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Abstract Background Patients from non-small cell lung cancer (NSCLC) controlled clinical trials do not always reflect real-world heterogeneous patient populations. We designed a study to describe the real-world patient characteristics and treatment patterns of first-line treatment in patients in the US with NSCLC. Methods This was an observational, retrospective cohort study based on electronic medical records of US adults with locally advanced or metastatic disease in the ConcertAI Patient360 NSCLC database who initiated first-line treatment with anti-programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) therapy between July 2016 and December 2020. The analysis used patient attributes, clinical characteristics, and treatments from each patient’s medical records. Results A total of 2175 patients were eligible for analysis. The median age was 68 years, and 26.2% of the patients were ≥75 years old. At treatment initiation, 96.4% and 3.6% of the patients had Stage 4 and Stage 3 (B or C) NSCLC, respectively. The most common histology type was nonsquamous adenocarcinoma (66.4%), and 19.8% had Eastern Cooperative Oncology Group performance status ≥2. Immunosuppressive medications were being used by 17.7% of patients, and 11.0% were immunocompromised. Almost all patients had metastases: 64.6% had 1, 23.2% had 2, and 8.0% had ≥3 metastatic sites. Brain metastases were present in 22.9% of patients. Treatment evolution was observed with first-line standard of care shifting from single-agent immunotherapy in 2016 (90.2%) to combination immunotherapy and chemotherapy in 2020 (60.2%). Conclusion Between 2016 and 2020, the first-line treatment paradigm for advanced NSCLC in the US shifted from anti–PD-1/PD-L1 monotherapy to combination chemoimmunotherapy, with increasing biomarker testing. Further research in heterogeneous patient populations to characterize treatment strategies is warranted.

Abstract Background Predictive biomarkers of immune checkpoint inhibitor (ICI) efficacy are currently lacking for non-small cell lung cancer (NSCLC). Here, we describe the results from the Anti–PD-1 Response Prediction DREAM Challenge, a crowdsourced initiative that enabled the assessment of predictive models by using data from two randomized controlled clinical trials (RCTs) of ICIs in first-line metastatic NSCLC. Methods Participants developed and trained models using public resources. These were evaluated with data from the CheckMate 026 trial (NCT02041533), according to the model-to-data paradigm to maintain patient confidentiality. The generalizability of the models with the best predictive performance was assessed using data from the CheckMate 227 trial (NCT02477826). Both trials were phase III RCTs with a chemotherapy control arm, which supported the differentiation between predictive and prognostic models. Isolated model containers were evaluated using a bespoke strategy that considered the challenges of handling transcriptome data from clinical trials. Results A total of 59 teams participated, with 417 models submitted. Multiple predictive models, as opposed to a prognostic model, were generated for predicting overall survival, progression-free survival, and progressive disease status with ICIs. Variables within the models submitted by participants included tumor mutational burden (TMB), programmed death ligand 1 (PD-L1) expression, and gene-expression–based signatures. The best-performing models showed improved predictive power over reference variables, including TMB or PD-L1. Conclusions This DREAM Challenge is the first successful attempt to use protected phase III clinical data for a crowdsourced effort towards generating predictive models for ICI clinical outcomes and could serve as a blueprint for similar efforts in other tumor types and disease states, setting a benchmark for future studies aiming to identify biomarkers predictive of ICI efficacy. Trial registration: CheckMate 026; NCT02041533, registered January 22, 2014. CheckMate 227; NCT02477826, registered June 23, 2015.

Background In CheckMate 9LA, nivolumab plus ipilimumab with chemotherapy prolonged overall survival (OS) versus chemotherapy regardless of tumor PD-L1 expression or histology. We report updated efficacy and safety in all randomized patients with a minimum 4-year follow-up and an exploratory treatment-switching adjustment analysis in all treated patients who received chemotherapy and subsequent immunotherapy.Methods Adults with stage IV/recurrent non-small cell lung cancer (NSCLC), no sensitizing EGFR/ALK alterations, and ECOG performance status ≤1 were randomized 1:1 to nivolumab 360 mg every 3 weeks plus ipilimumab 1 mg/kg every 6 weeks with chemotherapy (two cycles) or chemotherapy (four cycles, with optional maintenance pemetrexed for the nonsquamous population). Assessments included OS, progression-free survival, and objective response rate. Exploratory analyses included efficacy by tumor PD-L1 expression and histology and in patients who discontinued nivolumab plus ipilimumab with chemotherapy due to treatment-related adverse events (TRAEs), and a treatment-switching adjustment analysis using inverse probability of censoring weighting.Results With a 47.9-month minimum follow-up for OS, nivolumab plus ipilimumab with chemotherapy continued to prolong OS over chemotherapy in all randomized patients (HR 0.74, 95% CI 0.63 to 0.87; 4-year OS rate: 21% versus 16%), regardless of tumor PD-L1 expression (HR (95% CI): PD-L1

Abstract Background Neoadjuvant immunotherapy is emerging as novel effective intervention in lung cancer, but study to unearth effective surrogates indicating its therapeutic outcomes is limited. We investigated the genetic changes between non-small cell lung cancer (NSCLC) patients with varied response to neoadjuvant immunotherapy and discovered highly potential biomarkers with indicative capability in predicting outcomes. Methods In this study, 3 adenocarcinoma and 11 squamous cell carcinoma NSCLC patients were treated by neoadjuvant immunotherapy with variated regimens followed by surgical resection. Treatment-naive FFPE or fresh tissues and blood samples were subjected to whole-exome sequencing (WES). Genetic alternations were compared between differently-responded patients. Findings were further validated in multiple public cohorts. Results DNA damage repair (DDR)-related InDel signatures and DDR-related gene mutations were enriched in better-responded patients, i.e., major pathological response (MPR) group. Besides, MPR patients exhibited provoked genome instability and unique homologous recombination deficiency (HRD) events. By further inspecting alternation status of homology-dependent recombination (HR) pathway genes, the clonal alternations were exclusively enriched in MPR group. Additionally, associations between HR gene alternations, percentage of viable tumor cells and HRD event were identified, which orchestrated tumor mutational burden (TMB), mutational intratumor heterogeneity (ITH), somatic copy number alteration (SCNA) ITH and clonal neoantigen load in patients. Validations in public cohorts further supported the generality of our findings. Conclusions We reported for the first time the association between HRD event and enhanced neoadjuvant immunotherapy response in lung cancer. The power of HRD event in patient therapeutic stratification persisted in multifaceted public cohorts. We propose that HR pathway gene status could serve as novel and additional indicators guiding immune-neoadjuvant and immunotherapy treatment decisions for NSCLC patients.

Non-small cell lung cancer (NSCLC) is a heterogeneous disease with genetic and environmental parameters that influence cell metabolism. Because of the complex interplay of environmental factors within the tumor microenvironment (TME) and the profound impact of these factors on the metabolic activities of tumor and immune cells, there is an emerging interest to advance the understanding of these diverse metabolic phenotypes in the TME. High levels of adenosine are characteristic of the TME, and adenosine can have a significant impact on both tumor cell growth and the immune response. Consistent with this, we showed in NSCLC data from TCGA that high expression of the A2BR leads to worse outcome and that expression of A2BR may be different for different mutation backgrounds. We then investigated the metabolic reprogramming of tumor cells and immune cells (T and dendritic cells) by adenosine. We used A2AR and A2BR antagonism or agonism as well as receptor knockout animals to explore whether these treatments altered specific immune compartments or conferred specific therapeutic vulnerabilities. Using the seahorse assay, we found that an A2BR antagonist modulates oxidative stress homeostasis in NSCLC cell lines. In addition, we found distinct metabolic roles of A2AR and A2BR receptors in T cell activation and dendritic cell maturation. These data suggest potential mechanisms and therapeutic benefits of A2 receptor antagonist therapy in NSCLC.

Abstract Conventional PD‐L1 immunohistochemical tissue biopsies only predict 20%–40% of non‐small cell lung cancer (NSCLC) patients that will respond positively to anti‐PD‐1/PD‐L1 immunotherapy. Herein, we present an immunogold biochip to quantify single extracellular vesicular RNA and protein (AuSERP) as a non‐invasive alternative. With only 20 μl of purified serum, PD‐1/PD‐L1 proteins on the surface of extracellular vesicles (EVs) and EV PD‐1/PD‐L1 messenger RNA (mRNA) cargo were detected at a single‐vesicle resolution and exceeded the sensitivities of their bulk‐analysis conventional counterparts, ELISA and qRT‐PCR, by 1000 times. By testing a cohort of 27 non‐responding and 27 responding NSCLC patients, AuSERP indicated that the single‐EV mRNA biomarkers surpass the single‐EV protein biomarkers in predicting patient responses to immunotherapy. Dual single‐EV PD‐1/PD‐L1 mRNA detection differentiated responders from non‐responders with an accuracy of 72.2% and achieved an NSCLC diagnosis accuracy of 93.2%, suggesting the potential for AuSERP to provide enhanced immunotherapy predictions and cancer diagnoses within the clinical setting.

IWS1 regulates multiple steps in RNA metabolism, including RNA elongation and alternative RNA splicing. Here the authors show that AKT3 phosphorylates IWS1, which alters U2AF2 RNA splicing and promotes growth of lung adenocarcinomas via a Sororin/ERK-dependent pathway.

Abstract Small cell lung cancer (SCLC) remains a deadly form of cancer, with a 5-year survival rate of less than 10 percent, necessitating novel therapies. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal protein that is emerging as a therapeutic target and is co-expressed with BCL2 in multiple tumor types due to microRNA coregulation. We hypothesize that ROR1-targeted therapy is effective in small cell lung cancer and synergizes with therapeutic BCL2 inhibition. Tissue microarrays (TMAs) and formalin-fixed paraffin-embedded (FFPE) SCLC patient samples were utilized to determine the prevalence of ROR1 and BCL2 expression in SCLC. Eight SCLC-derived cell lines were used to determine the antitumor activity of a small molecule ROR1 inhibitor (KAN0441571C) alone and in combination with the BCL2 inhibitor venetoclax. The Chou-Talalay method was utilized to determine synergy with the drug combination. ROR1 and BCL2 protein expression was identified in 93% (52/56) and 86% (48/56) of SCLC patient samples, respectively. Similarly, ROR1 and BCL2 were shown by qRT-PCR to have elevated expression in 79% (22/28) and 100% (28/28) of SCLC patient samples, respectively. KAN0441571C displayed efficacy in 8 SCLC cell lines, with an IC50 of 500 nM or less. Synergy as defined by a combination index of

Introduction: To evaluate whether and the degree to which patients with advanced NSCLC (aNSCLC) receiving lung cancer treatments will experience functional disability or have resilience and to identify characteristics associated with functional disability. Methods: We evaluated longitudinal data of patients with aNSCLC receiving treatment in the Beating Lung Cancer in Ohio prospective cohort study. Disability versus resilience in functional status (usual activities, mobility, and self-care) was measured monthly for 8 months using the EuroQol-5D-5L. Data captured included baseline demographics (Eastern Cooperative Oncology Group performance status), comorbidities, cancer and depressive symptoms (Patient Health Questionnaire-9), anxiety (Generalized Anxiety Disorder-7 scale), and cancer stress (impact of events). Group-based latent class trajectory modeling was used to determine clinically distinct functional disability trajectories jointly with attrition probability (death or withdrawal) in the study period. Results: Among 207 participants, the mean age was 63.5 years (range: 34–92 y), 58.9% were male, 6.8% were African American or Black, 73.3% were former smokers, and 35% resided in rural areas. At baseline, participants had adenocarcinoma histological subtype (74.9%), 40.3% had brain metastases, and 46.1% had bone metastases. Participants received chemotherapy plus immunotherapy (46.9%), immunotherapy single agent (21.7%), targeted treatments (18.8%), or no treatment (12.6%). Three distinct functional trajectory groups were identified, as follows: none/mild (n = 79, 38.2%), moderate (n = 99, 47.8%), and severe disability (n = 29, 14.0%). Characteristics associated with severe disability included baseline Eastern Cooperative Oncology Group performance status greater than 1, worse dyspnea and pain, and higher Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7 scale scores. At month 8, 95 participants (45.9%) displayed resilience, 11 (5.3%) experienced functional decline, and 69 (33.3%) were deceased. Conclusions: We identified three distinct functional trajectories among patients with aNSCLC. Risk stratification tools and targeted interventions designed to target these three groups are needed to improve functional resilience and prevent disability.

Abstract Background The microbiome has been shown to affect the response to Immune Checkpoint Inhibitors (ICIs) in a small number of cancers and in preclinical models. Here, we sought to broadly survey cancers to identify those in which the microbiome may play a prognostic role using retrospective analyses of patients with advanced cancer treated with ICIs. Methods We conducted a retrospective analysis of 690 patients who received ICI therapy for advanced cancer. We used a literature review to define a causal model for the relationship between medications, the microbiome, and ICI response to guide the abstraction of electronic health records. Medications with precedent for changes to the microbiome included antibiotics, corticosteroids, proton pump inhibitors, histamine receptor blockers, non-steroid anti-inflammatories and statins. We tested the effect of medication timing on overall survival (OS) and evaluated the robustness of medication effects in each cancer. Finally, we compared the size of the effect observed for different classes of antibiotics to taxa that have been correlated to ICI response using a literature review of culture-based antibiotic susceptibilities. Results Of the medications assessed, only antibiotics and corticosteroids significantly associated with shorter OS. The hazard ratios (HRs) for antibiotics and corticosteroids were highest near the start of ICI treatment but remained significant when given prior to ICI. Antibiotics and corticosteroids remained significantly associated with OS even when controlling for multiple factors such as Eastern Cooperative Oncology Group performance status, Charlson Comorbidity Index score, and stage. When grouping antibiotics by class, β-lactams showed the strongest association with OS across all tested cancers. Conclusions The timing and strength of the correlations with antibiotics and corticosteroids after controlling for confounding factors are consistent with the microbiome involvement with the response to ICIs across several cancers.

Introduction: This study investigates the immune profile of the primary lung tumors and the corresponding brain metastasis from patients with NSCLC using multiplex fluorescence immunohistochemistry. Methods: The study evaluated 34 patients who underwent autopsy or surgical resection for brain metastasis and autopsy, surgical resection, or core biopsy for primary lung cancer. We compared the densities of various immune cells in the primary tumors and the brain metastases by multiplex fluorescence immunohistochemical analysis. Results: The density of CD4-positive (CD4+) T-cells, CD8-positive T-cells, and CD4+ Foxp3-positive T-cells were statistically higher in both tumor and stromal areas in primary lung cancer specimens when compared with brain metastases samples (p < 0.0001). Only CD204-positive cells were statistically higher in the tumor areas of the brain metastases (p = 0.0118). Tumor-infiltrating lymphocytes associated with brain metastases positively correlated with overall survival, but primary lung tumor-infiltrating lymphocytes did not. The density of CD4+ and CD4+ Foxp3-positive T-cells in brain metastases with radiation was statistically higher in the carcinoma and stromal areas compared with those without radiation (p = 0.0343, p = 0.0173). Conclusions: Our findings that CD204-positive cells were higher in brain metastases may have broader implications for treatment as these macrophages may be immunosuppressive and make the immune environment less reactive. Furthermore, the finding that the density of CD4+ T-cells was higher in cancer and stroma areas of brain metastases after radiotherapy supports the addition of immunotherapy to radiation therapy in the treatment of brain metastases in NSCLC.

Lung cancer is the leading cause of cancer-related death worldwide with non-small cell lung cancer (NSCLC) being the most common type. Advanced NSCLC is not curable and carries a poor prognosis. It also is associated with the highest burden on mental and physical health-related quality of life (HRQoL) of all patients with cancer. Patients’ subjective experience with their illness and treatment (illness perceptions) may influence treatment decision making and health outcomes, including HRQoL. Illness perception studies with patients with lung cancer are reviewed. Using Leventhal and colleagues’ Self-Regulation Model to better understand patients’ experience and coping with their advanced-stage NSCLC (N=156) assessed illness perceptions (Illness Perception Questionnaire-Revised [BIPQ]) and HRQoL (EuroQol-visual analogue scale [EQ-VAS]). Patients reported high perceived consequences and stress (concern) at diagnosis along with moderate levels of symptoms (identity) and belief in their ability to manage their NSCLC (personal control). Patients reported low HRQoL compared to population norms. The illness perceptions of consequences, concern, and identity were negatively correlated with HRQoL, while personal control was positively correlated with HRQoL. Assessment of illness perceptions provides a nuanced understanding for patients as they cope with cancer diagnosis. To advance study, prospective longitudinal designs might study how illness perceptions might relate to HRQoL trajectories of patients with newly diagnosed advanced NSCLC as they receive first and later lines of cancer therapies.

Abstract Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers. Despite high rates of response to first-line chemotherapy and radiotherapy, patients with extensive-stage disease eventually relapse, and very few patients survive more than 5 years from diagnosis. Treatment options for recurrent or refractory disease are limited, and the treatments that do exist are associated with significant treatment-related toxicities. Delta-like ligand 3 (DLL3) is an inhibitory Notch ligand that is highly expressed in SCLC and other neuroendocrine tumors but minimally expressed in normal tissues. It is therefore being explored as a potential therapeutic target in SCLC. Here, we review the preclinical and clinical evidence for targeting DLL3 in SCLC and discuss several DLL3-specific therapies being developed for the treatment of SCLC: the antibody-drug conjugate rovalpituzumab tesirine, the bispecific T cell engager immuno-oncology therapy AMG 757, and the chimeric antigen receptor T cell therapy AMG 119.

Abstract Background Locally advanced or metastatic non-small cell lung cancer (NSCLC) that has progressed after first-line treatment has a poor prognosis. Recent randomized clinical trials (RCTs) have demonstrated survival benefits of alternative treatments to docetaxel. However, information is lacking on which patients benefit the most and what drug or regimen is optimal. We report a systematic review and network meta-analysis (NMA) of second-line treatments in all subgroup combinations determined by histology, programmed death ligand 1 (PD-L1) expression, and epidermal growth factor receptor (EGFR) mutation. Methods MEDLINE, PubMed, EMBASE, Biosciences Information Service (using the Dialog Platform), Cochrane Library, and abstracts from scientific meetings were searched for RCTs published up to September 2015. Key outcomes were overall survival (OS) and progression-free survival (PFS). Bayesian hierarchical exchangeable NMAs were conducted to calculate mean survival times and relative differences for eight subgroups, using docetaxel as the reference comparator. For OS, the NMA was based on hazard ratios applied to a first-order fractional polynomial model fitted to the reference treatment. For PFS, a second-order fractional polynomial model was fitted to reconstructed patient-level data for the entire network of evidence. Results The search identified 30 studies containing 17 different treatment regimens. Docetaxel plus ramucirumab was associated with a significant improvement in OS and PFS, relative to docetaxel, regardless of patient type. Docetaxel plus nintedanib showed similar efficacy to docetaxel plus ramucirumab in the nonsquamous populations. EGFR tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib showed superior levels of efficacy in EGFR mutation-positive populations and the one PD-1 immunotherapy (nivolumab) studied showed superior efficacy in the populations exhibiting high PD-L1 expression. Conclusions In the absence of head-to-head comparisons, we performed a mixed-treatment analysis to synthesize evidence of the efficacy of each treatment. Benefits are optimized by targeting specific treatments to individual patients guided by histology, PD-L1 expression, and EGFR mutation status. Systematic review registration This review is registered in PROSPERO (registration number: CRD42014013780 available at www.crd.york.ac.uk/PROSPERO).

Abstract Background Notch intercellular communication instructs tissue-specific T-cell development and function. In this study, we explored the roles of dendritic cell (DC)-expressed Notch ligands in the regulation of T-cell effector function. Methods We generated mice with CD11c lineage-specific deletion of Notch Delta-like ligand (Dll)1 and Jagged (Jag)2. Using these genetically-ablated mice and engineered pharmacological Notch ligand constructs, the roles of various Delta-like and Jagged ligands in the regulation of T-cell-mediated immunity were investigated. We assessed tumor growth, mouse survival, cytokine production, immunophenotyping of myeloid and lymphoid populations infiltrating the tumors, expression of checkpoint molecules and T-cell function in the experimental settings of murine lung and pancreatic tumors and cardiac allograft rejection. Correlative studies were also performed for the expression of NOTCH ligands, NOTCH receptors and PD-1 on various subsets of myeloid and lymphoid cells in tumor-infiltrating immune cells analyzed from primary human lung cancers. Results Mice with CD11c lineage-specific deletion of Notch ligand gene Dll1, but not Jag2, exhibited accelerated growth of lung and pancreatic tumors concomitant with decreased antigen-specific CD8+T-cell functions and effector-memory (Tem) differentiation. Increased IL-4 but decreased IFN-γ production and elevated populations of T-regulatory and myeloid-derived suppressor cells were observed in Dll1-ablated mice. Multivalent clustered DLL1-triggered Notch signaling overcame DC Dll1 deficiency and improved anti-tumor T-cell responses, whereas the pharmacological interference by monomeric soluble DLL1 construct suppressed the rejection of mouse tumors and cardiac allograft. Moreover, monomeric soluble JAG1 treatment reduced T-regulatory cells and improved anti-tumor immune responses by decreasing the expression of PD-1 on CD8+Tem cells. A significant correlation was observed between DC-expressed Jagged and Delta-like ligands with Tem-expressed PD-1 and Notch receptors, respectively, in human lung tumor-infiltrates. Conclusion Our data show the importance of specific expression of Notch ligands on DCs in the regulation of T-cell effector function. Thus, strategies incorporating selectively engineered Notch ligands could provide a novel approach of therapeutics for modulating immunity in various immunosuppressive conditions including cancer.

Introduction: Relapsed SCLC is characterized by therapeutic resistance and high mortality rate. Despite decades of research, mechanisms responsible for therapeutic resistance have remained elusive owing to limited tissues available for molecular studies. Thus, an unmet need remains for molecular characterization of relapsed SCLC to facilitate development of effective therapies. Methods: We performed whole-exome and transcriptome sequencing of metastatic tumor samples procured from research autopsies of five patients with relapsed SCLC. We implemented bioinformatics tools to infer subclonal phylogeny and identify recurrent genomic alterations. We implemented immune cell signature and single-sample gene set enrichment analyses on tumor and normal transcriptome data from autopsy and additional primary and relapsed SCLC data sets. Furthermore, we evaluated T cell-inflamed gene expression profiles in neuroendocrine (ASCL1, NEUROD1) and non-neuroendocrine (YAP1, POU2F3) SCLC subtypes. Results: Exome sequencing revealed clonal heterogeneity (intertumor and intratumor) arising from branched evolution and identified resistance-associated truncal and subclonal alterations in relapsed SCLC. Transcriptome analyses further revealed a noninflamed phenotype in neuroendocrine SCLC subtypes (ASCL1, NEUROD1) associated with decreased expression of genes involved in adaptive antitumor immunity whereas non-neuroendocrine subtypes (YAP1, POU2F3) revealed a more inflamed phenotype. Conclusions: Our results reveal substantial tumor heterogeneity and complex clonal evolution in relapsed SCLC. Furthermore, we report that neuroendocrine SCLC subtypes are immunologically cold, thus explaining decreased responsiveness to immune checkpoint blockade. These results suggest that the mechanisms of innate and acquired therapeutic resistances are subtype-specific in SCLC and highlight the need for continued investigation to bolster therapy selection and development for this cancer.

Background: The CheckMate 227 trial has indicated that nivolumab plus ipilimumab compared with chemotherapy significantly increases long-term survival in the first-line setting of advanced non-small-cell lung cancer (NSCLC).Methods: A Markov model was built to estimate the cost and effectiveness of nivolumab plus ipilimumab vs. chemotherapy as the first-line therapy in patients with advanced NSCLC based on outcomes data from the CheckMate 227 trial. We calculated the cost and health outcomes at a willingness-to-pay (WTP) threshold of $150,000 per quality adjusted life year (QALY) in populations with different programmed death ligand 1 (PD-L1) expression levels (≥50, ≥1, and

Understanding and targeting Notch signaling effectively has long been valued in the field of cancer and other immune disorders. Here, we discuss key discoveries at the intersection of Notch signaling, cancer and immunology. While there is a plethora of Notch targeting agents tested in vitro, in vivo and in clinic, undesirable off-target effects and therapy-related toxicities have been significant obstacles. We make a case for the clinical application of ligand-derived and affinity modifying compounds as novel therapeutic agents and discuss major research findings with an emphasis on Notch ligand-specific modulation of immune responses.

Treatment of EGFR mutant non-small cell lung cancer (NSCLC) often develops resistance to EGFR TKIs. In this study, the authors discover a non-canonical activation of β-catenin signaling through Notch3 as a mechanism of adaptation to and resistance to EGFR TKI treatment in NSCLC.

Despite tremendous advances in targeted therapies against lung adenocarcinoma, the majority of patients do not benefit from personalized treatments. A deeper understanding of potential therapeutic targets is crucial to increase the survival of patients. One promising target, ADAR, is amplified in 13% of lung adenocarcinomas and in-vitro studies have demonstrated the potential of its therapeutic inhibition to inhibit tumor growth. ADAR edits millions of adenosines to inosines within the transcriptome, and while previous studies of ADAR in cancer have solely focused on protein-coding edits, >99% of edits occur in non-protein coding regions. Here, we develop a pipeline to discover the regulatory potential of RNA editing sites across the entire transcriptome and apply it to lung adenocarcinoma tumors from The Cancer Genome Atlas. This method predicts that 1413 genes contain regulatory edits, predominantly in non-coding regions. Genes with the largest numbers of regulatory edits are enriched in both apoptotic and innate immune pathways, providing a link between these known functions of ADAR and its role in cancer. We further show that despite a positive association between ADAR RNA expression and apoptotic and immune pathways, ADAR copy number is negatively associated with apoptosis and several immune cell types' signatures.

Following publication of the original article [1], the author reported the wrong version of Figs. 5 and 7 have been published. The correct version of the figures can be found below:

We have identified a non-canonical role of0 Notch3 in response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy, whereby Notch3 associates with β-catenin, resulting in increased catenin beta-1 (CTNNB1, best known as β-catenin) stability and increased survival of drug persister cells (DPCs). Furthermore, combined treatment of an EGFR TKI with a β-catenin inhibitor demonstrated improved therapeutic outcomes in xenograft models.

Patients with EGFR-mutant lung adenocarcinomas (LUADs) who initially respond to first-generation tyrosine kinase inhibitors (TKIs) develop resistance to these drugs. A combination of the irreversible TKI afatinib and the EGFR antibody cetuximab can be used to overcome resistance to first-generation TKIs; however, resistance to this drug combination eventually emerges. We identified activation of the mTORC1 signaling pathway as a mechanism of resistance to dual inhibition of EGFR in mouse models. The addition of rapamycin reversed resistance in vivo. Analysis of afatinib-plus-cetuximab-resistant biopsy specimens revealed the presence of genomic alterations in genes that modulate mTORC1 signaling, including NF2 and TSC1. These findings pinpoint enhanced mTORC1 activation as a mechanism of resistance to afatinib plus cetuximab and identify genomic mechanisms that lead to activation of this pathway, revealing a potential therapeutic strategy for treating patients with resistance to these drugs.

While numerous cell signaling pathways are known to play decisive roles in chemotherapeutic response, relatively little is known about the impact of the Smad-dependent transforming growth factor β pathway on the therapeutic outcome. Previous reports suggested that patients with lung cancer who continue to smoke while receiving chemotherapy have a poorer outcome than their nonsmoking counterparts do. In our previous study, we showed that long-term cigarette smoke condensate (CSC)-mediated down-regulation of Smad3 induces tumorigenesis. The objective of this study was to determine the mechanism of function of Smad3 in chemoresistance induced by CSC in human lung cell lines, namely, A549 and HPL1A. Long-term CSC treatment increases the half-maximal inhibitory concentration (IC50) of carboplatin and makes cells resistant to carboplatin. The increase in IC50 of long-term CSC-treated cells is due to the reduced induction in apoptosis by carboplatin. The increase in IC50 and decrease in apoptosis in long-term CSC-treated cells is correlated with the expression of Bcl2. We have determined that Bcl2 is both necessary and sufficient to make the cells resistant to carboplatin. We have also shown that Smad3 acts upstream to regulate the expression of Bcl2 specifically and, thus, sensitivity of the cells to carboplatin. This is supported by the inverse correlation between the expressions of Smad3 and Bcl2 in human lung tumors. Collectively, these data suggest that loss of Smad3 expression in CSC-treated cells induces resistance to carboplatin by upregulating the expression of Bcl2. This study explains, at least in part, the higher chemoresistance rate observed in smokers.

Lung carcinogenesis in humans involves an accumulation of genetic and epigenetic changes that lead to alterations in normal lung epithelium, to in situ carcinoma, and finally to invasive and metastatic cancers. The loss of transforming growth factor β (TGF-β)-induced tumor suppressor function in tumors plays a pivotal role in this process, and our previous studies have shown that resistance to TGF-β in lung cancers occurs mostly through the loss of TGF-β type II receptor expression (TβRII). However, little is known about the mechanism of down-regulation of TβRII and how histone deacetylase (HDAC) inhibitors (HDIs) can restore TGF-β-induced tumor suppressor function. Here we show that HDIs restore TβRII expression and that DNA hypermethylation has no effect on TβRII promoter activity in lung cancer cell lines. TGF-β-induced tumor suppressor function is restored by HDIs in lung cancer cell lines that lack TβRII expression. Activation of mitogen-activated protein kinase/extracellular signal-regulated kinase pathway by either activated Ras or epidermal growth factor signaling is involved in the down-regulation of TβRII through histone deacetylation. We have immunoprecipitated the protein complexes by biotinylated oligonucleotides corresponding to the HDI-responsive element in the TβRII promoter (−127/(−75) and identified the proteins/factors using proteomics studies. The transcriptional repressor Meis1/2 is involved in repressing the TβRII promoter activity, possibly through its recruitment by Sp1 and NF-YA to the promoter. These results suggest a mechanism for the downregulation of TβRII in lung cancer and that TGF-β tumor suppressor functions may be restored by HDIs in lung cancer patients with the loss of TβRII expression.

Recent studies suggest that tumor-infiltrating immune cells can benefit the tumor by producing factors that promote angiogenesis and suppress immunity. Because the tumor microenvironment is characterized by high adenosine levels, we hypothesized that the low-affinity A2B adenosine receptor located on host immune cells may participate in these effects. In the current study, we tested this hypothesis in a Lewis lung carcinoma isograft model using A2B receptor knockout (A2BKO) mice. These mice exhibited significantly attenuated tumor growth and longer survival times after inoculation with Lewis lung carcinoma compared to wild type (WT) controls. Lewis lung carcinoma tumors in A2BKO mice contained significantly lower levels of vascular endothelial growth factor (VEGF) compared to tumors growing in WT animals. This difference was due to VEGF production by host cells, which comprised 30 ± 2% of total tumor cell population. Stimulation of adenosine receptors on WT tumorinfiltrating CD45+ immune cells increased VEGF production fivefold, an effect not seen in tumor-associated CD45+ immune cells lacking A2B receptors. In contrast, we found no significant difference in VEGF production between CD45− tumor cells isolated from WT and A2BKO mice. Thus, our data suggest that tumor cells promote their growth by exploiting A2B adenosine receptor–dependent regulation of VEGF in host immune cells.

Objective: Activation of the hedgehog pathway is an important signaling mechanism crucial in embryogenesis and has strong links to carcinogenesis. This study investigates the expression of the Sonic hedgehog pathway molecules in non-small cell lung tumors as it relates to clinical outcome of various non-small cell lung cancers. Methods: A tissue microarray with 81 samples from 42 patients with various non-small cell lung cancer histologies was examined without the aid of laser microdissection. All samples were stained with antibodies directed against Sonic hedgehog, Ptch-1, Smoothened, and Gli-1. Results: Most of the tumor samples showed negative to weak expression of the pathway proteins (Sonic hedgehog, 38% negative to 20% weak; Ptch-1, 100% negative; Smoothened, 69% negative to 7% weak; Gli-1, 57% negative to 5% weak) compared with higher expression in normal lung epithelial cells. Conclusion: The same pathway expression did not correlate with clinical outcome. While our results do not provide any indication that the pathway molecules are correlated to overall patient survival possibly due to the limited sample size, our study shows minimum overexpression of Sonic hedgehog pathway in non-small cell lung cancer and this did not correlate clinically with patient outcome.