Prevalence, molecular markers, and outcome of bronchial squamous carcinoma in situ in high-risk subjects

Bronchial squamous carcinoma in situ (CIS) is a preinvasive lesion that is thought to precede invasive carcinoma. We conducted prospective autofluorescence and white light bronchoscopy trials between 1992 and 2016 to assess the prevalence, molecular markers, and outcome of individuals with CIS and other preneoplastic bronchial lesions. Biopsies were evaluated at multiple levels and selected biopsies were tested for aneuploidy and DNA sequenced for TP53 mutation. Thirty-one individuals with CIS were identified. Twenty-two cases of CIS occurred in association with concurrent invasive carcinomas. Seven of the invasive tumors were radiographically occult. In two cases, CIS spread from the focus of invasive carcinoma into contralateral lung lobes, forming secondary invasive tumors. In nine cases, CIS occurred as isolated lesions and one progressed to invasive squamous carcinoma at the same site 40 months after discovery. In a second case, CIS was a precursor of carcinoma at a separate site in a different lobe. In seven cases CIS regressed to a lower grade or disappeared. High level chromosomal aneusomy was often associated with TP53 mutation and with invasive carcinoma. CIS most often occurs in association with invasive squamous carcinoma and may extend along the airways into distant lobes. In rare cases, CIS may be observed to directly transform into invasive carcinoma. CIS may be indicative of invasive tumor at a separate distant site. Isolated CIS may regress. Molecular changes parallel histological changes in CIS and may be used to map clonal expansion in the airways.

Telemedicine-based inspiratory muscle training and walking promotion with lung cancer survivors following curative intent therapy: a parallel-group pilot randomized trial

PURPOSE

Following curative-intent therapy of lung cancer, many survivors experience dyspnea and physical inactivity. We investigated the feasibility, acceptability, safety, and potential efficacy of inspiratory muscle training (IMT) and walking promotion to disrupt a postulated "dyspnea-inactivity" spiral.

METHODS

Between January and December 2022, we recruited lung cancer survivors from Kaiser Permanente Colorado who completed curative-intent therapy within 1-6 months into a phase-IIb, parallel-group, pilot randomized trial (1:1 allocation). The 12-week intervention, delivered via telemedicine, consisted of exercise training (IMT + walking), education, and behavior change support. Control participants received educational materials on general exercise. We determined feasibility a priori: enrollment of ≥ 20% eligible patients, ≥ 75% retention, study measure completion, and adherence. We assessed acceptability using the Telemedicine-Satisfaction-and-Usefulness-Questionnaire and safety events that included emergency department visits or hospitalizations. Patient-centered outcome measures (PCOMs) included dyspnea (University-of-California-San-Diego-Shortness-of-Breath-Questionnaire), physical activity (activPAL™ steps/day), functional exercise capacity (mobile-based-six-minute-walk-test), and health-related quality of life (HRQL, St.-George's-Respiratory-Questionnaire). We used linear mixed-effects models to assess potential efficacy.

RESULTS

We screened 751 patients, identified 124 eligible, and consented 31 (25%) participants. Among 28 participants randomized (14/group), 22 (11/group) completed the study (79% retention). Intervention participants returned > 90% of self-reported activity logs, completed > 90% of PCOMs, and attended > 90% of tele-visits; 75% of participants performed IMT at the recommended dose. Participants had high satisfaction with tele-visits and found the intervention useful. There was no statistically significant difference in safety events between groups. Compared to control participants from baseline to follow-up, intervention participants had statistically significant and clinically meaningful improved HRQL (SGRQ total, symptom, and impact scores) (standardized effect size: -1.03 to -1.30).

CONCLUSIONS

Among lung cancer survivors following curative-intent therapy, telemedicine-based IMT + walking was feasible, acceptable, safe, and had potential to disrupt the "dyspnea-inactivity" spiral. Future efficacy/effectiveness trials are warranted and should incorporate IMT and walking promotion to improve HRQL.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05059132.

Phase Ib trial of inhaled iloprost for the prevention of lung cancer with predictive and response biomarker assessment

Introduction

Iloprost, a prostacyclin analog, has lung cancerpreventive activity in preclinical models and improved dysplasia in former smokers in a phase IIb trial. Oral iloprost is currently unavailable. We performed a phase Ib trial of inhaled iloprost in former smokers to assess tolerance and compliance.

Methods

Participants self-administered nebulized iloprost (5ug) or placebo four (QID) or two (BID) times daily. As QID dose was well tolerated and due to expiration of the placebo, the BID dosing and placebo were eliminated early on in the trial. Bronchoscopy with biopsyat six standard sites was performed at treatment initiation and two months post-iloprost, with exploratory histological analysis. Bulk RNA sequencing, single cell RNA sequencing and an in vitro assay of epithelial progenitor cell iloprost response were performed on a subset of biopsies in an exploratory investigation of response mechanisms and predictive biomarkers.

Results and discussion

Thirty-four of a planned 48 participants were recruited to the trial.Inhaled iloprost was well tolerated with no adverse events > grade 2. Compliance was 67% in the QID group. The trial was not powered to detect histologic response and none was found. Bulk RNA sequencing of biopsies pre/post iloprost suggest that iloprost is immunomodulatory and downregulates cell proliferation pathways. Single cell RNA sequencing showed an increase in CD8-positive T cells with upregulation of genes in interferon γ signaling. In vitro iloprost response by epithelial progenitor cells correlated with histologic response with kappa coefficient of 0.81 (95% CI 0.47, 1.0). Inhaled iloprost was well tolerated with suboptimal compliance. Molecular analysis suggested that iloprosthas immunomodulatory and antiproliferative effects.The progenitor cell iloprost response assay may be a promising avenue to develop predictive biomarkers.

Clinical trial registration

https://clinicaltrials.gov/study/NCT02237183, identifier NCT02237183.

Lung cancer survivors' views on telerehabilitation following curative intent therapy: a formative qualitative study

OBJECTIVES

To inform personalised home-based rehabilitation interventions, we sought to gain in-depth understanding of lung cancer survivors' (1) attitudes and perceived self-efficacy towards telemedicine; (2) knowledge of the benefits of rehabilitation and exercise training; (3) perceived facilitators and preferences for telerehabilitation; and (4) health goals following curative intent therapy.

DESIGN

We conducted semi-structured interviews guided by Bandura's Social Cognitive Theory and used directed content analysis to identify salient themes.

SETTING

One USA Veterans Affairs Medical Center.

PARTICIPANTS

We enrolled 20 stage I-IIIA lung cancer survivors who completed curative intent therapy in the prior 1-6 months. Eighty-five percent of participants had prior experience with telemedicine, but none with telerehabilitation or rehabilitation for lung cancer.

RESULTS

Participants viewed telemedicine as convenient, however impersonal and technologically challenging, with most reporting low self-efficacy in their ability to use technology. Most reported little to no knowledge of the potential benefits of specific exercise training regimens, including those directed towards reducing dyspnoea, fatigue or falls. If they were to design their own telerehabilitation programme, participants had a predominant preference for live and one-on-one interaction with a therapist, to enhance therapeutic relationship and ensure correct learning of the training techniques. Most participants had trouble stating their explicit health goals, with many having questions or concerns about their lung cancer status. Some wanted better control of symptoms and functional challenges or engage in healthful behaviours.

CONCLUSIONS

Features of telerehabilitation interventions for lung cancer survivors following curative intent therapy may need to include strategies to improve self-efficacy and skills with telemedicine. Education to improve knowledge of the benefits of rehabilitation and exercise training, with alignment to patient-formulated goals, may increase uptake. Exercise training with live and one-on-one therapist interaction may enhance learning, adherence, and completion. Future work should determine how to incorporate these features into telerehabilitation.

Precision Cut Lung Slices as a Preclinical Model for Non-Small Cell Lung Cancer Chemoprevention

Lung cancer chemoprevention is critical to addressing cancer burden in high-risk populations. Chemoprevention clinical trials rely on data from preclinical models; however, in vivo studies have high financial, technical, and staffing requirements. Precision cut lung slices (PCLS) provide an ex vivo model that maintains the structure and function of native tissues. This model can be used for mechanistic investigations and drug screenings and reduces the number of animals and time required to test hypotheses compared with in vivo studies. We tested the use of PCLS for chemoprevention studies, demonstrating recapitulation of in vivo models. Treatment of PCLS with the PPARγ agonizing chemoprevention agent iloprost produced similar effects on gene expression and downstream signaling as in vivo models. This occurred in both wild-type tissue and Frizzled 9 knockout tissue, a transmembrane receptor required for iloprost's preventive activity. We explored new areas of iloprost mechanisms by measuring immune and inflammation markers in PCLS tissue and media, and immune cell presence with immunofluorescence. To demonstrate the potential for drug screening, we treated PCLS with additional lung cancer chemoprevention agents and confirmed activity markers in culture. PCLS offers an intermediate step for chemoprevention research between in vitro and in vivo models that can facilitate drug screening prior to in vivo studies and support mechanistic studies with more relevant tissue environments and functions than in vitro models.

PREVENTION RELEVANCE

PCLS could be a new model for premalignancy and chemoprevention research, and this work evaluates the model with tissue from prevention-relevant genetic and carcinogen exposed in vivo mouse models, in addition to evaluating chemoprevention agents.

Lung adenocarcinoma promotion by air pollutants

A complete understanding of how exposure to environmental substances promotes cancer formation is lacking. More than 70 years ago, tumorigenesis was proposed to occur in a two-step process: an initiating step that induces mutations in healthy cells, followed by a promoter step that triggers cancer development1. Here we propose that environmental particulate matter measuring ≤2.5 μm (PM2.5), known to be associated with lung cancer risk, promotes lung cancer by acting on cells that harbour pre-existing oncogenic mutations in healthy lung tissue. Focusing on EGFR-driven lung cancer, which is more common in never-smokers or light smokers, we found a significant association between PM2.5 levels and the incidence of lung cancer for 32,957 EGFR-driven lung cancer cases in four within-country cohorts. Functional mouse models revealed that air pollutants cause an influx of macrophages into the lung and release of interleukin-1β. This process results in a progenitor-like cell state within EGFR mutant lung alveolar type II epithelial cells that fuels tumorigenesis. Ultradeep mutational profiling of histologically normal lung tissue from 295 individuals across 3 clinical cohorts revealed oncogenic EGFR and KRAS driver mutations in 18% and 53% of healthy tissue samples, respectively. These findings collectively support a tumour-promoting role for  PM2.5 air pollutants  and provide impetus for public health policy initiatives to address air pollution to reduce disease burden.

Protocol for intranasal chemoprevention delivery in a urethane mouse lung cancer model

Mouse iloprost lung cancer chemoprevention studies typically use oral delivery. Here, we present a protocol for intranasal iloprost delivery within a urethane lung adenocarcinoma mouse model. We detail steps for intraperitoneal urethane injection in mice, followed by nine-week monitoring, intranasal iloprost treatment, and lungs harvesting for analysis. This iloprost delivery approach parallels an ongoing phase II clinical trial of inhaled iloprost for lung cancer chemoprevention. This protocol diversifies options for chemoprevention studies and offers a relevant and translatable model. For complete details on the use and execution of this protocol, please refer to Sompel et al. (2022).

PPARgamma agonism inhibits progression of premalignant lesions in a murine lung squamous cell carcinoma model

The N-nitroso-trischloroethylurea (NTCU)-induced mouse model of squamous lung carcinoma recapitulates human disease from premalignant dysplasia through invasive tumors, making it suitable for preclinical chemoprevention drug testing. Pioglitazone is a peroxisome proliferator-activated receptor γ (PPARγ) agonist shown to prevent lung tumors in preclinical models. We investigated pioglitazone's effect on lesion development and markers of potential preventive mechanisms in the NTCU model. Female FVB/N mice were exposed to vehicle, NTCU or NTCU + oral pioglitazone for 32 weeks. NTCU induces the appearance of basal cells in murine airways while decreasing/changing their epithelial cell makeup, resulting in development of bronchial dysplasia. H&E and keratin 5 (KRT5) staining were used to detect and grade squamous lesions in formalin fixed lungs. mRNA expression of epithelial to mesenchymal transition (EMT) markers and basal cell markers were measured by qPCR. Dysplasia persistence markers desmoglein 3 and polo like kinase 1 were measured by immunohistochemistry. Basal cell markers KRT14 and p63, club cell specific protein and ciliated cell marker acetylated tubulin were measured by immunofluorescence. Pioglitazone treatment significantly reduced squamous lesions and the presence of airway basal cells, along with increasing normal epithelial cells in the airways of NTCU-exposed mice. Pioglitazone also significantly influenced EMT gene expression to promote a more epithelial, and less mesenchymal, phenotype. Pioglitazone reduced the presence of squamous dysplasia and maintained normal airway cell composition. This work increases the knowledge of mechanistic pathways in PPARγ agonism for lung cancer interception and provides a basis for further investigation to advance this chemoprevention strategy.

Loss of Frizzled 9 in Lung Cells Alters Epithelial Phenotype and Promotes Premalignant Lesion Development

The transmembrane receptor Frizzled 9 (FZD9) is important for fetal neurologic and bone development through both canonical and non-canonical WNT/FZD signaling. In the adult lung, however, Fzd9 helps to maintain a normal epithelium by signaling through peroxisome proliferator activated receptor γ (PPARγ). The effect of FZD9 loss on normal lung epithelial cells and regulators of its expression in the lung are unknown. We knocked down FZD9 in human bronchial epithelial cell (HBEC) lines and found that downstream EMT targets and PPARγ activity are altered. We used a FZD9-/- mouse in the urethane lung adenocarcinoma model and found FZD9-/- adenomas had more proliferation, increased EMT signaling, decreased activation of PPARγ, increased expression of lung cancer associated genes, increased transformed growth, and increased potential for invasive behavior. We identified PPARγ as a transcriptional regulator of FZD9. We also demonstrated that extended cigarette smoke exposure in HBEC leads to decreased FZD9 expression, decreased activation of PPARγ, and increased transformed growth, and found that higher exposure to cigarette smoke in human lungs leads to decreased FZD9 expression. These results provide evidence for the role of FZD9 in lung epithelial maintenance and in smoking related malignant transformation. We identified the first transcriptional regulator of FZD9 in the lung and found FZD9 negative lesions are more dangerous. Loss of FZD9 creates a permissive environment for development of premalignant lung lesions, making it a potential target for intervention.

Iloprost requires the Frizzled-9 receptor to prevent lung cancer

Prevention of premalignant lesion progression is a promising approach to reducing lung cancer burden in high-risk populations. Substantial preclinical and clinical evidence has demonstrated efficacy of the prostacyclin analogue iloprost for lung cancer chemoprevention. Iloprost activates peroxisome proliferator-activated receptor gamma (PPARG) to initiate chemopreventive signaling and in vitro, which requires the transmembrane receptor Frizzled9 (FZD9). We hypothesized a Fzd 9 -/- mouse would not be protected by iloprost in a lung cancer model. Fzd 9 -/- mice were treated with inhaled iloprost in a urethane model of lung adenoma. We found that Fzd 9 -/- mice treated with iloprost were not protected from adenoma development compared to wild-type mice nor did they demonstrate increased activation of iloprost signaling pathways. Our results established that iloprost requires FZD9 in vivo for lung cancer chemoprevention. This work represents a critical advancement in defining iloprost's chemopreventive mechanisms and identifies a potential response marker for future clinical trials.

Lung cancer: Premalignant biology and medical prevention

Lung cancer (both adenocarcinoma and squamous cell) progress through a series of pre-malignant histologic changes before the development of invasive disease. Each of these carcinogenic cascades is defined by genetic and epigenetic alterations in pulmonary epithelial cells. Additionally, alterations in the immune response, progenitor cell function, mutational burden, and microenvironmental mediated survival of mutated clones contribute to the risk of pre-malignant lesions progressing to cancer. Medical preventions studies have been completed and current and future trials are informed by the improved understanding of pre-malignancy. This will lead to precision chemoprevention trials based on lesional biology and histologic characteristics.

Modifiable factors associated with health-related quality of life among lung cancer survivors following curative intent therapy

OBJECTIVE

The number of lung cancer survivors is increasing along with advances in screening, diagnosis, and treatment. Following curative intent therapy, many lung cancer survivors experience significant health-related quality of life (HRQL) impairments. We sought to identify potentially modifiable factors that contribute to the HRQL of these patients.

MATERIALS AND METHODS

In this cross-sectional observational study of disease-free, stage I-IIIA lung cancer survivors following curative intent therapy, we used a conceptual model to examine factors that included behavioral, objective functional and physiologic, self-rated function and symptom burden, specific comorbidities, and non-modifiable demographic and clinical lung cancer-related characteristics. We assessed HRQL using the valid and prognostic European Organization for Research and Treatment of Cancer Quality of Life (QoL) Core 30 global health/QoL subscale. We used univariable and multivariable linear regression modeling with backward elimination of potentially modifiable and non-modifiable factors, and interpreted clinically and statistically significant, consistent, and independent modifiable factors as meaningful.

RESULTS

Among 75 participants at a median of 12 months since treatment completion, the mean (standard deviation) C30 global health/QoL score was 62.7 (23.3) points (0-100 scale range). In multivariable analysis, with and without non-modifiable factors, we identified three clinically and statistically significant, consistent, and independent factors (unstandardized β range) associated with global health/QoL: 1) abnormal exercise-induced dyspnea (-9.23 to -10.0 points); 2) impaired self-rated role function (or inability to perform work or daily activities and pursuing leisure-time activities) (-12.6 to -16.4 points); and 3) abnormal insomnia (or trouble sleeping) (-12.6 to -16.4 points).

CONCLUSION

We identified meaningful modifiable factors associated with the HRQL of disease-free, stage I-IIIA lung cancer survivors following curative intent therapy. Interventions to improve the HRQL of these patients should aim to reduce exercise-induced dyspnea, improve role function - the ability to perform work and other daily including leisure-time activities, and control insomnia.

Intranasal iloprost prevents tumors in a murine lung carcinogenesis model

Lung cancer chemoprevention with the prostacyclin analogue iloprost is the most promising approach to date for intercepting progression of premalignant lung lesions in former smokers. Previous pre-clinical studies of iloprost used oral delivery, but a study modeling delivery directly to the target organ was needed. In vivo and in vitro studies have identified gene expression changes following iloprost treatment, including increased E-cadherin and PPAR𝛄 and decreased COX2 and Vimentin. We used tumor counts and gene expression to demonstrate the effectiveness of intranasal delivery of iloprost in a murine model of premalignant adenomas. Intranasal delivery of iloprost reduced adenoma multiplicity14 weeks after urethane exposure in FVB mice compared to untreated urethane controls. Intranasal iloprost reversed urethane-induced gene expression changes in tumors and whole lung. These results correspond to previous studies of oral iloprost and in vitro treatment of human bronchial epithelial cells. This study demonstrates that intranasal delivery of iloprost in a mouse model of lung premalignant lesions is effective chemoprevention. This will be an essential tool for exploring mechanisms and outcomes of iloprost chemoprevention, along with supporting ongoing clinical trials of inhaled iloprost chemoprevention.

Association of Leisure-Time Physical Activity With Health-Related Quality of Life Among US Lung Cancer Survivors

Background

Physical activity and exercise improve function, symptom control, and health-related quality of life (QoL) for many cancer survivors; however, the evidence is limited and inconsistent in lung cancer. We examined the relationship between leisure-time physical activity (LTPA) and health-related QoL in a national sample of US lung cancer survivors.

Methods

We conducted a cross-sectional study using the Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System. We defined LTPA as a self-report of engaging in any physical activity or exercise such as running, calisthenics, golf, gardening, or walking for exercise in the past 30 days, health-related QoL as the number of days of having poor physical or mental health in the past 30 days, and general health status. We analyzed using multivariable logistic regressions with 95% confidence intervals (CIs).

Results

Among 614 lung cancer survivors, 316 (51.5%) reported engaging in LTPA. The counts (and proportions) of participants who engaged in LTPA vs no LTPA were, respectively, 135 (42.7%) vs 63 (21.1%) for 0 days of poor physical health, 222 (70.3%) vs 174 (58.4%) for 0 days of poor mental health, and 158 (50.0%) vs 77 (25.8%) for good to excellent general health. In multivariable analyses, participating in LTPA was associated with odds ratios of 2.64 (95% CI = 1.76 to 3.96) and 1.43 (95% CI = 0.97 to 2.10) for 0 days of poor physical and mental health, respectively, and 2.61 (95% CI = 1.74 to 3.91) for good to excellent general health.

Conclusions

Participating in LTPA was associated with improved health-related QoL. Interventions to promote LTPA and/or exercise-based rehabilitation may improve QoL among lung cancer survivors.

Impact of Proactive Integrated Care on Chronic Obstructive Pulmonary Disease

Background

Up to 50% of chronic obstructive pulmonary disease (COPD) patients do not receive recommended care for COPD. To address this issue, we developed Proactive Integrated Care (Proactive iCare), a health care delivery model that couples integrated care with remote monitoring.

Methods

We conducted a prospective, quasi-randomized clinical trial in 511 patients with advanced COPD or a recent COPD exacerbation, to test whether Proactive iCare impacts patient-centered outcomes and health care utilization. Patients were allocated to Proactive iCare (n=352) or Usual Care ( =159) and were examined for changes in quality of life using the St George's Respiratory Questionnaire (SGRQ), symptoms, guideline-based care, and health care utilization.

Findings

Proactive iCare improved total SGRQ by 7-9 units (p < 0.0001), symptom SGRQ by 9 units (p<0.0001), activity SGRQ by 6-7 units (p<0.001) and impact SGRQ by 7-11 units (p<0.0001) at 3, 6 and 9 months compared with Usual Care. Proactive iCare increased the 6-minute walk distance by 40 m (p<0.001), reduced annual COPD-related urgent office visits by 76 visits per 100 participants (p<0.0001), identified unreported exacerbations, and decreased smoking (p=0.01). Proactive iCare also improved symptoms, the body mass index-airway obstruction-dyspnea-exercise tolerance (BODE) index and oxygen titration (p<0.05). Mortality in the Proactive iCare group (1.1%) was not significantly different than mortality in the Usual Care group (3.8%; p=0.08).

Interpretation

Linking integrated care with remote monitoring improves the lives of people with advanced COPD, findings that may have been made more relevant by the coronavirus 2019 (COVID-19) pandemic.

An Improved Murine Premalignant Squamous Cell Model: Tobacco Smoke Exposure Augments NTCU-Induced Murine Airway Dysplasia

Tobacco smoke-induced squamous cell lung cancer (SCC) develops from endobronchial dysplastic lesions that progress to invasive disease. A reproducible murine model recapitulating histologic progression observed in current and former smokers will advance testing of new preventive and therapeutic strategies. Previous studies show that prolonged topical application of N-nitroso-tris-chloroethylurea (NTCU) generates a range of airway lesions in sensitive mice similar to those induced by chronic tobacco smoke exposure in humans. To improve the current NTCU model and better align it with human disease, NTCU was applied to mice twice weekly for 4-5 weeks followed by a recovery period before cigarette smoke (CS) or ambient air (control) exposure for an additional 3-6 weeks. Despite the short time course, the addition of CS led to significantly more premalignant lesions (PML; 2.6 vs. 0.5; P < 0.02) and resulted in fewer alveolar macrophages (52,000 macrophages/mL BALF vs. 68,000; P < 0.05) compared with control mice. This improved NTCU + CS model is the first murine SCC model to incorporate tobacco smoke and is more amenable to preclinical studies because of the increased number of PML, decreased number of mice required, and reduced time needed for PML development.

Exhaustion of Airway Basal Progenitor Cells in Early and Established Chronic Obstructive Pulmonary Disease

RATIONALE

Up to 40% of smokers develop chronic obstructive pulmonary disease (COPD) over a period that spans decades. Despite the importance of COPD, much remains to be learned about susceptibility and pathogenesis, especially during early, prediagnostic stages of disease. Airway basal progenitor cells are crucial for lung health and resilience because of their ability to repair injured airways. In COPD, the normal airway epithelium is replaced with increased basal and secretory (mucous) cells and decreased ciliated cells, suggesting that progenitors are impaired.

OBJECTIVES

To examine airway basal progenitor cells and lung function in smokers with and without COPD.

METHODS

Bronchial biopsies taken from smokers at risk for COPD and lung cancer were used to acquire airway basal progenitor cells. They were evaluated for count, self-renewal, and multipotentiality (ability to differentiate to basal, mucous, and ciliated cells), and progenitor count was examined for its relationship with lung function.

MEASUREMENTS AND MAIN RESULTS

Basal progenitor count, self-renewal, and multipotentiality were all reduced in COPD versus non-COPD. COPD progenitors produced an epithelium with increased basal and mucous cells and decreased ciliated cells, replicating the COPD phenotype. Progenitor depletion correlated with lung function and identified a subset of subjects without COPD with lung function that was midway between non-COPD with high progenitor counts and those with COPD.

CONCLUSIONS

Basal progenitor dysfunction relates to the histologic and physiologic manifestations of COPD and identifies a subset that may represent an early, prediagnostic stage of COPD, indicating that progenitor exhaustion is involved in COPD pathogenesis.

A Randomized Phase II Trial of Pioglitazone for Lung Cancer Chemoprevention in High-Risk Current and Former Smokers

Lung cancer chemoprevention, especially in high-risk former smokers, has great potential to reduce lung cancer incidence and mortality. Thiazolidinediones prevent lung cancer in preclinical studies, and diabetics receiving thiazolidinediones have lower lung cancer rates which led to our double-blind, randomized, phase II placebo-controlled trial of oral pioglitazone in high-risk current or former smokers with sputum cytologic atypia or known endobronchial dysplasia. Bronchoscopy was performed at study entry and after completing 6 months of treatment. Biopsies were histologically scored, and primary endpoint analysis tested worst biopsy scores (Max) between groups; Dysplasia index (DI) and average score (Avg) changes were secondary endpoints. Biopsies also received an inflammation score. The trial accrued 92 subjects (47 pioglitazone, 45 placebo), and 76 completed both bronchoscopies (39 pioglitazone, 37 placebo). Baseline dysplasia was significantly worse for current smokers, and 64% of subjects had mild or greater dysplasia at study entry. Subjects receiving pioglitazone did not exhibit improvement in bronchial dysplasia. Former smokers treated with pioglitazone exhibited a slight improvement in Max, while current smokers exhibited slight worsening. While statistically significant changes in Avg and DI were not observed in the treatment group, former smokers exhibited a slight decrease in both Avg and DI. Negligible Avg and DI changes occurred in current smokers. A trend toward decreased Ki-67 labeling index occurred in former smokers with baseline dysplasia receiving pioglitazone. While pioglitazone did not improve endobronchial histology in this high-risk cohort, specific lesions showed histologic improvement, and further study is needed to better characterize responsive dysplasia.

Prostacyclin and EMT Pathway Markers for Monitoring Response to Lung Cancer Chemoprevention

Lung cancer is the leading cause of cancer death worldwide and global burden could be reduced through targeted application of chemoprevention. The development of squamous lung carcinoma has been linked with persistent, high-grade bronchial dysplasia. Bronchial histology improved in former smokers in a chemoprevention trial with the prostacyclin analogue iloprost. Prostacyclin acts through peroxisome proliferator-activated receptor gamma (PPARγ) to reverse epithelial to mesenchymal transition and promote anticancer signaling. We hypothesized that the prostacyclin signaling pathway and EMT could provide response markers for prostacyclin chemoprevention of lung cancer. Human bronchial epithelial cells were treated with cigarette smoke condensate (CSC) or iloprost for 2 weeks, CSC for 16 weeks, or CSC for 4 weeks followed by 4 weeks of CSC and/or iloprost, and RNA was extracted. Wild-type or prostacyclin synthase transgenic mice were exposed to 1 week of cigarette smoke or one injection of urethane, and RNA was extracted from the lungs. We measured potential markers of prostacyclin and iloprost efficacy in these models. We identified a panel of markers altered by tobacco carcinogens and inversely affected by prostacyclin, including PPARγ, 15PGDH, CES1, COX-2, ECADHERIN, SNAIL, VIMENTIN, CRB3, MIR34c, and MIR221 These data introduce a panel of potential markers for monitoring interception of bronchial dysplasia progression during chemoprevention with prostacyclin. Chemoprevention is a promising approach to reduce lung cancer mortality in a high-risk population. Identifying markers for targeted use is critical for success in future clinical trials of prostacyclin for lung cancer chemoprevention. Cancer Prev Res; 11(10); 643-54. ©2018 AACR.

Abstract B35: Biomarkers for precision application of prostacyclin lung cancer chemoprevention

Lung cancer remains the leading cause of cancer death in the United States, and chemoprevention offers an appealing area of investigation in the face of limited therapeutic success. Improvement in endobronchial histology was demonstrated in former smokers after oral iloprost chemoprevention in a phase II clinical trial. Of the 48 patients who received iloprost in the chemoprevention trial, 23 had regressive histology and 25 had stable or progressive histology. Identifying markers that predict which patients will respond to treatment will help refine target populations for future trials and clinical applications. Markers of drug activity will also facilitate clinical application by allowing monitoring during treatment. Preclinical studies indicate that iloprost, a prostacyclin analogue, acts through peroxisome proliferator activated receptor gamma (PPAR) to reduce transformed lung epithelial cell growth and markers of epithelial-to-mesenchymal transition (EMT). We hypothesize that PPAR expression status predicts response to prostacyclin chemoprevention and that expression changes in known downstream targets of PPAR and prostacyclin indicate response to prostacyclin treatment. Prostacyclin may also induce expression of PPAR, leading to increased antitumor signaling. We found that expression of PPAR and markers of prostacyclin signaling (15pgdh, CES1, and PTGS2) and EMT markers (Snail, Vimentin, Ecadherin, and CRB3) changed in cultured human bronchial epithelial cells (HBEC) in response to cigarette smoke condensate (CSC) and that iloprost reversed these changes. Expression in mice also changed in response to cigarette smoke carcinogens and prostacyclin. miR-34c is inversely correlated with bronchial histology grade and suppresses lung cancer progression. In our study, the level of miR-34c was lower in the NSCLC cell line H322 compared to HBEC. In H322, miR-34c increased with PPAR agonist treatment and decreased with PPAR antagonist treatment. In HBEC and mouse models of lung cancer chemoprevention, miR-34c increased with prostacyclin and decreased with cigarette smoke carcinogen exposure. In cultured primary progressive dysplastic bronchial epithelial cells, treatment with iloprost resulted in similar expression changes in Vimentin, Snail, Ecadherin, CRB3, CES1, and miR-34c. This study has the potential to improve iloprost lung cancer chemoprevention by allowing future trials to more effectively target high-risk patients, by providing a clinical biomarker for identification of chemoprevention candidates, and by identifying biomarkers for intermediate monitoring of response. Future studies will test expression of these markers in lung tissue biopsy and liquid biopsy samples from the oral and inhaled iloprost chemoprevention trials.

Citation Format: Melissa New, Debbie McArthur, Lori Nield, Dan Merrick, Robert L. Keith, Meredith A. Tennis. Biomarkers for precision application of prostacyclin lung cancer chemoprevention [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr B35.

Abstract A14: Changes in miRNA profile in a murine model of lung adenocarcinoma are attenuated by increased prostacyclin levels

Rationale: Lung cancer has a high mortality even when it is diagnosed at an early stage. Intercepting these early changes using chemoprevention could dramatically improve survival. Increased prostacyclin provides effective chemoprevention in multiple murine models and its oral analogue, iloprost, increased regression of dysplastic lesions in former smokers in clinical trials. MicroRNAs are short, noncoding RNA that are important post-transcriptional regulators during carcinogenesis. miRNA stability makes them attractive as potential biomarkers of premalignancy and response to chemoprevention. We hypothesize that alterations in the miRNA profile in early tumors and at-risk lung tissue are attenuated by increased levels of prostacyclin.

Methods: Wild-type and transgenic prostacyclin synthase overexpressing (PGIS-OE) FVB/N mice were sacrificed at time = 0 as well as 8 and 16 weeks after intraperitoneal injection with urethane, which is known to induce Kras mutations resulting in adenocarcinoma. Transgenic mice and wild-type littermates were sacrificed at multiple timepoints (baseline, 8 weeks and 16 weeks post-urethane). Visible tumors were dissected and separated from remaining lung tissue. Tissue was lysed and homogenized and total RNA was extracted using the QIAGEN AllPrep DNA/RNA/miRNA Universal Kit. Samples from time = 0 and 16 weeks were analyzed using the Nanostring nCounter analysis system, which analyzed 550 murine miRNAs per sample. Quantitative real-time PCR (qRT-PCR) was performed using primers from QIAGEN.

Results: miRNAs from lungs of naive WT and PGIS-OE mice were compared using Nanostring nCounter, without significant differences. From the 16-week group, miRNAs from tumors were compared with uninvolved lung tissue, with significant changes identified in over 80% of miRNAs tested. These data were cross-referenced with published human data, and a subset of biologically relevant miRNAs was chosen for further investigation with qRT-PCR in the earlier, 8-week timepoint: miR-143 (fold change=1.84), miR-146b (1.41), miR-154 (1.29), miR-410 (0.57), miR-429 (2.01), miR-451 (0.47). The miRNA fold-changes observed in the urethane-treated WT mice at 8 weeks were attenuated in the PGIS-OE mice.

Conclusions: There are important changes to the miRNA profile in adenomas (early tumors) at 16 weeks, and these miRNAs are aberrant in the lungs at an even earlier time point when tumors have not yet developed (8 weeks). The changes to the miRNA profile in early carcinogenesis are attenuated by the presence of increased prostacyclin, even though prostacyclin does not cause significant changes to the miRNA profile at baseline. Ongoing investigation includes the evaluation of additional miRNAs in these samples, some from later time points (24 weeks), in cancer cell lines exposed to iloprost and in bronchial epithelial cells from a clinical trial of high-risk subjects treated with inhaled iloprost.

Citation Format: Melissa L. New, Meredith A. Tennis, Lori D. Nield, Debbie McArthur, Robert L. Keith. Changes in miRNA profile in a murine model of lung adenocarcinoma are attenuated by increased prostacyclin levels [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr A14.

Altered Cell-Cycle Control, Inflammation, and Adhesion in High-Risk Persistent Bronchial Dysplasia

Persistent bronchial dysplasia is associated with increased risk of developing invasive squamous cell carcinoma (SCC) of the lung. In this study, we hypothesized that differences in gene expression profiles between persistent and regressive bronchial dysplasia would identify cellular processes that underlie progression to SCC. RNA expression arrays comparing baseline biopsies from 32 bronchial sites that persisted/progressed to 31 regressive sites showed 395 differentially expressed genes [ANOVA, FDR ≤ 0.05). Thirty-one pathways showed significantly altered activity between the two groups, many of which were associated with cell-cycle control and proliferation, inflammation, or epithelial differentiation/cell-cell adhesion. Cultured persistent bronchial dysplasia cells exhibited increased expression of Polo-like kinase 1 (PLK1), which was associated with multiple cell-cycle pathways. Treatment with PLK1 inhibitor induced apoptosis and G2-M arrest and decreased proliferation compared with untreated cells; these effects were not seen in normal or regressive bronchial dysplasia cultures. Inflammatory pathway activity was decreased in persistent bronchial dysplasia, and the presence of an inflammatory infiltrate was more common in regressive bronchial dysplasia. Regressive bronchial dysplasia was also associated with trends toward overall increases in macrophages and T lymphocytes and altered polarization of these inflammatory cell subsets. Increased desmoglein 3 and plakoglobin expression was associated with higher grade and persistence of bronchial dysplasia. These results identify alterations in the persistent subset of bronchial dysplasia that are associated with high risk for progression to invasive SCC. These alterations may serve as strong markers of risk and as effective targets for lung cancer prevention.Significance: Gene expression profiling of high-risk persistent bronchial dysplasia reveals changes in cell-cycle control, inflammatory activity, and epithelial differentiation/cell-cell adhesion that may underlie progression to invasive SCC. Cancer Res; 78(17); 4971-83. ©2018 AACR.

Targeted overexpression of prostacyclin synthase inhibits lung tumor progression by recruiting CD4+ T lymphocytes in tumors that express MHC class II

Lung-specific overexpression of prostacyclin synthase (PGIS) decreases tumor initiation in murine lung cancer models. Prostacyclin analogs prevent lung tumor formation in mice and reverse bronchial dysplasia in former smokers. However, the effect of prostacyclin on lung cancer progression has not been well studied. We investigated the effects of pulmonary PGIS overexpression in an orthotopic immunocompetent mouse model of lung cancer using two murine lung cancer cell lines. Pulmonary PGIS overexpression significantly inhibited CMT167 lung tumor growth, increased CXCL9 expression, and increased CD4+ tumor-infiltrating lymphocytes. Immunodepletion of CD4+ T cells abolished the inhibitory effect of pulmonary PGIS overexpression on CMT167 lung tumor growth. In contrast, pulmonary PGIS overexpression failed to inhibit growth of a second murine lung cancer cell line, Lewis Lung Carcinoma (LLC) cells, and failed to increase CXCL9 expression or CD4+ T lymphocytes in LLC lung tumors. Transcriptome profiling of CMT167 cells and LLC cells recovered from tumor-bearing mice demonstrated that in vivo, CMT167 cells but not LLC cells express MHC class II genes and cofactors necessary for MHC class II processing and presentation. These data demonstrate that prostacyclin can inhibit lung cancer progression and suggest that prostacyclin analogs may serve as novel immunomodulatory agents in a subset of lung cancer patients. Moreover, expression of MHC Class II by lung cancer cells may represent a biomarker for response to prostacyclin.

The Second-Generation PGI2 Analogue Treprostinil Fails to Chemoprevent Tumors in a Murine Lung Adenocarcinoma Model

Prostacyclin (prostaglandin I₂, PGI₂) overproduction in FVB/N mice prevents the formation of carcinogen and tobacco smoke-induced adenomas, and administration of the oral prostacyclin analogue iloprost to wild-type mice also prevented carcinogen-induced mouse lung adenoma formation. Former smokers taking oral iloprost showed improved bronchial dysplasia histology compared with placebo. Next-generation oral prostacyclin analogues, like treprostinil, were developed for the treatment of pulmonary arterial hypertension (PAH). On the basis of our prior studies with iloprost, we performed preclinical studies examining the ability of treprostinil to chemoprevent urethane-induced murine lung adenocarcinoma. We determined the MTD in chow (prior studies had delivered treprostinil by gavage), and this dose produced serum levels in the experimental animals similar to those found in PAH patients treated with treprostinil. We then examined the chemopreventive efficacy of treprostinil exposure initiated both before (1 week) and after (6 weeks) urethane exposure to better model chemoprevention studies conducted in former smokers. Neither of these dosing strategies prevented murine lung cancer; however, we did detect changes in pulmonary inflammatory cell infiltrate and expression of CXCR4 (a chemokine receptor previously shown to increase in response to treprostinil exposure) in tumor-bearing, treprostinil-treated animals, indicating that the drug was bioavailable. One potential explanation stems from iloprost and treprostinil differentially activating cell surface prostaglandin receptors and intracellular peroxisome proliferator-activated receptors. When murine lung tumor cells were treated with treprostinil, their proliferation rate increased; in contrast, iloprost had no effect on proliferation. Future investigations comparing these two agents will provide insight into iloprost's chemopreventive mechanisms. Cancer Prev Res; 10(11); 671-9. ©2017 AACR.

Persistence of Bronchial Dysplasia Is Associated with Development of Invasive Squamous Cell Carcinoma

Bronchial dysplasia (BD), a presumed precursor of pulmonary squamous cell carcinoma (SCC), rarely progresses to invasive cancer. A high-risk cohort at the University of Colorado provided an opportunity to directly sample airway epithelium at mapped sites on successive bronchoscopies. We have hypothesized that persistent dysplastic lesions showing a similar or higher level of dysplasia on follow-up biopsy, are associated with increased risk for the development of SCC. Endoscopic biopsies from 188 high-risk subjects were histologically classified according to the current WHO classification for BD using a numeric histology score ranging from 1 to 8 representing normal bronchial mucosa through invasive lung cancer. Differences in follow-up histology scores were compared between sites classified by clinical, histologic, and immunohistochemical variables. Subjects with a higher frequency of sites that persist or progress to high-grade dysplasia (≥37.5% persist/progress, N = 35 versus <37.5% persist/progress, N = 114) show a significant association with development of incident invasive SCC (adjusted HR, 7.84; 95% confidence interval, 1.56-39.39), and those with incident lung SCC have adjusted mean follow-up histology scores 1.55 U higher than in subjects without lung cancer. Current smoking, elevated Ki67 growth fraction, histologic features of angiogenic squamous dysplasia (ASD) and higher histology score in baseline biopsies are significantly associated with increased follow-up histology scores. These results show that persistent BD is associated with the development of invasive SCC. Furthermore, increased expression of Ki67, the presence of angiogenic change and degree of baseline atypia are associated with persistence of BD.

Abstract B19: Malfunction and mutation of airway stem/progenitor cells in preneoplastic bronchial dysplasia

Squamous cell lung cancer (SCC) is the second leading cause of lung cancer death in the US with a 5-year survival rate of 16.8%. Since most SCC is diagnosed at a late stage, chemoprevention or early detection could improve survival. SCC develops through a series of histological alterations including dysplasia and carcinoma in situ. Previous studies have identified genetic changes in epithelial progenitor cells in dysplastic lesions. The goal of this project is to establish a correlation between specific genetic changes in epithelial progenitors and their function. A tissue stem cell is a progenitor cell that is capable of long-term self-renewal as well as differentiation to all the cell-types that make up a specific tissue and therefore is multipotential. Because the normal function of a progenitor cell is to repair and regenerate a native epithelium after injury, histologic changes in dysplasia led us hypothesize that “normal function of airway progenitors is altered in dysplasia”. To address this hypothesis we purified and established clonal cultures of basal progenitors from normal, moderate and severely dysplastic biopsies and compared their self-renewal and differentiation abilities. These analyses revealed that the self-renewal capacity of progenitor cells decreased as dysplasia grade increased. The progenitors from normal biopsies differentiated to all three cell-types (basal, secretory or mucin-secreting and ciliated) of the airways. In contrast, progenitors from dysplasia generated increased numbers of basal cells (p&lt;0.05) and lacked secretory (p&lt;0.001) and ciliated cells (p&lt;0.001), suggesting that multipotential differentiation is impaired in dysplasia. Genetic analyses of dysplastic lesions and cultured dysplastic progenitors (n=4, histology grade ≥ 5.5) identified several mutations (p53, Notch 1, 2 and 3, FBXW7, and FGFR1) that have been previously reported in SCC. Thus, we demonstrate that we are able to culture airway stem/progenitor cells that recapitulate both the phenotypic and mutational characteristics of the lesions from which they originate. We propose that understanding the effect of these mutations in altered progenitor function will help to devise prevention as well as early detection strategies.

Citation Format: Moumit Ghosh, Ichiro Nakachi, Robert L. Keith, Daniel T. Merrick, Wilbur A. Franklin, York E. Miller. Malfunction and mutation of airway stem/progenitor cells in preneoplastic bronchial dysplasia. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr B19.

Tracheal dysplasia precedes bronchial dysplasia in mouse model of N-nitroso trischloroethylurea induced squamous cell lung cancer

Squamous cell lung cancer (SCC) is the second leading cause of lung cancer death in the US and has a 5-year survival rate of only 16%. Histological changes in the bronchial epithelium termed dysplasia are precursors to invasive SCC. However, the cellular mechanisms that cause dysplasia are unknown. To fill this knowledge gap, we used topical application of N-nitroso-tris chloroethylurea (NTCU) for 32 weeks to induce squamous dysplasia and SCC in mice. At 32 weeks the predominant cell type in the dysplastic airways was Keratin (K) 5 and K14 expressing basal cells. Notably, basal cells are extremely rare in the normal mouse bronchial epithelium but are abundant in the trachea. We therefore evaluated time-dependent changes in tracheal and bronchial histopathology after NTCU exposure (4, 8, 12, 16, 25 and 32 weeks). We show that tracheal dysplasia occurs significantly earlier than that of the bronchial epithelium (12 weeks vs. 25 weeks). This was associated with increased numbers of K5⁺/K14⁺ tracheal basal cells and a complete loss of secretory (Club cell secretory protein expressing CCSP⁺) and ciliated cells. TUNEL staining of NTCU treated tissues confirmed that the loss of CCSP⁺ and ciliated cells was not due to apoptosis. However, mitotic index (measured by bromodeoxyuridine incorporation) showed that NTCU treatment increased proliferation of K5⁺ basal cells in the trachea, and altered bronchial mitotic population from CCSP⁺ to K5⁺ basal cells. Thus, we demonstrate that NTCU-induced lung epithelial dysplasia starts in the tracheal epithelium, and is followed by basal cell metaplasia of the bronchial epithelium. This analysis extends our knowledge of the NTCU-SCC model by defining the early changes in epithelial cell phenotypes in distinct airway locations, and this may assist in identifying new targets for future chemoprevention studies.

Abstract 1675: Variations in the composition of inflammatory infiltrates are associated with persistence or regression of bronchial dysplasia

INTRODUCTION: The clinical course of dysplastic bronchial lesions is variable. While some regress, others progress to invasive carcinoma. We sought to identify how variations in inflammatory infiltrates might influence the clinical outcome of dysplastic bronchial lesions.

METHODS AND RESULTS: Gene expression microarray analyses identified 318 genes that distinguish persistent from regressive bronchial dysplastic lesions. Pathway analysis utilizing this genelist was performed using Ingenuity© software. Gene expression data showed several inflammation related pathways with statistically different levels of activity in persistent versus regressive lesions. Expression of genes associated with CD4 positive T-cells and HLA-DRA positive macrophages were both increased in regressive lesions. To further investigate these findings, a similar set of progressive and regressive lesions were selected for immunohistochemical (IHC) analysis. For each biopsy, IHC for T-cell markers CD3, CD4 and CD8 and macrophage marker CD68 was performed. Immunohistochemically positive inflammatory cell subsets were counted in a single high power field corresponding to the focus of maximum inflammation. For each marker, separate counts for epithelium and stroma-associated inflammation were performed. Preliminary IHC data (n=6) shows a strong trend towards increased numbers of macrophages in the dysplastic epithelium of regressive lesions (4.6 fold increase, p=0.082).

CONCLUSION: Our findings suggest that differences in inflammatory cell subsets may distinguish persistent and regressive bronchial dysplasia. Preliminary data points to CD4 positive T-cells and intraepithelial macrophages as differentiating factors that correlate with regression.

Citation Format: Mary C. O'Keefe, Lori Dwyer-Nield, Michael Edwards, Robert L. Keith, Wilbur A. Franklin, Michio Sugita, York E. Miller, Micah Friedman, Meredith Tennis, Kevin S. Choo, Gregory Hickey, Jeannine Porter, Storey Wilson, Andrea Osypuk, Mary Weiser, Adrie van Bokhoven, Mark Geraci, Raphael Nemenoff, Daniel T. Merrick. Variations in the composition of inflammatory infiltrates are associated with persistence or regression of bronchial dysplasia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1675. doi:10.1158/1538-7445.AM2014-1675

Abstract 231: Gene expression analysis of persistent and regressive bronchial dysplasia identifies polo-like kinase 1 (PLK1) and epoxide hydrolase 3 (EPHX3) as potential mediators of malignant progression

Introduction: Gene expression microarray analysis was employed to identify alterations that distinguish persistent from regressive bronchial dysplasia (BD). BD is a precursor of squamous cell carcinoma (SCC), and persistent BDs represent a high risk subset of these lesions. A potential role for promotion of genomic instability in persistence of BD is suggested by the overexpression of polo-like kinase 1 (PLK1), which abrogates G2-M checkpoint DNA damage repair, and epoxide hydrolase 3 (EPHX3), which converts tobacco smoke derived pro-carcinogens to mutagens.

Methods and Results: Sixty-three frozen baseline biopsies were classified, based on the presence or absence of BD in follow-up biopsies, into persistent BD, regressive BD, progressive non-dysplasia and stable non-dysplasia groups. ANOVA statistical analysis with a false discovery rate of 10% revealed 318 differentially expressed genes between persistent and regressive BD, whereas all other intergroup comparisons except persistent BD versus stable non-dysplasia revealed no or very few (&lt;15) differentially expressed genes. This confirmed the unique biological nature of persistent BD. A pathway analysis using this genelist and employing Ingenuity© software revealed “mitotic roles of PLKs” as having the most significant association with persistence. Based on their potential complimentary contribution to genomic instability, PLK1 and EPHX3 were further studied. Gene expression levels from all specimens with BD at baseline were used to classify biopsies as PLK1 and/or EPHX3 overexpressers based on expression levels greater than the mean expression for the gene. Using a histology score (1-8 for normal-SCC), a significant increase in outcome histology was noted in progressing from groups composed of cases without overexpression either gene, overexpression of one gene or overexpression of both genes (2.58 vs. 3.60 vs. 5.06 respectively). Validational analyses employing quantitative RT-PCR using cultures of 8 persistent BD and 6 regressive BD confirmed increased expression in persistent BD of PLK1 (2.77X, p=0.002) and EPHX3 (2.36X, p=0.081). Treatment of a persistent BD cell line with Volasertib, a specific inhibitor of PLK1, at 100nM showed potent inhibition of cell viability (live cell protease activity, 0.61 fold change vs untreated, p&lt;0.05) and a strong trend toward increased apoptotic activity (caspase 3/7 activity, 1.71 fold change vs. untreated, p=0.076). Volasertib had no effect on these activities in cultured normal bronchial epithelial cells.

Conclusion: Gene expression analysis demonstrates the biologically distinct, high risk nature of persistent BD and suggests a potential role for overexpression of PLK1 and EPHX3 in the development of invasive SCC of the lung.

Citation Format: Daniel T. Merrick, Michael G. Edwards, Wilbur A. Franklin, Michio Sugita, Micah Friedman, York E. Miller, Lori Dwyer-Nield, Meredith Tennis, Kevin Choo, Greg Hickey, van Bokhoven Adriaan, Lynn Heasley, Paul A. Bunn, Mark Geraci, Robert L. Keith, Raphael Nemenoff. Gene expression analysis of persistent and regressive bronchial dysplasia identifies polo-like kinase 1 (PLK1) and epoxide hydrolase 3 (EPHX3) as potential mediators of malignant progression. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 231. doi:10.1158/1538-7445.AM2014-231

Abstract 233: Prostacyclin analogs, iloprost and treprostinil, differentially influence proliferation of lung tumor cells

Lung cancer will kill approximately 160,000 Americans this year–more than the next four cancer subtypes (breast, prostate, colorectal, and pancreatic) combined. Even if lung cancer is diagnosed at an early stage, the 5 year survival rate is 52.2%. The poor survival rates for early stage disease suggests that chemopreventive interventions in high-risk populations are necessary. We found that prostacyclin (prostaglandin I2 or PGI2) synthase (PGIS) overexpression retards lung tumor growth in preclinical chemical carcinogen and smoking models, and treatment with iloprost (a PGI2 analog currently approved for treatment of pulmonary hypertension) inhibits lung adenocarcinoma formation in these same preclinical models. Oral iloprost also improves bronchial dysplasia (precursor lesions to squamous cell lung cancer) in former smokers. Mechanistic in vitro and in vivo studies using genetically modified mice showed that PGI2 and iloprost exert their chemopreventive effects through activation of the peroxisome proliferator-activated receptor γ (PPARγ) pathway rather than the classic PGI2 receptor, IP1, and that this activation requires frizzled 9 (Fzd9) activity. Treprostinil, a next generation PGI2 analog also approved to treat pulmonary hypertension, activates IP1 as well, but its ability to activate PPARγ/Fzd9 has yet to be fully characterized. In vitro studies show that in addition to binding to IP, iloprost and treprostinil differentially activate other prostaglandin (PG) receptors suggesting that they may have different chemopreventive efficacies. Molecular modeling of iloprost and treprostinil binding to PPARγ indicates these molecules may induce different PPARγ conformations which could affect binding of co-activators/repressors or interaction with the retinoic acid receptor (which is required for induction of gene transcription). While iloprost does not affect mouse lung tumor cell proliferation in vitro, treprostinil and prostaglandin E2 actually increase proliferation 2-5 fold in a dose dependent manner. Alveolar macrophage conditioned media also increases mouse lung tumor cell proliferation, and this increase is enhanced if macrophages are treated with treprostinil or PGE2 prior to media harvest. If macrophages are pretreated with iloprost, either alone or in combination with PGE2 or treprostinil, this increased proliferation is attenuated suggesting that iloprost may be exerting its chemopreventive effects directly on tumor cells and by modulating macrophage production of pro-growth factors. Macrophage IL-6 production decreased almost 80% with iloprost pre-treatment while little effect was seen with treprostinil pre-treatment. Comparisons between iloprost and treprostinil may indicate new agents/targets for lung cancer chemoprevention.

Citation Format: Lori D. Dwyer-Nield, Gregory Hickey, Meredith A. Tennis, Kevin S. Choo, Donald S. Backos, Robert L. Keith. Prostacyclin analogs, iloprost and treprostinil, differentially influence proliferation of lung tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 233. doi:10.1158/1538-7445.AM2014-233

Application of SNP microarrays to the genome-wide analysis of chromosomal instability in premalignant airway lesions

Chromosomal instability is central to the process of carcinogenesis. The genome-wide detection of somatic chromosomal alterations (SCA) in small premalignant lesions remains challenging because sample heterogeneity dilutes the aberrant cell information. To overcome this hurdle, we focused on the B allele frequency data from single-nucleotide polymorphism microarrays (SNP arrays). The difference of allelic fractions between paired tumor and normal samples from the same patient (delta-θ) provides a simple but sensitive detection of SCA in the affected tissue. We applied the delta-θ approach to small, heterogeneous clinical specimens, including endobronchial biopsies and brushings. Regions identified by delta-θ were validated by FISH and quantitative PCR in heterogeneous samples. Distinctive genomic variations were successfully detected across the whole genome in all invasive cancer cases (6 of 6), carcinoma in situ (3 of 3), and high-grade dysplasia (severe or moderate; 3 of 11). Not only well-described SCAs in lung squamous cell carcinoma, but also several novel chromosomal alterations were frequently found across the preinvasive dysplastic cases. Within these novel regions, losses of putative tumor suppressors (RNF20 and SSBP2) and an amplification of RASGRP3 gene with oncogenic activity were observed. Widespread sampling of the airway during bronchoscopy demonstrated that field cancerization reflected by SCAs at multiple sites was detectable. SNP arrays combined with delta-θ analysis can detect SCAs in heterogeneous clinical sample and expand our ability to assess genomic instability in the airway epithelium as a biomarker of lung cancer risk.

Lung cancer chemoprevention: current status and future prospects

Lung cancer is the leading cause of cancer death worldwide, making it an attractive disease for chemoprevention. Although avoidance of tobacco use and smoking cessation will have the greatest impact on lung cancer development, chemoprevention could prove to be very effective, particularly in former smokers. Chemoprevention is the use of agents to reverse or inhibit carcinogenesis and has been successfully applied to other common malignancies. Despite prior studies in lung cancer chemoprevention failing to identify effective agents, we now have the ability to identify high-risk populations, and our understanding of lung tumour and premalignant biology continues to advance. There are distinct histological lesions that can be reproducibly graded as precursors of non-small-cell lung cancer and similar precursor lesions exist for adenocarcinoma. These premalignant lesions are being targeted by chemopreventive agents in current trials and will continue to be studied in the future. In addition, biomarkers that predict risk and response to targeted agents are being investigated and validated. In this Review, we discuss the principles of chemoprevention, data from preclinical models, completed clinical trials and observational studies, and describe new treatments for novel targeted pathways and future chemopreventive efforts.

Chemoprevention of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Lung cancer is the most common cause of cancer death in men and women in the United States. Cigarette smoking is the main risk factor. Former smokers are at a substantially increased risk of developing lung cancer compared with lifetime never smokers. Chemoprevention refers to the use of specific agents to reverse, suppress, or prevent the process of carcinogenesis. This article reviews the major agents that have been studied for chemoprevention.

METHODS

Articles of primary, secondary, and tertiary prevention trials were reviewed and summarized to obtain recommendations.

RESULTS

None of the phase 3 trials with the agents β-carotene, retinol, 13-cis-retinoic acid, α-tocopherol, N-acetylcysteine, acetylsalicylic acid, or selenium has demonstrated beneficial and reproducible results. To facilitate the evaluation of promising agents and to lessen the need for a large sample size, extensive time commitment, and expense, surrogate end point biomarker trials are being conducted to assist in identifying the most promising agents for later-stage chemoprevention trials. With the understanding of important cellular signaling pathways and the expansion of potentially important targets, agents (many of which target inflammation and the arachidonic acid pathway) are being developed and tested which may prevent or reverse lung carcinogenesis.

CONCLUSIONS

By integrating biologic knowledge, additional early-phase trials can be performed in a reasonable time frame. The future of lung cancer chemoprevention should entail the evaluation of single agents or combinations that target various pathways while working toward identification and validation of intermediate end points.

Endobronchial miRNAs as biomarkers in lung cancer chemoprevention

Lung cancers express lower levels of prostacyclin than normal lung tissues. Prostacyclin prevents lung cancer in a variety of mouse models. A randomized phase II trial comparing oral iloprost (a prostacyclin analog) with placebo in high-risk subjects showed improvement in bronchial histology in former, but not current, smokers. This placebo-controlled study offered the opportunity for investigation of other potential intermediate endpoint and predictive biomarkers to incorporate into chemoprevention trials. Matched bronchial biopsies were obtained at baseline and at 6-month follow-up from 125 high-risk individuals who completed the trial: 31/29 and 37/28 current/former smokers in the iloprost and placebo arm, respectively. We analyzed the expression of 14 selected miRNAs by Real Time PCR in 496 biopsies. The expression of seven miRNAs was significantly correlated with histology at baseline. The expression of miR-34c was inversely correlated with histology at baseline (P < 0.0001) and with change in histology at follow-up (P = 0.0003), independent of treatment or smoking status. Several miRNAs were also found to be differentially expressed in current smokers as compared with former smokers. In current smokers, miR-375 was upregulated at baseline (P < 0.0001) and downregulated after treatment with iloprost (P = 0.0023). No miRNA at baseline reliably predicted a response to iloprost. No biomarker predictive of response to iloprost was found. MiR-34c was inversely correlated with baseline histology and with histology changes. Mir-34c changes at follow-up could be used as a quantitative biomarker that parallels histologic response in formalin-fixed bronchial biopsies in future lung cancer chemoprevention studies.

Lung cancer chemoprevention

Lung cancer is the leading cause of cancer death in the United States, and the majority of diagnoses are made in former smokers. Although avoidance of tobacco abuse and smoking cessation clearly will have the greatest impact on lung cancer development, effective chemoprevention could prove to be more effective than treatment of established, advanced-stage disease. Chemoprevention is the use of dietary or pharmaceutical agents to reverse or block the carcinogenic process and has been successfully applied to common malignancies other than lung (including recent reports on the prevention of breast cancer in high-risk individuals). Despite previous studies in lung cancer chemoprevention failing to identify effective agents, our ability to define the highest-risk populations and the understanding of lung tumor and premalignant biology continue to make advances. Squamous cell carcinogenesis in the bronchial epithelium starts with normal epithelium and progresses through hyperplasia, metaplasia, dysplasia, and carcinoma in situ to invasive cancer. Precursor lesions also have been identified for adenocarcinoma, and these premalignant lesions are targeted by chemopreventive agents in current and future trials. Chemopreventive agents can currently only be recommended as part of well-designed clinical trials, and multiple trials have recently been completed or are enrolling subjects.

Abstract B16: Histology and intervention related miRNA expression changes from baseline to follow-up paired bronchial biopsies of patient in the iloprost chemoprevention trial

The iloprost lung cancer chemoprevention trial is the first to meet a primary endpoint of improvement in endobronchial histology, which is currently considered to be the best intermediate endpoint for chemoprevention (Keith et al, Cancer Prev Res, 2011). This placebo-controlled study offers the opportunity for discovering other surrogate endpoints and predictive biomarkers to incorporate into chemoprevention trials.

We compared miRNA expression in follow-up (FU) versus baseline biopsies in relation with histology change or not globally and stratified by treatment arm and smoking status.

In the 152 patients randomized in the iloprost trial, the paired baseline and FU biopsies were available in 125 patients: 40/35 current/former smokers in the iloprost arm and 25/25 current/former smokers in the placebo arm, respectively. We planned to analyze 500 biopsies: four biopsies from each of the 125 patients, 2 biopsies at baseline (worst and best diagnosis) and 2 biopsies at FU at the same site after six months of treatment with iloprost or placebo. We selected and analyzed 14 miRNAs differentially expressed during squamous cell lung carcinogenesis in our previous study (Mascaux et al, Eur Resp J, 2009).

In total, 496/500 biopsies with appropriate tissue were available. For every biopsy, total RNA was extracted from 8 adjacent 4 um cuts of formalin fixed paraffin embedded (FFPE) adjacent to the diagnostic section. A good reproducibility of the previously published data for the expression changes in the 14 miRNA accross lung preneoplasia stages was shown in the current study in baseline samples. This new study identifies significant changes in miR-34c expression between paired samples when histology is up- or downgraded. miR-34c is significantly down-regulated in paired biopsies when histology is up-graded and inversely. This correlation between miR-34c expression and histology changes is shown including all samples (r spearman correlation=0.23 p=0.0003), but also consistently in subgroups (iloprost.arm, current r=0.26, p=0.041 and former smokers r=0.24, p=0.066, placebo arm, current (r=0.23, p=0.046)). In contrast, miR-9 was significantly down-regulated in follow-up as compared with baseline biopsies, but was not correlated with histology changes. The down-regulation of miR-9 in follow-up versus baseline samples was found in all samples (t test, p&lt;0.0001) and was consistent in all and significant in most of subgroups (iloprost arm, all patients (p=0.0007) and current smokers (p=0.0023) and placebo arm, all patients (p=0.001), current smokers (p=0.047) and former smokers (p=0.0071).

In conclusion, miR-34c, a transcriptional target of p53 which is down-regulated by hypermethylation in lung cancer, is down-regulated when histology changes from the normal bronchial mucosa to high-grade bronchial lesions, and inversely, independently of treatment and smoking status. miR-34c expression is a good reflection of baseline histology and histology changes. Alternatively, miR-9 is systematically down-regulated in follow-up biopsies 6 months later at the same site independently of histology, treatment and tobacco status. This suggests that the down-regulation of miR-9 in the follow-up samples may be related to the biopsy: this miRNA could be involved in the tissue repair.

N-nitroso-tris-chloroethylurea induces premalignant squamous dysplasia in mice

Squamous cell carcinoma (SCC) and premalignant endobronchial lesions have been difficult to study in murine models. In this study, we evaluate the topical N-nitroso-tris-chloroethylurea (NTCU) murine SCC model, determine the extent to which resulting premalignant airway dysplasia develops, discuss clinicopathologic grading criteria in lesion progression, and confirm that immunohistochemical (IHC) staining patterns are consistent with those observed in human endobronchial dysplasia and SCC. Male and female FVB mice were treated biweekly with topical NTCU (4, 8, or 40 mmol/L) or vehicle for 32 weeks. Following sacrifice, squamous cell lesions were enumerated and categorized into the following groups: flat atypia, low-grade dysplasia, high-grade dysplasia, and invasive SCC. The 40 mmol/L NTCU concentration produced the entire spectrum of premalignant dysplasias and squamous cell carcinomas, but was associated with poor survival. Concentrations of 4 and 8 mmol/L NTCU were better tolerated and produced only significant levels of flat atypia. Squamous origin of the range of observed lesions was confirmed with IHC staining for cytokeratin 5/6, p63, thyroid transcription factor-1 (TTF-1), and Napsin-A. This study shows that topical application of high-dose NTCU produces endobronchial premalignant lesions with classic squamous characteristics and should allow for improved preclinical evaluation of potential chemopreventive agents.

Abstract ED01-03: Chemoprevention of lung cancer with prostacyclins or PPAR gamma agonists

Introduction: Prostacyclin genetic overexpression or the oral prostacyclin analogue iloprost prevent development of lung cancer in a variety of murine models, including cigarette smoke exposure mice. The mechanism of action is through non-canonical PPARγ activation. PPARγ agonists also prevent development of lung cancer in experimental models. These observations have led to completed ongoing and planned phase II chemoprevention clinical trials using bronchial histology as the primary endpoint.

Methods: In the completed randomized Phase II study comparing iloprost to placebo entry criteria included: current or former smoker (&gt; 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Autofluorescence and white light bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a second bronchoscopy with repeat biopsy of all the central airway areas sampled during the first bronchoscopy, as well as any new areas suspicious for dysplasia. The predetermined primary endpoint for the study was average bronchial histologic score (based on the WHO classification of premalignant lesions) in all subjects, as well as in current and ex-smokers separately. In the ongoing study of the PPRAα agonist, pioglitazone, entry criteria, sample size and endpoints are similar.

Results: For the iloprost study, 152 subjects were randomized and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI - defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups. In the ongoing pioglitazone study - patients have been enrolled and dropout rates are also very low.

Conclusions and Future Directions: Oral iloprost significantly improved endobronchial dysplasia in former heavy smokers with sputum dysplasia. Unfortunately, the oral iloprost studied is no longer available commercially. Since the ultimate goal is to prevent lung cancer and the groups at highest risk and greatest numbers are resected stage I lung cancer and head and neck cancer patients. We are planning a randomized phase II trial in resected stage I NSCLC and SCCHN patients. The study drug will be a new oral prostacyclin or to placebo for one year with bronchial biopsies at times 0, 6 month and 12 months. CT scan will also be obtained at these times with bronchial histology as primary endpoint. When the pioglitazone study and this study are completed, a phase III randomized trial with prevention of secondary lung cancer as the primary endpoint in contemplated.

Disclosures: RLK, YEM and MWG hold a patent for the use of prostacylin analogs for the prevention of cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr ED01-03.

Abstract PL04-02: Oral iloprost for the chemoprevention of lung cancer: A multicenter, SPORE-initiated trial

Background: Tissue microarray studies have shown that the majority of NSCLC have decreased expression of prostacyclin synthase (PGIS) and prostacyclin supplementation (genetic overexpression and the oral prostacyclin analogue iloprost) chemoprevent lung cancer in a variety of murine models, including cigarette smoke exposure. Based on these promising results, a multi-center, double-blind, placebo controlled, phase II trial of iloprost in subjects at increased risk for lung cancer conducted at SPORE in lung cancer sites.

Methods: Subjects were selected for the trial if they meet the following criteria: current or former smoker (&gt; 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Fluorescent bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a repeat bronchoscopy with biopsy of all the central airway areas sampled on the first bronchoscopy. The primary endpoints for the study are bronchial histology and Ki-67 labeling index.

Results: For the iloprost study, 152 subjects were randomized and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI - defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups. Analyses for other biomarkers in iloprost samples (including urinary prostaglandin metabolites, miRNAs, and EMT markers) are in progress.

Conclusions: Oral iloprost significantly improves endobronchial dysplasia in former smokers and deserves further study to determine if it can prevent the development of lung cancer.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):PL04-02.

Oral iloprost improves endobronchial dysplasia in former smokers

There are no established chemopreventive agents for lung cancer, the leading cause of cancer death in the United States. Prostacyclin levels are low in lung cancer and supplementation prevents lung cancer in preclinical models. We carried out a multicenter double-blind, randomized, phase II placebo-controlled trial of oral iloprost in current or former smokers with sputum cytologic atypia or endobronchial dysplasia. Bronchoscopy was performed at study entry and after completion of six months of therapy. Within each subject, the results were calculated by using the average score of all biopsies (Avg), the worst biopsy score (Max), and the dysplasia index (DI). Change in Avg was the primary end point, evaluated in all subjects, as well as in current and former smokers. The accrual goal of 152 subjects was reached and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure, and baseline histology. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). When compared with placebo, former smokers receiving oral iloprost exhibited a significantly greater improvement in Avg (0.41 units better, P = 0.010), in Max (1.10 units better, P = 0.002), and in DI (12.45%, P = 0.006). No histologic improvement occurred in current smokers. Oral iloprost significantly improves endobronchial histology in former smokers and deserves further study to determine if it can prevent the development of lung cancer.

Abstract LB-90: Oral iloprost improves endobronchial dysplasia in former smokers

Introduction: Prostacyclin supplementation by either genetic overexpression or the oral prostacyclin analogue iloprost prevents development of lung cancer in a variety of murine models, including cigarette smoke exposure. We conducted a multi-center, double-blind, placebo controlled, phase II trial of iloprost in subjects at increased risk for lung cancer.

Methods: Entry criteria included: current or former smoker (&gt; 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Autofluorescence and white light bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a second bronchoscopy with repeat biopsy of all the central airway areas sampled during the first bronchoscopy, as well as any new areas suspicious for dysplasia. The predetermined primary endpoint for the study was average bronchial histologic score (based on the WHO classification of premalignant lesions) in all subjects, as well as in current and ex-smokers separately.

Results: The accrual goal of 152 subjects was reached and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI – defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups.

Conclusions: Oral iloprost significantly improves endobronchial dysplasia in former smokers and deserves further study to determine if it can prevent the development of lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-90. doi:10.1158/1538-7445.AM2011-LB-90

Assessing lung cancer risk in bronchial dysplasia by identification of prognostic gene expression profiles

Bronchial dysplasia (BD) is a premalignant lesion that develops frequently in smokers and is thought to be a direct precursor of squamous cell carcinoma of the lung. Identification of BD lesions that are associated with high risk for progression to cancer is important so that adequate follow-up and establishment of chemopreventive therapy can be provided. We have reviewed specimens from the Colorado SPORE in lung cancer tissue bank to determine if persistence of BD over time is related to the initial degree of histologic atypia and the development of lung cancer, and to select appropriate groups of BD to assess for the presence of potential prognostic markers by microarray gene expression analysis.

Histologic diagnoses (1=normal, 2=hyperplasia, 3=metaplasia, 4-6=mild, moderate and severe dysplasia, 7=CIS and 8=cancer) and clinical data from 186 subjects enrolled in SPORE bronchoscopy protocols that underwent at least two bronchoscopies were obtained from the SPORE database. 2,847 biopsies from 1,119 sites were assigned to baseline diagnostic groups according to the first non-normal biopsy obtained at a site. Atypia in follow-up biopsies was assessed per annum. Aditionally, RNA was extracted from bronchoscopic biopsies snap frozen in liquid nitrogen at collection. Cryostat sections were produced to establish histology and RNA was then extracted from the remaining tissue for gene expression analysis. Gene expression profiles for persistent and non-persistent BDs are being assessed on the Affymetrix Human Gene 1.0 ST array.

A direct correlation between the degree of atypia at baseline and degree of atypia at follow-up was found at all time intervals (.25-1, 1-2, 2-3, 3-4 and &gt;4 years follow-up biopsies) except for the 3-4 year timeframe. Biopsy sites from subjects with squamous cell lung cancer diagnosed prior to, during or after participation in bronchoscopy studies showed one full point higher histologic diagnosis on follow-up than sites with equivalent baseline diagnoses in subjects without known cancer. An interim assessment of data quality in 20 RNA specimens from baseline biopsies processed for gene expression analysis has been completed. Quality measurements show that distribution of signal intensity is similar across the cohort indicating comparability of specimens from the different study groups as defined by their histologic diagnoses on follow-up biopsy. Expression data from 40 specimens is targeted for the final dataset.

The degree of atypia in BD is higher at sites with higher levels of a baseline atypia and in subjects with a history of or subsequent development of squamous cell carcinoma of the lung. These features suggest that persistence of BD over time may be indicative of risk for the development of invasive lung cancer. Preliminary data from ongoing gene expression analyses of BD of differing outcomes indicates that consistent data quality can be produced across the specimen types to be studied. This suggests that the gene expression analysis will be adequate to detect differentially expressed genes with the potential to provide prognostic information in BD and reveal targets for the chemoprevention of lung cancer.

Abstract 1492: Histological and molecular characteristics of 29 cases of carcinoma in situ from a prospective bronchoscopic cohort

Introduction: The identification of carcinoma in situ (CIS) in a bronchial biopsy may indicate 1.) an adjacent invasive Lung Cancer (LC) 2.) a premalignant lesion that will progress to invasive LC or 3.) a lesion that can regress to a lower histologic grade or normal mucosa. The study of markers that identify lesions at high risk for invasive LC is of critical importance for early detection and treatment.

Methods: Over a sixteen year period more than one thousand smokers underwent autofluorsecence bronchoscopy and biopsy. Biopsies were serially sectioned and graded for level of dysplasia according to standard WHO histological criteria. The distribution of the CIS lesions was assessed with the aid of a web-based bronchial mapping tool. Immunohistochemical stains for for Ki-67 (Ki-67 growth fraction) and p53 and FISH tests for seven DNA markers including centromere 6, EGFR, 5p15.2, MYC, NKX21, TP63 and KRAS were performed on subsets of biopsies. Finally, areas of mucosa in a subset of biopsies with features of CIS were marked and microdissected for mutational analysis of TP53 (exons 5-8). Histologic slides and immunohistochemical stains for all biopsies from the date of CIS diagnosis and follow up studies were reviewed, imaged and entered on a web-based bronchial map to visually track histological and molecular changes in the airways.

Results: CIS was identified 29 subjects from the more than 1000 who were bronchoscopically examined. Fifty-eight bronchoscopies were conducted on these individuals and 435 biopsies examined. Maximum follow-up time averaged 13 mos. with a maximum of 94 mos. Among the twenty nine 65% had an associated invasive LC at the time of biopsy or during a short period of follow up whereas CIS lesions in 35% did not progress to invasive carcinoma during the follow-up period. All CIS had high Ki-67 growth fraction; p53 staining was variable. FISH analysis showed higher degrees of aneusomy in CIS lesions than lower histological grades and multiple chromosomal gains in CIS lesions shared among subjects and within a given lesion. In one patient, a CIS lesion with a TP53 mutation (G245V, GGC-GTC) spread intramucosally from the site of origin in the right lung to the contralateral lung over a period of 2 years. In another patient, nearly diffuse CIS with extremely high Ki-67 growth fraction was absent on rebiopsy of several bronchial sites three years later.

Conclusions: These data indicate that a clonal subset of cells with histologic features of CIS may spread across bronchial mucosal surfaces and be detected by fluorescence bronchoscopy and available histological and molecular studies. CIS lesions with TP53 mutation and multiple genomic gains by FISH analysis are associated with an invasive LC at the time of diagnosis or during follow up. Molecular testing of CIS may assist in determining which lesions will progress.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1492.

The detection of chromosomal aneusomy by fluorescence in situ hybridization in sputum predicts lung cancer incidence

Lung cancer usually is disseminated (advanced) and has a poor prognosis at diagnosis. Current and former smokers are at a high risk for lung cancer and are candidates for prevention and early detection strategies. Sputum is a potential source of biomarkers that might determine either lung cancer risk or the presence of early lung cancer, but no current sputum test is sufficiently sensitive and specific for effective screening. We used fluorescence in situ hybridization (FISH) to measure chromosomal aneusomy (CA) in sputum samples collected prospectively from 100 incident lung cancer cases and 96 controls (matched on age, gender, and date of collection) nested within an ongoing high-risk cohort. The CA-FISH assay was aimed at four DNA targets: epidermal growth factor receptor, MYC, 5p15, and CEP 6. The sensitivity of a positive CA-FISH assay (abnormal for two or more of the four markers) for lung cancer was substantially higher for samples collected within 18 months (76% sensitivity) than for samples collected more than 18 months (31%) before lung cancer diagnosis. Sensitivity was higher for squamous cell cancers (94%) than for other histologic types (69%). CA-FISH specificity based on samples collected within 18 months before diagnosis was 88%. The adjusted odds ratio (OR) of lung cancer for specimens collected within 18 months before a cancer diagnosis was higher for the CA-FISH assay [OR, 29.9; 95% confidence interval (95% CI), 9.5-94.1] than for previously studied ORs of cytologic atypia (OR, 1.8; 95% CI, 1.3-2.6) and gene promoter methylation (OR, 6.5; 95% CI, 1.2-35.5). Whether CA-FISH is an indicator of extreme risk for incident lung cancer or detects exfoliated cancer cells is unknown. The apparent promise of CA-FISH in sputum for assessing lung cancer risk and/or for lung cancer early detection now needs to be validated in a clinical screening trial.

The role of prostacyclin in lung cancer

Prostanoids are bioactive lipids that interact with 7-membrane-spanning G-protein-coupled receptors on target cells to impart their biologic effects. They include prostaglandins, prostacyclin, and thromboxane. Prostanoids are widely distributed; mediate several diverse biologic effects like platelet aggregation and smooth-muscle contraction; and are known to be involved in allergies, acquired immunity, and cancer metastasis. Prostanoids have also been associated with breast and endometrial cancer promotion, and with the inhibition of melanoma. The role of prostanoids in the development of lung disease has been poorly understood. In particular, prostacyclin possesses significant anti-inflammatory and antimetastatic properties and is the main product of cyclooxygenase-2 activity in the lung. In fact, the balance of the various members of the prostanoids family, specifically the prostaglandins PGE(2) and prostacyclin (PGI(2)), seems to play an increasingly important role in the development of lung cancer. Gaining a better understanding of prostanoids and their associated pathways is critical to the future development of molecular-based and pharmaceutical treatments of lung disease.

Chemoprevention of murine lung cancer by gefitinib in combination with prostacyclin synthase overexpression

INTRODUCTION

We hypothesized that the combination of the EGFR tyrosine kinase inhibitor (TKI) gefitinib with the powerful chemopreventive manipulation of lung-specific transgenic prostacyclin synthase (PGIS) overexpression on tumorigenesis in FVB/N mice would result in augmented chemoprevention.

MATERIALS AND METHODS

Wildtype and littermate PGIS overexpressors (OE) were given urethane, 1 mg/kg i.p. followed by thrice weekly i.p. injections of gefitinib, 50 mg/kg or 100 mg/kg, or vehicle. Pulmonary adenomas were enumerated and measured.

RESULTS

Gefitinib at either 50 mg/kg or 100 mg/kg administered i.p. three times weekly was effective in inhibiting EGF induced EGFR tyrosine phosphorylation and downstream signaling. The PGIS overexpressors showed significant decreases in tumor multiplicity consistent with prior studies. Gefitinib had no effect on tumor multiplicity or volume in wildtype mice. Among the PGIS overexpressors, a significant reduction in tumor multiplicity was shown in the 50 mg/kg, but not the 100 mg/kg, gefitinib treatment group vs. vehicle control animals (1.13+/-0.29 vs. 2.29+/-0.32 tumors/mouse, p=0.015). We examined the phosphorylation status in selected downstream effectors of EGFR (Erk, Akt, Src, PTEN). The major difference in the 50 mg/kg vs. 100 mg/kg group was an increase in p-Src in the PGIS OE mice receiving the higher dose.

CONCLUSION

We conclude that gefitinib alone has no chemopreventive efficacy in this model; it augmented the effect of PGIS overexpression at 50 mg/kg but not 100 mg/kg. Increased p-Src is correlated with loss of efficacy at the higher dose, suggesting the potential for combined EGFR and Src inhibition strategies in chemoprevention.