Characterization of the Immune Landscape of EGFR-Mutant NSCLC Identifies CD73/Adenosine Pathway as a Potential Therapeutic Target

INTRODUCTION

Lung adenocarcinomas harboring EGFR mutations do not respond to immune checkpoint blockade therapy and their EGFR wildtype counterpart. The mechanisms underlying this lack of clinical response have been investigated but remain incompletely understood.

METHODS

We analyzed three cohorts of resected lung adenocarcinomas (Profiling of Resistance Patterns of Oncogenic Signaling Pathways in Evaluation of Cancer of Thorax, Immune Genomic Profiling of NSCLC, and The Cancer Genome Atlas) and compared tumor immune microenvironment of EGFR-mutant tumors to EGFR wildtype tumors, to identify actionable regulators to target and potentially enhance the treatment response.

RESULTS

EGFR-mutant NSCLC exhibited low programmed death-ligand 1, low tumor mutational burden, decreased number of cytotoxic T cells, and low T cell receptor clonality, consistent with an immune-inert phenotype, though T cell expansion ex vivo was preserved. In an analysis of 75 immune checkpoint genes, the top up-regulated genes in the EGFR-mutant tumors (NT5E and ADORA1) belonged to the CD73/adenosine pathway. Single-cell analysis revealed that the tumor cell population expressed CD73, both in the treatment-naive and resistant tumors. Using coculture systems with EGFR-mutant NSCLC cells, T regulatory cell proportion was decreased with CD73 knockdown. In an immune-competent mouse model of EGFR-mutant lung cancer, the CD73/adenosine pathway was markedly up-regulated and CD73 blockade significantly inhibited tumor growth.

CONCLUSIONS

Our work revealed that EGFR-mutant NSCLC has an immune-inert phenotype. We identified the CD73/adenosine pathway as a potential therapeutic target for EGFR-mutant NSCLC.

The KRASG12C Inhibitor MRTX849 Reconditions the Tumor Immune Microenvironment and Sensitizes Tumors to Checkpoint Inhibitor Therapy

KRAS^G12C inhibitors, including MRTX849, are promising treatment options for KRAS-mutant non-small cell lung cancer (NSCLC). PD-1 inhibitors are approved in NSCLC; however, strategies to enhance checkpoint inhibitor therapy (CIT) are needed. KRAS^G12C mutations are smoking-associated transversion mutations associated with high tumor mutation burden, PD-L1 positivity, and an immunosuppressive tumor microenvironment. To evaluate the potential of MRTX849 to augment CIT, its impact on immune signaling and response to CIT was evaluated. In human tumor xenograft models, MRTX849 increased MHC class I protein expression and decreased RNA and/or plasma protein levels of immunosuppressive factors. In a Kras^G12C -mutant CT26 syngeneic mouse model, MRTX849 decreased intratumoral myeloid-derived suppressor cells and increased M1-polarized macrophages, dendritic cells, CD4⁺, and CD8⁺ T cells. Similar results were observed in lung Kras^G12C -mutant syngeneic and a genetically engineered mouse (GEM) model. In the CT26 Kras^G12C model, MRTX849 demonstrated marked tumor regression when tumors were established in immune-competent BALB/c mice; however, the effect was diminished when tumors were grown in T-cell-deficient nu/nu mice. Tumors progressed following anti-PD-1 or MRTX849 single-agent treatment in immune-competent mice; however, combination treatment demonstrated durable, complete responses (CRs). Tumors did not reestablish in the same mice that exhibited durable CRs when rechallenged with tumor cell inoculum, demonstrating these mice developed adaptive antitumor immunity. In a GEM model, treatment with MRTX849 plus anti-PD-1 led to increased progression-free survival compared with either single agent alone. These data demonstrate KRAS inhibition reverses an immunosuppressive tumor microenvironment and sensitizes tumors to CIT through multiple mechanisms.

Recent advances in preclinical models for lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC) represents a major subtype of non-small cell lung cancer with limited treatment options. Previous studies have elucidated the complex genetic landscape of LUSC and revealed multiple altered genes and pathways. However, in stark contrast to lung adenocarcinoma, few targetable driver mutations have been established so far and targeted therapies for LUSC remain unsuccessful. Immunotherapy has revolutionized LUSC treatment and is currently approved as the new standard of care. To gain a better understanding of the LUSC biology, improved modeling systems are urgently needed. Preclinical models, particularly those mimicking human disease with an intact tumor immune microenvironment, are an invaluable tool to study cancer development and evaluate new therapeutic targets. Here, we discuss recent advances in LUSC preclinical models, with a focus on genetically engineered mouse models (GEMMs) and organoids, in the context of evolving precision medicine and immunotherapy.

Mobocertinib (TAK-788): A Targeted Inhibitor of EGFR Exon 20 Insertion Mutants in Non-Small Cell Lung Cancer

Most EGFR exon 20 insertion (EGFRex20ins) driver mutations in non-small cell lung cancer (NSCLC) are insensitive to approved EGFR tyrosine kinase inhibitors (TKI). To address the limitations of existing therapies targeting EGFR-mutated NSCLC, mobocertinib (TAK-788), a novel irreversible EGFR TKI, was specifically designed to potently inhibit oncogenic variants containing activating EGFRex20ins mutations with selectivity over wild-type EGFR. The in vitro and in vivo activity of mobocertinib was evaluated in engineered and patient-derived models harboring diverse EGFRex20ins mutations. Mobocertinib inhibited viability of various EGFRex20ins-driven cell lines more potently than approved EGFR TKIs and demonstrated in vivo antitumor efficacy in patient-derived xenografts and murine orthotopic models. These findings support the ongoing clinical development of mobocertinib for the treatment of EGFRex20ins-mutated NSCLC. SIGNIFICANCE: No oral EGFR-targeted therapies are approved for EGFR exon 20 insertion (EGFRex20ins) mutation-driven NSCLC. Mobocertinib is a novel small-molecule EGFR inhibitor specifically designed to target EGFRex20ins mutants. Preclinical data reported here support the clinical development of mobocertinib in patients with NSCLC with EGFR exon 20 insertion mutations.See related commentary by Pacheco, p. 1617.This article is highlighted in the In This Issue feature, p. 1601.

Lower Airway Dysbiosis Affects Lung Cancer Progression

In lung cancer, enrichment of the lower airway microbiota with oral commensals commonly occurs, and ex vivo models support that some of these bacteria can trigger host transcriptomic signatures associated with carcinogenesis. Here, we show that this lower airway dysbiotic signature was more prevalent in the stage IIIB-IV tumor-node-metastasis lung cancer group and is associated with poor prognosis, as shown by decreased survival among subjects with early-stage disease (I-IIIA) and worse tumor progression as measured by RECIST scores among subjects with stage IIIB-IV disease. In addition, this lower airway microbiota signature was associated with upregulation of the IL17, PI3K, MAPK, and ERK pathways in airway transcriptome, and we identified Veillonella parvula as the most abundant taxon driving this association. In a KP lung cancer model, lower airway dysbiosis with V. parvula led to decreased survival, increased tumor burden, IL17 inflammatory phenotype, and activation of checkpoint inhibitor markers. SIGNIFICANCE: Multiple lines of investigation have shown that the gut microbiota affects host immune response to immunotherapy in cancer. Here, we support that the local airway microbiota modulates the host immune tone in lung cancer, affecting tumor progression and prognosis.See related commentary by Zitvogel and Kroemer, p. 224.This article is highlighted in the In This Issue feature, p. 211.

An Empirical Antigen Selection Method Identifies Neoantigens That Either Elicit Broad Antitumor T-cell Responses or Drive Tumor Growth

Neoantigens are critical targets of antitumor T-cell responses. The ATLAS bioassay was developed to identify neoantigens empirically by expressing each unique patient-specific tumor mutation individually in Escherichia coli, pulsing autologous dendritic cells in an ordered array, and testing the patient's T cells for recognition in an overnight assay. Profiling of T cells from patients with lung cancer revealed both stimulatory and inhibitory responses to individual neoantigens. In the murine B16F10 melanoma model, therapeutic immunization with ATLAS-identified stimulatory neoantigens protected animals, whereas immunization with peptides associated with inhibitory ATLAS responses resulted in accelerated tumor growth and abolished efficacy of an otherwise protective vaccine. A planned interim analysis of a clinical study testing a poly-ICLC adjuvanted personalized vaccine containing ATLAS-identified stimulatory neoantigens showed that it is well tolerated. In an adjuvant setting, immunized patients generated both CD4⁺ and CD8⁺ T-cell responses, with immune responses to 99% of the vaccinated peptide antigens. SIGNIFICANCE: Predicting neoantigens in silico has progressed, but empirical testing shows that T-cell responses are more nuanced than straightforward MHC antigen recognition. The ATLAS bioassay screens tumor mutations to uncover preexisting, patient-relevant neoantigen T-cell responses and reveals a new class of putatively deleterious responses that could affect cancer immunotherapy design.This article is highlighted in the In This Issue feature, p. 521.

MUC1-C integrates activation of the IFN-γ pathway with suppression of the tumor immune microenvironment in triple-negative breast cancer

Background

Immune checkpoint inhibitors (ICIs) have had a profound impact on the treatment of many tumors; however, their effectiveness against triple-negative breast cancers (TNBCs) has been limited. One factor limiting responsiveness of TNBCs to ICIs is a lack of functional tumor-infiltrating lymphocytes (TILs) in ‘non-inflamed’ or ‘cold’ tumor immune microenvironments (TIMEs), although by unknown mechanisms. Targeting MUC1-C in a mouse transgenic TNBC tumor model increases cytotoxic tumor-infiltrating CD8+ T cells (CTLs), supporting a role for MUC1-C in immune evasion. The basis for these findings and whether they extend to human TNBCs are not known.

Methods

Human TNBC cells silenced for MUC1-C using short hairpin RNAs (shRNAs) were analyzed for the effects of MUC1-C on global transcriptional profiles. Differential expression and rank order analysis was used for gene set enrichment analysis (GSEA). Gene expression was confirmed by quantitative reverse-transcription PCR and immunoblotting. The The Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets were analyzed for effects of MUC1 on GSEA, cell-type enrichment, and tumor immune dysfunction and exclusion. Single-cell scRNA-seq datasets of TNBC samples were analyzed for normalized expression associations between MUC1 and selected genes within tumor cells.

Results

Our results demonstrate that MUC1-C is a master regulator of the TNBC transcriptome and that MUC1-C-induced gene expression is driven by STAT1 and IRF1. We found that MUC1-C activates the inflammatory interferon (IFN)-γ-driven JAK1→STAT1→IRF1 pathway and induces the IDO1 and COX2/PTGS2 effectors, which play key roles in immunosuppression. Involvement of MUC1-C in activating the immunosuppressive IFN-γ pathway was extended by analysis of human bulk and scRNA-seq datasets. We further demonstrate that MUC1 associates with the depletion and dysfunction of CD8+ T cells in the TNBC TIME.

Conclusions

These findings demonstrate that MUC1-C integrates activation of the immunosuppressive IFN-γ pathway with depletion of TILs in the TNBC TIME and provide support for MUC1-C as a potential target for improving TNBC treatment alone and in combination with ICIs. Of translational significance, MUC1-C is a druggable target with chimeric antigen receptor (CAR) T cells, antibody-drug conjugates (ADCs) and a functional inhibitor that are under clinical development.

Multiple screening approaches reveal HDAC6 as a novel regulator of glycolytic metabolism in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer without a targeted form of therapy. Unfortunately, up to 70% of patients with TNBC develop resistance to treatment. A known contributor to chemoresistance is dysfunctional mitochondrial apoptosis signaling. We set up a phenotypic small-molecule screen to reveal vulnerabilities in TNBC cells that were independent of mitochondrial apoptosis. Using a functional genetic approach, we identified that a "hit" compound, BAS-2, had a potentially similar mechanism of action to histone deacetylase inhibitors (HDAC). An in vitro HDAC inhibitor assay confirmed that the compound selectively inhibited HDAC6. Using state-of-the-art acetylome mass spectrometry, we identified glycolytic substrates of HDAC6 in TNBC cells. We confirmed that inhibition or knockout of HDAC6 reduced glycolytic metabolism both in vitro and in vivo. Through a series of unbiased screening approaches, we have identified a previously unidentified role for HDAC6 in regulating glycolytic metabolism.

Serial single-cell profiling analysis of metastatic TNBC during Nab-paclitaxel and pembrolizumab treatment

PURPOSE

Immunotherapy has recently been shown to improve outcomes for advanced PD-L1-positive triple-negative breast cancer (TNBC) in the Impassion130 trial, leading to FDA approval of the first immune checkpoint inhibitor in combination with taxane chemotherapy. To further develop predictive biomarkers and improve therapeutic efficacy of the combination, interrogation of the tumor immune microenvironment before therapy as well as during each component of treatment is crucial. Here we use single-cell RNA sequencing (scRNA-seq) on tumor biopsies to assess immune cell changes from two patients with advanced TNBC treated in a prospective trial at predefined serial time points, before treatment, on taxane chemotherapy and on chemo-immunotherapy.

METHODS

Both patients (one responder and one progressor) received the trial therapy, in cycle 1 nab-paclitaxel given as single agent, in cycle 2 nab-paclitaxel in combination with pembrolizumab. Tumor core biopsies were obtained at baseline, 3 weeks (after cycle 1, chemotherapy alone) and 6 weeks (after cycle 2, chemo-immunotherapy). Single-cell RNA sequencing (scRNA-seq) of both cancer cells and infiltrating immune cells isolated were performed from fresh tumor core biopsy specimens by 10 × chromium sequencing.

RESULTS

ScRNA-seq analysis showed significant baseline heterogeneity of tumor-infiltrating immune cell populations between the two patients as well as modulation of the tumor microenvironment by chemotherapy and immunotherapy. In the responding patient there was a population of PD-1high-expressing T cells which significantly decreased after nab-paclitaxel plus pembrolizumab treatment as well as a presence of tissue-resident memory T cells (TRM). In contrast, tumors from the patient with rapid disease progression showed a prevalent and persistent myeloid compartment.

CONCLUSIONS

Our study provides a deep cellular analysis of on-treatment changes during chemo-immunotherapy for advanced TNBC, demonstrating not only feasibility of single-cell analyses on serial tumor biopsies but also the heterogeneity of TNBC and differences in on-treatment changes in responder versus progressor.

Shining a light on metabolic vulnerabilities in non-small cell lung cancer

Metabolic reprogramming is a hallmark of cancer which contributes to essential processes required for cell survival, growth, and proliferation. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and its genomic classification has given rise to the design of therapies targeting tumors harboring specific gene alterations that cause aberrant signaling. Lung tumors are characterized with having high glucose and lactate use, and high heterogeneity in their metabolic pathways. Here we review how NSCLC cells with distinct mutations reprogram their metabolic pathways and highlight the potential metabolic vulnerabilities that might lead to the development of novel therapeutic strategies.

MEK inhibitor resistance mechanisms and recent developments in combination trials

The mitogen-activated protein kinase (MAPK) pathway plays a vital role in cellular processes such as gene expression, cell proliferation, cell survival, and apoptosis. Also known as the RAS-RAF-MEK-ERK pathway, the MAPK pathway has been implicated in approximately one-third of all cancers. Mutations in RAS or RAF genes such as KRAS and BRAF are common, and these mutations typically promote malignancies by over-activating MEK and ERK downstream, which drives sustained cell proliferation and uninhibited cell growth. Development of drugs targeting this pathway has been a research area of great interest, especially drugs targeting the inhibition of MEK. In vitro and clinical studies have shown promise for certain MEK inhibitors (MEKi) , and MEKi have become the first treatment option for certain cancers. Despite promising results, not all patients have a response to MEKi, and mechanisms of resistance typically arise in patients who do have a positive initial response. This paper summarizes recent developments regarding MEKi, the mechanisms of adaptive resistance to MEKi, and the potential solutions to the issue of adaptive MEKi resistance.

IL-23/IL-17 axis in the pathogenesis and treatment of systemic lupus erythematosus and rheumatoid arthritis

Interleukin-23 (IL-23) and IL-17 are the gatekeepers of CD4+ T helper 17 (Th17) cells where IL-23 is required for the development and expansion of Th17 cells that subsequently produce IL-17 to promote inflammation. Owing to such pro-inflammatory properties, the IL-23/IL-17 axis has emerged as an important mechanism in the pathogenesis of autoimmune diseases including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In recent years, therapeutic antibodies targeting IL-23 (e.g. ustekinumab, tildrakizumab, guselkumab) or IL-17 (e.g. brodalumab, secukinumab, ixekizumab) have been approved for the treatment of various autoimmune diseases. In this review, we describe the pathogenic mechanisms of IL-23/IL-17 axis in SLE and RA, as well as summarising the findings from phase II and III clinical trials of anti-IL-23/IL-17 therapeutic antibodies in SLE and RA patients. In particular, phase II study has demonstrated that the anti-IL-23 antibody (ustekinumab) confers enhanced treatment outcomes in SLE patients, while anti-IL-17 antibodies (secukinumab and ixekizumab) have shown improved clinical benefits for RA patients in phase II/III studies. Our review highlights the emerging importance of targeting the IL-23/IL-17 axis in SLE and RA patients.

Branched-Chain Amino Acid Metabolic Reprogramming Orchestrates Drug Resistance to EGFR Tyrosine Kinase Inhibitors

Drug resistance is a significant hindrance to effective cancer treatment. Although resistance mechanisms of epidermal growth factor receptor (EGFR) mutant cancer cells to lethal EGFR tyrosine kinase inhibitors (TKI) treatment have been investigated intensively, how cancer cells orchestrate adaptive response under sublethal drug challenge remains largely unknown. Here, we find that 2-h sublethal TKI treatment elicits a transient drug-tolerant state in EGFR mutant lung cancer cells. Continuous sublethal treatment reinforces this tolerance and eventually establishes long-term TKI resistance. This adaptive process involves H3K9 demethylation-mediated upregulation of branched-chain amino acid aminotransferase 1 (BCAT1) and subsequent metabolic reprogramming, which promotes TKI resistance through attenuating reactive oxygen species (ROS) accumulation. Combination treatment with TKI- and ROS-inducing reagents overcomes this drug resistance in preclinical mouse models. Clinical information analyses support the correlation of BCAT1 expression with the EGFR TKI response. Our findings reveal the importance of BCAT1-engaged metabolism reprogramming in TKI resistance in lung cancer.

BRG1 Loss Predisposes Lung Cancers to Replicative Stress and ATR Dependency

Inactivation of SMARCA4/BRG1, the core ATPase subunit of mammalian SWI/SNF complexes, occurs at very high frequencies in non-small cell lung cancers (NSCLC). There are no targeted therapies for this subset of lung cancers, nor is it known how mutations in BRG1 contribute to lung cancer progression. Using a combination of gain- and loss-of-function approaches, we demonstrate that deletion of BRG1 in lung cancer leads to activation of replication stress responses. Single-molecule assessment of replication fork dynamics in BRG1-deficient cells revealed increased origin firing mediated by the prelicensing protein, CDC6. Quantitative mass spectrometry and coimmunoprecipitation assays showed that BRG1-containing SWI/SNF complexes interact with RPA complexes. Finally, BRG1-deficient lung cancers were sensitive to pharmacologic inhibition of ATR. These findings provide novel mechanistic insight into BRG1-mutant lung cancers and suggest that their dependency on ATR can be leveraged therapeutically and potentially expanded to BRG1-mutant cancers in other tissues. SIGNIFICANCE: These findings indicate that inhibition of ATR is a promising therapy for the 10% of non-small cell lung cancer patients harboring mutations in SMARCA4/BRG1. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/18/3841/F1.large.jpg.

Notch inhibition overcomes resistance to tyrosine kinase inhibitors in EGFR-driven lung adenocarcinoma

EGFR-mutated lung adenocarcinoma patients treated with gefitinib and osimertinib show a therapeutic benefit limited by the appearance of secondary mutations, such as EGFRT790M and EGFRC797S. It is generally assumed that these secondary mutations render EGFR completely unresponsive to the inhibitors, but contrary to this, we uncovered here that gefitinib and osimertinib increased STAT3 phosphorylation (p-STAT3) in EGFRT790M and EGFRC797S tumoral cells. Interestingly, we also found that concomitant Notch inhibition with gefitinib or osimertinib treatment induced a p-STAT3-dependent strong reduction in the levels of the transcriptional repressor HES1. Importantly, we showed that tyrosine kinase inhibitor-resistant tumors, with EGFRT790M and EGFRC797S mutations, were highly responsive to the combined treatment of Notch inhibitors with gefitinib or osimertinib, respectively. Finally, in patients with EGFR mutations treated with tyrosine kinase inhibitors, HES1 protein levels increased during relapse and correlated with shorter progression-free survival. Therefore, our results offer a proof of concept for an alternative treatment to chemotherapy in lung adenocarcinoma osimertinib-treated patients after disease progression.

Abstract 923: Pulsatile MEK inhibition improves anti-tumor immunity and T cell function in Kras mutant lung cancer

KRAS is one of the most commonly identified driver oncogenes in non-small cell lung cancer (NSCLC) and is frequently associated with disease refractory to currently available modalities of treatment. Targeted therapy to inhibit MEK signaling has shown promising tumor growth control in preclinical models, but is followed by quick rebound in tumor growth. Recently, immune checkpoint blockade has demonstrated clinical activity by dis-inhibiting T cells suppressed in the tumor microenvironment. Thus, we sought to identify the most effective therapy for the treatment of KRAS mutant NSCLC patients by targeting cancer cells and activating immune infiltrating cell populations concurrently. To achieve this, we focused on studying the impact of pulsatile MEK inhibition on the immune microenvironment utilizing Kras mutant lung cancer cell lines and Kras mutant transgenic lung cancer mouse models. We found that pulsatile MEK inhibition maintained T cell activation better than continuous treatment ex vivo and in vivo. Treatment with two different MEK inhibitors (selumetinib and trametinib) each resulted in higher CTLA-4 and PD-1 expression in T cells using pulsatile treatment, compared to continuous treatment ex vivo. In addition, the pulsatile schedule showed superior anti-tumor effects and delayed drug resistance compared to continuous administration in vivo. Further, a combination of pulsatile MEK inhibitor treatment and CTLA-4 blockade resulted in the most prolonged survival of Kras tumor-bearing mice. Similar experiments in immune-deficient mice confirmed that this prolonged survival is conferred by adaptive immunity. Our findings set the foundation for a combinatorial therapeutic strategy using pulsatile targeted therapy together with immune checkpoint blockade in patients to optimally enhance tumor apoptosis and promote long-term immune response simultaneously. We are now continuing our studies using a KRAS G12C inhibitor to define its immune modulating properties and will then rationally combine with immune based therapy.

Citation Format: Hyejin Choi, Jiehui Deng, Shuai Li, Tarik Silk, Lauren Dong, Elliott J. Brea, Sean Houghton, David Redmond, Hong Zhong, Jonathan Boiarsky, Esra A. Akbay, Paul D. Smith, Taha Merghoub, Kwok-Kin Wong, Jedd D. Wolchok. Pulsatile MEK inhibition improves anti-tumor immunity and T cell function in Kras mutant lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 923.

Epigenetic CRISPR Screens Identify Npm1 as a Therapeutic Vulnerability in Non-Small Cell Lung Cancer

Despite advancements in treatment options, the overall cure and survival rates for non-small cell lung cancers (NSCLC) remain low. While small-molecule inhibitors of epigenetic regulators have recently emerged as promising cancer therapeutics, their application in patients with NSCLC is limited. To exploit epigenetic regulators as novel therapeutic targets in NSCLC, we performed pooled epigenome-wide CRISPR knockout screens in vitro and in vivo and identified the histone chaperone nucleophosmin 1 (Npm1) as a potential therapeutic target. Genetic ablation of Npm1 significantly attenuated tumor progression in vitro and in vivo. Furthermore, KRAS-mutant cancer cells were more addicted to NPM1 expression. Genetic ablation of Npm1 rewired the balance of metabolism in cancer cells from predominant aerobic glycolysis to oxidative phosphorylation and reduced the population of tumor-propagating cells. Overall, our results support NPM1 as a therapeutic vulnerability in NSCLC. SIGNIFICANCE: Epigenome-wide CRISPR knockout screens identify NPM1 as a novel metabolic vulnerability and demonstrate that targeting NPM1 is a new therapeutic opportunity for patients with NSCLC.

Generation of Genetically Engineered Mouse Lung Organoid Models for Squamous Cell Lung Cancers Allows for the Study of Combinatorial Immunotherapy

PURPOSE

Lung squamous cell carcinoma (LSCC) is a deadly disease for which only a subset of patients responds to immune checkpoint blockade (ICB) therapy. Therefore, preclinical mouse models that recapitulate the complex genetic profile found in patients are urgently needed.

EXPERIMENTAL DESIGN

We used CRISPR genome editing to delete multiple tumor suppressors in lung organoids derived from Cre-dependent SOX2 knock-in mice. We investigated both the therapeutic efficacy and immunologic effects accompanying combination PD-1 blockade and WEE1 inhibition in both mouse models and LSCC patient-derived cell lines.

RESULTS

We show that multiplex gene editing of mouse lung organoids using the CRISPR-Cas9 system allows for efficient and rapid means to generate LSCCs that closely mimic the human disease at the genomic and phenotypic level. Using this genetically defined mouse model and three-dimensional tumoroid culture system, we show that WEE1 inhibition induces DNA damage that primes the endogenous type I IFN and antigen presentation system in primary LSCC tumor cells. These events promote cytotoxic T-cell-mediated clearance of tumor cells and reduce the accumulation of tumor-infiltrating neutrophils. Beneficial immunologic features of WEE1 inhibition are further enhanced by the addition of anti-PD-1 therapy.

CONCLUSIONS

We developed a mouse model system to investigate a novel combinatory approach that illuminates a clinical path hypothesis for combining ICB with DNA damage-inducing therapies in the treatment of LSCC.

Pulsatile MEK Inhibition Improves Anti-tumor Immunity and T Cell Function in Murine Kras Mutant Lung Cancer

KRAS is one of the driver oncogenes in non-small-cell lung cancer (NSCLC) but remains refractory to current modalities of targeted pathway inhibition, which include inhibiting downstream kinase MEK to circumvent KRAS activation. Here, we show that pulsatile, rather than continuous, treatment with MEK inhibitors (MEKis) maintains T cell activation and enables their proliferation. Two MEKis, selumetinib and trametinib, induce T cell activation with increased CTLA-4 expression and, to a lesser extent, PD-1 expression on T cells in vivo after cyclical pulsatile MEKi treatment. In addition, the pulsatile dosing schedule alone shows superior anti-tumor effects and delays the emergence of drug resistance. Furthermore, pulsatile MEKi treatment combined with CTLA-4 blockade prolongs survival in mice bearing tumors with mutant Kras. Our results set the foundation and show the importance of a combinatorial therapeutic strategy using pulsatile targeted therapy together with immunotherapy to optimally enhance tumor delay and promote long-term anti-tumor immunity.

0669 The Effects Of Continuous Positive Airway Pressure Therapy In Moderate To Severe Obstructive Sleep Apnea: A High-density EEG Study

Introduction

A previous high-density electroencephalography (EEG) investigation in asymptomatic OSA showed regional deficits in sleep EEG power particularly slow wave activity (SWA) during NREM sleep in the parietal region. It is unclear whether treatment with CPAP can reverse local sleep EEG abnormalities in OSA, and whether any recovery is related to improvement in sleep-dependent memory consolidation.

Methods

Fifteen male participants (age 50.4±6.5yrs, AHI 51.7±23.5/h) with moderate-severe OSA (AHI>15/h) underwent overnight polysomnography with 256-channel high-density EEG at baseline and following 3 months of CPAP therapy. A word paired associates declarative memory task was administered before and after sleep. After artefact removal, spectral analysis was performed for all channels. Topographical power maps were calculated for standard frequency ranges for NREM sleep (164 channels within a 0.57 radius from the vertex). Maps were compared using both absolute and normalized power (z-scores computed for each subject) and differences between baseline and treatment were determined by statistical nonparametric mapping.

Results

In 11 CPAP compliant patients (intolerant of CPAP [n=3]/high-density EEG [n=1]), analysis of polysomnographic variables showed that total sleep time did not differ but N1 (baseline vs. treatment: 66.9 vs. 39.5 mins,p=0.008) and N2 (195.0 vs. 150.6 mins,p=0.002) sleep was lower and N3 (89.8 vs. 128.7 mins,p=0.003) was higher after CPAP. Topographic analysis of high-density EEG data revealed a regional increase in SWA (1-4.5Hz) EEG power during N3 sleep in a cluster of electrodes overlying the centro-parietal cortex (cluster mean t-value=2.87,p=0.02). The change in overnight declarative memory consolidation (% recognition) after CPAP was significantly correlated with the change in slow spindle frequency activity in frontal regions (cluster mean r=0.875,p=0.003).

Conclusion

CPAP treatment may enhance localised deficits in sleep EEG activity in OSA, and specific regional recovery may translate to memory improvements in the short-term. These data also highlight the potential for long-term therapeutic effects on cognitive outcomes in OSA.

Support

 

Progression free survival (PFS) in Asian vs non-Asian patients (pts) with EGFR mutant non-small cell lung cancer (NSCLC) receiving osimertinib

e21679

Background: Third generation EGFR tyrosine kinase inhibitor (TKI) osimertinib demonstrated superior PFS and OS compared to earlier generation TKIs in pts with EGFR+ NSCLC. These pts are disproportionately Asian, female, and never-smokers. Contradictory data has been reported regarding the PFS and OS to osimertinib in Asian pts as compared to 1st and 2nd generation EGFR TKI. These inconsistencies warrant further investigation. The purpose of this study is to evaluate the PFS in Asian vs non-Asian pts with EGFR+ NSCLC receiving osimertinib. Methods: We conducted a single institution IRB approved retrospective study of pts with EGFR+ NSCLC. PFS was evaluated in pts treated from 1/2013 – 12/2019. Disease and treatment characteristics were summarized using frequency distributions and Kaplan-Meier curves for comparison of subgroups. Results: Of 190 EGFR+ pts: 52 (27%) Asian, 108 (57%) Caucasian, 125 (66%) female, 172 (91%) advanced disease, 107 (56%) never-smokers. Baseline characteristics in Asian and non-Asian pts were similar in regards to de-novo stage IV disease (71% vs 65%, p = 0.80), brain metastases (42% vs 54%, p = 0.48), and differed with regards to ever-smoking (29% vs 56%, p = 0.04). Treatment: 126/172 (73%) pts with advanced disease received TKI across all lines of therapy; 92/126 received osimertinib (22 (24%) 1st line; 45 (49%) 2nd line; 18 (19%) 3rd line; 7 (8%) ≥4th line). There were insufficient number of pts who received osimertinib in the 1st line to comment on differences in PFS between Asian and non-Asian pts. In the 2nd line, 19 Asian pts and 26 non-Asian pts received osimertinib, with no observed difference in PFS (median 15.4 v 13.8 months, p = 0.20). Moreover, Asian pts who received osimertinib as second line therapy had superior PFS (median 15.4 vs 9.6 months, p < 0.01) compared to Asian pts who received earlier generation TKIs, likely due to T790M resistance. Conclusions: Among second line advanced EGFR+ NSCLC, we did not observe a difference in PFS between Asian and non-Asian pts treated with osimertinib. Median PFS in Asian pts treated with osimertinib was longer compared to those treated with 1st or 2nd generation TKIs in the 2nd line setting. Our study highlights the the role of ethnic background in response to EGFR therapies and may warrant further study.

Ground-glass opacity-featured lung adenocarcinoma has no response to chemotherapy

PURPOSE

We aimed to investigate the treatment effect of chemotherapy on ground-glass opacity (GGO)-featured lung adenocarcinoma radiologically and pathologically.

METHODS

This retrospective study included patients who met the following criteria: (1) presence of lung GGO lesions before chemotherapy for other concurrent malignancies; (2) underwent surgical resection of GGO-featured primary lung adenocarcinoma. The last computed tomography images before chemotherapy (CT1) and the last images before GGO resection (CT2) were reviewed to assess radiologic response. Specimens of the resected tumors were reviewed to evaluate the histopathologic response. Immunohistochemical staining of ki-67, caspase-3 and β-gal was performed and compared between these tumors and a propensity score-matched (1:1) cohort of GGO-featured lung adenocarcinoma without prior chemotherapy.

RESULTS

Forty-four patients with 55 GGO lesions were included. There were 20 mixed GGOs and 22 invasive adenocarcinomas. These patients all received at least three cycles of chemotherapy for other concurrent malignancies in breast, lung, cervix, ovary or rectum. Thirty-four (77%) patients received chemotherapy regimens that contained platinum, pemetrexed, paclitaxel, docetaxel or gemcitabine. The median interval between CT1 and CT2 was 10 months. Radiologically, all the GGO lesions either remained unchanged or enlarged. There was no chemotherapy-induced histopathologic response (necrosis, fibrosis or inflammation) in any of these tumors. The protein expression of ki-67, caspase-3 and β-gal was comparable between GGO-featured lung adenocarcinoma with or without prior chemotherapy.

CONCLUSION

GGO-featured lung adenocarcinoma has no response to chemotherapy. For these patients, chemotherapy should not be a treatment option.