Morphologic and molecular study of lung cancers associated with idiopathic pulmonary fibrosis and other pulmonary fibroses

Impact of preexisting interstitial lung disease on outcomes of lung cancer surgery: A monocentric retrospective study

INTRODUCTION

Interstitial lung disease (ILD) is a known risk factor for lung cancer (LC). However, the surgical risk of LC in patients with ILD remains unclear. Therefore, we conducted a single-center retrospective study to assess clinical features and outcomes of LC population who underwent surgery with or without ILD.

METHODS

Patients who underwent surgery for LC between January 2006 and June 2023 in our center were assessed using data extracted from the nationwide EPITHOR thoracic surgery database. Suspicion of ILD was based on patients' records. Confirmation of ILD was then made on the patient's medical and radiological history. Patients were classified according to the pattern of ILD. The study aimed to describe the outcomes after lung cancer resection in patients with confirmed LC-ILD group compared to those without ILD (LC-non-ILD): post-operative complications, disease-free survival (DFS) and overall survival (OS). A subgroup analysis was also performed on patients with idiopathic pulmonary fibrosis and lung cancer (LC-IPF).

RESULTS

4073 patients underwent surgery for LC at Assistance Publique des Hôpitaux de Marseille between January 2006 and June 2023. Of these, 4030 were in the LC-non-ILD group and 30 were LC-ILD patients. In the LC-ILD group, the predominant CT scan pattern was probable UIP (50 %). OS was not significantly lower in the LC-ILD group (45 months versus 84 months, p = 0.068). Dyspnea and tumor size were identified as potential univariate predictors of OS. No significant differences were observed on post-operative complications or their severity. The most common post-operative complications in the LC-ILD group were prolonged air leak, respiratory failure, or pneumonia. 13 patients had cancer recurrence in the LC-ILD group.

CONCLUSION

Our study provides a comprehensive analysis of a LC-ILD population features and outcome when undergoing surgery for LC. Patients with LC-ILD appeared to have a reduced OS compared with LC-non-ILD. Further investigations with larger prospective studies could be useful to confirm and develop these preliminary findings.

Interstitial Lung Diseases and Non-Small Cell Lung Cancer: Particularities in Pathogenesis and Expression of Driver Mutations

INTRODUCTION

Interstitial lung diseases are a varied group of diseases associated with chronic inflammation and fibrosis. With the emerging and current treatment options, survival rates have vastly improved. Having in mind that the most common type is idiopathic pulmonary fibrosis and that a significant proportion of these patients will develop lung cancer as the disease progresses, prompt diagnosis and personalized treatment of these patients are fundamental.

SCOPE AND METHODS

The scope of this review is to identify and characterize molecular and pathogenetic pathways that can interconnect Interstitial Lung Diseases and lung cancer, especially driver mutations in patients with NSCLC, and to highlight new and emerging treatment options in that view.

RESULTS

Common pathogenetic pathways have been identified in sites of chronic inflammation in patients with interstitial lung diseases and lung cancer. Of note, the expression of driver mutations in EGFR, BRAF, and KRAS G12C in patients with NSCLC with concurrent interstitial lung disease is vastly different compared to those patients with NSCLC without Interstitial Lung Disease.

CONCLUSIONS

NSCLC in patients with Interstitial Lung Disease is a challenging diagnostic and clinical entity, and a personalized medicine approach is fundamental to improving survival and quality of life. Newer anti-fibrotic medications have improved survival in IPF/ILD patients; thus, the incidence of lung cancer is going to vastly increase in the next 5-10 years.

Subsolid Nodules: Significance and Current Understanding

Subsolid nodules are heterogeneously appearing and behaving entities, commonly encountered incidentally and in high-risk populations. Accurate characterization of subsolid nodules, and application of evolving surveillance guidelines, facilitates evidence-based and multidisciplinary patient-centered management.

Exploring the efficacy and molecular mechanism of Danhong injection comprehensively in the treatment of idiopathic pulmonary fibrosis by combining meta-analysis, network pharmacology, and molecular docking methods

BACKGROUND

Danhong injection, a compound injection of Chinese herbal medicine, has been widely used in idiopathic pulmonary fibrosis (IPF) at present as an adjuvant treatment. However, the clinical efficacy and molecular mechanism of IPF are still unclear. This study will evaluate and explore the clinical efficacy and molecular mechanism of Danhong injection in the treatment of IPF.

METHODS

In meta-analysis, the computer was used to search 8 databases (PubMed, EMbase, CENTRAL, MEDLINE, CBM, CNKI, WanFang, and VIP) to collect the RCTs, and RevMan 5.3 and Stata 14.0 were used for statistical analysis. It has been registered on PROSPERO: CRD42020221096. In network pharmacology, the main chemical components and targets of the chemical components of Danhong injection were obtained in TCMSP and Swiss Target Prediction databases. The main targets of IPF were obtained through Gencards, Disgenet, OMIM, TTD, and DRUGBANK databases. The String platform was used to construct PPI networks. Cytoscape 3.8.2 was used to construct the "Danhong components - IPF targets-pathways" network. The molecular docking verification was conducted by Auto Dock.

RESULTS

Twelve RCTs were finally included with a total of 896 patients. The meta-analysis showed that Danhong injection could improve the clinical efficiency ([OR] = 0.25, 95% CI [0.15, 0.41]), lung function, arterial blood gas analysis, inflammatory cytokines, and serum cytokines associated with pulmonary fibrosis of IPF patients, respectively (P < .05). The core active components of Danhong injection on IPF were Luteolin, Quercetin, and Kaempferol, and the core targets were PTGS2, AR, ESR1, PPARG, and RELA. Danhong injection mainly improved IPF through PD-L1 expression and PD-1 checkpoint path in cancer, pathways in cancer, PI3K-Akt signaling pathway, etc.

CONCLUSION

These results provided scientific basis for the clinical use of Danhong injection for the treatment of IPF, and provided a new direction to explore the potential mechanism of action of Danhong injection.

Clinical characteristics, proteins, and genes related to interstitial pneumonia-associated squamous cell carcinoma of the lungs

Squamous cell carcinoma (SCC) is a common histological type of lung carcinoma that is associated with interstitial pneumonia (IP). We hypothesized that identifying specific genetic alterations or molecular markers of SCC with IP may aid the development of novel therapeutic strategies for the same. Therefore, in the present study, we aimed to identify tumorigenic genetic alterations and molecular markers in cases of SCC with IP. We included 28 lung SCC cases (14 cases with IP and 14 cases without IP). We performed immunohistochemistry for STAT3, STAT5, and TLE1, and next-generation sequencing was performed using an iSeq 100 system. The panel used in this study targeted 50 cancer-associated genes. Immunohistochemically, the rate of TLE1 positivity was higher in the SCC without IP group (93 %) than in the SCC with IP group (29 %), while that of STAT5 was higher in the SCC with IP group (79 %) than in the SCC without IP group (14 %). STAT3 expression was high in both the groups (SCC with IP, 64 %; SCC without IP, 71 %). Eighteen genes were mutated in more than six samples, and FBXW7 mutation was mainly observed in the SCC with IP group (p < 0.01). Mechanisms underlying tumorigenesis in SCC with IP included STAT5 activation via inflammation, while that in SCC without IP included squamous TLE1-mediated metaplasia. These findings are based on smoking-induced STAT3 activation; therefore, patients with IP who smoke are more likely to have progressive SCC. We also found that FBXW7 mutations may be associated with SCC with IP and keratinization. ERBB4 and KDR mutations were observed in both with or without IP, and these genes may be tumor-related genes in SCC. These molecular markers may help determine the prognoses of patients with SCC with IP and direct the development of treatment approaches.

KRASG12C Inhibitor as a Treatment Option for Non-Small-Cell Lung Cancer with Comorbid Interstitial Pneumonia

Non-small-cell lung cancer (NSCLC) with comorbid interstitial pneumonia (IP) is a population with limited treatment options and a poor prognosis. Patients with comorbid IP are at high risk of developing fatal drug-induced pneumonitis, and data on the safety and efficacy of molecularly targeted therapies are lacking. KRAS mutations have been frequently detected in patients with NSCLC with comorbid IP. However, the low detection rate of common driver gene mutations, such as epidermal growth factor receptor and anaplastic lymphoma kinase, in patients with comorbid IP frequently results in inadequate screening for driver mutations, and KRAS mutations may be overlooked. Recently, sotorasib and adagrasib were approved as treatment options for advanced NSCLC with KRASG12C mutations. Although patients with comorbid IP were not excluded from clinical trials of these KRASG12C inhibitors, the incidence of drug-induced pneumonitis was low. Therefore, KRASG12C inhibitors may be a safe and effective treatment option for NSCLC with comorbid IP. This review article discusses the promise and prospects of molecular-targeted therapies, especially KRASG12C inhibitors, for NSCLC with comorbid IP, along with our own clinical experience.

Inhibitor of PD-1/PD-L1: a new approach may be beneficial for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a globally prevalent, progressive disease with limited treatment options and poor prognosis. Because of its irreversible disease progression, IPF affects the quality and length of life of patients and imposes a significant burden on their families and social healthcare services. The use of the antifibrotic drugs pirfenidone and nintedanib can slow the progression of the disease to some extent, but it does not have a reverse effect on the prognosis. The option of lung transplantion is also limited owing to contraindications to transplantation, possible complications after transplantation, and the risk of death. Therefore, the discovery of new, effective treatment methods is an urgent need. Over recent years, various studies have been undertaken to investigate the relationship between interstitial pneumonia and lung cancer, suggesting that some immune checkpoints in IPF are similar to those in tumors. Immune checkpoints are a class of immunosuppressive molecules that are essential for maintaining autoimmune tolerance and regulating the duration and magnitude of immune responses in peripheral tissues. They can prevent normal tissues from being damaged and destroyed by the immune response. While current studies have focused on PD-1/PD-L1 and CTLA-4, PD-1/PD-L1 may be the only effective immune checkpoint IPF treatment. This review discusses the application of PD-1/PD-L1 checkpoint in IPF, with the aim of finding a new direction for IPF treatment.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

Expression profiles of circular RNAs and interaction networks of competing endogenous RNAs in neurogenic bladder of rats following suprasacral spinal cord injury

Background

Neurogenic bladder (NB) following suprasacral spinal cord injury (SSCI) is an interstitial disease with the structural remodeling of bladder tissue and matrix over-deposition. Circular RNAs (circRNAs) are involved in fibrotic disease development through their post-transcriptional regulatory functions. This study aimed to use transcriptome high-throughput sequencing to investigate the process of NB and bladder fibrosis after SSCI.

Methods

Spinal cord transection at the T10-T11 level was used to construct the SSCI model in rats (10-week-old female Wistar rats, weighing 200 ± 20 g). The bladders were collected without (sham group) and with (SSCI 1-3 groups) NB status. Morphological examination was conducted to assess the extent of bladder fibrosis. Additionally, RNA sequencing was utilized to determine mRNAs and circRNAs expression patterns. The dynamic changes of differentially expressed mRNAs (DEMs) and circRNAs (DECs) in different periods of SSCI were further analyzed.

Results

Bladder weight, smooth muscle cell hypertrophy, and extracellular matrix gradually increased after SSCI. Compared with the sham group, 3,255 DEMs and 1,339 DECs, 3,449 DEMs and 1,324 DECs, 884 DEMs, and 1,151 DECs were detected in the SSCI 1-3 groups, respectively. Specifically, circRNA3621, circRNA0617, circRNA0586, and circRNA4426 were significant DECs common to SSCI 1-3 groups compared with the sham group. Moreover, Gene Ontology (GO) enrichment suggested that inflammatory and chronic inflammatory responses were the key events in NB progression following SSCI. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment associated with the "Chemokine signaling pathway", the "IL-17 signaling pathway", and the "TGF-beta signaling pathway" suggests their potential involvement in regulating biological processes. The circRNA-miRNA-mRNA interaction networks of DECs revealed rno-circ-2239 (micu2) as the largest node, indicating that the rno-circ-2239-miRNA-mRNA-mediated network may play a critical role in the pathogenesis of SSCI-induced NB.

Conclusions

This study offers a comprehensive outlook on the possible roles of DEMs and DECs in bladder fibrosis and NB progression following SSCI. These findings have the potential to serve as novel biomarkers and therapeutic targets.

Association between idiopathic pulmonary fibrosis and risk of different pathological types of lung cancer: a Mendelian randomization study

BACKGROUND

Many epidemiological studies have shown that idiopathic pulmonary fibrosis (IPF) is a risk factor for lung cancer (LC), but these studies do not provide direct evidence of a causal association between the two diseases. We investigated the causal association between IPF and different pathological types of LC based on the Mendelian randomization (MR) study.

METHODS

The genome-wide association study (GWAS) data of IPF and LC were obtained from the latest published articles, and instrumental variables (IVs) for analysis were obtained after screening and eliminating the confounders. MR Analysis was carried out with the help of random effects inverse variance weighting (re-IVW), MR-egger, and weighted median method, and a comprehensive sensitivity test was conducted.

RESULTS

The results of re-IVW analysis showed that IPF may increase the risk of lung squamous cell carcinoma (LUSC) (OR = 1.045, 95% CI 1.011 to 1.080, P = 0.008). In addition, no causal relationship was found between IPF and overall LC (OR = 0.977, 95% CI 0.933 to 1.023, P = 0.32), lung adenocarcinoma (LUAD) (OR = 0.967, 95% CI 0.903 to 1.036, P = 0.345) and small cell lung carcinoma (SCLC) (OR = 1.081, 95% CI 0.992 to 1.177, P = 0.074). A comprehensive sensitivity analysis ensured the reliability of the study.

CONCLUSION

In conclusion, from the perspective of genetic association, we found that IPF is an independent risk factor for LUSC and may increase the risk of LUSC, but no such causal relationship was found in LUAD and SCLC.

Therapeutic modulation of V Set and Ig domain-containing 4 (VSIG4) signaling in immune and inflammatory diseases

Inflammation is the result of acute and chronic stresses, caused by emotional or physical trauma, or nutritional or environmental pollutants, and brings serious harm to human life and health. As an important cellular component of the innate immune barrier, the macrophage plays a key role in maintaining tissue homeostasis and promoting tissue repair by controlling infection and resolving inflammation. Several studies suggest that V Set and Ig domain-containing 4 is specifically expressed in tissue macrophages and is associated with a variety of inflammatory diseases. In this paper, we mainly summarize the recent research on V Set and Ig domain-containing 4 structures, functions, function and roles in acute and chronic inflammatory diseases, and provide a novel therapeutic avenue for the treatment of inflammatory diseases, including nervous system, urinary, respiratory and metabolic diseases.

[French practical guidelines for the diagnosis and management of IPF - 2021 update, full version]

BACKGROUND

Since the previous French guidelines were published in 2017, substantial additional knowledge about idiopathic pulmonary fibrosis has accumulated.

METHODS

Under the auspices of the French-speaking Learned Society of Pulmonology and at the initiative of the coordinating reference center, practical guidelines for treatment of rare pulmonary diseases have been established. They were elaborated by groups of writers, reviewers and coordinators with the help of the OrphaLung network, as well as pulmonologists with varying practice modalities, radiologists, pathologists, a general practitioner, a head nurse, and a patients' association. The method was developed according to rules entitled "Good clinical practice" in the overall framework of the "Guidelines for clinical practice" of the official French health authority (HAS), taking into account the results of an online vote using a Likert scale.

RESULTS

After analysis of the literature, 54 recommendations were formulated, improved, and validated by the working groups. The recommendations covered a wide-ranging aspects of the disease and its treatment: epidemiology, diagnostic modalities, quality criteria and interpretation of chest CT, indication and modalities of lung biopsy, etiologic workup, approach to familial disease entailing indications and modalities of genetic testing, evaluation of possible functional impairments and prognosis, indications for and use of antifibrotic therapy, lung transplantation, symptom management, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are aimed at guiding the diagnosis and the management in clinical practice of idiopathic pulmonary fibrosis.

French practical guidelines for the diagnosis and management of idiopathic pulmonary fibrosis - 2021 update. Full-length version

BACKGROUND

Since the latest 2017 French guidelines, knowledge about idiopathic pulmonary fibrosis has evolved considerably.

METHODS

Practical guidelines were drafted on the initiative of the Coordinating Reference Center for Rare Pulmonary Diseases, led by the French Language Pulmonology Society (SPLF), by a coordinating group, a writing group, and a review group, with the involvement of the entire OrphaLung network, pulmonologists practicing in various settings, radiologists, pathologists, a general practitioner, a health manager, and a patient association. The method followed the "Clinical Practice Guidelines" process of the French National Authority for Health (HAS), including an online vote using a Likert scale.

RESULTS

After a literature review, 54 guidelines were formulated, improved, and then validated by the working groups. These guidelines addressed multiple aspects of the disease: epidemiology, diagnostic procedures, quality criteria and interpretation of chest CT scans, lung biopsy indication and procedures, etiological workup, methods and indications for family screening and genetic testing, assessment of the functional impairment and prognosis, indication and use of antifibrotic agents, lung transplantation, management of symptoms, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are intended to guide the diagnosis and practical management of idiopathic pulmonary fibrosis.

Lung cancer in recipients after lung transplant: single-centre experience and literature review

Introduction

Lung cancer is a major challenge facing modern medicine. It is the leading cause of cancer-related death in the USA. Little is known of the incidence, prevalence and disease characteristics in lung transplant recipients, a population unique in its vulnerability and exposure to carcinogenic risk factors. We aimed to elaborate these characteristics of lung cancer in our population through a retrospective cohort study.

Methods

We retrospectively reviewed our institution’s 8-year experience with lung transplantation and searched for patients with a post-transplant diagnosis of lung cancer, neoplasia or mass. We focused on patient demographics, indication for transplant, smoking history, stage at diagnosis, location of the tumour, length of time between transplant and diagnosis, the treatment offered and length of time from diagnosis to death or last follow-up. Descriptive statistics and survival analysis standard Kaplan-Meier method was conducted from the date of cancer diagnosis to death from all-cause mortality or last follow-up as of August 2021.

Results

We identified 24 patients with de novo lung cancer postlung transplant in 905 recipients. More patients with an underlying diagnosis of idiopathic pulmonary fibrosis developed lung cancer. Twenty-one patients were diagnosed with non-small cell lung cancer and three had small cell lung cancer. The remaining native lung was involved most in single lung recipients with 17 patients. Patients with a diagnosis of lung cancer had a mean survival of 17.6 months after diagnosis.

Discussion

The incidence rate of lung cancer in our cohort was higher than reported for smokers from the general population in previous studies. In this study, we compare our findings with available literature. We also explore screening strategies, treatment modalities, survival and postulated mechanisms for the development of lung cancer in lung transplant recipients.

Discovery of 4-cyclopropyl-3-(2-((1-cyclopropyl-1H-pyrazol-4-yl) amino) quinazolin-6-yl)-N-(3-(trifluoromethyl) phenyl) benzamides as potent discoidin domain receptor inhibitors for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease with a median survival time of 3–5 years. Inaccurate diagnosis, limited clinical therapy and high mortality together indicate that the development of effective therapeutics for IPF is an urgent need. In recent years, it was reported that DDRs are potential targets in anti-fibrosis treatment. Based on previous work we carried out further structure modifications and led to a more selective inhibitor 47 by averting some fibrosis-unrelated kinases, such as RET, AXL and ALK. Extensive profiling of compound 47 has demonstrated that it has potent DDR1/2 inhibitory activities, low toxicity, good pharmacokinetic properties and reliable in vivo anti-fibrosis efficacy. Therefore, we confirmed that discoidin domain receptors are promising drug targets for IPF, and compound 47 would be a promising candidate for further drug development.

Lung cancer and interstitial lung diseases: the lack of prognostic impact of lung cancer in IPF

Lung Cancer (LC) is the first cause of death worldwide. Recently increased interest in interstitial lung diseases (ILD) has highlighted an association with lung cancer, offering interesting insights into the pathogenesis of the latter. Describe the association between lung cancer and ILD and evaluate the impact of LC on survival in these populations. We collected clinical, radiological, histologic data of 53 cases of advanced pulmonary fibrosis with lung cancer: 17 with UIP pattern (usual interstitial pneumonia, UIP/IPF-LC) and 36 with non-UIP pattern (ILD-LC). Adenocarcinoma was the most frequent histological subtype of lung cancer in all three groups and in UIP/IPF-LC developed in the lung periphery and in an advanced fibrosis context. Patients with DLCO% < 38% showed survival < 10 months, irrespective of group and development of carcinoma in UIP/IPF does not necessarily affect survival, unlike in SR-ILD. Our results confirm that the oncogenic mechanism is closely linked to fibrotic and inflammatory processes and that the development of carcinoma affects survival in SR-ILD but not in IPF.

Myeloid Fbxw7 Prevents Pulmonary Fibrosis by Suppressing TGF-β Production

Idiopathic pulmonary fibrosis (IPF) is a group of chronic interstitial pulmonary diseases characterized by an inexorable decline in lung function with limited treatment options. The abnormal expression of transforming growth factor-β (TGF-β) in profibrotic macrophages is linked to severe pulmonary fibrosis, but the regulation mechanisms of TGF-β expression are incompletely understood. We found that decreased expression of E3 ubiquitin ligase Fbxw7 in peripheral blood mononuclear cells (PBMCs) was significantly related to the severity of pulmonary fibrosis in IPF patients. Fbxw7 is identified to be a crucial suppressing factor for pulmonary fibrosis development and progression in a mouse model induced by intratracheal bleomycin treatment. Myeloid cell-specific Fbxw7 deletion increases pulmonary monocyte-macrophages accumulation in lung tissue, and eventually promotes bleomycin-induced collagen deposition and progressive pulmonary fibrosis. Notably, the expression of TGF-β in profibrotic macrophages was significantly upregulated in myeloid cell-specific Fbxw7 deletion mice after bleomycin treatment. C-Jun has long been regarded as a critical transcription factor of Tgfb1, we clarified that Fbxw7 inhibits the expression of TGF-β in profibrotic macrophages by interacting with c-Jun and mediating its K48-linked ubiquitination and degradation. These findings provide insight into the role of Fbxw7 in the regulation of macrophages during the pathogenesis of pulmonary fibrosis.

Arecanut-induced fibrosis display dual phases of reorganising glycans and amides in skin extracellular matrix

The habit of chewing arecanut leads to fibrosis in the oral tissues, which can lead to cancer. Despite high mortality, fibrosis has limited clinical success owing to organ-specific variations, genetic predispositions, and slow progression. Fibrosis is a progressive condition that is unresponsive to medications in the severe phase. To understand underlying macromolecular changes we studied the extracellular matrix's (ECM) key molecular modifications in the early and late phase of arecanut-induced fibrosis in skin. To study the fibrosis, we topically applied arecanut extract on the mice skin. We observed that the matrix changes observe early and late phases based on ECM characteristics including the matrix proteins and the glycans. A spike in the levels of proteoglycans and β-sheet structures are noted in the early phase. A significant drop in the proteoglycans and strengthening of amide covalent interactions is observed in the late phase. Although, almost no physical changes are noticeable only in the early phase; the late phase observes thick collagen bundling and a 4-fold stiffening of the skin tissue. The study indicates that the temporal interplay of proteins and glycans determine the matrix's severity state while opening avenues to research directed towards the phase-specific clinical discovery.

Repurposing Anticancer Drugs for the Treatment of Idiopathic Pulmonary Fibrosis and Antifibrotic Drugs for the Treatment of Cancer: State of the Art

Idiopathic pulmonary fibrosis (IPF) is an aggressive pulmonary disease which shares several molecular, pathophysiological and clinical aspects with lung cancer, including high mortality rates. The antifibrotic drugs Nintedanib and Pirfenidone have recently been introduced in clinical practice for the treatment of IPF. Nintedanib is also used for the treatment of several malignancies, including non-small cell lung cancer (NSCLC) in combination with Docetaxel, while Pirfenidone showed some anti-neoplastic effects in preclinical studies. On the other hand, novel targeted agents and immunotherapies have been introduced in the last decade for the treatment of NSCLC, and some of them showed anti-fibrotic properties in recent studies. These evidences, based on the common pathophysiological backgrounds of IPF and lung cancer, make possible the mutual or combined use of anti-fibrotic and anti-neoplastic drugs to treat these highly lethal diseases. The aim of the present review is to depict the current scientific landscape regarding the repurposing of anti-neoplastic drugs in IPF and anti-fibrotic drugs in lung cancer, and to identify future research perspectives on the topic.

Impact of idiopathic pulmonary fibrosis on clinical outcomes of lung cancer patients

The clinical characteristics of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) differ from those of lung cancer in patients without IPF. Thus, we aimed to evaluate the impact of IPF on the clinical course of patients with lung cancer. Clinical data of IPF patients with lung cancer (n = 122) were compared with those of patients with lung cancer without IPF (n = 488) matched by age, sex, histopathology, stage, and date of diagnosis of lung cancer. The median follow-up period after diagnosis of lung cancer was 16 months. Among patients with IPF, the mean age was 68 years, 95.9% were male, 93.2% were ever-smokers, and squamous cell carcinoma was the most common cancer type (48.4%). The IPF group had poorer lung function and lower lobe predominance of lung cancer than the no-IPF group. The IPF group showed a poorer prognosis than the no-IPF group (5-year survival rate: 14.5% vs. 30.1%, respectively; P < 0.001), even after adjusting for lung function and regardless of the treatment method. Among patients with IPF, 16.8% experienced acute exacerbation within 1 month after treatment of lung cancer. The treatment outcome of patients with lung cancer and IPF was generally unfavorable, and acute exacerbation triggered by treatment frequently occurred.

The relationship between the severity of pulmonary fibrosis and the lung cancer stage

Background: The incidence of idiopathic pulmonary fibrosis (IPF) and mortality related to the disease have steadily increased in recent years. The risk of cancer is approximately eight times higher in IPF patients than in the general population. The purpose of this study is to determine whether the severity of IPF is related to the time interval between IPF diagnosis and lung cancer diagnosis and to the stage of lung cancer at diagnosis.

Methods: In this retrospective cohort study, we reviewed the medical records of patients with lung cancer after IPF diagnosis from two tertiary hospitals in South Korea between 2003 and 2018. We identified 61 patients diagnosed with lung cancer at least 3 months after being diagnosed with IPF.

Results: The included patients had a mean age of 71.0 years, and all but one were men (98.4%). The interval between IPF diagnosis and lung cancer diagnosis was not related to the gender-age-physiology (GAP) stage (p=0.662). However, in cox proportional hazard models, a higher GAP stage was significantly correlated with an advanced lung cancer stage (odds ratio 11.1, p=0.003).

Conclusions: The lung cancer stage at diagnosis was higher in patients with a higher GAP stage than in those with a lower GAP stage. Physicians should consider implementing more frequent surveillance with computed tomography scans for patients with advanced IPF.

Paired genetic analysis by next-generation sequencing of lung cancer and associated idiopathic pulmonary fibrosis

The pathogenesis of lung cancer associated with idiopathic pulmonary fibrosis (IPF) has remained largely uncharacterized. To provide insight into this condition, we undertook genomic profiling of IPF-associated lung cancer as well as of adjacent fibrosing lung tissue in surgical specimens. Isolated DNA and RNA from 17 IPF-associated non-small cell lung cancer and 15 paired fibrosing lung tissue specimens were analyzed by next-generation sequencing with a panel that targets 161 cancer-related genes. Somatic genetic alterations were frequently identified in TP53 (n = 6, 35.3%) and PIK3CA (n = 5, 29.4%) genes in tumor samples as well as in EGFR (n = 7, 46.7%), PIK3CA (n = 5, 33.3%), ERBB3 (n = 4, 26.7%), and KDR (n = 4, 26.7%) in IPF samples. Genes related to the RAS-RAF signaling pathway were also frequently altered in tumor (n = 7, 41.2%) and IPF (n = 3, 20.0%) samples. The number of somatic alterations identified in IPF samples was almost as large as that detected in paired tumor samples (81 vs 90, respectively). However, only 6 of the 81 somatic alterations detected in IPF samples overlapped with those in paired tumor samples. The accumulation of somatic mutations was thus apparent in IPF tissue of patients with IPF-associated lung cancer, and the RAS-RAF pathway was implicated in lung tumorigenesis. The finding that somatic alterations were not frequently shared between tumor and corresponding IPF tissue indicates that IPF-associated lung cancer does not develop through the stepwise accumulation of somatic alterations in IPF.

The Oncogene ECT2 Contributes to a Hyperplastic, Proliferative Lung Epithelial Cell Phenotype in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) and lung cancer are progressive lung diseases with a poor prognosis. IPF is a risk factor for the development of lung cancer, and the incidence of lung cancer is increased in patients with IPF. The disease pathogenesis of IPF and lung cancer involves common genetic alterations, dysregulated pathways, and the emergence of hyperplastic and metaplastic epithelial cells. Here, we aimed to identify novel, common mediators that might contribute to epithelial cell reprogramming in IPF. Gene set enrichment analysis of publicly available non-small cell lung cancer and IPF datasets revealed a common pattern of misregulated genes linked to cell proliferation and transformation. The oncogene ECT2 (epithelial cell transforming sequence 2), a guanine nucleotide exchange factor for Rho GTPases, was highly enriched in both IPF and non-small cell lung cancer compared with nondiseased controls. Increased expression of ECT2 was verified by qPCR and Western blotting in bleomycin-induced lung fibrosis and human IPF tissue. Immunohistochemistry demonstrated strong expression of ECT2 staining in hyperplastic alveolar epithelial type II (ATII) cells in IPF, as well as its colocalization with proliferating cell nuclear antigen, a well-known proliferation marker. Increased ECT2 expression coincided with enhanced proliferation of primary mouse ATII cells as analyzed by flow cytometry. ECT2 knockdown in ATII cells resulted in decreased proliferation and collagen I expression in vitro. These data suggest that the oncogene ECT2 contributes to epithelial cell reprogramming in IPF, and further emphasize the hyperplastic, proliferative ATII cell as a potential target in patients with IPF and lung cancer.

Highlights of high-resolution computed tomography imaging in evaluation of complications and co-morbidities in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) represents a condition included in the heterogeneous group of interstitial lung diseases without known causes. The recent ATS/ERS/JRS/ALAT guidelines and the white paper published by the Fleischner Society have well-defined diagnosis and management of idiopathic pulmonary fibrosis. Idiopathic pulmonary fibrosis management is complex because it is also influenced by several co-morbidities and complications. The new frontier in idiopathic pulmonary fibrosis is represented by the effort to understand the complex mechanism of the pathogenesis and progression of disease in order to predict several consequences and co-morbidities. In our review, we tried to distinguish co-morbidities from complications of idiopathic pulmonary fibrosis. In each complication, we have reviewed the existing literature and we have emphasized the complex pathobiological pathway which links the progression of idiopathic pulmonary fibrosis to the development of the complication itself. For every co-morbidity, we tried to identify share common risk factors which explain the coexistence of idiopathic pulmonary fibrosis with its co-morbidities. We then analyzed high-resolution computed tomography (CT) aspects of co-morbidities and complications of idiopathic pulmonary fibrosis that the radiologist should be aware of. In this review, we focused on the role of high-resolution CT imaging in the evaluation of co-morbidities and complications in idiopathic pulmonary fibrosis because their early diagnosis and treatment could change the prognosis in patients with idiopathic pulmonary fibrosis. We have also pointed out that in some cases the final combined quantitative CT tools and conventional visual CT score would allow to get an accurate analysis and quantification of disease progression, co-morbidities, and complications of idiopathic pulmonary fibrosis in order to improve staging systems in idiopathic pulmonary fibrosis.

Immune Checkpoints as Promising Targets for the Treatment of Idiopathic Pulmonary Fibrosis?

Idiopathic pulmonary fibrosis is a rare, progressive and fatal lung disease which affects approximately 5 million persons worldwide. Although pirfenidone and/or nintedanib treatment improves patients’ wellbeing, the prognosis of IPF remains poor with 5-year mortality rates still ranging from 70 to 80%. The promise of the anti-cancer agent nintedanib in IPF, in combination with the recent notion that IPF shares several pathogenic pathways with cancer, raised hope that immune checkpoint inhibitors, the novel revolutionary anticancer agents, could also be the eagerly awaited ground-breaking and unconventional novel treatment modality limiting IPF-related morbidity/mortality. In the current review, we analyse the available literature on immune checkpoint proteins in IPF to explore whether immune checkpoint inhibition may be as promising in IPF as it is in cancer. We conclude that despite several promising papers showing that inhibiting specific immune checkpoint proteins limits pulmonary fibrosis, overall the data seem to argue against a general role of immune checkpoint inhibition in IPF and suggest that only PD-1/PD-L1 inhibition may be beneficial.

Upregulation of Neural Precursor Cell Expressed Developmentally Downregulated 4-1 is Associated with Poor Prognosis and Chemoresistance in Lung Adenocarcinoma

BACKGROUND

The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) negatively regulates phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein levels through polyubiquitination and proteolysis, but its significance in lung cancer is still unclear. This study investigated the expression and the role of NEDD4-1 in tumor development and chemosensitivity of lung adenocarcinoma (ADC).

METHODS

We retrospectively investigated the expression and significance of NEDD4-1, PTEN, and p-Akt proteins in 135 paired ADC and adjacent noncancerous tissue specimens using immunohistochemistry. Furthermore, we evaluated the relationship between NEDD4-1 expression and clinicopathologic characteristics and prognosis. The effects of small interfering RNA against NEDD4-1 on proliferation and chemosensitivity were examined in A549 cells in vitro using 3- (4,5-dimethylthiazol-2-yl) -5-(3-carboxymethoxyphenyl) -2-(4-sulfophenyl)- 2H-tetrazolium method. The ability of migration and invasion of A549 cells was tested by transwell assay. Moreover, reverse-transcription quantitative polymerase chain reaction and Western blotting analyses were used to determine the expression of NEDD4-1, PTEN, phosphoinositide 3-kinase (PI3K)/Akt activity, and its downstream target proteins.

RESULTS

NEDD4-1 protein was significantly upregulated in lung ADC tissues, whereas it was weak or negative in normal lung epithelial cells. The expression of NEDD4-1 in ADC (78.5%, 106/135) was significantly much higher than that in adjacent normal lung tissue (13.3%, 29/135, P < 0.01), and it was associated with lymph node metastasis, tumor-node-metastasis (TNM) stage, and chemotherapy resistance. PTEN expression was downregulated in lung ADC (60.7% vs. 100.0% in noncancerous specimens, P = 0.007), and was negatively correlated with lymph node metastasis, histological variants, clinical stage, chemoresistance. In addition, expression of p-Akt in ADC tissues (71.1% 96/135) was much higher than that in adjacent lung epithelial cells (6.7%, 9/135, P < 0.01). Kaplan-Meier and multivariate analysis demonstrated that expressions of NEDD4-1 and PTEN were both independent risk factors for survival in patients with lung ADC. NEDD4-1 knockdown in vivo decreased proliferation, migration, and invasion and improved chemosensitivity to cisplatin and paclitaxel in A549 cells. NEDD4-1 knockdown also significantly enhanced PTEN expression and inhibited p-Akt activity and downstream target proteins.

CONCLUSIONS

NEDD4-1 upregulation may contribute to the progression of lung ADC. NEDD4-1 may regulate the proliferation, invasion, migration, and chemoresistance of lung ADC cells through the PI3K/Akt pathway, suggesting that it may be regarded as a therapeutic target for the treatment of lung ADC.

Trade-offs in aging lung diseases: a review on shared but opposite genetic risk variants in idiopathic pulmonary fibrosis, lung cancer and chronic obstructive pulmonary disease

PURPOSE OF REVIEW

The process of aging involves biological changes that increases susceptibility for disease. In the aging lung disease IPF, GWAS studies identified genes associated with risk for disease. Recently, several of these genes were also found to be involved in risk for COPD or lung cancer. This review describes GWAS-derived risk genes for IPF that overlap with risk genes for lung cancer or COPD.

RECENT FINDINGS

Risk genes that overlap between aging lung diseases, include FAM13A, DSP and TERT. Most interestingly, disease predisposing alleles for IPF are opposite to those for COPD or lung cancer. Studies show that the alleles are associated with differential gene expression and with physiological traits in the general population. The opposite allelic effect sizes suggest the presence of trade-offs in the aging lung. For TERT, the trade-off involves cellular senescence versus proliferation and repair. For FAM13A and DSP, trade-offs may involve protection from noxious gases or tissue integrity.

SUMMARY

The overlap in risk genes in aging lung diseases provides evidence that processes associated with FAM13A, DSP and TERT are important for healthy aging. The opposite effect size of the disease risk alleles may represent trade-offs, for which a model involving an apicobasal gene expression gradient is presented.

Idiopathic Pulmonary Fibrosis and Lung Cancer: Mechanisms and Molecular Targets

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial pulmonary disease with a median survival of 2–4 years after diagnosis. A significant number of IPF patients have risk factors, such as a history of smoking or concomitant emphysema, both of which can predispose the patient to lung cancer (LC) (mostly non-small cell lung cancer (NSCLC)). In fact, IPF itself increases the risk of LC development by 7% to 20%. In this regard, there are multiple common genetic, molecular, and cellular processes that connect lung fibrosis with LC, such as myofibroblast/mesenchymal transition, myofibroblast activation and uncontrolled proliferation, endoplasmic reticulum stress, alterations of growth factors expression, oxidative stress, and large genetic and epigenetic variations that can predispose the patient to develop IPF and LC. The current approved IPF therapies, pirfenidone and nintedanib, are also active in LC. In fact, nintedanib is approved as a second line treatment in NSCLC, and pirfenidone has shown anti-neoplastic effects in preclinical studies. In this review, we focus on the current knowledge on the mechanisms implicated in the development of LC in patients with IPF as well as in current IPF and LC-IPF candidate therapies based on novel molecular advances.

Characteristics of lung cancer among patients with idiopathic pulmonary fibrosis and interstitial lung disease - analysis of institutional and population data

Background

Lung Cancer is occasionally observed in patients with Idiopathic Pulmonary Fibrosis (IPF). We sought to describe the epidemiologic and clinical characteristics of lung cancer for patients with IPF and other interstitial lung disease (ILD) using institutional and statewide data registries.

Methods

We conducted a retrospective analysis of IPF and non-IPF ILD patients from the ILD center registry, to compare with lung cancer registries at the University of Pittsburgh as well as with population data of lung cancer obtained from Pennsylvania Department of Health between 2000 and 2015.

Results

Among 1108 IPF patients, 31 patients were identified with IPF and lung cancer. The age-adjusted standard incidence ratio of lung cancer was 3.34 (with IPF) and 2.3 (with non-IPF ILD) (between-group Hazard ratio = 1.4, p = 0.3). Lung cancer worsened the mortality of IPF (p <  0.001). Lung cancer with IPF had higher mortality compared to lung cancer in non-IPF ILD (Hazard ratio = 6.2, p = 0.001). Lung cancer among IPF was characterized by a predilection for lower lobes (63% vs. 26% in non-IPF lung cancer, p <  0.001) and by squamous cell histology (41% vs. 29%, p = 0.07). Increased incidence of lung cancer was observed among single lung transplant (SLT) recipients for IPF (13 out of 97, 13.4%), with increased mortality compared to SLT for IPF without lung cancer (p = 0.028) during observational period.

Conclusions

Lung cancer is approximately 3.34 times more frequently diagnosed in IPF patients compared to general population, and associated with worse prognosis compared with IPF without lung cancer, with squamous cell carcinoma and lower lobe predilection. The causality between non-smoking IPF patients and lung cancer is to be determined.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0899-4) contains supplementary material, which is available to authorized users.

Cancer driver mutations in endometriosis: Variations on the major theme of fibrogenesis

BACKGROUND

One recent study reports cancer driver mutations in deep endometriosis, but its biological/clinical significance remains unclear. Since the natural history of endometriosis is essentially gradual progression toward fibrosis, it is thus hypothesized that the six driver genes reported to be mutated in endometriosis (the RP set) may play important roles in fibrogenesis but not necessarily malignant transformation.

METHODS

Extensive PubMed search to see whether RP and another set of driver genes not yet reported (NR) to be mutated in endometriosis have any roles in fibrogenesis. All studies reporting on the role of fibrogenesis of the genes in both RP and NR sets were retrieved and evaluated in this review.

RESULTS

All six RP genes were involved in various aspects of fibrogenesis as compared with only three NR genes. These nine genes can be anchored in networks linking with their upstream and downstream genes that are known to be aberrantly expressed in endometriosis, piecing together seemingly unrelated findings.

CONCLUSIONS

Given that somatic driver mutations can and do occur frequently in physiologically normal tissues, it is argued that these mutations in endometriosis are not necessarily synonymous with malignancy or premalignancy, but the result of enormous pressure for fibrogenesis.

Lung cancer in idiopathic pulmonary fibrosis: A systematic review and meta-analysis

BACKGROUND

There are many epidemiological pieces of evidence that show IPF patients have the highest risk of lung cancer. We conducted a systematic review of all published data to define the characteristics of lung cancer that develops in IPF by performing a meta-analysis.

METHOD

This study was performed based on the PRISMA guideline. Documents gathered by searching through the Web of Sciences, Scopus, PubMed/Medline, OVID, and COCHRANE databases which published before 03/25/2018 that related to lung cancer in IPFs' patients. Articles were searched using standard keywords as well as Mesh and Mesh Entry and all probabilistic combinations of words using Boolean operators. Data searching, extracting and quality appraising were done by two researchers, independently. At last, Random-effects size based on Cochrane test and I2 were used. The review protocol has been registered in PROSPERO with ID: CRD42018094037.

RESULTS

Based on the meta-analysis conducted in 35 (0.18%) included studies, the total sample size of patients with IPF was estimated 131947 among whom 6384 had LC. The total rate of LC prevalence in IPF patients was estimated to be 13.54% (95% CI: 10.43-17.4) that was significantly 9 times higher in men vs. Women and smoker vs. non-smoker. Highest to lowest prevalence of cellular (histological) subtypes of lung cancer in IPF were SQCC (37.82%), ADC (30.79%), SmCC (20.48%), LCC (5.21%), and ADQC (4.81%), respectively. The highest and lowest stage of lung cancer in IPF patients was estimated at III and II, respectively. The highest involvement location of lung cancer in IPF patients was in the Peripheral. Also, the prevalence of the tumor region involved from the highest to the lowest was estimated to be in the RLL, LLL, RUL and LUL regions.

CONCLUSIONS

Lung cancer in IPF, most commonly SQCC, presents in elderly heavy smokers with a male, locating in peripheral regions and the lower part of lung predominance.

Lung cancer and interstitial lung disease: a literature review

The association between lung cancer (LC) and interstitial lung disease (ILD) can be explained by the shared risk factors like smoking and physiopathology of fibrogenesis and cancerogenesis. The relative LC risk is shown to be 3.5- to 7.3-times higher in ILD, with LC occurrence estimated at 10-20% in ILD, with >15% of ILD patients likely to die from LC. ILD incidence upon LC diagnosis varied from 2.4-10.9%. Primary radiological presentations consist of peripheral lesions, mostly in the inferior pulmonary lobes, either close to or within the ILD areas. There is a trend towards inverted proportion of adenocarcinomas and squamous-cell carcinomas, with EGFR mutations very rarely found. ILD negatively impacted LC prognosis, with surgery associated with increased morbidity-mortality, particularly due to acute exacerbation (AE) of ILD. Limited resection reduced this risk, whilst increasing that of cancer mortality. Studies on radiotherapy that can induce AE-ILD are scarce. Chemotherapy was associated with similar response rates to those in LC patients without ILD, yet worse survival. This difference may be accounted for by ILD patients' poorer health and higher risk of drug-induced pneumonitis. Further studies are warranted to better understand cancer physiopathology within the fibrotic areas, along with the therapeutic strategies required.

Inhibition of microRNA-23b prevents polymicrobial sepsis-induced cardiac dysfunction by modulating TGIF1 and PTEN

Cardiovascular dysfunction is a major complication associated with sepsis induced mortality. Cardiac fibrosis plays a critical role in sepsis induced cardiac dysfunction. The mechanisms of the activation of cardiac fibrosis is unclarified. In this study, we found that microRNA-23b (miR-23b) was up-regulated in heart tissue during cecal ligation and puncture (CLP)-induced sepsis and transfection of miR-23b inhibitor improved survival in late sepsis. Inhibition of miR-23b in the myocardium protected against cardiac output and enhanced left ventricular systolic function. miR-23b inhibitor also alleviated cardiac fibrosis in late sepsis. MiR-23b mediates the activation of TGF-β1/Smad2/3 signaling to promote the differentiation of cardiac fibroblasts through suppression of 5'TG3'-interacting factor 1 (TGIF1). MiR-23b also induces AKT/N-Cadherin signaling to contribute to the deposition of extracellular matrix by inhibiting phosphatase and tensin homologue (PTEN). TGIF1 and PTEN were confirmed as the targets of miR-23b in vitro by Dual-Glo Luciferase assay. miR-23b inhibitor blocked the activation of adhesive molecules and restored the imbalance of pro-fibrotic and anti-fibrotic factors. These data provide direct evidence that miR-23b is a critical contributor to the activation of cardiac fibrosis to mediate the development of myocardial dysfunction in late sepsis. Blockade of miR-23b expression may be an effective approach for prevention sepsis-induced cardiac dysfunction.

From bad to worse: when lung cancer complicates idiopathic pulmonary fibrosis

Patients with idiopathic pulmonary fibrosis have a significantly increased risk for the development of lung cancer. The morbidity and mortality of this disease combination are substantial, and, unfortunately, there are currently few data to help guide clinicians in its diagnosis and treatment. In a recent issue of this journal, Hwang et al presented one of the first studies to evaluate lung cancer in patients with idiopathic pulmonary fibrosis at the molecular level. They demonstrate variants in regulators of the cell cycle, which are known to be important in malignant transformation and may also be important in the pathogenesis of idiopathic pulmonary fibrosis. Further understanding of the pathogenic overlap between lung cancer and idiopathic pulmonary fibrosis could help point the direction to specific diagnostic modalities and targeted treatment of both conditions in the future. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Protein corona of airborne nanoscale PM2.5 induces aberrant proliferation of human lung fibroblasts based on a 3D organotypic culture

Exposure to PM2.5 has become one of the most important factors affecting public health in the world. Both clinical and research studies have suggested that PM2.5 inhalation is associated with impaired lung function. In this study, material characterization identified the existence of nanoscale particulate matter (NPM) in airborne PM2.5 samples. When coming into contact with protein-rich fluids, the NPM becomes covered by a protein layer that forms a “protein corona”. Based on a 3D organotypic cell culture, the protein corona was shown to mitigate NPM cytotoxicity and further stimulate the proliferation of human lung fibroblasts (HLFs). ROS-activated alpha-smooth muscle actin (α-SMA) is considered to be one of the proliferation pathways. In this research, 3D cell cultures exhibited more tissue-like properties compared with the growth in 2D models. Animal models have been widely used in toxicological research. However, species differences make it impossible to directly translate discoveries from animals to humans. In this research, the 3D HLF model could partly simulate the biological responses of NPM-protein corona-induced aberrant HLF proliferation in the human lung. Our 3D cellular results provide auxiliary support for an animal model in research on PM2.5-induced impaired lung function, particularly in lung fibrosis.