Breath of Health: spectroscopy-based breath test for the detection of SARS-CoV-2

BACKGROUND

Nucleic acid amplification tests (NAAT) are considered the gold standard for COVID-19 diagnosis. These tests require professional manpower and equipment, long processing and swab sampling which is unpleasant to the patients. Several volatile organic compounds (VOCs) have been identified in the breath of COVID-19 patients. Detection of these VOCs using a breath test could help rapidly identify COVID-19 patients.

OBJECTIVE

Assess the accuracy of 'Breath of Health' (BOH) COVID-19 Fourier-transform infra-red (FTIR) Spectroscopy-based breath test.

METHODS

Breath samples from patients with or without symptoms suggestive for COVID-19 who had NAAT results were collected using Tedlar bags and were blindly analysed using BOH FTIR spectroscopy. BOH Measures several VOCs simultaneously and differentiating positive and negative results. BOH results were compared to NAAT results as gold standard.

RESULTS

Breath samples from 531 patients were analysed. The sensitivity of BOH breath test was found to be 79.5% and specificity was 87.2%. Positive predictive value (PPV) was 74.7% and negative predictive value (NPV) 90.0%. Calculated accuracy rate was 84.8% and area under the curve 0.834. Subgroup analysis revealed that the NPV of patients without respiratory symptoms was superior over the NPV of symptomatic patients (94.7% vs 80.7%, P-value < 0.0001) and PPV of patients with respiratory symptoms outranks the PPV of individuals without symptoms (85.3% vs 69.2%, P-value 0.0196).

CONCLUSION

We found BOH COVID-19 breath test to be a patient-friendly, rapid, non-invasive diagnostic test with high accuracy rate and NPV that could efficiently rule out COVID-19 especially among individuals with low pre-test probability.

RNA Sequencing Reveals Unique Transcriptomic Signatures of the Thyroid in a Murine Lung Cancer Model Treated with PD-1 and PD-L1 Antibodies

Immune checkpoint inhibitors (ICI) are commonly associated with thyroid immune-related adverse events, yet the mechanism has not been fully elucidated. We aimed to further explore the mechanism of ICI-induced thyroid dysfunction by assessing changes induced in the thyroid transcriptome by ICI treatment (αPD-1/αPD-L1) in a lung cancer murine model. RNA-sequencing of thyroid tissues revealed 952 differentially expressed genes (DEGs) with αPD-1 treatment (|fold-change| ≥1.8, FDR < 0.05). Only 35 DEG were identified with αPD-L1, and we therefore focused on the αPD-1 group alone. Ingenuity Pathway Analysis revealed that of 952 DEGs with αPD-1 treatment, 362 were associated with functions of cell death and survival, with predicated activation of pathways for apoptosis and necrosis (Z = 2.89 and Z = 3.21, respectively) and negative activation of pathways for cell viability and cell survival (Z = -6.22 and Z = -6.45, respectively). Compared to previously published datasets of interleukin-1β and interferon γ-treated human thyroid cells, apoptosis pathways were similarly activated. However, unique changes related to organ inflammation and upstream regulation by cytokines were observed. Our data suggest that there are unique changes in gene expression in the thyroid associated with αPD-1 therapy. ICI-induced thyroid dysfunction may be mediated by increased tissue apoptosis resulting in destructive thyroiditis.

Elevated cfDNA after exercise is derived primarily from mature polymorphonuclear neutrophils, with a minor contribution of cardiomyocytes

Strenuous physical exercise causes a massive elevation in the concentration of circulating cell-free DNA (cfDNA), which correlates with effort intensity and duration. The cellular sources and physiological drivers of this phenomenon are unknown. Using methylation patterns of cfDNA and associated histones, we show that cfDNA in exercise originates mostly in extramedullary polymorphonuclear neutrophils. Strikingly, cardiomyocyte cfDNA concentration increases after a marathon, consistent with elevated troponin levels and indicating low-level, delayed cardiac cell death. Physical impact, low oxygen levels, and elevated core body temperature contribute to neutrophil cfDNA release, while muscle contraction, increased heart rate, β-adrenergic signaling, or steroid treatment fail to cause elevation of cfDNA. Physical training reduces neutrophil cfDNA release after a standard exercise, revealing an inverse relationship between exercise-induced cfDNA release and training level. We speculate that the release of cfDNA from neutrophils in exercise relates to the activation of neutrophils in the context of exercise-induced muscle damage.

How Accurate Is the Diagnosis of "Chronic Obstructive Pulmonary Disease" in Patients Hospitalized with an Acute Exacerbation?

Rationale: COPD diagnosis requires relevant symptoms and an FEV1/FVC ratio of <0.7 post-bronchodilator on spirometry. Patients are frequently labeled as COPD based on clinical presentation and admitted to the hospital with this diagnosis even though spirometry is either not available or has never been performed. The aim of this study was to evaluate the accuracy of COPD diagnosis based on post-bronchodilator spirometry, following hospital admission for COPD exacerbation. Methods: This is a retrospective study with a cross-sectional analysis of a subgroup of patients. Demographic and clinical data and pre-admission spirometry were collected from electronic records of patients hospitalized with a primary diagnosis of COPD. Patients without available spirometry were contacted for a pulmonary consultation and spirometry. Three groups were compared: patients with a confirmed COPD diagnosis (FEV1/FVC < 0.7), without COPD (FEV1/FVC > 0.7), and those who have never performed spirometry. Results: A total of 1138 patients with a recorded diagnosis of COPD were identified of which 233 patients were included in the analysis. Only 44.6% of patients had confirmed COPD according to GOLD criteria. In total, 32.6% of the patients had never undergone spirometry but were treated as COPD, and 22.7% had performed spirometry without evidence of COPD. Recurrent admission due to COPD was a strong predictor of a confirmed COPD diagnosis. Conclusions: Among the patients admitted to the hospital with a COPD diagnosis, a high proportion were not confirmed by the current GOLD report or had never performed spirometry. Stricter implementation of the diagnostic criteria of COPD in admitted patients is necessary to improve diagnosis and the treatment outcomes in these patients.

OR11-2 RNA Sequencing Reveals Unique Transcriptomic Signatures of the Thyroid in a Murine Lung Cancer Model Treated with PD-1 and PD-L1 Antibodies

Immune checkpoint inhibitors (ICI) have revolutionized cancer therapy, however, are associated with immune-related adverse events (irAEs). Thyroid dysfunction is among the most common irAEs, yet its mechanism has not been fully elucidated. To further explore the molecular mechanism of ICI-induced thyroid dysfunction, we profiled changes in transcription induced by PD-1/PD-L1 antibody treatment in a non-small cell lung cancer murine model using RNA-seq. We used bioinformatic tools to compare transcriptional changes in our model to previously published transcription data sets of drug-induced thyroiditis. C57BL6/129SvJ mice harboring LKR-M (Lung cancer K-ras metastatic tumor) flank tumors were treated with PD-1 antibody, PD-L1 antibody, or vehicle every 3 days over a period of 7 days when mice were sacrificed, and thyroid glands were removed. The tumor volume increased in the control mice (1.38 ± 0.19) and decreased in the anti PD-1 treated (0.64 ± 0.15; P=0.0001) and PD-L1 treated mice (0.74 ± 0.11; P=0.004). RNA-seq was performed in the LKR-M tumor-bearing control mice and in the anti PD-1/PD-L1 treated mice (n=4 per group). A total of 952 differentially expressed genes (DEGs), including 265 upregulated and 688 downregulated, were identified with anti PD-1 treatment (fold-change ≥1.8, FDR ≤0.05). Only 35 genes were differentially expressed with anti PD-L1 treatment, and we therefore chose to focus on the anti PD-1 treated group alone. Using Ingenuity Pathway Analysis (IPA), we determined that of the DEGs in the PD-1 treatment group, 362 were associated with functions of cell death and survival, with a predicated activation of pathways for apoptosis and necrosis (Z=2.89 and 3.21, respectively) and negative activation of pathways for cell viability and cell survival (Z=-6.22 and -6.45, respectively). When compared to previously published datasets of interleukin-1β and interferon gamma-treated human thyroid cells, the apoptosis pathways were similarly activated. To our knowledge this is the first study to evaluate transcriptomic changes in thyroid tissue following ICI therapy. Our data suggest that there are unique changes in gene expression in the thyroid associated with anti PD-1 therapy. ICI-induced thyroid dysfunction may be mediated by increased tissue apoptosis resulting in destructive thyroiditis.

Presentation: Sunday, June 12, 2022 11:15 a.m. - 11:30 a.m.

Targeted nanoparticles modify neutrophil function in vivo

Neutrophils play critical roles in a broad spectrum of clinical conditions. Accordingly, manipulation of neutrophil function may provide a powerful immunotherapeutic approach. However, due to neutrophils characteristic short half-life and their large population number, this possibility was considered impractical. Here we describe the identification of peptides which specifically bind either murine or human neutrophils. Although the murine and human neutrophil-specific peptides are not cross-reactive, we identified CD177 as the neutrophil-expressed binding partner in both species. Decorating nanoparticles with a neutrophil-specific peptide confers neutrophil specificity and these neutrophil-specific nanoparticles accumulate in sites of inflammation. Significantly, we demonstrate that encapsulating neutrophil modifying small molecules within these nanoparticles yields specific modulation of neutrophil function (ROS production, degranulation, polarization), intracellular signaling and longevity both in vitro and in vivo. Collectively, our findings demonstrate that neutrophil specific targeting may serve as a novel mode of immunotherapy in disease.

Neutrophil phenotypes and functions in cancer: A consensus statement

Neutrophils are the first responders to infection and inflammation and are thus a critical component of innate immune defense. Understanding the behavior of neutrophils as they act within various inflammatory contexts has provided insights into their role in sterile and infectious diseases; however, the field of neutrophils in cancer is comparatively young. Here, we summarize key concepts and current knowledge gaps related to the diverse roles of neutrophils throughout cancer progression. We discuss sources of neutrophil heterogeneity in cancer and provide recommendations on nomenclature for neutrophil states that are distinct in maturation and activation. We address discrepancies in the literature that highlight a need for technical standards that ought to be considered between laboratories. Finally, we review emerging questions in neutrophil biology and innate immunity in cancer. Overall, we emphasize that neutrophils are a more diverse population than previously appreciated and that their role in cancer may present novel unexplored opportunities to treat cancer.

The Bilateral Interplay between Cancer Immunotherapies and Neutrophils’ Phenotypes and Sub-Populations

Immunotherapy has become a leading modality for the treatment of cancer, but despite its increasing success, a substantial number of patients do not benefit from it. Cancer-related neutrophils have become, in recent years, a subject of growing interest. Distinct sub-populations of neutrophils have been identified at advanced stages of cancer. In this study, we aimed to evaluate the role of neutrophils in mediating the efficacy of immune checkpoint inhibitors (ICI) treatments (α-PD-1/PD-L1), by assessing lung tumor models in mice. We found that G-CSF overexpression by the tumor significantly potentiates the efficacy of ICI, whereas neutrophils’ depletion abrogated their responses. Adoptive transfer of circulating normal-density neutrophils (NDN) resulted in significantly reduced tumor growth, whereas low-density neutrophils (LDN) had no effect. We next investigated the effect of ICI on neutrophils’ functions. Following α-PD-L1 treatment, NDN displayed increased ROS production and increased cytotoxicity toward tumor cells but decreased degranulation. Together, our results suggest that neutrophils are important mediators of the ICI treatments and that mainly NDN are modulated following α-PD-L1 treatment. This research provides a better understanding of the function of neutrophils following immunotherapies and their impact on the efficacy of immunotherapy, supporting better understanding and future improvement of currently available treatments.

Tumor-Derived Factors Differentially Affect the Recruitment and Plasticity of Neutrophils

Neutrophils play a key role in cancer biology. In contrast to circulating normal-density neutrophils (NDN), the amount of low-density neutrophils (LDN) significantly increases with tumor progression. The correlation between these neutrophil subpopulations and intratumoral neutrophils (TANs) is still under debate. Using 4T1 (breast) and AB12 (mesothelioma) tumor models, we aimed to elucidate the source of TANs and to assess the mechanisms driving neutrophils' plasticity in cancer. Both NDN and LDN were found to migrate in response to CXCL1 and CXCL2 exposure, and co-infiltrate the tumor site ex vivo and in vivo, although LDN migration into the tumor was higher than NDN. Tumor-derived factors and chemokines, particularly CXCL1, were found to drive neutrophil phenotypical plasticity, inducing NDN to transition towards a low-density state (LD-NDN). LD-NDN appeared to differ from NDN by displaying a phenotypical profile similar to LDN in terms of nuclear morphology, surface receptor markers, decreased phagocytic abilities, and increased ROS production. Interestingly, all three subpopulations displayed comparable cytotoxic abilities towards tumor cells. Our data suggest that TANs originate from both LDN and NDN, and that a portion of LDN derives from NDN undergoing phenotypical changes. NDN plasticity resulted in a change in surface marker expression and functional activity, gaining characteristics of LDN.

Tumor-Associated Neutrophils Drive B-cell Recruitment and Their Differentiation to Plasma Cells

A major mechanism through which neutrophils have been suggested to modulate tumor progression involves the interaction and subsequent modulation of other infiltrating immune cells. B cells have been found to infiltrate various cancer types and play a role in tumor immunity, offering new immunotherapy opportunities. Nevertheless, the specific impact of tumor-associated neutrophils (TAN) on B cells has largely been overlooked. In the current study, we aimed to characterize the role of TANs in the recruitment and modulation of B cells in the tumor microenvironment (TME). We showed that TANs actively participate in the recruitment of B cells to the TME and identified TNFα as the major cytokine mediating B-cell chemotaxis by TANs. The recruitment of CD45⁺B220⁺CD138^- splenic B cells by TANs in vitro resulted in B-cell phenotypic modulation, with 68.6% ± 2.1% of the total migrated B cells displaying a CD45^-B220⁺CD138⁺ phenotype, which is typical for plasma cells. This phenotype mirrored the large proportion (54.0% ± 6.1%) of CD45^-B220⁺CD138⁺ intratumoral B cells (i.e., plasma cells) in Lewis lung carcinoma tumors. We next confirmed that the differentiation of CD45⁺B220⁺CD138^- B cells to functionally active CD45^-B220⁺CD138⁺ plasma cells required contact with TANs, was independent of T cells, and resulted in IgG production. We further identified membranal B-cell activating factor (BAFF) on TANs as a potential contact mechanism mediating B-cell differentiation, as blocking BAFF-receptor (BAFF-R) significantly reduced IgG production by 20%. Our study, therefore, demonstrates that TANs drive the recruitment and modulation of B cells into plasma cells in the TME, hence opening new avenues in the targeting of the immune system in cancer.

Blocking Migration of Polymorphonuclear Myeloid-Derived Suppressor Cells Inhibits Mouse Melanoma Progression

Simple Summary

Myeloid-derived suppressor cells (MDSC) represent a heterogeneous myeloid cell population that is expanded in tumor bearing hosts and substantially contributes to immunosuppression, representing thereby a valuable therapeutic target. Our study analyzes polymorphonuclear (PMN) and monocytic (M) MDSC subsets regarding their immunosuppressive capacity and recruitment mechanisms in murine melanoma. The immunosuppressive activity of both subsets was comparable. We identified the C-X-C Motif Chemokine Receptor (CXCR) 2/chemokine C-X-C motif ligand (CXCL) 1 axis as an important mediator of PMN-MDSC recruitment. Inhibition of CXCR2 resulted in a decreased infiltration of tumors with PMN-MDSC and increased survival of melanoma bearing mice. Furthermore, adjuvant treatment of mice with resected tumors reduced the infiltration of pre-metastatic sites with PMN-MDSC and the occurrence of distant metastasis. The decrease in PMN-MDSC infiltration was accompanied by an increase in natural killer (NK) cell frequency, suggesting an important role of PMN-MDSC in suppressing the NK cell-mediated anti-tumor response.

Abstract

Background: Despite recent improvement in the treatment of malignant melanoma by immune-checkpoint inhibitors, the disease can progress due to an immunosuppressive tumor microenvironment (TME) mainly represented by myeloid-derived suppressor cells (MDSC). However, the relative contribution of the polymorphonuclear (PMN) and monocytic (M) MDSC subsets to melanoma progression is not clear. Here, we compared both subsets regarding their immunosuppressive capacity and recruitment mechanisms. Furthermore, we inhibited PMN-MDSC migration in vivo to determine its effect on tumor progression. Methods: Using the RET transgenic melanoma mouse model, we investigated the immunosuppressive function of MDSC subsets and chemokine receptor expression on these cells. The effect of CXCR2 inhibition on PMN-MDSC migration and tumor progression was studied in RET transgenic mice and in C57BL/6 mice after surgical resection of primary melanomas. Results: Immunosuppressive capacity of intratumoral M- and PMN-MDSC was comparable in melanoma bearing mice. Anti-CXCR2 therapy prolonged survival of these mice and decreased the occurrence of distant metastasis. Furthermore, this therapy reduced the infiltration of melanoma lesions and pre-metastatic sites with PMN-MDSC that was associated with the accumulation of natural killer (NK) cells. Conclusions: We provide evidence for the tumor⁻promoting properties of PMN-MDSC as well as for the anti-tumor effects upon their targeting in melanoma bearing mice.

Prophylactic use of tranexamic acid for prevention of bleeding during transbronchial lung biopsies - A randomized, double-blind, placebo-controlled trial

BACKGROUND

Although massive bleeding following transbronchial lung biopsies (TBLB) is rare, even minor hemorrhage may prolong the procedure and result in inadequate sampling. Tranexamic acid (TXA) is an antifibrinolytic agent, which reduces bleeding in numerous scenarios, however, its prophylactic use in mitigating post-TBLB bleeding has not been investigated. We conducted a prospective, randomized, double-blind, placebo-controlled trial to determine whether topical infusion of TXA prior to TBLB would reduce bleeding, shorten procedure duration and increase the number of biopsies obtained.

METHODS

We blindly randomized patients undergoing TBLB to receive topical TXA or placebo in the lobar bronchus prior to biopsies. Vital signs, procedure length, fluid balance (as a measure of the amount of bleeding), operator's assessment of bleeding, and number of biopsies obtained were measured. Data was analyzed using the two-tailed Student's T-Test, Chi-square or Mann-Whitney tests as appropriate.

RESULTS

Fifty patients were randomized, 26 to the TXA arm. The bleeding in the TXA group was significantly lower (P = 0.0037), with more specimens being obtained (placebo 7 (6, 9) (median and interquartile range) vs. TXA 9 (8, 10), P = 0.023) and no difference in procedure length (placebo 30 min (29.3, 34.3) vs. TXA 30 (24.8, 36), P = 0.90). There were no clinically significant adverse events in any of the groups up to one month of follow up.

CONCLUSION

Endobronchial installation of TXA prior to obtaining TBLB results in less bleeding and allows more biopsies to be obtained with no additional adverse events. The prophylactic use of TXA during TBLB may be considered as standard.

Circulating neutrophil subsets in advanced lung cancer patients exhibit unique immune signature and relate to prognosis

The accumulation of circulating low-density neutrophils (LDN) has been described in cancer patients and associated with tumor-supportive properties, as opposed to the high-density neutrophils (HDN). Here we aimed to evaluate the clinical significance of circulating LDN in lung cancer patients, and further assessed its diagnostic vs prognostic value. Using mass cytometry (CyTOF), we identified major subpopulations within the circulating LDN/HDN subsets and determined phenotypic modulations of these subsets along tumor progression. LDN were highly enriched in the low-density (LD) fraction of advanced lung cancer patients (median 7.0%; range 0.2%-80%, n = 64), but not in early stage patients (0.7%; 0.05%-6%; n = 35), healthy individuals (0.8%; 0%-3.5%; n = 15), or stable chronic obstructive pulmonary disease (COPD) patients (1.2%; 0.3%-7.4%, n = 13). Elevated LDN (>10%) remarkably related with poorer prognosis in late stage patients. We identified three main neutrophil subsets which proportions are markedly modified in cancer patients, with CD66b⁺ /CD10^low /CXCR4⁺ /PDL1^inter subset almost exclusively found in advanced lung cancer patients. We found substantial variability in subsets between patients, and demonstrated that HDN and LDN retain a degree of inherent spontaneous plasticity. Deep phenotypic characterization of cancer-related circulating neutrophils and their modulation along tumor progression is an important advancement in understanding the role of myeloid cells in lung cancer.

Neutrophil Diversity in Health and Disease

New evidence has challenged the outdated dogma that neutrophils are a homogeneous population of short-lived cells. Although neutrophil subpopulations with distinct functions have been reported under homeostatic and pathological conditions, a full understanding of neutrophil heterogeneity and plasticity is currently lacking. We review here current knowledge of neutrophil heterogeneity and diversity, highlighting the need for deep genomic, phenotypic, and functional profiling of the identified neutrophil subpopulations to determine whether these cells truly represent bona fide novel neutrophil subsets. We suggest that progress in understanding neutrophil heterogeneity will allow the identification of clinically relevant neutrophil subpopulations that may be used in the diagnosis of specific diseases and lead to the development of new therapeutic approaches.

Interactions among myeloid regulatory cells in cancer

Mounting evidence has accumulated on the critical role of the different myeloid cells in the regulation of the cancerous process, and in particular in the modulation of the immune reaction to cancer. Myeloid cells are a major component of host cells infiltrating tumors, interacting with each other, with tumor cells and other stromal cells, and demonstrating a prominent plasticity. We describe here various myeloid regulatory cells (MRCs) in mice and human as well as their relevant therapeutic targets. We first address the role of the monocytes and macrophages that can contribute to angiogenesis, immunosuppression and metastatic dissemination. Next, we discuss the differential role of neutrophil subsets in tumor development, enhancing the dual and sometimes contradicting role of these cells. A heterogeneous population of immature myeloid cells, MDSCs, was shown to be generated and accumulated during tumor progression as well as to be an important player in cancer-related immune suppression. Lastly, we discuss the role of myeloid DCs, which can either contribute to effective anti-tumor responses or play a more regulatory role. We believe that MRCs play a critical role in cancer-related immune regulation and suggest that future anti-cancer therapies will focus on these abundant cells.

Microenvironmental Cues Determine Tumor Cell Susceptibility to Neutrophil Cytotoxicity

We have recently shown that neutrophil antitumor cytotoxicity is Ca²⁺ dependent and is mediated by TRPM2, an H₂O₂-dependent Ca²⁺ channel. However, neutrophil antitumor activity is dependent on context and is manifested in the premetastatic niche, but not at the primary site. We therefore hypothesized that expression of TRPM2 and the consequent susceptibility to neutrophil cytotoxicity may be associated with the epithelial/mesenchymal cellular state. We found that TRPM2 expression was upregulated during epithelial-to-mesenchymal transition (EMT), and mesenchymal cells were more susceptible to neutrophil cytotoxicity. Conversely, cells undergoing mesenchymal-to-epithelial transition (MET) expressed reduced levels of TRPM2, rendering them resistant to neutrophil cytotoxicity. Cells expressing reduced levels of TRPM2 were protected from neutrophil cytotoxicity and seeded more efficiently in the premetastatic lung. These data identify TRPM2 as the link between environmental cues at the primary tumor site, tumor cell susceptibility to neutrophil cytotoxicity, and disease progression. Furthermore, these data identify EMT as a process enhancing tumor-cell immune susceptibility and, by contrast, MET as a novel mode of immune evasion.Significance: EMT is required for metastatic spread and concomitantly enhances tumor cell susceptibility to neutrophil cytotoxicity. Cancer Res; 78(17); 5050-9. ©2018 AACR.

Cancer-related circulating and tumor-associated neutrophils - subtypes, sources and function

In recent years, the role of neutrophils in cancer biology has been a matter of increasing interest. Many patients with advanced cancer show high levels of neutrophilia, tumor neutrophils are connected to dismal prognosis, and the neutrophil-to-lymphocyte ratio has been introduced as a significant prognostic factor for survival in many types of cancer. Neutrophils constitute an important portion of the infiltrating immune cells in the tumor microenvironment, but controversy has long surrounded the function of these cells in the context of cancer. Multiple evidences have shown that neutrophils recruited to the tumor can acquire either protumor or antitumor function. These findings have led to the identification of multiple and heterogeneous neutrophil subsets in the tumor and circulation. In addition, tumor-associated neutrophils (TANs) were shown to demonstrate functional plasticity, driven by multiple factors present in the tumor microenvironment. In this review, we examine the current knowledge on cancer-related circulating neutrophils, their source and the function of the different subtypes, both mature and immature. We then discuss the pro vs antitumor nature of TANs in cancer, their functional plasticity and the mechanisms that regulate neutrophil recruitment and polarization. Although the vast majority of the knowledge on neutrophils in cancer comes from murine studies, recent work has been done on human cancer-related neutrophils. In the final paragraphs, we expand on the current knowledge regarding the role of neutrophils in human cancer and examine the question whether cancer-related neutrophils (circulating or intratumoral) could be a new possible target for cancer immunotherapy.

Inhaled therapies in patients with moderate COPD in clinical practice: current thinking

COPD is a complex, heterogeneous condition. Even in the early clinical stages, COPD carries a significant burden, with breathlessness frequently leading to a reduction in exercise capacity and changes that correlate with long-term patient outcomes and mortality. Implementation of an effective management strategy is required to reduce symptoms, preserve lung function, quality of life, and exercise capacity, and prevent exacerbations. However, current clinical practice frequently differs from published guidelines on the management of COPD. This review focuses on the current scientific evidence and expert opinion on the management of moderate COPD: the symptoms arising from moderate airflow obstruction and the burden these symptoms impose, how physical activity can improve disease outcomes, the benefits of dual bronchodilation in COPD, and the limited evidence for the benefits of inhaled corticosteroids in this disease. We emphasize the importance of maximizing bronchodilation in COPD with inhaled dual-bronchodilator treatment, enhancing patient-related outcomes, and enabling the withdrawal of inhaled corticosteroids in COPD in well-defined patient groups.

Tumor-associated neutrophils induce apoptosis of non-activated CD8 T-cells in a TNFα and NO-dependent mechanism, promoting a tumor-supportive environment

The role of neutrophils in tumor progression has become in recent years a subject of growing interest. Tumor-associated neutrophils (TANs), which constitute an important portion of the tumor microenvironment, promote immunosuppression in advanced tumors by modulating the proliferation, activation and recruitment of a variety of immune cell types. Studies which investigated the consequences of manipulating TAN polarization suggest that the impact of these neutrophils on tumor progression is considerably mediated by and dependent on the presence of CD8 T-cells. It has been previously shown that granulocytic myeloid regulatory cells, i.e. TANs and granulocytic myeloid-derived suppressor cells (G-MDSCs) are capable of suppressing CD8 T-cell proliferation and affect their activation. In the current study, we find that in addition, TANs isolated from different models of murine cancer promote immunosuppression by strongly inducing CD8 T-cell apoptosis. We demonstrate that the TNFα pathway in TANs is critical for the induction of apoptosis, and that the mechanism through which apoptosis is induced involves the production of NO, but not ROS. In the absence of pre-activation, TANs are capable of activating CD8 T-cells, but specifically induce the apoptosis of non-activated CD8⁺CD69^- cells. Despite this contradictive effect on T-cell function, we show in vivo that TANs suppress the anti-tumor effect of CD8 T-cells and abolish their ability to delay tumor growth. Our results add another important layer on the understanding of the possible mechanisms by which TANs regulate the anti-tumor immune response mediated by CD8 T-cells, therefore promoting a tumor-supportive environment.

Control of immune cell entry through the tumour vasculature: a missing link in optimising melanoma immunotherapy?

Metastatic melanoma remains a fatal disease to many worldwide, even after the breakthrough introduction of targeted therapies such as BRAF inhibitors and immune checkpoint blockade therapies such as CTLA-4 and PD-1 inhibitors. With advances in our understanding of this disease, as well as the increasing data gathered from patient studies, the significance of the host immune response to cancer progression and response to treatment is becoming clear. More specifically, the presence of intratumoral CD8⁺ cytotoxic T-cells correlates with better prognosis whereas the accumulation of monocytes/macrophages and neutrophils in the tumour is often associated with worse prognosis. Access and infiltration of circulating leukocytes into the tumour is governed by adhesion molecules and chemokines expressed by the endothelial cells of the vasculature. This review focuses on the adhesion molecules and chemokines which control the homing of CD8⁺ cytotoxic T-cells, monocytes and neutrophils to peripheral tissues, including tumours. We discuss the role of these leukocyte subsets in regulating melanoma growth, and detail the mechanisms used by tumours to selectively recruit or exclude these leukocytes for their own advantage. In doing so, we bring to light an underappreciated component of tumour biology which should be considered in combination with current treatments to selectively alter the leukocyte composition of tumours and ultimately enhance treatment outcome.

Neutrophils as active regulators of the immune system in the tumor microenvironment

In recent years, the role of immune cells in tumor progression has been a matter of increasing interest. Neutrophils constitute an important portion of the immune cells infiltrating the tumor microenvironment. Traditionally viewed as the first line of defense against infections, it is now well accepted that neutrophils also have an important role in multiple aspects of cancer biology. Multiple and heterogeneous neutrophil subsets have been identified in tumors and in circulation. Evidence from many studies now supports the notion that tumor-associated neutrophils (TANs) show functional plasticity driven by multiple factors present in the tumor microenvironment. In this review, we first concisely discuss the pro-tumor vs. anti-tumor nature of neutrophils in cancer, their functional plasticity, and the mechanisms that regulate neutrophil polarization. We then expand on the various crosstalks and mutual effects between TANs and other tumor-infiltrating immune cell types, emphasizing the active role of neutrophils as regulators of the immune system, promoting or inhibiting the establishment of a permissive tumor microenvironment. Finally, the possible modulation of cancer-related neutrophils by therapies directed toward immune checkpoints is discussed briefly.

The association between osteopontin gene polymorphisms, osteopontin expression and sarcoidosis

Background

Sarcoidosis is a systemic inflammatory disease of unknown etiology. Osteopontin (SPP1, OPN) is an extra cellular matrix glycoprotein and cytokine with a known role in granuloma formation and in autoimmune and inflammatory diseases.

Objective

To determine whether plasma OPN levels are elevated in patients with sarcoidosis and compare the frequency of four single nucleotide polymorphism (SNPs) variants in the OPN gene in sarcoidosis patients compared to healthy controls.

Methods

Demographic and clinical information, radiological studies and pulmonary function tests were evaluated in 113 patients with sarcoidosis and in 79 healthy controls. Blood samples were analyzed for SNPs of the OPN gene and for plasma OPN and CRP levels. Association between clinical features of disease and OPN levels as well as SNP frequencies was determined.

Results

Plasma OPN levels were higher in sarcoidosis patients than in healthy subjects, (median: 217 vs 122ng/ml, p<0.001). Area under the curve for receiver operator curves (ROC) was 0.798 (0.686–0.909 95% CI.) No differences were observed between sarcoidosis patients and controls in the frequency of any of the SNPs evaluated. Presence of lung parenchymal involvement was associated with SNP distribution at rs1126772 (p = 0.02). We found no correlation between SNPs distribution and plasma OPN levels.

Conclusions

Osteopontin protein levels are elevated in sarcoidosis. We found no evidence for an association between SNPs on the osteopontin gene and plasma OPN levels or the presence of sarcoidosis, however, an association between genotype and several phenotypic clinical parameters of disease was observed.

Organizing pneumonia following treatment with pembrolizumab for metastatic malignant melanoma - A case report

Pembrolizumab is a monoclonal antibody against the programmed cell death 1 (PD-1) receptor, and is widely used for the treatment of various malignancies, most commonly malignant melanoma. Here we report the first documented and pathology proven case of Organizing Pneumonia complicating treatment with Pembrolizumab. This was a man who presented with a dense lung consolidation four months following treatment with Pembrolizumab. A thorough microbiological workup was negative and his findings did not improve with broad spectrum anti-microbial treatment. Transbronchial biopsy revealed organizing pneumonia, and treatment with cortico-steroids resulted in complete resolution of clinical and radiological disease.

This report highlights the importance of recognizing immune related adverse events, specifically pulmonary inflammation, in patients receiving treatment with novel immune-modulating agents.

Tumor-associated neutrophils display a distinct N1 profile following TGFβ modulation: A transcriptomics analysis of pro- vs. antitumor TANs

It is becoming increasingly clear that tumor-associated neutrophils (TANs) play an important role in cancer biology, through direct impact on tumor growth and by recruitment of other cells types into the tumor. The function of neutrophils in cancer has been the subject of seemingly contradicting reports, pointing toward a dual role played by TANs in tumor progression. The existence of multiple neutrophil subsets, as well as phenotypic modulation of the neutrophils by various factors in the tumor microenvironment, has been shown. TGFβ plays a significant role in the determination of neutrophils' phenotype, by shifting the balance from an antitumor (N1) toward a more permissive (N2) phenotype. The full range of mechanisms responsible for the pro- vs. antitumor effects of TANs has not yet been elucidated. Therefore, the ability to identify the different neutrophil subpopulations in the tumor is critical in order to understand TANs evolution and contribution throughout tumor progression. Using a transcriptomic approach, we identified alternations in gene expression profile following TGFβ inhibition. We show that N1 and N2 TANs represent distinct subpopulations with different transcriptional signatures and both differ from naive bone marrow neutrophils. The analysis highlights a clear difference in pathways involved in neutrophil function such as cytoskeletal organization and antigen presentation, as well as alterations in chemokine profile, eventually affecting their effect on tumor cells and tumor growth. These data highlights several potential new pathways and mechanisms by which neutrophils can influence both the tumor cells and the adaptive immune system.

Plasticity beyond cancer cells and the "immunosuppressive switch"

Tumor initiation, growth, and metastatic progression are complex processes that, in order to be successful, require extraordinary cellular plasticity. Accordingly, tumor cell plasticity and how it affects disease progression have been studied extensively. However, as our understanding of the tumor microenvironment deepens, we are confronted with the notion that functional plasticity in the context of cancer is not limited to tumor cells alone but is also commonly seen in normal stromal cells of the microenvironment, and specifically in immune cells. Here, we review the functional plasticity these cells exhibit in the context of cancer, highlighting the role of circulating and tumor-associated neutrophils. We further discuss how this plasticity supports or limits tumor progression, inducing an "immunosuppressive switch" to promote further tumor growth and development.

Isolation and Characterization of Neutrophils with Anti-Tumor Properties

Neutrophils, the most abundant of all white blood cells in the human circulation, play an important role in the host defense against invading microorganisms. In addition, neutrophils play a central role in the immune surveillance of tumor cells. They have the ability to recognize tumor cells and induce tumor cell death either through a cell contact-dependent mechanism involving hydrogen peroxide or through antibody-dependent cell-mediated cytotoxicity (ADCC). Neutrophils with anti-tumor activity can be isolated from peripheral blood of cancer patients and of tumor-bearing mice. These neutrophils are termed tumor-entrained neutrophils (TEN) to distinguish them from neutrophils of healthy subjects or naïve mice that show no significant tumor cytotoxic activity. Compared with other white blood cells, neutrophils show different buoyancy making it feasible to obtain a > 98% pure neutrophil population when subjected to a density gradient. However, in addition to the normal high-density neutrophil population (HDN), in cancer patients, in tumor-bearing mice, as well as under chronic inflammatory conditions, distinct low-density neutrophil populations (LDN) appear in the circulation. LDN co-purify with the mononuclear fraction and can be separated from mononuclear cells using either positive or negative selection strategies. Once the purity of the isolated neutrophils is determined by flow cytometry, they can be used for in vitro and in vivo functional assays. We describe techniques for monitoring the anti-tumor activity of neutrophils, their ability to migrate and to produce reactive oxygen species, as well as monitoring their phagocytic capacity ex vivo. We further describe techniques to label the neutrophils for in vivo tracking, and to determine their anti-metastatic capacity in vivo. All these techniques are essential for understanding how to obtain and characterize neutrophils with anti-tumor function.

Surgical cytoreduction restores the antitumor efficacy of a Listeria monocytogenes vaccine in malignant pleural mesothelioma

Recent studies suggest that immunotherapy may offer a promising treatment strategy for early-stage malignant pleural mesothelioma (MPM), but advanced tumor burden may limit the efficacy of immunotherapy. Therefore, we hypothesized that surgical cytoreduction could restore the efficacy of vaccine-based immunotherapy for MPM. We developed a murine model of MPM through transduction of a mesothelioma cell line with mesothelin. We used this model to evaluate the efficacy of a Listeria monocytogenes vaccine expressing mesothelin. Tumor growth was significantly inhibited at four weeks in animals vaccinated two weeks prior to tumor cell inoculation as compared to those given an empty vector control (1371 ± 420 mm(3) versus 405 ± 139 mm(3); p < 0.01). Mice vaccinated one week prior to tumor challenge also displayed significant reduction in tumor volume (1227 ± 406 mm(3) versus 309 ± 173 mm(3); p < 0.01). The vaccine had no effect when administered concurrently with tumor challenge, or after tumors were established. Flow cytometry showed reduced mesothelin expression in large tumors, as well as tumor-associated immunosuppression due to increased myeloid derived suppressor cells (MDSCs). These factors may have limited vaccine efficacy for advanced disease. Surgical cytoreduction of established tumors restored the antitumor potency of the therapeutic vaccine, with significantly reduced tumor burden at post-operative day 18 (397 ± 103 mm(3) versus 1047 ± 258 mm(3); p < 0.01). We found that surgery reduced MDSCs to levels comparable to those in tumor-naïve mice. This study demonstrates that cytoreduction surgery restores the efficacy of cancer vaccines for MPM by reducing tumor-related immunosuppression that impairs immunotherapy.

Splenectomy inhibits non-small cell lung cancer growth by modulating anti-tumor adaptive and innate immune response

It has been shown that inhibitors of the immune system reside in the spleen and inhibit the endogenous antitumor effects of the immune system. We hypothesized that splenectomy would inhibit the growth of relatively large non-small lung cancer (NSCLC) tumors by modulating the systemic inhibition of the immune system, and in particular Myeloid Derived Suppressor Cells (MDSC). The effect of splenectomy was evaluated in several murine lung cancer models. We found that splenectomy reduces tumor growth and the development of lung metastases, but only in advanced tumors. In immune-deficient NOD-SCID mice the effect of splenectomy on tumor growth and metastatic spread disappeared. Splenectomy significantly reduced the presence of MDSC, and especially monocytic-MDSC in the circulation and inside the tumor. Specific reduction of the CCR2+ subset of monocytic MDSC was demonstrated, and the importance of the CCL2-CCR2 axis was further shown by a marked reduction in CCL2 following splenectomy. These changes were followed by changes in the macrophages contents of the tumors to become more antitumorigenic, and by increased activation of CD8⁺ Cytotoxic T-cells (CTL). By MDSC depletion, and adoptive transfer of MDSCs, we demonstrated that the effect of splenectomy on tumor growth was substantially mediated by MDSC cells. We conclude that the spleen is an important contributor to tumor growth and metastases, and that splenectomy can blunt this effect by depletion of MDSC, changing the amount and characteristics of myeloid cells and enhancing activation of CTL.

Phenotypic diversity and plasticity in circulating neutrophil subpopulations in cancer

Controversy surrounds neutrophil function in cancer because neutrophils were shown to provide both pro- and antitumor functions. We identified a heterogeneous subset of low-density neutrophils (LDNs) that appear transiently in self-resolving inflammation but accumulate continuously with cancer progression. LDNs display impaired neutrophil function and immunosuppressive properties, characteristics that are in stark contrast to those of mature, high-density neutrophils (HDNs). LDNs consist of both immature myeloid-derived suppressor cells (MDSCs) and mature cells that are derived from HDNs in a TGF-β-dependent mechanism. Our findings identify three distinct populations of circulating neutrophils and challenge the concept that mature neutrophils have limited plasticity. Furthermore, our findings provide a mechanistic explanation to mitigate the controversy surrounding neutrophil function in cancer.

Neutrophils recruit regulatory T-cells into tumors via secretion of CCL17--a new mechanism of impaired antitumor immunity

The mechanisms by which tumor-associated neutrophils (TANs) affect tumor growth are to a large extent unknown. Regulatory T-cells (T-regs) are functionally immune-suppressive subsets of T-cells. Depletion or inhibition of T-regs can enhance antitumor immunity. We demonstrated both by RT-PCR and by ELISA that murine TANs secrete significant amounts of the T-regs chemoattractant, CCL17, much more than circulating or splenic neutrophils, and at a level progressively increasing during tumor development. Migration assays, both in vitro and in vivo, showed recruitment of T-regs by TANs, which was inhibited with anti-CCL17 monoclonal antibodies. Systemic neutrophil depletion in tumor-bearing mice using anti-Ly6G monoclonal antibodies reduced the migration of T-regs into the tumors. We further showed, using flow cytometry, that CCL17 secretion by TANs is not limited to mouse models of cancer but is also relevant to human TANs. Our results suggest a new indirect mechanism by which TANs may inhibit antitumor immune activity, thus promoting tumor growth. We further describe, for the first time, a clear link between TANs and T-regs acting together to impair antitumor immunity.

Modifying tumor-associated macrophages: An important adjunct to immunotherapy

The therapeutic success of immunotherapy requires specific alterations of the tumor microenvironment and/or the inhibition of tumor-elicited immunosuppression. Tumor-associated macrophages (TAMs) are a major component of the tumor microenvironment. We have recently shown that modulating TAMs dramatically augments the efficacy of immunotherapy. TAM-activating agents should hence be considered as an addition to immunotherapy in future clinical trials.

Using macrophage activation to augment immunotherapy of established tumours

Background:

Successful immunotherapy will require alteration of the tumour microenvironment and/or decreased immune suppression. Tumour-associated macrophages (TAMs) are one major factor affecting tumour microenvironment. We hypothesised that altering TAM phenotype would augment the efficacy of immunotherapy.

Methods:

We and others have reported that 5,6-Dimethylxanthenone-4-acetic-acid (DMXAA, Vadimezan) has the ability to change TAM phenotypes, inducing a tumour microenvironment conducive to antitumour immune responses. We therefore combined DMXAA with active immunotherapies, and evaluated anti-tumour efficacy, immune cell phenotypes (flow cytometry), and tumour microenvironment (RT–PCR).

Results:

In several different murine models of immunotherapy for lung cancer, DMXAA-induced macrophage activation significantly augmented the therapeutic effects of immunotherapy. By increasing influx of neutrophils and anti-tumour (M1) macrophages to the tumour, DMXAA altered myeloid cell phenotypes, thus changing the intratumoural M2/non-M2 TAM immunoinhibitory ratio. It also altered the tumour microenvironment to be more pro-inflammatory. Modulating macrophages during immunotherapy resulted in increased numbers, activity, and antigen-specificity of intratumoural CD8⁺ T cells. Macrophage depletion reduced the effect of combining immunotherapy with macrophage activation, supporting the importance of TAMs in the combined effect.

Conclusion:

Modulating intratumoural macrophages dramatically augmented the effect of immunotherapy. Our observations suggest that addition of agents that activate TAMs to immunotherapy should be considered in future trials.

Randomized controlled crossover trial of a new oscillatory device as add-on therapy for COPD

A new oscillatory device administers predetermined pressure oscillation sequences into the chest cavity over inhaled/exhaled air streams at low positive pressure. We assessed device safety and effect on 6MW performance, pulmonary function, and health-related quality-of-life (HRQOL) in moderate-to-very severe COPD in a randomized, double-blind, controlled, crossover study. Outcomes with an oscillatory device (Pulsehaler(TM), Respinova Ltd, Herzliya, Israel) and a "muted" sham device (control) of identical appearance that delivered continuous positive air pressure were compared in two groups receiving opposite treatment sequences: 2-week oscillatory device/control, 2-week washout, 2-week control/oscillatory device, 2-week washout. The clinical trial was registered ( www.clinicaltrials.gov , NCT00821418) and approved by the Hadassah-Hebrew University Medical Center Institutional Review Board (08-608). All participants signed informed consent; 22 patients completed the study with no marked differences in COPD exacerbations or side effects. A total of 91% of patients treated with the oscillatory device had a clinically significant improvement (increase >40 m) in 6MW performance. The 6MW distance with the oscillatory device increased significantly after 1 week of treatment (51.6 ± 7.6 m, +13.5 ± 2.3%, p < 0.001), and more after 2 weeks (61.8 ± 9.0 m, 16.3 ± 2.7%, p < 0.001). This increase with the oscillatory device was significantly greater (p < 0.001) than the 15.4 ± 10.4 m increase (4.2 ± 2.6%, NS) with control. FVC and inspiratory capacity (IC) improved significantly (p = 0.03 for each) with the oscillatory device but not with control. HRQL improved markedly (≥1 point) for dyspnea and mastery with the oscillatory device (p = 0.02) but not control. Treatment with a new oscillatory device appears to be safe, and to improve 6MW performance, pulmonary function, and HRQL in COPD. Further evaluation is warranted.

A positive-margin resection model recreates the postsurgical tumor microenvironment and is a reliable model for adjuvant therapy evaluation

Up to 30% of cancer patients undergoing curative surgery develop local recurrences due to positive margins. Patients typically receive adjuvant chemotherapy, immunotherapy and/or radiation to prevent such relapses. Interestingly, evidence supporting these therapies is traditionally derived in animal models of primary tumors, thus failing to consider surgically induced tumor microenvironment changes that may influence adjuvant therapy efficacy. To address this consideration, we characterized a murine model of local cancer recurrence. This model was reproducible and generated a postoperative inflammatory tumor microenvironment that resembles those observed following human cancer surgery. To further validate this model, antagonists of two pro-inflammatory mediators, TGFβ and COX-2, were tested and found to be effective in decreasing the growth of recurrent tumors. We appreciated that preoperative TGFβ inhibition led to wound dehiscence, while postoperative initiation of COX-2 inhibition resulted in a loss of efficacy. In summary, although not an exact replica of all human cancer surgeries, our proposed local recurrence approach provides a biologically relevant and reliable model useful for preclinical evaluation of novel adjuvant therapies. The use of this model yields results that may be overlooked using traditional preclinical cancer models that fail to incorporate a surgical component.

Characterization of surgical models of postoperative tumor recurrence for preclinical adjuvant therapy assessment

PURPOSE

Nearly 30% of cancer patients undergoing curative surgery succumb to distant recurrent disease. Despite large implications and known differences between primary and recurrent tumors, preclinical adjuvant therapy evaluation frequently occurs only in primary tumors and not recurrent tumors. We hypothesized that well characterized and reproducible models of postoperative systemic recurrences should be used for preclinical evaluation of adjuvant approaches.

EXPERIMENTAL DESIGN

We examined traditional animal models of cancer surgery that generate systemic cancer recurrences. We also investigated models of systemic cancer recurrences that incorporate spontaneously metastatic cell lines and surgical resection. For each model, we critiqued feasibility, reproducibility and similarity to human recurrence biology. Using our novel model, we then tested the adjuvant use of a novel systemic inhibitor of TGF-β, 1D11.

RESULTS

Traditional surgical models are confounded by immunologic factors including concomitant immunity and perioperative immunosuppression. A superior preclinical model of postoperative systemic recurrences incorporates spontaneously metastatic cell lines and primary tumor excision. This approach is biologically relevant and readily feasible. Using this model, we discovered that "perioperative" TGF-β blockade has strong anti-tumor effects in the setting of advanced disease that would not be appreciated in primary tumor cell lines or other surgical models.

CONCLUSIONS

There are multiple immunologic effects that rendered previous models of postoperative cancer recurrences inadequate. Use of spontaneously metastatic cell lines followed by surgical resection eliminates these confounders, and best resembles the clinical scenario. This preclinical model provides more reliable preclinical information when evaluating new adjuvant therapies.

Sildenafil to facilitate weaning from inhaled nitric oxide and mechanical ventilation in a patient with severe secondary pulmonary hypertension and a patent foramen ovale

We describe the case of a woman who presented to the intensive care unit with acute respiratory failure that required mechanical ventilation. She had severe pulmonary hypertension secondary to interstitial lung disease, and her history included sarcoidosis and tuberculosis. She was dependent on inhaled nitric oxide (INO) to maintain safe arterial oxygen saturation and could not be weaned from mechanical ventilation. Echocardiography revealed a patent foramen ovale with substantial right-to-left shunt, which probably contributed to her hypoxemia. Sildenafil enabled weaning from INO and substantially reduced the flow through the patent foramen ovale. She was successfully extubated and discharged home. To our knowledge, this is the first report of weaning from INO and mechanical ventilation in a patient with both severe secondary pulmonary hypertension and a right-to-left shunt through a patent foramen ovale.

Pharmacologic activation of the innate immune system to prevent respiratory viral infections

Drugs that can rapidly inhibit respiratory infection from influenza or other respiratory pathogens are needed. One approach is to engage primary innate immune defenses against viral infection, such as activating the IFN pathway. In this study, we report that a small, cell-permeable compound called 5,6-di-methylxanthenone-4-acetic acid (DMXAA) can induce protection against vesicular stomatitis virus in vitro and H1N1 influenza A virus in vitro and in vivo through innate immune activation. Using the mouse C10 bronchial epithelial cell line and primary cultures of nasal epithelial cells, we demonstrate DMXAA activates the IFN regulatory factor-3 pathway leading to production of IFN-β and subsequent high-level induction of IFN-β-dependent proteins, such as myxovirus resistance 1 (Mx1) and 2',5'-oligoadenylate synthetase 1 (OAS1). Mice treated with DMXAA intranasally elevate mRNA/protein expression of Mx1 and OAS1 in the nasal mucosa, trachea, and lung. When challenged intranasally with a lethal dose of H1N1 influenza A virus, DMXAA reduced viral titers in the lungs and protected 80% of mice from death, even when given at 24 hours before infection. These data show that agents, like DMXAA, that can directly activate innate immune pathways, such as the IFN regulatory factor-3/IFN-β system, in respiratory epithelial cells can be used to protect from influenza pneumonia and potentially in other respiratory viral infections. Development of this approach in humans could be valuable for protecting health care professionals and "first responders" in the early stages of viral pandemics or bioterror attacks.

Chemotherapy delivered after viral immunogene therapy augments antitumor efficacy via multiple immune-mediated mechanisms

The most widely used approach to cancer immunotherapy is vaccines. Unfortunately, the need for multiple administrations of antigens often limits the use of one of the most effective vaccine approaches, immunogene therapy using viral vectors, because neutralizing antibodies are rapidly produced. We hypothesized that after viral immunogene therapy "primed" an initial strong antitumor immune response, subsequent "boosts" could be provided by sequential courses of chemotherapy. Three adenoviral (Ad)-based immunogene therapy regimens were administered to animals with large malignant mesothelioma and lung cancer tumors followed by three weekly administrations of a drug regimen commonly used to treat these tumors (Cisplatin/Gemcitabine). Immunogene therapy followed by chemotherapy resulted in markedly increased antitumor efficacy associated with increased numbers of antigen-specific, activated CD8(+) T-cells systemically and within the tumors. Possible mechanisms included: (i) decreases in immunosuppressive cells such as myeloid-derived suppressor cells (MDSC), T-regulatory cells (T-regs), and B-cells, (ii) stimulation of memory cells by intratumoral antigen release leading to efficient cross-priming, (iii) alteration of the tumor microenvironment with production of "danger signals" and immunostimulatory cytokines, and (iv) augmented trafficking of T-cells into the tumors. This approach is currently being tested in a clinical trial and could be applied to other trials of viral immunogene therapy.

Association between CD14 gene polymorphisms and disease phenotype in sarcoidosis

Although the etiology of sarcoidosis is unknown, genetic susceptibility has been demonstrated. Granuloma formation is a key feature in the pathophysiology of sarcoidosis and Crohn's Disease, raising the possibility that these diseases share common pathogenetic pathways. An association between sarcoidosis and the protein "CD14", a molecule that is part of the lipopolysaccharide (LPS) cell surface receptor complex, has been suggested. In the current study we evaluated the CD14 gene promoter 159 C-->T polymorphic site and soluble CD14 levels in a cohort of 74 sarcoidosis patients compared to 85 healthy controls. We further sought to identify correlations between clinical phenotype, specific genotypes and soluble CD14 levels. We found the TT genotype to be more prevalent in the sarcoidosis patient group than in controls (p=0.03). Serum levels of soluble CD14 were higher in the sarcoidosis patients (p=0.001). Within the patient cohort, CC homozygous patients presented at an older age with milder disease as assessed with the SAC score, longer time to diagnosis, and less impairment of pulmonary function tests. Our study suggests a role of CD14 in the pathogenesis of sarcoidosis, and a clinical phenotype-genotype association. Further mechanistic and epidemiologic studies are needed in order to establish the specific role of CD14 in the etiology, pathogenesis and clinical phenotype of sarcoidosis.

Abstract 5600: Macrophage activation and differentiation augment immunotherapy of established mouse lung tumors

Background: An immunosuppressive environment exists within tumors, induced by both cancer and immune cells, that inhibits the effect of cytotoxic T-lymphocytes. 5,6-Dimethylxanthenone-4 acetic acid (DMXAA) is a small flavanoid-like compound, previously shown to have a strong anti-tumor activity in murine models of cancer, and currently being tested in phase 3 trials in humans. We have shown that part of the effect induced by DMXAA as monotherapy is by activating tumor-associated macrophages. Given the ability of DMXAA alone to potentially induce a tumor microenvironment conducive to anti-tumor immune responses, we hypothesized that it would be a useful adjunct to immuno-gene therapy (immunoRx) in lung cancer.

Methods: We injected 18 mg/kg i.p. of DMXAA (Sigma) to tumor-bearing animals and evaluated its impact in three immunoRx models of non-small cell lung cancer (NSCLC): two aimed at an expressed HPV-E7 antigen, using an adenovirus (Ad. E7) or a Listeria (Listeria. E7) vector, and one using an adenovirus expressing Interferon-α. We compared the effect of immunoRx alone to combination treatment on tumor growth and assessed the mechanism of these changes by evaluating cytotoxic T cells, changes in macrophage phenotype, and tumor microenvironment. This was done by real time RT-PCR, flow cytometry, and staining (IHC).

Results: DMXAA markedly augmented the effect of immuno-gene therapy on large (&gt;200 mm3) established NSCLC flank tumors in the three models and two cell lines of NSCLC tested, resulting in cures in 30-40% of mice. We evaluated mechanisms in the Ad. E7 model. There was no significant difference in the subtypes of systemic (Splenic) immunocytes between the two groups. In contrast, DMXAA increased the intra-tumoral influx of neutrophils, macrophages, and CD8+ T-cells compared to the immunoRx group. Furthermore, adding DMXAA to immunoRx decreased the percentage of intra-tumoral M2 (CD206+) macrophages (out of all tumor cells) by 2-fold, while increasing the percentage of M1 macrophages by 2-fold. Although the percentage of CD8+ T-cells was increased in tumors with the combined treatment compared to immunoRx alone, as seen both by flow cytometry and IHC, there was no difference in their activation or E7 antigen-specificity. They were no changes in the influx of T-regulatory cells. Adding DMXAA to immunoRx up-regulated mRNA levels for a host of pro-inflammatory and chemo-attractant cytokines in tumors including TNF-α, IFN-γ, IL-10, CCL-5 and CCL2.

Conclusion: Macrophage activation and differentiation using DMXAA significantly augments the efficacy of immunoRx in established murine NSCLC tumor models by increasing the traffic of immunocytes into the tumors, activating and differentiating macrophages to a more anti-tumor phenotype and creating an immunostimulatory microenvironment. Our data suggests that combining agents like DMXAA with vaccines should be considered in future immunoRx trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5600.

Abstract 1912: Significant changes in chemokine genes in tumor-associated neutrophils (TANs) using a microarray approach

Background: The role of tumor-associated neutrophils (TAN) in tumor biology is unclear. We have recently published that resident TAN can acquire a protumor phenotype (similar to M2 macrophages), largely driven by TGF-beta to become N2 neutrophils. After TGF-beta blockade, neutrophils acquire an antitumor phenotype (N1 TAN (similar to M1 macrophages). In the current study, we further evaluated the characteristics of TAN using a gene microarray approach.

Methods: Balb/C mice (10-20 in each group) bearing large flank tumors of the mesothelioma line AB12, where treated with either control or SM16 (a TGF-β-R1 kinase inhibitor) chow. After one week of treatment, the tumors were harvested, and neutrophils were isolated using microbeads (CD11b) and flow cytometry (Ly6G), into two groups - control TAN (N2) and SM16 TAN (N1). Neutrophils were also isolated from bone marrow of naïve mice (BM) and from spleens harvested from tumor-bearing mice (i.e., the granulocytic fraction of myeloid derived suppressor cells (G-MDSC)). mRNA from each subgroup (4-6 samples) was isolated and subjected to microarray analysis on Illumina chips. Selected results were validated by RT-PCR and neutrophils from a second non Small Cell Lung Cancer tumor, LKR, were studied.

Results: After filtering, we found 16,322 informative probes. Hierarchical clustering and PCA analysis showed that the four groups were clearly separated. We found that many more genes were up-regulated than down-regulated in the N2 TAN from untreated mice compared to either BM or G-MDSC. Many of the highly up-regulated genes in TAN were chemokines, and genes encoding for inflammatory and immune responses, especially chemokines. This includes chemoattractants for T-cells (e.g. CXCL-9, CXCL10 and CXCL16), neutrophils (eg. CXCL1, CXCL2 and CCL3), B-cells (CXCL13) and macrophages (e.g. CCL2, CXCL-10 and CCL7). N1 (SM16-treated) and N2 TAN were more similar to each other than to the other groups, suggesting an intra-tumoral polarization between them. In N1 TAN, three different chemokines attracting macrophages were up-regulated - CCL2, CCL6 and CXCL10, and only one major chemokine, the T-regs chemoattractant CCL17, was downregulated. There was no significant difference in most other chemokines.

Conclusion: Our data shows the major differences between naïve neutrophils, G-MDSC and N1/N2 TAN. The patterns support the hypothesis that neutrophils enter the tumor, possibly as G-MDSC, and the change between N2 and N1 is intra-tumoral (and not by differential recruitment). Our data further suggests that TAN secrete many chemokines, initiating the recruitment of other inflammatory cells of the immune system. N1 neutrophils appear to up-regulate several macrophage attracting chemokines compared to N2 TAN.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1912.

Monocyte chemoattractant protein-1 blockade inhibits lung cancer tumor growth by altering macrophage phenotype and activating CD8+ cells

The role of chemokines in the pathogenesis of lung cancer has been increasingly appreciated. Monocyte chemoattractant protein-1 (MCP-1, also known as CCL2) is secreted from tumor cells and associated tumor stromal cells. The blockade of CCL2, as mediated by neutralizing antibodies, was shown to reduce tumorigenesis in several solid tumors, but the role of CCL2 in lung cancer remains controversial, with evidence of both protumorigenic and antitumorigenic effects. We evaluated the effects and mechanisms of CCL2 blockade in several animal models of non-small-cell lung cancer (NSCLC). Anti-murine-CCL2 monoclonal antibodies were administered in syngeneic flank and orthotopic models of NSCLC. CCL2 blockade significantly slowed the growth of primary tumors in all models studied, and inhibited lung metastases in a model of spontaneous lung metastases of NSCLC. In contrast to expectations, no significant effect of treatment was evident in the number of tumor-associated macrophages recruited into the tumor after CCL2 blockade. However, a change occurred in the polarization of tumor-associated macrophages to a more antitumor phenotype after CCL2 blockade. This was associated with the activation of cytotoxic CD8(+) T lymphocytes (CTLs). The antitumor effects of CCL2 blockade were completely lost in CB-17 severe combined immunodeficient mice or after CD8 T-cell depletion. Our data from NSCLC models show that CCL2 blockade can inhibit the tumor growth of primary and metastatic disease. The mechanisms of CCL2 blockade include an alteration of the tumor macrophage phenotype and the activation of CTLs. Our work supports further evaluation of CCL2 blockade in thoracic malignancies.

Evaluation of an attenuated vesicular stomatitis virus vector expressing interferon-beta for use in malignant pleural mesothelioma: heterogeneity in interferon responsiveness defines potential efficacy

Abstract Vesicular stomatitis virus (VSV) has shown promise as an oncolytic agent, although unmodified VSV can be neurotoxic. To avoid toxicity, a vector was created by introducing the interferon-beta (IFN-beta) gene (VSV.IFN-beta). We conducted this study to determine the ability of VSV.IFN-beta to lyse human cancer (mesothelioma) cells and to evaluate the potential of this recombinant virus for clinical translation. Four normal human mesothelial and 12 mesothelioma cell lines were tested for their susceptibility to VSV vectors in vitro. VSV.hIFN-beta did not cause cytotoxicity in any normal lines. Only 4 of 12 lines were effectively lysed by VSV.hIFN-beta. In the eight resistant lines, pretreatment with IFN-beta prevented lysis of cells by VSV.GFP, and VSV infection or addition of IFN-beta protein resulted in the upregulation of double-stranded RNA-dependent protein kinase (PKR), myxovirus resistance A (MxA), and 2',5'-oligo-adenylate-synthetase (2'5'-OAS) mRNA. In the susceptible lines, there was no protection by pretreatment with IFN-beta protein and no IFN- or VSV-induced changes in PKR, MxA, and 2'5'-OAS mRNA. This complete lack of IFN responsiveness could be explained by marked downregulation of interferon alpha receptors (IFNARs), p48, and PKR in both the mesothelioma cell lines and primary tumor biopsies screened. Presence of p48 in three tumor samples predicted responsiveness to IFN. Our data indicate that many mesothelioma tumors have partially intact IFN pathways that may affect the efficacy of oncolytic virotherapy. However, it may be feasible to prescreen individual susceptibility to VSV.IFN-beta by immunostaining for the presence of p48 protein.