Carcinogens In Cigarette Smoke Research Articles

A Multi-Omics Study of Epigenetic Changes in Type II Alveolar Cells of A/J Mice Exposed to Environmental Tobacco Smoke.

Lung cancer remains a major contributor to cancer fatalities, with cigarette smoking known to be responsible for up to 80% of cases. Based on the ability of cigarette smoke to induce inflammation in the lungs and increased lung cancer incidence in smokers with inflammatory conditions such as COPD, we hypothesized that inflammation plays an important role in the carcinogenicity of cigarette smoke. To test this hypothesis, we performed multi-omic analyses of Type II pneumocytes of A/J mice exposed to cigarette smoke for various time periods. We found that cigarette smoke exposure resulted in significant changes in DNA methylation and hydroxymethylation, gene expression patterns, and protein abundance that were partially reversible and contributed to an inflammatory and potentially oncogenic phenotype.

Advanced Materials Design for Adsorption of Toxic Substances in Cigarette Smoke.

Cigarettes, despite being economically important legal consumer products, are highly addictive and harmful, particularly to the respiratory system. Tobacco smoke is a complex mixture containing over 7000 chemical compounds, 86 of which are identified to have "sufficient evidence of carcinogenicity" in either animal or human tests. Thus, tobacco smoke poses a significant health risk to humans. This article focuses on materials that help reduce the levels of major carcinogens in cigarette smoke; these include nicotine, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, hydrogen cyanide, carbon monoxide, and formaldehyde. Specifically, the research progress on adsorption effects and mechanisms of advanced materials such as cellulose, zeolite, activated carbon, graphene, and molecularly imprinted polymers are highlighted. The future trends and prospects in this field are also discussed. Notably, with advancements in supramolecular chemistry and materials engineering, the design of functionally oriented materials has become increasingly multidisciplinary. Certainly, several advanced materials can play a critical role in reducing the harmful effects of cigarette smoke. This review aims to serve as an insightful reference for the design of hybrid and functionally oriented advanced materials.

Reduction of nitrosamines in cigarette smoke vapors through a filter functionalized with polyphenols from olive tree.

In our study, we present the development of a novel cigarette filter enriched with polyphenols, with a particular focus on hydroxytyrosol extracted from olive sources. Our objective was to trap the presence of carcinogens in cigarette smoke by chemically modifying the filter surface. To evaluate the filtration efficiency of the newly developed filter, we employed an automated Stain Pattern technique, enabling non-intrusive measurement of behavioral vent blocking. The surface modification of cigarette filters was meticulously carried out to target the reduction of nitrosamines formed during combustion. Our extensive investigation underscores the potential of functionalizing cigarette filters using olive polyphenols, in particular hydroxytyrosol to mitigate the formation of harmful compounds, particularly nitrosamines, during smoking. Functionalized filters exhibited remarkable filtering efficiency, as evidenced by a capture factor (f=2.9×103) for two layers. This innovative approach has the capacity to revolutionize the utilization of filters in commercial cigarettes, significantly reducing consumers' exposure to toxic chemicals. Our research demonstrates that hydroxytyrosol-functionalized cigarette filters can effectively remove noxious substances like nitrosamines, offering a promising avenue for enhancing public health. Further in-depth research is essential to assess the protective impact of hydroxytyrosol-functionalized filters cigarettes, ensuring their potential to safeguard consumers' health effectively.

Blockade of the protease ADAM17 ameliorates experimental pancreatitis

Acute and chronic pancreatitis, the latter associated with fibrosis, are multifactorial inflammatory disorders and leading causes of gastrointestinal disease-related hospitalization. Despite the global health burden of pancreatitis, currently, there are no effective therapeutic agents. In this regard, the protease A Disintegrin And Metalloproteinase 17 (ADAM17) mediates inflammatory responses through shedding of bioactive inflammatory cytokines and mediators, including tumor necrosis factor α (TNFα) and the soluble interleukin (IL)-6 receptor (sIL-6R), the latter of which drives proinflammatory IL-6 trans-signaling. However, the role of ADAM17 in pancreatitis is unclear. To address this, Adam17ex/ex mice-which are homozygous for the hypomorphic Adam17ex allele resulting in marked reduction in ADAM17 expression-and their wild-type (WT) littermates were exposed to the cerulein-induced acute pancreatitis model, and acute (1-wk) and chronic (20-wk) pancreatitis models induced by the cigarette smoke carcinogen nicotine-derived nitrosamine ketone (NNK). Our data reveal that ADAM17 expression was up-regulated in pancreatic tissues of animal models of pancreatitis. Moreover, the genetic (Adam17ex/ex mice) and therapeutic (ADAM17 prodomain inhibitor [A17pro]) targeting of ADAM17 ameliorated experimental pancreatitis, which was associated with a reduction in the IL-6 trans-signaling/STAT3 axis. This led to reduced inflammatory cell infiltration, including T cells and neutrophils, as well as necrosis and fibrosis in the pancreas. Furthermore, up-regulation of the ADAM17/IL-6 trans-signaling/STAT3 axis was a feature of pancreatitis patients. Collectively, our findings indicate that the ADAM17 protease plays a pivotal role in the pathogenesis of pancreatitis, which could pave the way for devising novel therapeutic options to be deployed against this disease.

Abstract 1347: Novel lung cancer mouse model to study the effects of cigarette smoke on immune therapy

Abstract Background: In 2021, 235,760 new cases of lung cancer will be diagnosed in the United States. The treatment regimen of non-small cell lung cancer (NSCLC) has drastically changed owing to the superior anti-cancer effects generated by the immune-checkpoint inhibitor (ICI). However, only a subset of patients experience benefit after receiving ICI. Tumor Mutation Burden (TMB) and PD-L1 expression in tumor cells are known to be potential biomarkers in predicting a patient’s survival and response to ICI. Several studies showed that NSCLC patients with smoking history had a better response than never smokers due to increased TMB caused by carcinogens in cigarette smoke. However, the roles of tumor microenvironment especially immune microenvironment between smokers and never smokers in response to ICI are poorly understood. We hypothesize that the functions of T cells are influenced by the exposure of cigarette smoke prior to the ICI treatment which affect patients’ response to ICI. Method: A cohort of 216 patients diagnosed with NSCLC who had received at least one dosage of Immune Checkpoint Inhibitor (ICI) at Atrium Wake Forest Baptist Hospital were split into three groups: current smokers, former smokers, and never-smokers. Both PFS and OS analyses were performed to examine whether smoking history is correlated with the ICI response. To establish an in vivo model that recapitulates the patients with different smoking history, we treated mice with cigarette extract (CSE) followed by accessing the peripheral T cell functions by FACS analyses using antibodies targeting GZMB, TNF and IFNG. LL/2 and CMT167 cells will be inoculated to those CSE treated mice by flank injection once we observe a stable activation of T cells compared to control group. Tumor growth will be measured and the amount of tumor infiltrated CD4 and CD8 T cells will be examined by immunocytochemistry at the end point. Results: We found it took around 9 weeks of CSE treatment to observe a significant increase of CD8 and CD4 populations in CSE treated mice. We also treated mouse CD8 T cells isolated from the spleen with CSE and observed a strong activation of GZMB, TNF and IFNG by FACS analyses. Future directions: We will test the efficacy of anti-tumor effect of anti-PD-1 ab in tumor bearing mice exposed with or without CSE prior to the immune therapy. We will also establish a mice model that mimics the former smokers by halting the CSE treatment after 9 weeks of CSE exposure followed by examine the amount of memory T cells. We believe our study will provide additional mechanisms of how cigarette smoke affects the response of ICI by affecting the properties of immune cells. Citation Format: Margaret Rose Smith, Yuezhu Wang, Jimmy Ruiz, Jason Grayson, Yin Liu, Fei Xing. Novel lung cancer mouse model to study the effects of cigarette smoke on immune therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1347.

Smokeless tobacco and cigarette smoking: chemical mechanisms and cancer prevention.

Tobacco products present a deadly combination of nicotine addiction and carcinogen exposure resulting in millions of cancer deaths per year worldwide. A plethora of smokeless tobacco products lead to unacceptable exposure to multiple carcinogens, including the tobacco-specific nitrosamine N'-nitrosonornicotine, a likely cause of the commonly occurring oral cavity cancers observed particularly in South-East Asian countries. Cigarettes continue to deliver a large number of carcinogens, including tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons and volatile organic compounds. The multiple carcinogens in cigarette smoke are responsible for the complex mutations observed in critical cancer genes. The exposure of smokeless tobacco users and smokers to carcinogens and toxicants can now be monitored by urinary and DNA adduct biomarkers that may be able to identify those individuals at highest risk of cancer so that effective cancer prevention interventions can be initiated. Regulation of the levels of carcinogens, toxicants and nicotine in tobacco products and evidence-based tobacco control efforts are now recognized as established pathways to preventing tobacco related cancer.

Study of the effect of smoking on sperm count in male infertility

Cigarette smoking, one of the main causes of preventable morbidity and mortality, has a multitude of well-known side effects. Tobacco smoking is considered one of the major factors leading to male infertility. A lot is known now about the carcinogens in tobacco cigarette smoke and their resultant effects on organs like lungs and urinary bladder, but their effects on fertility status have been less documented. The present study was aimed at studying the effect of cigarette smoking on sperm count in infertile men. A total of one hundred infertile men (50 Nonsmokers and 50 Smokers) between the age group 20-45 years were taken into this study. The Sperm count in the infertile nonsmokers and the infertile smokers group were compared using Z Test. Infertile Smokers which were divided into Group A (≥1 and ≤10 cigarettes/ day), Group B (>10 and <20 cigarettes/ day) and Group C (≥20 cigarettes/ day) were analyzed for Sperm count levels by ANOVA Test. It was observed that the sperm count was significantly lower (p<0.01) in an infertile smokers group than the infertile nonsmokers group. It was also observed that the sperm count was significantly decreased (p<0.05) in relation to the quantity of cigarette smoking.

Molecular docking and dynamics studies of cigarette smoke carcinogens interacting with acetylcholinesterase and butyrylcholinesterase enzymes of the central nervous system.

The free radicals produced by cigarette smoking are responsible for tissue damage, heart and lung diseases, and carcinogenesis. The effect of tobacco on the central nervous system (CNS) has received increased attention nowadays in research. Therefore, to explore the molecular interaction of cigarette smoke carcinogens (CSC) 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK), and N'-nitrosonornicotine (NNN) with well-known targets of CNS-related disorders, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes, a cascade of the computational study was conducted including molecular docking and molecular dynamics simulations (MDS). The investigated results of NNAL+AChEcomplex, NNK+AChEcomplex, and NNK+BuChEcomplex based on intermolecular energies (∆G) were found to -8.57 kcal/mol, -8.21 kcal/mol, and -8.08 kcal/mol, respectively. MDS deviation and fluctuation plots of the NNAL and NNK interaction with AChE and BuChE have shown significant results. Further, Molecular Mechanics Poisson-Boltzmann Surface Area(MM-PBSA) results shown the best total binding energy (Binding∆G) -87.381 (+/-13.119) kJ/mol during NNK interaction with AChE. Our study suggests that CSC is well capable of altering the normal biomolecular mechanism of CNS; thus, obtained data could be useful to design extensive wet laboratory experimentation to know the effects of CSC on human CNS.

Deciphering the Influence of Cigarette Smoke Carcinogens on CNS Associated Biomolecules: A Computational Synergistic Approach.

Human health issues caused by Cigarette Smoke Carcinogens (CSC) are increasing rapidly every day and challenging the scientific community to provide a better understanding in order to avoid its impact on communities. Cigarette smoke also contains tobacco-based chemical compounds harmful to human beings, either smokers or non-smokers. We have tested 7H-Dibenzo[c,g]carbazole (7H-DBC) and Dibenz[a,h]acridine (DBAD) derivatives of Asz-arenes along with N'-Nitrosoanabasine (NAB) and N-Nitrosoanatabine (NAT) derivatives of N-Nitrosamines molecular interaction with CNS biomolecules. Computational synergistic approaches like system biology and molecular interaction techniques were implemented to conduct the analysis. CSC efficiently interacted with NRAS, KRAS, CDH1, and RAC1 molecular targets in CNS. We have also performed the interactome analysis followed by system biology approaches and found that HSPA8 is the most important hub protein for the network generated for CSC-hampered genes of CNS. We have also identified 6 connector proteins, namely TP53, HSP90AA1, PPP2CA, CDH1, CTNNB1, and ARRB1. Further analysis revealed that NRAS and CDH1 have maximum interactions with all the selected CSC. The obtained structural analysis data could be utilized to assess the carcinogenic effect of CSC and could be useful in the treatment of CNS diseases and disorders induced, especially by tobacco-specific carcinogens, or it could also be used in vivo/ in vitro experimentation model designing.

Smoking and P53 polymorphism association with chromosomal aberration in lung cancer

Tobacco exposure is the primary leading cause for cancer of the oral cavity, the airways and lung. The carcinogens in cigarette smoke have been linked as an environmental risk factor for causing genetic mutations in tumor suppressor, including TP53 (p53) which has been linked as a causative for occurrence and progression in lung cancer. The aim of the current case-control study is to assess the presence and frequency of chromosomal aberrations between smokers and non-smokers in case and control group. Further, analysis was also extended to include the p53 codon 72 Arg/Pro mutation analysis between the groups of study cohort. In methods, the case-control epidemiological study included a total of 100 cases and controls who were further categorized as smokers and non-smokers for analysis. Chromosomal aberration assay was done on peripheral blood lymphocytes and studied using Geimsa stain, while analysis of the p53 codon 72 Arg/Pro mutation was done by allele-specific polymerase chain reaction assay. The chromosomal aberration assessed include structural abnormalities like breaks, fragment, dysenteric and gaps, as well as numerical aneuploidies. Results showing the number of chromosomal aberrations was higher among smoker cases as compared to controls, and numerical aneuploidy was also detected only among this cohort. The mean of chromosomal aberrations observed between cases and controls and smokers as well as non-smokers was significant at p < 0.0001. In case of the p53 genotyping result, the frequency of the Arg/Arg allele was higher among controls as compared to cases and the difference significant at p < 0.005. Among female participants, the difference between Arg/Arg and Pro/Arg was also found to be significant between cases and controls. Combined analysis of the p53 codon 72 alleles and mean of chromosomal aberrations between cases and controls was found to be significant at p < 0.005. Our study found an association between risk of lung cancer as well as occurrence of chromosomal aberrations. In case of the p53 polymorphism, the significance was detected only among females. In Conclusion, the studied p53 variant and chromosomal aberration along with smoking has shown significant association with increased risk of lung cancer.

Mechanisms of the synergistic lung tumorigenic effect of arsenic and benzo(a)pyrene combined- exposure.

Humans are often exposed to mixtures of environmental pollutants especially environmental chemical carcinogens, representing a significant environmental health issue. However, our understanding on the carcinogenic effects and mechanisms of environmental carcinogen mixture exposures is limited and mostly relies on the findings from studying individual chemical carcinogens. Both arsenic and benzo(a)pyrene (BaP) are among the most common environmental carcinogens causing lung cancer and other types of cancer in humans. Millions of people are exposed to arsenic via consuming arsenic-contaminated drinking water and even more people are exposed to BaP via cigarette smoking and consuming BaP-contaminated food. Thus arsenic and BaP combined-exposure in humans is common. Previous epidemiology studies indicated that arsenic-exposed people who were cigarette smokers had significantly higher lung cancer risk than those who were non-smokers. Since BaP is one of the major carcinogens in cigarette smoke, it has been speculated that arsenic and BaP combined-exposure may play important roles in the increased lung cancer risk observed in arsenic-exposed cigarette smokers. In this review, we summarize important findings and inconsistencies about the co-carcinogenic effects and underlying mechanisms of arsenic and BaP combined-exposure and propose new areas for future studies. A clear understanding on the mechanism of co-carcinogenic effects of arsenic and BaP combined exposure may identify novel targets to more efficiently treat and prevent lung cancer resulting from arsenic and BaP combined-exposure.

Exposure to a mixture of cigarette smoke carcinogens disturbs gut microbiota and influences metabolic homeostasis in A/J mice

An increased risk of developing lung cancer has been associated with exposure to cigarette smoke carcinogens and alteration in the gut microbiota. However, there is limited understanding about the impact of exposure to NNK and BaP, the two important components of cigarette smoke carcinogens, on gut microbiota in lung cancer. The present study characterized the influence of exposure to a mixture of NNK plus BaP on lung cancer, feces metabolite composition, and gut microbiota in the A/J mice. The A/J mice were administered NNK plus BaP, and the changes in gut microbiota and feces metabolic profiles were characterized using 16S rRNA gene sequencing and metabolomics, respectively. Results presented here illustrated that a mixture of NNK plus BaP exposure triggered lung carcinogenesis as shown by light microscopy and histopathological evaluation. 16S rRNA sequencing of gut microbiota indicated that exposure to NNK plus BaP could modified fecal bacterial composition. Elevated levels of Actinobacteria, Bifidobacterium, and Intestinimonas and reduced levels of Alistipes, Odoribacter, and Acetatifactor are associated with NNK plus BaP triggered lung cancer. In addition, metabolomics profile revealed the regulation of metabolism including purine metabolism, phenylalanine metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and others. In conclusion, the results provide some guidance for using gut microbes as biomarkers to assess the progression of lung cancer, and lead to interventional targets to control the development of the disease in the future.

Regulatory function of peroxiredoxin I on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung cancer development.

Smoking is a major cause of lung cancer, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is one of the most important carcinogens in cigarette smoke. NNK modulates the expression of peroxiredoxin (Prdx) I in lung cancer. Prdx1 is upregulated in lung squamous cell carcinoma and lung adenocarcinoma, and considered a potential biomarker for lung cancer. The current article reviewed the role and regulatory mechanisms of Prdx1 in NNK-induced lung cancer cells. Prdx1 protects erythrocytes and DNA from NNK-induced oxidative damage, prevents malignant transformation of cells and promotes cytotoxicity of natural killer cells, hence suppressing tumor formation. In addition, Prdx1 has the ability to prevent NNK-induced lung tumor metabolic activity and generation of large amount of reactive oxygen species (ROS) and ROS-induced apoptosis, thus promoting tumor cell survival. In contrast to this, Prdx1, together with NNK, can promote the epithelial-mesenchymal transition and migration of lung tumor cells. The signaling pathways associated with NNK and Prdx1 in lung cancer cells have been discussed in present review; however, numerous potential pathways are yet to be studied. To develop novel methods for treating NNK-induced lung cancer, and improve the survival rate of patients with lung cancer, further research is needed to understand the complete mechanism associated with NNK.

Degradation of SARS-CoV-2 receptor ACE2 by the E3 ubiquitin ligase Skp2 in lung epithelial cells

An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4%–18.5% of hospitalized adults, calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection. Here, we show that cigarette smoke extract (CSE) and carcinogen benzo(a)pyrene (BaP) increase ACE2 mRNA but trigger ACE2 protein catabolism. BaP induces an aryl hydrocarbon receptor (AhR)-dependent upregulation of the ubiquitin E3 ligase Skp2 for ACE2 ubiquitination. ACE2 in lung tissues of non-smokers is higher than in smokers, consistent with the findings that tobacco carcinogens downregulate ACE2 in mice. Tobacco carcinogens inhibit SARS-CoV-2 spike protein pseudovirions infection of the cells. Given that tobacco smoke accounts for 8 million deaths including 2.1 million cancer deaths annually and Skp2 is an oncoprotein, tobacco use should not be recommended and cessation plan should be prepared for smokers in COVID-19 pandemic.Electronic Supplementary MaterialSupplementary material is available for this article at 10.1007/s11684-021-0837-6 and is accessible for authorized users.

Lung carcinomas induced by NNK and LPS.

Cigarette smoking is the major culprit of chronic lung diseases and the most dominant risk factor for the development of both lung cancer and chronic obstructive pulmonary disease (COPD). In addition, chronic inflammation has been shown to increase the risk of lung cancer and COPD in clinical and epidemiological studies. For pulmonary disease-related research, mice are the most commonly used model system. Multiple lung cancer mouse models driven by targeted genetic alterations are used to evaluate the critical roles of oncogenes and tumor suppressor genes. These models are useful in addressing lung tumorigenesis associated with specific genetic changes, but they are not able to provide a global insight into cigarette smoke-induced carcinogenesis. To fill this knowledge gap, we developed a lung cancer model by treating mice with cigarette smoke carcinogen nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) with/without repeated lipopolysaccharides (LPS) exposure in order to determine the role of chronic inflammation in lung tumorigenesis. Notably, combined LPS/NNK treatment increased tumor number, tumor incidence, and tumor area compared to NNK treatment alone. Therefore, this model offers a feasible approach to investigate lung cancer development on a more global level, determine the role of inflammation in carcinogenesis, and provide a tool for evaluating chemoprevention and immunotherapy.

Saccharomyces cerevisiae and Caffeine Implications on the Eukaryotic Cell.

Caffeine–a methylxanthine analogue of the purine bases adenine and guanine–is by far the most consumed neuro-stimulant, being the active principle of widely consumed beverages such as coffee, tea, hot chocolate, and cola. While the best-known action of caffeine is to prevent sleepiness by blocking the adenosine receptors, caffeine exerts a pleiotropic effect on cells, which lead to the activation or inhibition of various cell integrity pathways. The aim of this review is to present the main studies set to investigate the effects of caffeine on cells using the model eukaryotic microorganism Saccharomyces cerevisiae, highlighting the caffeine synergy with external cell stressors, such as irradiation or exposure to various chemical hazards, including cigarette smoke or chemical carcinogens. The review also focuses on the importance of caffeine-related yeast phenotypes used to resolve molecular mechanisms involved in cell signaling through conserved pathways, such as target of rapamycin (TOR) signaling, Pkc1-Mpk1 mitogen activated protein kinase (MAPK) cascade, or Ras/cAMP protein kinase A (PKA) pathway.

Degradation of SARS-CoV-2 Receptor ACE2 by Tobacco Carcinogens

An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4-18.5% of hospitalized adults, calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection. Here, we show that cigarette smoke extract (CSE) and carcinogen benzo(a)pyrene (BaP) increase ACE2 mRNA but trigger ACE2 protein catabolism. BaP induces an aryl hydrocarbon receptor (AhR)-dependent upregulation of the ubiquitin E3 ligase Skp2 for ACE2 ubiquitination. ACE2 in lung tissues of non-smokers is higher than in smokers, consistent with the findings that tobacco carcinogens downregulate ACE2 in mice. Tobacco carcinogens inhibit SARS-CoV-2 Spike protein pseudovirions infection of the cells. These data indicate that recommendation of cessation of tobacco smoking remains valid because it is the carcinogens that are responsible for ACE2 degradation.

Cancer genomics of lung cancer including malignant mesothelioma: A brief overview of current status and future prospects.

Cancer as a genetic disease is by now well recognized. Genomic analysis of cancer cells, therefore, has greatly enhanced our ability to identify genetic alterations associated with various cancer types, including both lympho-hematopoietic as well as solid tumors. Chronic myeloid leukemia (CML), based on the specific diagnostic genetic abnormality has served as a prototype disease to clearly demonstrate the significance of the genomic analysis of cancer in identifying targeted therapy. Such a success has provided extra ordinary opportunities to investigate the role of genetic abnormalities and the pathways amenable to targeted therapy, not only in blood cancers but solid tumors such as Lung, Brain, Colon, Renal, Breast cancers as well as other epithelial and mesenchymal tumors. The main focus of this presentation is to illustrate the role of genomic analysis in targeting lung cancer, based on abnormalities or the pathways deregulated in tumor cells from individual patients. Lung cancer is one of the most common epithelial cancers associated with chronic inflammation due to cigarette smoking and other environmental carcinogens, and includes four distinct histologic type; non-small cell lung cancer (NSCLC); small cell lung cancer (SCLC) and squamous cell lung cancer. According to current estimates, 1.3 million cases of lung cancer are expected to be diagnosed worldwide annually, resulting in one million deaths. Since the discovery that patient's tumors with specific mutations in the EGFR may be sensitive to targeted therapeutic approach and the subsequent realization that the such mutations in the gene are not as prevalent, several cancer centers including ours initiated intense efforts to find other mutations or genomic alterations, which may serve as targets of specific therapy. Such efforts have successfully resulted in a battery of genes such as KRAS, ALK, C-MET, HER-2/neu, ROS1, etc., which have helped oncologists to triage the patients for personalized therapies. A significant proportion of patients with lung cancer, however, do not show any of the above genetic abnormalities. Approximately 90% of lung cancers exhibit RB1 mutation/deletion and or KRAS mutations, therefore, the signaling pathways, which regulate multistep tumorigenesis in lung cancer, are important for the treatment of histologic subtypes of lung cancer, which includes NSCLC & SCLC. Equally important was the findings that similar signaling pathways are also shared by other solid tumor types. We have investigated the role of these pathways to target these cancers and develop new strategies to treat lung, brain and related cancers. In addition, our translational studies in other tumor types such as NF2 related malignancies, specifically, Malignant Mesothelioma (MM), in which NF2 related pathway amenable to targeted therapies was identified. Selected examples representing experimental approaches will be discussed to illustrate the critical role of translational research in developing novel therapeutics for the successful and durable responses in some of these cancer types.

Inflammation synergistically promotes cigarette smoke carcinogen-induced lung tumorigenesis and determines immunotherapy efficacy

Abstract Chronic obstructive pulmonary disease (COPD) is a chronic lung inflammatory disease with an increased risk of lung cancer. Pseudomonas aeruginosa (PA) are opportunistic bacteria frequently found in patients with COPD, and associated with increased lung inflammation and acute exacerbations. The impacts of COPD-related inflammation, especially those induced by the PA-produced lipopolysaccharides (LPS), on lung tumorigenesis and the efficacy of immune checkpoint blockades remain poorly understood. In this study, we established a novel murine lung cancer model by treating mice with cigarette smoke carcinogen nitrosamine (NNK) combined with recurrent LPS exposure. LPS-mediated chronic inflammation in NNK-treated mice generates an immunosuppressive microenvironment characterized by the accumulation of myeloid-derived suppressive cells (MDSCs) and regulatory T cells, induced T-cell exhaustion, and enhanced PD-1/PD-L1 activity that resulted in synergistic increases of lung tumorigenesis than NNK treatment alone (&amp;gt;8-fold increase in tumor numbers, P&amp;lt;0.0001). Immunotherapy using anti-PD-1 antibody or anti-Ly6G antibody (to deplete MDSCs) alone reduced tumor growth, and in combination further enhanced the anti-tumor activity. We also identified immune gene signatures from the RNA transcript expression data of our murine cancer model and the published datasets of PD-1 blockade, which effectively predicted treatment responses and survival outcome in cohorts with immunotherapy and conventional treatments. Our results indicate that LPS-mediated chronic inflammation creates a favorable immunosuppressive microenvironment for tumor progression and correlates with the efficacy of anti-PD-1 treatment.

Characterization of Extracellular Vesicle LINE‐1 mRNA, Protein, and Reverse Transcriptase Activity Profiles

Lung cancer has the highest mortality rate among all cancers, making early detection of this malignancy imperative for survival. Ongoing studies in our laboratory have focused on developing Long Interspersed Nuclear Element‐1 (LINE‐1) in circulating lung extracellular vesicles (EVs) as a novel mechanism‐based ‘liquid biopsy’ for lung cancer. LINE‐1 is a mammalian retroelement that can ‘copy and paste’ itself and other DNAs into different loci via a reverse transcriptase‐mediated mechanism. While LINE‐1 is epigenetically silenced in most healthy cells, its activity can be initiated by harmful environmental exposures and is strongly associated with cancer risk and mortality. Evidence is presented here that LINE‐1 mRNA and protein are present in EVs isolated from H460 lung cancer cells and human plasma and are segregated into distinct EV populations. Because reverse transcription (RT) of LINE‐1 requires formation of a ribonucleoprotein complex containing LINE‐1 mRNA and proteins, we hypothesize that this segregation has been engineered to control RT. In support of this hypothesis, we found that RT activity is only present when these two EV populations are lysed and combined. We then isolated EVs from ostensibly healthy plasma donors and found substantial inter‐individual variability with respect to LINE‐1 protein, mRNA, and RT activity. The variability between individuals and the ease of measurement from clinical samples further supports the use of these LINE‐1 metrics as health‐related biomarkers. After characterizing EV LINE‐1, we sought to determine whether EV LINE‐1 levels could serve as a proxy of cellular LINE‐1 content, which is critical to our overall goal of using isolated lung EVs as a liquid biopsy of the lung epithelium. Using a panel of six different lung epithelial cell lines, we compared baseline LINE‐1 expression between cells and EVs. We also treated lung epithelial cells with different concentrations of benzo(a)pyrene (BaP), a cigarette smoke carcinogen known to induce LINE‐1, and compared LINE‐1 levels in cells and EVs. Thus far we discovered that, in both baseline and toxicant‐induced scenarios, EV LINE‐1 mRNA levels mirror cellular levels. Together, these data demonstrate that EV LINE‐1 content and RT activity can be quantified in cultured cells and clinical samples and supports the use of EV LINE‐1 cargo as a biomarker of lung epithelial cell status.Support or Funding InformationThis work was funded in part by grants from the University of Arizona Health Sciences, the Southwest Environmental Health Sciences Center (P30 ES006694), the National Cancer Institute Cancer Center Support Grant (P30CA023074), the UAZ Bio5 Fellowship and GURI Texas.