factor, interleukine-32 (IL-32), is suggested as a risk factor of COPD. Budesonide is widely used for COPD treatment as anti-inflammatory drug. However, the inflammatory inhibition mechanism of budesonide is not fully understood. In this study, we used a rat model with COPD to investigate the effect of budesonide on IL-32 expression in lung tissue. We found that cigarette smoking (CS) strongly induced IL-32 expression in lung tissue, seriously weakened lung function, and damaged pulmonary tissue. Budesonide inhibited the expression of IL-32 in lung tissue. In budesonide-treated rats, we observed no repair of damaged lung tissue but the pulmonary function was partly recovered. To our knowledge, this is the first report that budesonide inhibits the expression of IL-32 in lung tissues, which is strongly induced by CS.