Depleting regulatory T cells (T
cells) to counteract immunosuppressive features of the tumor microenvironment (TME) is an attractive strategy for cancer treatment; however, autoimmunity due to ...systemic impairment of their suppressive function limits its therapeutic potential. Elucidating approaches that specifically disrupt intratumoral T
cells is direly needed for cancer immunotherapy. We found that CD36 was selectively upregulated in intrautumoral T
cells as a central metabolic modulator. CD36 fine-tuned mitochondrial fitness via peroxisome proliferator-activated receptor-β signaling, programming T
cells to adapt to a lactic acid-enriched TME. Genetic ablation of Cd36 in T
cells suppressed tumor growth accompanied by a decrease in intratumoral T
cells and enhancement of antitumor activity in tumor-infiltrating lymphocytes without disrupting immune homeostasis. Furthermore, CD36 targeting elicited additive antitumor responses with anti-programmed cell death protein 1 therapy. Our findings uncover the unexplored metabolic adaptation that orchestrates the survival and functions of intratumoral T
cells, and the therapeutic potential of targeting this pathway for reprogramming the TME.
Next to white and brown adipocytes present in white and brown adipose tissue (WAT, BAT), vascular endothelial cells, tissue-resident macrophages and other immune cells have important roles in ...maintaining adipose tissue homeostasis but also contribute to the etiology of obesity-associated chronic inflammatory metabolic diseases. In addition to hormonal signals such as insulin and norepinephrine, extracellular adenine nucleotides modulate lipid storage, fatty acid release and thermogenic responses in adipose tissues. The complex regulation of extracellular adenine nucleotides involves a network of ectoenzymes that convert ATP via ADP and AMP to adenosine. However, in WAT and BAT the processing of extracellular adenine nucleotides and its relevance for intercellular communications are still largely unknown. Based on our observations that in adipose tissues the adenosine-generating enzyme CD73 is mainly expressed by vascular endothelial cells, we studied glucose and lipid handling, energy expenditure and adaptive thermogenesis in mice lacking endothelial CD73 housed at different ambient temperatures. Under conditions of thermogenic activation, CD73 expressed by endothelial cells is dispensable for the expression of thermogenic genes as well as energy expenditure. Notably, thermoneutral housing leading to a state of low energy expenditure and lipid accumulation in adipose tissues resulted in enhanced glucose uptake into WAT of endothelial CD73-deficient mice. This effect was associated with elevated expression levels of
lipogenesis genes. Mechanistic studies provide evidence that extracellular adenosine is imported into adipocytes and converted to AMP by adenosine kinase. Subsequently, activation of the AMP kinase lowers the expression of
lipogenesis genes, most likely via inactivation of the transcription factor carbohydrate response element binding protein (ChREBP). In conclusion, this study demonstrates that endothelial-derived extracellular adenosine generated via the ectoenzyme CD73 is a paracrine factor shaping lipid metabolism in WAT.
Intravenous iron supplementation is an effective therapy in iron deficiency anemia (IDA), but controversial in anemia of inflammation (AI). Unbound iron can be used by bacteria and viruses for their ...replication and enhance the inflammatory response. Nowadays available high molecular weight iron complexes for intravenous iron substitution, such as ferric carboxymaltose, might be useful in AI, as these pharmaceuticals deliver low doses of free iron over a prolonged period of time. We tested the effects of intravenous iron carboxymaltose in murine AI: Wild-type mice were exposed to the heat-killed Brucella abortus (BA) model and treated with or without high molecular weight intravenous iron. 4h after BA injection followed by 2h after intravenous iron treatment, inflammatory cytokines were upregulated by BA, but not enhanced by iron treatment. In long term experiments, mice were fed a regular or an iron deficient diet and then treated with intravenous iron or saline 14 days after BA injection. Iron treatment in mice with BA-induced AI was effective 24h after iron administration. In contrast, mice with IDA (on iron deficiency diet) prior to BA-IA required 7d to recover from AI. In these experiments, inflammatory markers were not further induced in iron-treated compared to vehicle-treated BA-injected mice. These results demonstrate that intravenous iron supplementation effectively treated the murine BA-induced AI without further enhancement of the inflammatory response. Studies in humans have to reveal treatment options for AI in patients.
BackgroundThe therapeutic scope of MEK inhibitors (MEKis) is currently limited to use in BRAF mutant melanoma. Therefore, we aim to develop new strategies to extend their usage to MEKi resistant RAS ...mutant cancers, which represent an unmet clinical need. In Ras mutant murine lung cancers, CH5126766 (CKI27) is novel due to its ability to inhibit both RAF and MEK, preventing the rebound of p-ERK that normally results from the relief of negative feedback in the MAPK/ERK pathway. However, CKI27 is also capable of inhibiting T cell functions because the MAPK/ERK pathway is activated downstream of T cell receptor signaling. We aim to balance the positive and negative immunomodulatory effects of MEKis for optimal combination with immunotherapy.MethodsTo evaluate the effects of CKI27 on tumor cells and T cells in vitro, we performed flow cytometry, cytokine analysis, and functional co-culture assays. Lewis lung carcinoma (LLC) tumor bearing mice were treated either with CKI27 combined with co-stimulatory agonist antibody targeting GITR and checkpoint blockade antibody targeting CTLA-4 or the appropriate controls to determine efficacy and changes in the tumor microenvironment.ResultsWe observed that CKI27 increased MHC expression on tumor cells and T cell mediated killing. Yet, CKI27 also decreased T cell proliferation, activation, and cytolytic activity. Implementing a break for T cells to recover with intermittent dosing of CKI27 partially relieved these inhibitory effects. Further combination with agonist antibodies anti-OX40 and GITR completely alleviated these T cell toxicities and increased combination efficacy with checkpoint blockade antibody anti-CTLA-4.ConclusionsUnderstanding the immunomodulatory effects of combining CKI27 with immunotherapy will elucidate the mechanism behind their increased efficacy. This will allow us to make more informed decisions in dosing regimens, overcoming resistance, and generating long-term immune responses in current and future clinical trials treating patients with RAS mutant cancers.
BackgroundThe immune system eliminates cancers in the early stages of malignant transformation. However, the presence of immune cells exerts selective pressure on tumors, which can result in tumor ...editing, leading to the development of immune escape variants. A common occurrence in cancers is the loss of antigenic protein expression on tumor cells, which creates antigenic heterogeneity and makes tumors resistant to immunotherapies such as adoptive cell therapies. Consequently, it is necessary to study and engage multiple components of the immune system in immunotherapeutic interventions to effectively eradicate heterogeneous tumors.MethodsThis study aimed to assess the efficacy of a combination therapy involving CD4+ T cells recognizing the melanoma antigen Trp1 in conjunction with either OX40 co-stimulation or CTLA-4 blockade (ICB) for eradicating advanced melanomas containing antigen escape variants in preclinical mouse models.ResultsThe combination therapy successfully eliminated antigen-loss variant clones in a preclinical mouse model of melanoma with heterogeneous Trp1 expression. Mechanistically, tumors from treated mice exhibited significant infiltration of activated neutrophils, which was also observed in cancer patients following ICB therapy. Depletion of neutrophils in our preclinical melanoma model of antigenic heterogeneity abolished the therapeutic efficacy of the combination treatment. Our findings revealed the importance of inducible nitric oxide synthase in neutrophil-mediated elimination of escape variants. Furthermore, neutrophils derived from tumors of treated mice exhibited a distinct transcriptomic and protein surface signature associated with anti-tumorigenic properties. This anti-tumorigenic neutrophil signature was also observed in tumors from melanoma patients treated with ICB that experienced survival benefits.ConclusionsOur findings demonstrate the interplay between T cells, which initiate the anti-tumor immune response, and neutrophils, which contribute to the elimination of tumor antigen loss variants in later stages. These insights underscore the potential of combined therapies in overcoming clonal escape variants in melanoma and provide valuable information on the role of neutrophils in tumor eradication when employing T cell immunotherapies.Ethics ApprovalAll tissues collected at MSKCC following study protocol approval by the MSKCC Institutional Review Board. Informed consent was obtained for all patients. The study was in strict compliance with all institutional ethical regulations.
BackgroundTargeted immune-based therapies such as adoptive T cell transfer (ACT) are often ineffective because tumors evolve over time and under selective pressure display antigen loss variant ...clones. A classic example in melanoma is de-differentiation and loss of expression of antigenic proteins. Therapies that activate multiple branches of the immune system may eliminate such escape variantsMethodsHere we show that melanoma-specific CD4+ ACT therapy in combination with OX40 co-stimulation or CTLA-4 blockade can eradicate large melanoma tumors with clonal escape variants.ResultsEarly on-target recognition of melanoma antigens by adoptively transferred tumor-specific CD4+ T cells was required. Surprisingly, however, complete tumor eradication was partially dependent on neutrophils. Supporting these findings, extensive neutrophil activation and neutrophil extracellular traps were found in mouse tumors and in biopsies of melanoma patients treated with immune checkpoint blockade.ConclusionsOur findings uncover a novel interplay between T cells mediating the initial tumor- and tissue-specific immune response, and neutrophils mediating tumor destruction of antigen loss variants.Ethics ApprovalAll tissues were collected at MSKCC following study protocol approval by the MSKCC Institutional Review Board. All mouse procedures were performed in accordance with institutional protocol guidelines at Memorial Sloan-Kettering Cancer Center (MSKCC) under an approved protocol.
A common metabolic alteration in the tumor microenvironment (TME) is lipid accumulation, a feature associated with immune dysfunction. Here, we examined how CD8+ tumor infiltrating lymphocytes (TILs) ...respond to lipids within the TME. We found elevated concentrations of several classes of lipids in the TME and accumulation of these in CD8+ TILs. Lipid accumulation was associated with increased expression of CD36, a scavenger receptor for oxidized lipids, on CD8+ TILs, which also correlated with progressive T cell dysfunction. Cd36−/− T cells retained effector functions in the TME, as compared to WT counterparts. Mechanistically, CD36 promoted uptake of oxidized low-density lipoproteins (OxLDL) into T cells, and this induced lipid peroxidation and downstream activation of p38 kinase. Inhibition of p38 restored effector T cell functions in vitro, and resolution of lipid peroxidation by overexpression of glutathione peroxidase 4 restored functionalities in CD8+ TILs in vivo. Thus, an oxidized lipid-CD36 axis promotes intratumoral CD8+ T cell dysfunction and serves as a therapeutic avenue for immunotherapies.
Display omitted
•The tumor microenvironment is enriched with lipids and oxidized lipids•Dysfunctional CD8+ TILs increase CD36 expression and OxLDL uptake•OxLDL uptake via CD36 inhibits T cell effector functions through lipid peroxidation•GPX4 overexpression promotes CD8+ TIL functionality
Lipid accumulation is a common metabolic alteration in the tumor microenvironment. Xu et al. show that intratumoral CD8+ T cells adapt to increased lipid concentrations by increasing expression of the scavenger receptor CD36. This, in turn, leads to intracellular accumulation of oxidized lipid and T cell dysfunction downstream of lipid peroxidation.
Most cases of adult myeloid neoplasms are routinely assumed to be sporadic. Here, we describe an adult familial acute myeloid leukemia (AML) syndrome caused by germline mutations in the DEAD/H-box ...helicase gene DDX41. DDX41 was also found to be affected by somatic mutations in sporadic cases of myeloid neoplasms as well as in a biallelic fashion in 50% of patients with germline DDX41 mutations. Moreover, corresponding deletions on 5q35.3 present in 6% of cases led to haploinsufficient DDX41 expression. DDX41 lesions caused altered pre-mRNA splicing and RNA processing. DDX41 is exemplary of other RNA helicase genes also affected by somatic mutations, suggesting that they constitute a family of tumor suppressor genes.
Cancer immunotherapies, including adoptive T cell transfer, can be ineffective because tumors evolve to display antigen-loss-variant clones. Therapies that activate multiple branches of the immune ...system may eliminate escape variants. Here, we show that melanoma-specific CD4+ T cell therapy in combination with OX40 co-stimulation or CTLA-4 blockade can eradicate melanomas containing antigen escape variants. As expected, early on-target recognition of melanoma antigens by tumor-specific CD4+ T cells was required. Surprisingly, complete tumor eradication was dependent on neutrophils and partly dependent on inducible nitric oxide synthase. In support of these findings, extensive neutrophil activation was observed in mouse tumors and in biopsies of melanoma patients treated with immune checkpoint blockade. Transcriptomic and flow cytometry analyses revealed a distinct anti-tumorigenic neutrophil subset present in treated mice. Our findings uncover an interplay between T cells mediating the initial anti-tumor immune response and neutrophils mediating the destruction of tumor antigen loss variants.
Display omitted
•T cell immunotherapies can eliminate antigenically heterogeneous tumors•Neutrophils are recruited and are responsible for killing antigen loss variants•Anti-tumorigenic neutrophils display a distinct genotype and phenotype•Neutrophil activation is observed in patients treated with T cell immunotherapies
The eradication of antigenically heterogeneous tumors by T cell immunotherapies requires neutrophils.
Genetic differences in immunity may contribute to toxicity and outcomes with immune checkpoint inhibitor (CPI) therapy, but these relationships are poorly understood. We examined the genetics of ...thyroid immune-related adverse events (irAE).
In patients with non-small cell lung cancer (NSCLC) treated with CPIs at Memorial Sloan Kettering (MSK) and Vanderbilt University Medical Center (VUMC), we evaluated thyroid irAEs. We typed germline DNA using genome-wide single-nucleotide polymorphism (SNP) arrays and imputed genotypes. Germline SNP imputation was also performed in an independent Dana-Farber Cancer Institute (DFCI) cohort. We developed and validated polygenic risk scores (PRS) for hypothyroidism in noncancer patients using the UK and VUMC BioVU biobanks. These PRSs were applied to thyroid irAEs and CPI response in patients with NSCLC at MSK, VUMC, and DFCI.
Among 744 patients at MSK and VUMC, thyroid irAEs occurred in 13% and were associated with improved outcomes progression-free survival adjusted HR (PFS aHR) = 0.68; 95% confidence interval (CI), 0.52-0.88. The PRS for hypothyroidism developed from UK Biobank predicted hypothyroidism in the BioVU dataset in noncancer patients OR per standard deviation (SD) = 1.33, 95% CI, 1.29-1.37; AUROC = 0.6. The same PRS also predicted development of thyroid irAEs in both independent cohorts of patients treated with CPIs (HR per SD = 1.34; 95% CI, 1.08-1.66; AUROC = 0.6). The results were similar in the DFCI cohort. However, PRS for hypothyroidism did not predict CPI benefit.
Thyroid irAEs were associated with response to anti-PD-1 therapy. Genetic risk for hypothyroidism was associated with risk of developing thyroid irAEs. Additional studies are needed to determine whether other irAEs also have shared genetic risk with known autoimmune disorders and the association with treatment response.
PDF
