The presence of circulating genetically abnormal cells in blood predicts risk of lung cancer in individuals with indeterminate pulmonary nodules

PURPOSE

Computed tomography is the standard method by which pulmonary nodules are detected. Greater than 40% of pulmonary biopsies are not lung cancer and therefore not necessary, suggesting that improved diagnostic tools are needed. The LungLB™ blood test was developed to aid the clinical assessment of indeterminate nodules suspicious for lung cancer. LungLB™ identifies circulating genetically abnormal cells (CGACs) that are present early in lung cancer pathogenesis.

METHODS

LungLB™ is a 4-color fluorescence in-situ hybridization assay for detecting CGACs from peripheral blood. A prospective correlational study was performed on 151 participants scheduled for a pulmonary nodule biopsy. Mann-Whitney, Fisher's Exact and Chi-Square tests were used to assess participant demographics and correlation of LungLB™ with biopsy results, and sensitivity and specificity were also evaluated.

RESULTS

Participants from Mount Sinai Hospital (n = 83) and MD Anderson (n = 68), scheduled for a pulmonary biopsy were enrolled to have a LungLB™ test. Additional clinical variables including smoking history, previous cancer, lesion size, and nodule appearance were also collected. LungLB™ achieved 77% sensitivity and 72% specificity with an AUC of 0.78 for predicting lung cancer in the associated needle biopsy. Multivariate analysis found that clinical and radiological factors commonly used in malignancy prediction models did not impact the test performance. High test performance was observed across all participant characteristics, including clinical categories where other tests perform poorly (Mayo Clinic Model, AUC = 0.52).

CONCLUSION

Early clinical performance of the LungLB™ test supports a role in the discrimination of benign from malignant pulmonary nodules. Extended studies are underway.

Cost-effectiveness analysis of LungLB for the clinical management of patients with indeterminate pulmonary nodules

BACKGROUND

There is currently a need for additional diagnostic information to help guide treatment decisions and to properly determine the best treatment pathway for patients identified with indeterminate pulmonary nodules (IPNs). The aim of this study was to demonstrate the incremental cost-effectiveness of LungLB compared to the current clinical diagnostic pathway (CDP) in the management of patients with IPNs, from a US payer's perspective.

METHODS

A decision tree and Markov model hybrid was chosen from a payer perspective in the US setting, based on published literature, to assess the incremental cost-effectiveness of LungLB compared to the current CDP in the management of patients with IPNs. Primary endpoints of the analysis include expected costs, life years (LYs), and quality-adjusted life years (QALYs) for each arm of the model, as well as an incremental cost-effectiveness ratio (ICER), which is calculated as the incremental costs per QALY, and net monetary benefit (NMB).

RESULTS

We find that, with the inclusion of LungLB to the current CDP diagnostic pathway, expected LYs over the typical patient's lifespan increase by 0.07 years and QALYs increase by 0.06. The average patient in the CDP arm will pay approximately $44,310 over their lifespan, while a patient in the LungLB arm will pay $48,492, resulting in a difference of $4,182. The differentials between the CDP and LungLB arms of the model in costs and QALYs yield an ICER of $75,740 per QALY and an incremental NMB of $1,339.

CONCLUSION

This analysis provides evidence that LungLB, in conjunction with CDP, is a cost-effective alternative compared to the current CDP alone in a US setting for individuals with IPNs.

Multiparametric liquid biopsy analysis in metastatic prostate cancer

Molecular profiling of prostate cancer with liquid biopsies, such as circulating tumor cells (CTCs) and cell-free nucleic acid analysis, yields informative yet distinct data sets. Additional insights may be gained by simultaneously interrogating multiple liquid biopsy components to construct a more comprehensive molecular disease profile. We conducted an initial proof-of-principle study aimed at piloting this multiparametric approach. Peripheral blood samples from men with metastatic castrate-resistant prostate cancer were analyzed simultaneously for CTC enumeration, single-cell copy number variations, CTC DNA and matched cell-free DNA mutations, and plasma cell-free RNA levels of androgen receptor (AR) and AR splice variant (ARV7). In addition, liquid biopsies were compared with matched tumor profiles when available, and a second liquid biopsy was drawn and analyzed at disease progression in a subset of patients. In this manner, multiparametric liquid biopsy profiles were successfully generated for each patient and time point, demonstrating the feasibility of this approach and highlighting shared as well as unique cancer-relevant alterations. With further refinement and validation in large cohorts, multiparametric liquid biopsies can optimally integrate disparate but clinically informative data sets and maximize their utility for molecularly directed, real-time patient management.

Identification of a Human Airway Epithelial Cell Subpopulation with Altered Biophysical, Molecular, and Metastatic Properties

Lung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant airway epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of the unselected immortalized epithelial cell lines. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8 weeks after selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short-term assays and enhanced outgrowth of premalignant lesions in longer-term assays, thus overcoming important aspects of "metastatic inefficiency." Overall, our findings indicate that among immortalized premalignant airway epithelial cell lines, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior. Cancer Prev Res; 10(9); 514-24. ©2017 AACRSee related editorial by Hynds and Janes, p. 491.

Abstract B22: The role of e-cigarette exposure on pulmonary epithelial cell transformation

Despite a strong correlation between cigarette smoking and the onset of lung cancer, the prevalence of smoking still remains high. The electronic cigarette (ECIG) is designed to deliver nicotine without combusting tobacco. Since nicotine is widely considered the addictive component in tobacco with limited ability to initiate cancer, ECIGs have been advertised to be a safer alternative to tobacco cigarettes. However, the potential health risks and carcinogenicity of ECIGs have not previously been evaluated. In this study, we assess the impact of ECIG exposure on the carcinogenic potential of immortalized human bronchial epithelial cells on a background of silenced p53 and activated KRAS (H3mut-P53/KRAS). This model is utilized because p53 and KRAS mutations are often observed in the airway of current and former smokers at risk for lung cancer. In anchorage independent growth assays, the in vitro correlate of malignant transformation, we found enhanced colony growth in the HBEC-P53/KRAS cells following a 12-day treatment with high concentrations of ECIG-conditioned media compared to the untreated and low concentration treatment groups. We next assessed the effect of ECIG and exposure on cell invasion using three-dimensional air-liquid interface (ALI) models. HBEC-P53/KRAS cells exhibited invasion-associated morphological changes following a 12-day treatment with the high conditioned media, including increased proliferation, diminished cell-cell cohesion and the appearance of cells percolating out of and breaching the modified basement membrane. Finally, to identify the biological impact of in vitro ECIG exposure in HBECs, we profiled the gene expression of P53/KRAS cells following a 96-hour exposure to ECIG- or tobacco cigarette (TCIG)-conditioned media. We found that epithelial cells exposed to clinically relevant concentrations of ECIG vapor-conditioned media have a gene expression pattern similar to those exposed to TCIG smoke-conditioned media and whole cigarette smoke. Rank-rank hyper-geometric overlap (RRHO) analysis indicated that differential expression - based ranked genes in TCIG and ECIG exposed groups were consistently overlapped at significant levels. There were 263 differentially expressed genes in the cells treated with high ECIG media versus untreated control. Annotations of the identified genes by the Molecular Signature database revealed several enriched biological pathways involved in malignant transformation and epithelial-mesenchymal transition (EMT). We have compared the resulting list of genes to publicly available microarray datasets and identified several transformation-related gene candidates. We are in the process of evaluating their contribution to ECIG-induced dissemination and carcinogenesis in vitro and in vivo. These studies will determine the impact of ECIG exposure on lung carcinogenicity and provide needed scientific guidance to the FDA regarding the physiologic effects of ECIGs. These studies were supported by funding from the following: NIH/NCI #U01CA152751 (SMD, TCW), NCI #U01CA152751-S1 (SMD, TCW, SJP), NCI #U01CA152751-AS (SMD, KK), NCI #T32-CA009120-36 (SMD, SJP, PCP), NIH/NHLBI #T32HL072752 (SMD, EL), University of California Tobacco-Related Disease Research Program (TRDRP) #18FT-0060 (TCW), TRDRP #20KT-0055 (TCW), Prevent Cancer Foundation (SJP), Lung Cancer SPORE (P50CA70907, JDM, JEL)

Citation Format: Stacy J. Park, Tonya C. Walser, Linh M. Tran, Catalina Perdomo, Teresa Wang, Long-Sheng Hong, Paul C. Pagano, Elvira L. Liclican, Jill E. Larsen, Kostyantyn Krysan, Michael C. Fishbein, John D. Minna, Marc E. Lenburg, Spira Avrum, Steven Dubinett. The role of e-cigarette exposure on pulmonary epithelial cell transformation. [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 B22.

Combination Treatment with Apricoxib and IL-27 Enhances Inhibition of Epithelial-Mesenchymal Transition in Human Lung Cancer Cells through a STAT1 Dominant Pathway

BACKGROUND

The cyclooxygenase 2 (COX-2) pathway has been implicated in the molecular pathogenesis of many malignancies, including lung cancer. Apricoxib, a selective COX-2 inhibitor, has been described to inhibit epithelial-mesenchymal transition (EMT) in human malignancies. The mechanism by which apricoxib may alter the tumor microenvironment by affecting EMT through other important signaling pathways is poorly defined. IL-27 has been shown to have anti-tumor activity and our recent study showed that IL-27 inhibited EMT through a STAT1 dominant pathway.

OBJECTIVE

The purpose of this study is to investigate the role of apricoxib combined with IL-27 in inhibiting lung carcinogenesis by modulation of EMT through STAT signaling.

METHODS AND RESULTS

Western blot analysis revealed that IL-27 stimulation of human non-small cell lung cancer (NSCLC) cell lines results in STAT1 and STAT3 activation, decreased Snail protein and mesenchymal markers (N-cadherin and vimentin) and a concomitant increase in expression of epithelial markers (E-cadherin, β-and γ-catenins), and inhibition of cell migration. The combination of apricoxib and IL-27 resulted in augmentation of STAT1 activation. However, IL-27 mediated STAT3 activation was decreased by the addition of apricoxib. STAT1 siRNA was used to determine the involvement of STAT1 pathway in the enhanced inhibition of EMT and cell migration by the combined IL-27 and apricoxib treatment. Pretreatment of cells with STAT1 siRNA inhibited the effect of combined IL-27 and apricoxib in the activation of STAT1 and STAT3. In addition, the augmented expression of epithelial markers, decreased expression mesenchymal markers, and inhibited cell migration by the combination treatment were also inhibited by STAT1 siRNA, suggesting that the STAT1 pathway is important in the enhanced effect from the combination treatment.

CONCLUSION

Combined apricoxib and IL-27 has an enhanced effect in inhibition of epithelial-mesenchymal transition and cell migration in human lung cancer cells through a STAT1 dominant pathway.

Abstract 932: The impact of e-cigarette exposure on pulmonary epithelium gene expression and transformation

Lung cancer is the leading cause of cancer-related mortality in the United States. Despite a strong correlation between cigarette smoking and the onset of lung cancer, the prevalence of smoking still remains high. The electronic cigarette (ECIG) is designed to deliver nicotine without combusting tobacco. Since nicotine is widely considered the addictive component in tobacco with limited ability to initiate cancer, ECIGs have been advertised to be a safer alternative to tobacco cigarettes (TCIGs). However, the potential health risks and carcinogenicity of ECIGs have not previously been evaluated. In this study, we assess the impact of in vitro ECIG exposure on the carcinogenic potential of immortalized human bronchial epithelial cells on a background of silenced p53 and activated KRAS (H-P53/KRAS). This model is utilized because p53 and KRAS mutations are often observed in the airway of current and former smokers at risk for lung cancer. Our preliminary results suggest that ECIG-induced alterations may be dependent upon the mutational landscape of the airway cells being exposed. In anchorage independent growth assays, the in vitro correlate of malignant transformation, we found enhanced colony growth in the H-P53/KRAS cells following a 10-day treatment with the high nicotine ECIG-conditioned media compared to the untreated and low nicotine treatment groups. We next assessed the effect of ECIG exposure on cell invasion using three-dimensional air-liquid interface (ALI) models. H-P53KRAS cells exhibited invasion-associated morphological changes following a 10-day treatment with the high nicotine conditioned media, including increased proliferation, diminished cell-cell cohesion and the appearance of cells percolating out of and breaching the modified basement membrane. Finally, gene expression profiles show 263 differentially expressed genes following exposure to high nicotine ECIG-conditioned media for 96hrs. The ECIG-conditioned media induced a gene expression pattern similar to TCIG-conditioned media and whole cigarette smoke exposure in the H-P53/KRAS cells. We will next compare the ECIG-induced gene expression signature to carcinogenicity-related gene signatures established in previous and ongoing clinical investigations and test ECIG-altered candidate genes for their ability to drive the malignant transformation of airway epithelial cells. These studies will determine the impact of ECIG exposure on lung carcinogenicity and provide needed scientific guidance to the FDA regarding the physiologic effects of ECIGs. These studies were supported by funding from the following: NIH/NCI #U01CA152751 (SMD, TCW), NCI #U01CA152751-S1 (SMD, TCW, SJP), NCI #U01CA152751-AS (SMD, KK), NCI #T32-CA009120-36 (SMD, SJP, PCP), NIH/NHLBI #T32HL072752 (SMD, EL), University of California Tobacco-Related Disease Research Program (TRDRP) #18FT-0060 (TCW), TRDRP #20KT-0055 (TCW), Lung Cancer SPORE (P50CA70907, JDM, JEL)

Citation Format: Stacy J. Park, Tonya C. Walser, Catalina Perdomo, Teresa Wang, Long-Sheng Hong, Paul C. Pagano, Elvira L. Liclican, Kostyantyn Krysan, Jill E. Larsen, Michael C. Fishbein, John D. Minna, Marc E. Lenburg, Avrum Spira, Steven M. Dubinett. The impact of e-cigarette exposure on pulmonary epithelium gene expression and transformation. [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 932. doi:10.1158/1538-7445.AM2014-932

Loss of miR125a expression in a model of K-ras-dependent pulmonary premalignancy

Understanding the molecular pathogenesis of lung cancer is necessary to identify biomarkers/targets specific to individual airway molecular profiles and to identify options for targeted chemoprevention. Herein, we identify mechanisms by which loss of microRNA (miRNA)125a-3p (miR125a) contributes to the malignant potential of human bronchial epithelial cells (HBEC) harboring an activating point mutation of the K-ras proto-oncogene (HBEC K-ras). Among other miRNAs, we identified significant miR125a loss in HBEC K-ras lines and determined that miR125a is regulated by the PEA3 transcription factor. PEA3 is upregulated in HBEC K-ras cells, and genetic knockdown of PEA3 restores miR125a expression. From a panel of inflammatory/angiogenic factors, we identified increased CXCL1 and vascular endothelial growth factor (VEGF) production by HBEC K-ras cells and determined that miR125a overexpression significantly reduces K-ras-mediated production of these tumorigenic factors. miR125a overexpression also abrogates increased proliferation of HBEC K-ras cells and suppresses anchorage-independent growth (AIG) of HBEC K-ras/P53 cells, the latter of which is CXCL1-dependent. Finally, pioglitazone increases levels of miR125a in HBEC K-ras cells via PEA3 downregulation. In addition, pioglitazone and miR125a overexpression elicit similar phenotypic responses, including suppression of both proliferation and VEGF production. Our findings implicate miR125a loss in lung carcinogenesis and lay the groundwork for future studies to determine whether miR125a is a possible biomarker for lung carcinogenesis and/or a chemoprevention target. Moreover, our studies illustrate that pharmacologic augmentation of miR125a in K-ras-mutated pulmonary epithelium effectively abrogates several deleterious downstream events associated with the mutation.

Circulating tumor cells: clinically relevant molecular access based on a novel CTC flow cell

Background

Contemporary cancer diagnostics are becoming increasing reliant upon sophisticated new molecular methods for analyzing genetic information. Limiting the scope of these new technologies is the lack of adequate solid tumor tissue samples. Patients may present with tumors that are not accessible to biopsy or adequate for longitudinal monitoring. One attractive alternate source is cancer cells in the peripheral blood. These rare circulating tumor cells (CTC) require enrichment and isolation before molecular analysis can be performed. Current CTC platforms lack either the throughput or reliability to use in a clinical setting or they provide CTC samples at purities that restrict molecular access by limiting the molecular tools available.

Methodology/Principal Findings

Recent advances in magetophoresis and microfluidics have been employed to produce an automated platform called LiquidBiopsy®. This platform uses high throughput sheath flow microfluidics for the positive selection of CTC populations. Furthermore the platform quantitatively isolates cells useful for molecular methods such as detection of mutations. CTC recovery was characterized and validated with an accuracy (<20% error) and a precision (CV<25%) down to at least 9 CTC/ml. Using anti-EpCAM antibodies as the capture agent, the platform recovers 78% of MCF7 cells within the linear range. Non specific recovery of background cells is independent of target cell density and averages 55 cells/mL. 10% purity can be achieved with as low as 6 CTCs/mL and better than 1% purity can be achieved with 1 CTC/mL.

Conclusions/Significance

The LiquidBiopsy platform is an automated validated platform that provides high throughput molecular access to the CTC population. It can be validated and integrated into the lab flow enabling CTC enumeration as well as recovery of consistently high purity samples for molecular analysis such as quantitative PCR and Next Generation Sequencing. This tool opens the way for clinically relevant genetic profiling of CTCs.

Abstract A08: The role of miR-125a in the pathogenesis of lung cancer

Lung cancer is the leading cause of cancer-related mortality in the U.S., and despite focused research pertaining to conventional therapies, the five-year survival rate remains only 17%. The lack of a systematic approach for chemoprevention agent selection and the disregard for individual differences when randomizing to intervention groups have led to clinical prevention trials that have failed or, in some cases, increased the risk for lung cancer. In this regard, understanding the molecular pathogenesis of lung cancer development in a given individual can facilitate identification of targets and/or biomarkers specific to their unique airway molecular profile and the application of targeted chemoprevention. This is expected to yield more effective lung cancer prevention and control. microRNAs (miRNA) have the potential to be robust biomarkers for lung cancer. Our work focuses on preclinical studies to identify mechanisms by which loss of miRNA-125a-3p (miR-125a) expression contributes to the malignant potential of pulmonary epithelial cells harboring an activating point mutation of the K-ras proto-oncogene, one of the most clinically challenging genetic changes commonly found in current and former smokers. Normal human bronchial epithelial cells (HBECs) isolated from large airways of patients were immortalized with hTERT and Cdk4 and subsequently manipulated to express oncogenic K-ras (HBEC K-ras). Compared to their respective vector controls (HBEC Vector), the basal expression of miR-125a is significantly reduced by 3- to 4-fold in premalignant HBEC K-ras lines. Subsequent studies demonstrated that the loss of miR-125a expression in K-ras-mutated HBECs is regulated by the PEA3 transcription factor. Compared with Vector, PEA3 expression is upregulated in HBEC K-ras cells at both the mRNA and protein level, and genetic knockdown of PEA3 with siRNA in HBEC K-ras cells restores miR-125a expression. To assess the impact of miR-125a loss on tumor-promoting factors in K-ras-mutated HBECs, we evaluated a panel of inflammatory and angiogenic proteins and found that the basal protein expression of CXCL1 and VEGF was significantly elevated in HBEC3 K-ras cells compared with Vector. Importantly, overexpression of miR-125a significantly reduced the levels of these tumorigenic factors in HBEC K-ras cells, while no changes were observed in Vector. miR-125a overexpression also reduced the increased proliferation rate of HBEC K-ras cells to the level of Vector and suppressed anchorage-independent growth of K-ras/P53-mutated HBECs by 50%, an inhibition found to be dependent on CXCL1. Importantly, our data also show that pioglitazone, a model chemopreventive agent, increases levels of miR-125a in HBEC K-ras cells through downregulation of PEA3. Moreover, pioglitazone exhibits similar anti-tumor activity as miR-125a overexpression. Treatment of HBEC K-ras cells with pioglitazone downregulates expression of VEGF, suppresses proliferation and induces morphological changes indicative of mesenchymal-to-epithelial transition. Taken together, our novel findings identify the loss of miR-125a expression as a putative biomarker for lung carcinogenesis and possible chemoprevention target. Moreover, our studies illustrate how augmentation of miR-125a by a model chemoprevention agent, in the setting of the K-ras-mutated pulmonary epithelium, can abrogate some of the deleterious downstream events associated with this mutation.

These studies were supported by NHLBI #T32HL072752 (EL) and Lung Cancer SPORE #P50CA70907 (JDM, JEL).

Citation Format: Elvira L. Liclican, Saswati Hazra, Jill E. Larsen, Stacy J. Park, Paul C. Pagano, Tonya C. Walser, Kostyantyn Krysan, John D. Minna, Steven M. Dubinett. The role of miR-125a in the pathogenesis of lung cancer. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A08.

Elevated neutrophil gelatinase-associated lipocalin contributes to erlotinib resistance in non-small cell lung cancer

PURPOSE

The EGFR tyrosine kinase inhibitors (TKIs) demonstrate efficacy in NSCLC patients whose tumors harbor activating EGFR mutations. However, patients who initially respond to EGFR TKI treatment invariably develop resistance to the drugs. Known mechanisms account for approximately 70% of native and acquired EGFR TKI resistance. In the current study we investigated a novel mechanism of NSCLC resistance to erlotinib.

EXPERIMENTAL DESIGN

The mechanisms of acquired erlotinib resistance were evaluated by microarray analysis in thirteen NSCLC cell lines and in vivo in mice. Correlations between plasma neutrophil gelatinase associated lipocalin (NGAL) levels, erlotinib response and the EGFR mutational status were assessed in advanced stage NSCLC patients treated with erlotinib.

RESULTS

In 5 of 13 NSCLC cell lines NGAL was significantly upregulated. NGAL knockdown in erlotinib-resistant cells increased erlotinib sensitivity in vitro and in vivo. NGAL overexpression in erlotinib-sensitive cells augmented apoptosis resistance. This was mediated by NGAL-dependent modulation of the pro-apoptotic protein Bim levels. Evaluation of the plasma NGAL levels in NSCLC patients that received erlotinib revealed that patients with lower baseline NGAL demonstrated a better erlotinib response. Compared to patients with wild type EGFR, patients with activating EGFR mutations had lower plasma NGAL at baseline and weeks 4 and 8.

CONCLUSIONS

Our studies uncover a novel mechanism of NGAL-mediated modulation of Bim levels in NSCLC that might contribute to TKI resistance in lung cancer patients. These findings provide the rationale for the further investigations of the utility of NGAL as a potential therapeutic target or diagnostic biomarker.