Lung macrophage subpopulations have been identified based on size. We investigated characteristics of small and large macrophages in the alveolar spaces and lung interstitium of COPD patients and ...controls. Alveolar and interstitial cells were isolated from lung resection tissue from 88 patients. Macrophage subpopulation cell-surface expression of immunological markers and phagocytic ability were assessed by flow cytometry. Inflammatory related gene expression was measured. Alveolar and interstitial macrophages had subpopulations of small and large macrophages based on size and granularity. Alveolar macrophages had similar numbers of small and large cells; interstitial macrophages were mainly small. Small macrophages expressed significantly higher cell surface HLA-DR, CD14, CD38 and CD36 and lower CD206 compared to large macrophages. Large alveolar macrophages showed lower marker expression in COPD current compared to ex-smokers. Small interstitial macrophages had the highest pro-inflammatory gene expression levels, while large alveolar macrophages had the lowest. Small alveolar macrophages had the highest phagocytic ability. Small alveolar macrophage CD206 expression was lower in COPD patients compared to smokers. COPD lung macrophages include distinct subpopulations; Small interstitial and small alveolar macrophages with more pro-inflammatory and phagocytic function respectively, and large alveolar macrophages with low pro-inflammatory and phagocytic ability.
BackgroundThe ability to modulate immune-inhibitory pathways using checkpoint blockade antibodies such as αPD-1, αPD-L1, and αCTLA-4 represents a significant breakthrough in cancer therapy in recent ...years. This has driven interest in identifying small-molecule-immunotherapy combinations to increase the proportion of responses. Murine syngeneic models, which have a functional immune system, represent an essential tool for pre-clinical evaluation of new immunotherapies. However, immune response varies widely between models and the translational relevance of each model is not fully understood, making selection of an appropriate pre-clinical model for drug target validation challenging.MethodsUsing flow cytometry, O-link protein analysis, RT-PCR, and RNAseq we have characterized kinetic changes in immune-cell populations over the course of tumor development in commonly used syngeneic models.ResultsThis longitudinal profiling of syngeneic models enables pharmacodynamic time point selection within each model, dependent on the immune population of interest. Additionally, we have characterized the changes in immune populations in each of these models after treatment with the combination of α-PD-L1 and α-CTLA-4 antibodies, enabling benchmarking to known immune modulating treatments within each model.ConclusionsTaken together, this dataset will provide a framework for characterization and enable the selection of the optimal models for immunotherapy combinations and generate potential biomarkers for clinical evaluation in identifying responders and non-responders to immunotherapy combinations.
The PI3Kα signaling pathway is frequently hyper-activated in breast cancer (BrCa), as a result of mutations/amplifications in oncogenes (e.g.
), decreased function in tumor suppressors (e.g.
) or ...activating mutations in key components of the pathway. In particular, activating mutations of
(~45%) are frequently found in luminal A BrCa samples. Genomic studies have uncovered inactivating mutations in
(13-20%) and
(~8%), two upstream kinases of the JNK apoptotic pathway in luminal A BrCa samples. Further, simultaneous mutation of
and
are found in ~11% of mutant
tumors. How these two alterations may cooperate to elicit tumorigenesis and impact the sensitivity to PI3K and AKT inhibitors is currently unknown. Using CRISPR gene editing we have genetically disrupted
expression in mutant
cell lines to specifically create
models reflecting the mutational status of
and
in BrCa patients.
deficient cell lines exhibited ~2.4-fold increased proliferation rate and decreased sensitivity to PI3Kα/δ(AZD8835) and AKT (AZD5363) inhibitors (~2.61 and ~5.23-fold IC
increases, respectively) compared with parental control cell lines. In addition, mechanistic analysis revealed that
disruption enhances AKT phosphorylation and downstream signaling and reduces sensitivity to AZD5363-mediated pathway inhibition. This appears to be a consequence of deficient MAP3K1-JNK signaling increasing IRS1 stability and therefore promoting IRS1 binding to p85, resulting in enhanced PI3Kα activity. Using 3D-MCF10A-PI3Kα
models, we found that MAP3K1 depletion increased overall acinar volume and counteracted AZD5363-mediated reduction of acinar growth due to enhanced proliferation and reduced apoptosis. Furthermore,
efficacy studies revealed that MAP3K1-deficient MCF7 tumors were less sensitive to AKT inhibitor treatment, compared with parental MCF7 tumors. Our study provides mechanistic and
evidence indicating a role for
as a tumor suppressor gene at least in the context of
-mutant backgrounds. Further, our work predicts that
mutational status may be considered as a predictive biomarker for efficacy in PI3K pathway inhibitor trials.
The CRISPR-Cas9 system has increased the speed and precision of genetic editing in cells and animals. However, model generation for drug development is still expensive and time-consuming, demanding ...more target flexibility and faster turnaround times with high reproducibility. The generation of a tightly controlled ObLiGaRe doxycycline inducible SpCas9 (ODInCas9) transgene and its use in targeted ObLiGaRe results in functional integration into both human and mouse cells culminating in the generation of the ODInCas9 mouse. Genomic editing can be performed in cells of various tissue origins without any detectable gene editing in the absence of doxycycline. Somatic in vivo editing can model non-small cell lung cancer (NSCLC) adenocarcinomas, enabling treatment studies to validate the efficacy of candidate drugs. The ODInCas9 mouse allows robust and tunable genome editing granting flexibility, speed and uniformity at less cost, leading to high throughput and practical preclinical in vivo therapeutic testing.
PI3K inhibitors with differential selectivity to distinct PI3K isoforms have been tested extensively in clinical trials, largely to target tumor epithelial cells. PI3K signaling also regulates the ...immune system and inhibition of PI3Kδ modulate the tumor immune microenvironment of pre-clinical mouse tumor models by relieving T-regs-mediated immunosuppression. PI3K inhibitors as a class and PI3Kδ specifically are associated with immune-related side effects. However, the impact of mixed PI3K inhibitors in tumor immunology is under-explored. Here we examine the differential effects of AZD8835, a dual PI3Kα/δ inhibitor, specifically on the tumor immune microenvironment using syngeneic models. Continuous suppression of PI3Kα/δ was not required for anti-tumor activity, as tumor growth inhibition was potentiated by an intermittent dosing/schedule in vivo. Moreover, PI3Kα/δ inhibition delivered strong single agent anti-tumor activity, which was associated with dynamic suppression of T-regs, improved CD8
T-cell activation and memory in mouse syngeneic tumor models. Strikingly, AZD8835 promoted robust CD8
T-cell activation dissociated from its effect on T-regs. This was associated with enhancing effector cell viability/function. Together these data reveal novel mechanisms by which PI3Kα/δ inhibitors interact with the immune system and validate the clinical compound AZD8835 as a novel immunoncology drug, independent of effects on tumor cells. These data support further clinical investigation of PI3K pathway inhibitors as immuno-oncology agents.
The Ataxia telangiectasia and Rad3-related (ATR) inhibitor ceralasertib in combination with the PD-L1 antibody durvalumab demonstrated encouraging clinical benefit in melanoma and lung cancer ...patients who progressed on immunotherapy. Here we show that modelling of intermittent ceralasertib treatment in mouse tumor models reveals CD8
T-cell dependent antitumor activity, which is separate from the effects on tumor cells. Ceralasertib suppresses proliferating CD8
T-cells on treatment which is rapidly reversed off-treatment. Ceralasertib causes up-regulation of type I interferon (IFNI) pathway in cancer patients and in tumor-bearing mice. IFNI is experimentally found to be a major mediator of antitumor activity of ceralasertib in combination with PD-L1 antibody. Improvement of T-cell function after ceralasertib treatment is linked to changes in myeloid cells in the tumor microenvironment. IFNI also promotes anti-proliferative effects of ceralasertib on tumor cells. Here, we report that broad immunomodulatory changes following intermittent ATR inhibition underpins the clinical therapeutic benefit and indicates its wider impact on antitumor immunity.
BackgroundThe combination of an ATR inhibitor ceralasertib and anti-PD-L1 antibody durvalumab is being tested in Phase III clinical trials in patients who have progressed on prior immunotherapy. ...Preclinical experiments were performed to build a greater understanding of the potential immune driven mechanisms-of-action by which ceralasertib enhances antitumor efficacy in combination with anti-PD-L1 in the context of the clinical dose and schedule.MethodsTo assess the antitumor efficacy and associated pharmacodynamic effects ceralasertib ceralasertib was administered to CT26 tumor-bearing BALB/c immunocompetent mice twice daily with continuously and intermittently 7 day-on/7 day-off schedules alone or in combination with PD-L1 blockade. Flow cytometry and immunohistochemistry was used to quantify CD8+ T-cells when on and off ceralasertib treatment. Immunophenotyping was performed using single-cell CyTOF protein expression mass cytometry and bulk tumor or single-cell RNA sequencing (scRNA-seq) transcriptomics analysis to evaluate intratumoral T-cell populations.ResultsModelling of intermittent ceralasertib dosing regimen in mouse tumor models revealed CD8+ T-cell and type I interferon (IFNI) dependent antitumor activity, which was enhanced in combination with anti-PD-L1 immune checkpoint blockade. Ceralasertib suppressed highly proliferating CD8+ T-cells when on-treatment which was rapidly reversed when off-treatment. This was linked to significant relative reductions in T-cells which displayed markers commonly associated with an exhausted phenotype and a concomitant increase in cells with naïve non-activated phenotypes with improved T-cell function in the tumor microenvironment. Continuous daily administration of ceralasertib led to the sustained suppression of CD8+ T-cells and impaired antitumor activity compared to intermittent dosing. In addition, ceralasertib caused up-regulation of type I interferon (IFNI) which may promote an inflammatory environment and drive direct anti-proliferative effects on tumor cells.ConclusionsBroad immunostimulatory and immunomodulatory changes following intermittent ATR treatment in combination with immune checkpoint blockade may underpin the durable clinical therapeutic benefit observed in patients and indicates its potential wider impact on antitumor immunity.
ABSTRACT
The chemokine CXCL10 is produced by many inflammatory cells found in the diseased lung and has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The ...present study demonstrates elevated CXCL10 protein in the lungs of COPD patients, which appears histologically in airway smooth muscle (hASM). In primary cultured hASM cells taken from normal donors, CXCL10 protein expression was induced by IFN‐γ and TNF‐α, cytokines reported as elevated in COPD, and a synergistic response was obtained when they were combined. TNF‐α stimulation of hASM enhanced accumulation of CXCL10 mRNA, indicating regulation at the transcriptional level, while IFN‐γ stimulation resulted in a smaller accumulation of CXCL10 mRNA. When these cytokines were applied simultaneously, an additive effect was obtained. TNF‐α ‐induced CXCL10 expression in hASM was dependent on NFκB activation, and a salicylanilide NFκB inhibitor blocked the CXCL10 expression. In contrast, IFN‐γ stimulation resulted in transient NFκB activation, and the inhibitor had little effect on CXCL10 expression. When these cytokines were added simultaneously, NFκB was activated earlier and lasted longer, and the effect was blocked by the inhibitor. These data demonstrate a potential active role for hASM in pulmonary inflammatory diseases such as COPD by producing CXCL10.
The liver X receptors (LXRα/β) are part of the nuclear receptor family and are believed to regulate cholesterol and lipid homeostasis. It has also been suggested that LXR agonists possess ...anti-inflammatory properties. The aim of this work was to determine the effect of LXR agonists on the innate immune response in human primary lung macrophages and a pre-clinical rodent model of lung inflammation. Before profiling the impact of the agonist, we established that both the human macrophages and the rodent lungs expressed LXRα/β. We then used two structurally distinct LXR agonists to demonstrate that activation of this transcription factor reduces cytokine production in THP-1 cells and lung macrophages. Then, using the expression profile of ATP binding cassettes A1 (ABCA-1; a gene directly linked to LXR activation) as a biomarker for lung exposure of the compound, we demonstrated an LXR-dependent reduction in lung neutrophilia rodents in vivo. This inhibition was not associated with a suppression of c-Fos/c-Jun mRNA expression or NF-κB/AP-1 DNA binding, suggesting that any anti-inflammatory activity of LXR agonists is not via inhibition of NF-κB/AP-1 transcriptional activity. These data do not completely rule out an impact of these agonists on these two prominent transcription factors. In summary, this study is the first to demonstrate anti-inflammatory actions of LXRs in the lung. Chronic innate inflammatory responses observed in some airway diseases is thought to be central to disease pathogenesis. Therefore, data suggest that LXR ligands have utility in the treatment of lung diseases that involves chronic inflammation mediated by macrophages and neutrophils.
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