Dipeptidyl Peptidase 4 Stimulation Induces Adipogenesis-Related Gene Expression of Adipose Stromal Cells.

Adipogenesis has emerged as a new therapeutic target for regulating metabolism and achieving anti-inflammatory and anti-atherosclerotic effects via the release of adiponectin. However, at present, the effects and mechanism of action of dipeptidyl peptidase 4 (DPP4) stimulation on adiponectin production and adipogenesis have not been clarified. Here, we investigated the effects of DPP4 stimulation with monocyte chemoattractant protein-1 (MCP-1) on platelet-derived growth factor receptor alpha (PDGFRα) expression in adipose tissue and blood adiponectin levels. Stromal vascular fractions (SVFs) purified from human subcutaneous adipose tissue and inguinal adipose tissue of obese and diabetic (Leprdb/db) mice were treated with 50 ng of MCP-1 and plasma from control (Lepr+/+) mice supplemented with 10 ng or 50 ng of MCP-1. Treatment of SVFs from human subcutaneous adipose tissues with 50 ng of MCP-1 significantly increased AdipoQ, DPP4, peroxisome proliferator-activated receptor gamma (PPARγ), fatty-acid-binding protein (FABP4), and SERBF1 mRNA expression. MCP-1-supplemented plasma increased adiponectin, CCAAT-Enhancer-binding protein alpha (C/EBPα), DPP4, IL-33, and PDGFRα mRNA expression and adiponectin and DPP4 protein expression, while decreasing the expression of IL-10 mRNA in SVFs compared with the levels in the plasma treatment group. MCP-1-supplemented plasma was shown to increase PPARγ, PPARγ2, adiponectin, DPP4, and FABP4 and decrease IL-10 mRNA expression in PDGFRα cells from adipose tissue. Meanwhile, MCP-1-supplemented plasma increased MCP-1, PDGFRα, TNFα, adiponectin, and IL-1ß and decreased IL-10 and FOXP3 mRNA expression in DPP4 cells. Moreover, the injection of MCP-1-supplemented plasma into adipose tissue increased the proportion of DPP4+ cells among PDGFRα+ cells from adipose tissue and plasma adiponectin levels of Leprdb/db mice compared with the levels in the plasma injection group. Our results demonstrate that DPP4+ cells are important adipose progenitor cells. Stimulation of DPP4 with MCP-1 increases adipogenesis-related gene expression and the population of DPP4+ cells among PDGFRα+ cells in SVFs and blood adiponectin levels. DPP4 stimulation could be a novel therapy to increase local adipogenesis and systemic adiponectin levels.

Mitochondrial morphology controls fatty acid utilization by changing CPT1 sensitivity to malonyl-CoA.

Changes in mitochondrial morphology are associated with nutrient utilization, but the precise causalities and the underlying mechanisms remain unknown. Here, using cellular models representing a wide variety of mitochondrial shapes, we show a strong linear correlation between mitochondrial fragmentation and increased fatty acid oxidation (FAO) rates. Forced mitochondrial elongation following MFN2 over-expression or DRP1 depletion diminishes FAO, while forced fragmentation upon knockdown or knockout of MFN2 augments FAO as evident from respirometry and metabolic tracing. Remarkably, the genetic induction of fragmentation phenocopies distinct cell type-specific biological functions of enhanced FAO. These include stimulation of gluconeogenesis in hepatocytes, induction of insulin secretion in islet ß-cells exposed to fatty acids, and survival of FAO-dependent lymphoma subtypes. We find that fragmentation increases long-chain but not short-chain FAO, identifying carnitine O-palmitoyltransferase 1 (CPT1) as the downstream effector of mitochondrial morphology in regulation of FAO. Mechanistically, we determined that fragmentation reduces malonyl-CoA inhibition of CPT1, while elongation increases CPT1 sensitivity to malonyl-CoA inhibition. Overall, these findings underscore a physiologic role for fragmentation as a mechanism whereby cellular fuel preference and FAO capacity are determined.

Circulating Th17 T cells at treatment onset predict autoimmune toxicity of PI3Kδ inhibitors.

PI3Kδ inhibitors are approved for the therapy of B cell malignancies, but their clinical use has been limited by unpredictable autoimmune toxicity, despite promising efficacy and evidence that toxicity is associated with improved clinical outcomes. Prior phenotypic evaluation by CyTOF has identified increases in activated CD8 T cells with activation of Th17 T cells, as well as decreases in Tregs, particularly in patients with toxicity. Here we sought to further understand the effects of idelalisib and duvelisib in vitro, and demonstrate that both idelalisib and duvelisib can inhibit T cell proliferation as well as Th1 and Treg differentiation in vitro, while promoting Th2 and Th17 differentiation. We further demonstrate directly using intracellular flow cytometry that autoimmune toxicity in patients is associated with higher absolute numbers of CD4 and CD8 T cells with Th17 differentiation in peripheral blood prior to therapy, and that gastrointestinal tissues from patients with active autoimmune complications of PI3Kδ inhibitors show infiltration with Th17+ T cells. These same tissues show depletion of Tregs as compared to CLL patients without toxicity, suggesting that loss of Tregs may be permissive for Th17 activation to lead to autoimmune toxicity. Clinical trials to restore this balance are warranted.

Monocyte Chemoattractant Protein-1-Supplemented Plasma Enhances Adiponectin and Adipogenesis-Related Gene Expression.

Increasing adipogenesis has been explored to treat metabolic diseases and atherosclerosis through the release of adiponectin. The effects and mechanism of platelet-rich plasma treatment on fat graft survival and adipogenesis have not been clarified. Here, we aimed to study the effects of monocyte chemoattractant protein-1 (MCP-1)-supplemented plasma on adipogenesis-related gene expression and adiponectin levels. Stromal vascular fractions (SVFs) purified from the inguinal adipose tissue of obese and diabetic (Leprdb/db) mice were treated with plasma from control (Lepr+/+) mice supplemented with 10 or 50 ng of MCP-1. The expression of adiponectin and interleukin-33 (IL-33) mRNA in adipose tissue was increased in Leprdb/db mice, whereas control (Lepr+/+) plasma reduced expression of IL-33 mRNA as well as peroxisome proliferator-activated receptor gamma (PPARγ), pJNK, and pNF-κB protein, and increased the expression of IL-10 mRNA in SVFs of Leprdb/db mice. MCP-1-supplemented control plasma increased the expression of adiponectin, CCAAT-enhancer-binding protein α (C/EBPα), dipeptidyl peptidase 4 (DPP4), IL-33, and PDGFα mRNA and the expression of adiponectin protein as well as PPARγ of SVFs and the expression of PPARγ mRNA in adipose tissue macrophages (ATMs). Injection of MCP-1-supplemented plasma into adipose tissue of Leprdb/db mice increased the expression of IL-33 and Col3a1 mRNA in SVFs and IL-33, FABP4, PDGFα, PPARγ and PPARγ2 of ATMs, protein expression of adiponectin and PPARγ of SVFs, and plasma adiponectin levels, as well as DPP4 activity. In conclusion, our results demonstrate that control plasma decreases adipogenesis and increases IL-10, and decreases IL-33, pJNK, and pNF-κB in adipose tissue. MCP-1-supplemented plasma enhances adipogenesis-related gene expression in SVFs and adiponectin levels, which may be mediated through an increase of IL-33 and PPARγ. Thus, our findings suggest that MCP-1-supplemented plasma represents a novel therapy to stimulate local adipogenesis and systemic adiponectin levels.

Adipose-derived stromal cells reverse insulin resistance through inhibition of M1 expression in a type 2 diabetes mellitus mouse model.

BACKGROUND: Adipose tissue inflammation is considered as one of the major mechanisms underlying the pathogenesis of insulin resistance and complications in diabetes. Here, we aimed to study the effects of adipose-derived stromal cells on diabetes-induced insulin resistance and M1 cytokine expression. METHODS: Stromal vascular fractions (SVFs) purified from the inguinal adipose tissue of diabetic mice were treated with plasma from either nondiabetic (Lepr+/+) or diabetic (Leprdb/db) mice and injected into the inguinal white adipose tissue of Leprdb/db mice. RESULTS: We found that diabetic plasma treatment induced, whereas nondiabetic plasma suppressed TNF-α, IL-1ß, and dipeptidyl peptidase 4 (DPP4) mRNA expression in SVFs in vitro. Importantly, the injection of nondiabetic plasma-treated SVFs significantly decreased TNF-α, IL-6, IL-1ß, CCL2, and IL-33 and induced IL-10 mRNA expression in adipose tissue of Leprdb/db mice in vivo. Furthermore, we observed that nondiabetic plasma-treated SVFs increased mRNA expression of Foxp3 in adipose tissue macrophages and Foxp3 in adipose CD4+ T cells, decreased CD11b+CD11c+ cells in adipose tissue, and suppressed mRNA expression of ICAM-1, FCM3, IL-6, IL-1ß, iNOS, TNF-α, and DPP4 as well as protein expression of DPP4 and phosphorylated JNK and NF-κB in the liver of Leprdb/db mice. Moreover, we found that nondiabetic plasma-treated SVFs increased Akt activation following insulin administration and attenuated glucose intolerance in Leprdb/db mice. CONCLUSIONS: Our results demonstrate that nondiabetic plasma inhibits M1 but increases M2 cytokine expression in adipose tissue of diabetic mice. Most importantly, our findings reveal that nondiabetic plasma-treated SVFs are capable of mitigating diabetes-induced plasma DPP4 activity, liver inflammation, and insulin resistance and that may be mediated through suppressing M1 cytokines but increasing IL-10 and Tregs in adipose tissue. Altogether, our findings suggest that adipose stromal cell-based therapy could potentially be developed as an efficient therapeutic strategy for the treatment of diabetes.

Aggregating exposures and toxicity equivalence approach into an integrated probabilistic dietary risk assessment for perchlorate, nitrate, and thiocyanate: Results from the National food monitoring study and National Food Consumption Database.

Perchlorate, nitrate, and thiocyanate, namely thyroid disrupting chemicals (TDCs), are found ubiquitously in the environment, leading to broad human exposure and primary uptake through the food web and drinking water. TDCs are all competitive inhibitors of thyroid iodide uptake activity, but limited studies have assessed the cumulative risk of dietary exposure to multiple TDCs. Thus, in this study, we analyzed the individual exposure risk from 310 food samples in 11 categories, and also assessed the cumulative health risks from TDCs for the Taiwanese population using a perchlorate equivalent concentration (PEC) approach. Consequently, this study not only demonstrated the non-carcinogenic health risks from individual exposure but also highlighted that the cumulative exposure to these TDCs may adversely affect human thyroid functioning. Vegetables, livestock, fruits, and dairy products are the most susceptible to PEC exposure. We highlighted nitrate as the main contributor to PEC exposure. Finally, controlling the overall TDC concentrations from vegetables, livestock, fruits, and dairy products is emphasized in this study. This is the first study to conduct a cumulative risk assessment of dietary exposure to TDCs using the PEC approach for the Taiwanese population through probabilistic and sensitivity analyses.

Unraveling the Origin of Sulfur-Doped Fe-N-C Single-Atom Catalyst for Enhanced Oxygen Reduction Activity: Effect of Iron Spin-State Tuning.

Heteroatom doped atomically dispersed Fe1 -NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However, the origin of the enhanced activity is still controversial because the structure-function relationship governing the enhancement remains elusive. Herein, sulfur(S)-doped Fe1 -NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe-NC materials. 57 Fe Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe1 -NC can induce the transition of spin polarization configuration. Operando 57 Fe Mössbauer spectra definitively identified the low spin single-Fe3+ -atom of C-FeN4 -S moiety as the active site for ORR. Moreover, DFT calculations unveiled that lower spin state of the Fe center after the S doping promotes OH* desorption process. This work elucidates the underlying mechanisms towards S doping for enhancing ORR activity, and paves a way to investigate the function of broader heteroatom doped Fe1 -NC catalysts to offer a general guideline for spin-state-determined ORR.

Multiplex Tissue Imaging Harmonization: A Multicenter Experience from CIMAC-CIDC Immuno-Oncology Biomarkers Network.

PURPOSE: The Cancer Immune Monitoring and Analysis Centers - Cancer Immunologic Data Commons (CIMAC-CIDC) network supported by the NCI Cancer Moonshot initiative was established to provide correlative analyses for clinical trials in cancer immunotherapy, using state-of-the-art technology. Fundamental to this initiative is implementation of multiplex IHC assays to define the composition and distribution of immune infiltrates within tumors in the context of their potential role as biomarkers. A critical unanswered question involves the relative fidelity of such assays to reliably quantify tumor-associated immune cells across different platforms. EXPERIMENTAL DESIGN: Three CIMAC sites compared across their laboratories: (i) image analysis algorithms, (ii) image acquisition platforms, (iii) multiplex staining protocols. Two distinct high-dimensional approaches were employed: multiplexed IHC consecutive staining on single slide (MICSSS) and multiplexed immunofluorescence (mIF). To eliminate variables potentially impacting assay performance, we completed a multistep harmonization process, first comparing assay performance using independent protocols followed by the integration of laboratory-specific protocols and finally, validating this harmonized approach in an independent set of tissues. RESULTS: Data generated at the final validation step showed an intersite Spearman correlation coefficient (r) of ≥0.85 for each marker within and across tissue types, with an overall low average coefficient of variation ≤0.1. CONCLUSIONS: Our results support interchangeability of protocols and platforms to deliver robust, and comparable data using similar tissue specimens and confirm that CIMAC-CIDC analyses may therefore be used with confidence for statistical associations with clinical outcomes largely independent of site, antibody selection, protocol, and platform across different sites.

Inhibiting adipose tissue M1 cytokine expression decreases DPP4 activity and insulin resistance in a type 2 diabetes mellitus mouse model.

Adipose tissue inflammation is a major cause of the pathogenesis of obesity and comorbidities. To study the involvement of M1/M2 cytokine expression of adipose tissue in the regulatory mechanisms of dipeptidyl peptidase 4 (DPP4) and insulin resistance in diabetes, stromal vascular fractions (SVFs) were purified from inguinal adipose tissue of diabetic (Leprdb/db) and non-diabetic (Lepr+/+) mice followed by analysis of M1/M2 cytokine expression. SVFs of Leprdb/db mice exhibited increased TNF-α, IL-6, IL-1ß, CCL2, and DPP4 mRNA expression but decreased IL-10 mRNA expression. Plasma from Leprdb/db mice induced TNF-α, IL-6, IL-1ß, CCL2, and DPP4 mRNA expression and plasma from Lepr+/+ mice induced IL-10 mRNA expression in SVFs from Leprdb/db mice. Injection of Lepr+/+ plasma into the adipose tissue of Leprdb/db mice decreased mRNA expression of TNF-α, IL-6, IL-1ß, CCL2, and DPP4 and protein expression of pJNK and DPP4 in SVFs, reduced mRNA expression of ICAM, FMO3, IL-1ß, iNOS, TNF-α, IL-6, and DPP4 and protein expression of ICAM, FMO3, and DPP4 in liver, and suppressed mRNA expression of TNF-α, IL-6, IL-1ß, and DPP4 in Kupffer cells. Plasma from Leprdb/db mice did not induce M1 cytokine expression in SVFs from Leprdb/db-Jnk1-/- mice. Altogether, we demonstrate that diabetes induces M1 but decreases M2 cytokine expression in adipose tissue. Diabetic plasma-induced M1 expression is potentially through pJNK signaling pathways. Non-diabetic plasma reverses M1/M2 cytokine expression, plasma CCL2 levels, DPP4 activity, and Kupffer cell activation in diabetes. Our results suggest M1/M2 cytokine expression in adipose tissue is critical in diabetes-induced DPP4 activity, liver inflammation, and insulin resistance.

Spatial signatures identify immune escape via PD-1 as a defining feature of T-cell/histiocyte-rich large B-cell lymphoma.

T-cell/histiocyte-rich large B-cell lymphoma (TCRLBCL) is an aggressive variant of diffuse large B-cell lymphoma (DLBCL) characterized by rare malignant B cells within a robust but ineffective immune cell infiltrate. The mechanistic basis of immune escape in TCRLBCL is poorly defined and not targeted therapeutically. We performed a genetic and quantitative spatial analysis of the PD-1/PD-L1 pathway in a multi-institutional cohort of TCRLBCLs and found that malignant B cells harbored PD-L1/PD-L2 copy gain or amplification in 64% of cases, which was associated with increased PD-L1 expression (P = .0111). By directed and unsupervised spatial analyses of multiparametric cell phenotypic data within the tumor microenvironment, we found that TCRLBCL is characterized by tumor-immune "neighborhoods" in which malignant B cells are surrounded by exceptionally high numbers of PD-L1-expressing TAMs and PD-1+ T cells. Furthermore, unbiased clustering of spatially resolved immune signatures distinguished TCRLBCL from related subtypes of B-cell lymphoma, including classic Hodgkin lymphoma (cHL) and DLBCL-NOS. Finally, we observed clinical responses to PD-1 blockade in 3 of 5 patients with relapsed/refractory TCRLBCL who were enrolled in clinical trials for refractory hematologic malignancies (NCT03316573; NCT01953692), including 2 complete responses and 1 partial response. Taken together, these data implicate PD-1 signaling as an immune escape pathway in TCRLBCL and also support the potential utility of spatially resolved immune signatures to aid the diagnostic classification and immunotherapeutic prioritization of diverse tumor types.

A peripheral immune signature of responsiveness to PD-1 blockade in patients with classical Hodgkin lymphoma.

PD-1 blockade is highly effective in classical Hodgkin lymphomas (cHLs), which exhibit frequent copy-number gains of CD274 (PD-L1) and PDC1LG2 (PD-L2) on chromosome 9p24.1. However, in this largely MHC-class-I-negative tumor, the mechanism of action of anti-PD-1 therapy remains undefined. We utilized the complementary approaches of T cell receptor (TCR) sequencing and cytometry by time-of-flight analysis to obtain a peripheral immune signature of responsiveness to PD-1 blockade in 56 patients treated in the CheckMate 205 phase II clinical trial (NCT02181738). Anti-PD-1 therapy was most effective in patients with a diverse baseline TCR repertoire and an associated expansion of singleton clones during treatment. CD4+, but not CD8+, TCR diversity significantly increased during therapy, most strikingly in patients who had achieved complete responses. Additionally, patients who responded to therapy had an increased abundance of activated natural killer cells and a newly identified CD3-CD68+CD4+GrB+ subset. These studies highlight the roles of recently expanded, clonally diverse CD4+ T cells and innate effectors in the efficacy of PD-1 blockade in cHL.

Axicabtagene Ciloleucel in the Non-Trial Setting: Outcomes and Correlates of Response, Resistance, and Toxicity.

PURPOSE: Axicabtagene ciloleucel (axi-cel) was approved by the Food and Drug Administration for relapsed aggressive B-cell non-Hodgkin lymphoma in part on the basis of durable remission rates of approximately 40% in a clinical trial population. Whether this efficacy, and the rates of toxicity, would be consistent in a postcommercial setting, with relaxed eligibility criteria and bridging therapy, is unknown. This study describes the efficacy and safety correlates and outcomes in this setting. PATIENTS AND METHODS: One hundred twenty-two patients from 7 medical centers in the United States were treated with axi-cel and were included in a modified intent-to-treat (mITT) analysis. Seventy-six patients (62%) were ineligible for the ZUMA-1 trial. Response and toxicity rates, duration of response (DOR), survival, and covariates are described on the basis of the mITT population. Correlative studies on blood and tumor samples were performed to investigate potential biomarkers of response and resistance. RESULTS: Median follow-up was 10.4 months. In the mITT population, the best overall and complete response (CR) rates were 70% and 50%, respectively. Median DOR and progression-free survival (PFS) were 11.0 and 4.5 months in all patients and were not reached (NR) in CR patients. Median overall survival (OS) was NR; 1-year OS was 67% (95% CI, 59% to 77%). Although response rates were similar in the ZUMA-1-eligible and ZUMA-1-ineligible groups (70% v 68%), there was a statistically significant improvement in CR rate (63% v 42%, P = .016), DOR (median, NR v 5.0 months; P = .014), PFS (median, NR v 3.3 months; P = .020), and OS (1-year OS, 89% v 54%; P < .001) in patients who were ZUMA-1 eligible. Rates of grade ≥ 3 cytokine release syndrome and neurotoxicty were 16% and 35%, respectively. CONCLUSION: Axi-cel yields similar rates of overall response and toxicity in commercial and trial settings, although CR rates and DOR were more favorable in patients eligible for ZUMA-1.

Autophagy: a promising process for the treatment of acetaminophen-induced liver injury.

Toxicity from drugs has become an important cause of acute liver failure. Acetaminophen, a commonly used analgesic, can cause severe acute liver injury that can worsen into acute liver failure. Autophagy, a protective cell programme, has been reported to have protective effects in a variety of diseases such as cancer, immune diseases, neurodegenerative diseases, and inflammatory diseases. In this review, we describe how an excess of acetaminophen causes liver injury step by step, from the formation of the initial protein adduct to the final hepatocyte necrosis, as well as the induction of autophagy and its beneficial effects on diseases. Emphasis is placed on the potential effect of autophagy on improving the damage of acetaminophen to hepatocytes. Finally, we are committed to providing insights into the treatment of acute liver failure through the mechanism of acetaminophen induced liver injury, the mechanism of autophagy, and the link between autophagy and liver injury.

Supplementation of endogenous Ahr ligands reverses insulin resistance and associated inflammation in an insulin-dependent diabetic mouse model.

Aryl-hydrocarbon receptor (Ahr) plays an important role in the regulation of intestinal homeostasis. Diabetes is characterized by vascular complications and intestinal dysfunction. We aimed at understanding the relationship between intestinal defense impairment and inflammation in diabetes and effects of Ahr ligands on diabetes-induced insulin resistance, endovascular inflammation, and intercellular adhesion molecule (ICAM) and flavin mono-oxygenase (FMO3) expression. Effects of Ahr ligands, such as tryptophan (Trp) and indole-3-carbinol (I3C) on intestinal barrier and inflammation of Ins2Akita mice were examined. Myeloid differentiation primary response 88 (MYD88) is the adaptor for inflammatory signaling pathways. Ins2Akita-MyD88-/- mice were used to study the role of MyD88. Ins2Akita mice demonstrated decreased Ahr and regenerating islet-derived 3-ß (Reg3ß) expression, and increased Klebsiella pneumoniae translocation. Ins2Akita mice demonstrated increased inducible nitric oxide synthase (iNOS) expression of intestine; ICAM, iNOS, interleukin 1 beta (IL-1ß), and FMO3 expression of liver; and ICAM, iNOS, and FMO3 expression in aorta. Trp and I3C decreased diabetes-induced translocation and increased Ahr and Reg3ß expression of intestine. Ahr ligands reduced diabetes-induced ICAM and FMO3 expression in liver and aorta; IL-6, tumor necrosis factor alpha (TNF-α), and iNOS expression in Kupffer cells; plasma IL-6 and TNF-α levels; dipeptidyl peptidase (DPP4) activity; and insulin insensitivity. Ins2Akita-MyD88-/- mice demonstrated decreased expression of p-NF-κB of liver and ICAM of aorta compared with Ins2Akita mice. Altogether, our data suggest that diabetes induces ICAM and FMO3 expression through the decrease in intestinal defense and MyD88. Ahr ligands reverse diabetes-induced intestinal defense impairment, insulin insensitivity, FMO3/ICAM expression, and systemic inflammation.

Activation of CAR and non-CAR T cells within the tumor microenvironment following CAR T cell therapy.

Mechanisms of chimeric antigen receptor (CAR) T cell-mediated antitumor immunity and toxicity remain poorly characterized because few studies examine the intact tumor microenvironment (TME) following CAR T cell infusion. Axicabtagene ciloleucel is an autologous anti-CD19 CAR T cell therapy approved for patients with large B cell lymphoma. We devised multiplex immunostaining and ISH assays to interrogate CAR T cells and other immune cell infiltrates in biopsies of diffuse large B cell lymphoma following axicabtagene ciloleucel infusion. We found that a majority of intratumoral CAR T cells expressed markers of T cell activation but, unexpectedly, constituted ≤5% of all T cells within the TME 5 days or more after therapy. Large numbers of T cells without CAR were also activated within the TME after axicabtagene ciloleucel infusion; these cells were positive for Ki-67, IFN-γ, granzyme B (GzmB), and/or PD-1 and were found at the highest levels in biopsies with CAR T cells. Additionally, non-CAR immune cells were the exclusive source of IL-6, a cytokine associated with cytokine release syndrome, and were found at their highest numbers in biopsies with CAR T cells. These data suggest that intratumoral CAR T cells are associated with non-CAR immune cell activation within the TME with both beneficial and pathological effects.

Inactivation of Fbxw7 Impairs dsRNA Sensing and Confers Resistance to PD-1 Blockade.

The molecular mechanisms leading to resistance to PD-1 blockade are largely unknown. Here, we characterize tumor biopsies from a patient with melanoma who displayed heterogeneous responses to anti-PD-1 therapy. We observe that a resistant tumor exhibited a loss-of-function mutation in the tumor suppressor gene FBXW7, whereas a sensitive tumor from the same patient did not. Consistent with a functional role in immunotherapy response, inactivation of Fbxw7 in murine tumor cell lines caused resistance to anti-PD-1 in immunocompetent animals. Loss of Fbxw7 was associated with altered immune microenvironment, decreased tumor-intrinsic expression of the double-stranded RNA (dsRNA) sensors MDA5 and RIG1, and diminished induction of type I IFN and MHC-I expression. In contrast, restoration of dsRNA sensing in Fbxw7-deficient cells was sufficient to sensitize them to anti-PD-1. Our results thus establish a new role for the commonly inactivated tumor suppressor FBXW7 in viral sensing and sensitivity to immunotherapy. SIGNIFICANCE: Our findings establish a role of the commonly inactivated tumor suppressor FBXW7 as a genomic driver of response to anti-PD-1 therapy. Fbxw7 loss promotes resistance to anti-PD-1 through the downregulation of viral sensing pathways, suggesting that therapeutic reactivation of these pathways could improve clinical responses to checkpoint inhibitors in genomically defined cancer patient populations.This article is highlighted in the In This Issue feature, p. 1241.

The microenvironmental niche in classic Hodgkin lymphoma is enriched for CTLA-4-positive T cells that are PD-1-negative.

Classic Hodgkin lymphoma (cHL) is a tumor composed of rare, atypical, germinal center-derived B cells (Hodgkin Reed-Sternberg [HRS] cells) embedded within a robust but ineffective inflammatory milieu. The cHL tumor microenvironment (TME) is compartmentalized into "niches" rich in programmed cell death-1 ligand (PD-L1)-positive HRS cells and tumor-associated macrophages (TAMs), which associate with PD-1-positive T cells to suppress antitumor immunity via PD-L1/PD-1 signaling. Despite the exquisite sensitivity of cHL to PD-1 checkpoint blockade, most patients eventually relapse and need therapeutic alternatives. Using multiplex immunofluorescence microscopy with digital image analysis, we found that cHL is highly enriched for non-T-regulatory, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4)-positive T cells (compared with reactive lymphoid tissues) that outnumber PD-1-positive and lymphocyte-activating gene-3 (LAG-3)-positive T cells. In addition, T cells touching HRS cells are more frequently positive for CTLA-4 than for PD-1 or LAG-3. We further found that HRS cells, and a subset of TAMs, are positive for the CTLA-4 ligand CD86 and that the fractions of T cells and TAMs that are CTLA-4-positive and CD86-positive, respectively, are greater within a 75 µm HRS cell niche relative to areas outside this region (CTLA-4, 38% vs 18% [P = .0001]; CD86, 38% vs 24% [P = .0007]). Importantly, CTLA-4-positive cells are present, and focally contact HRS cells, in recurrent cHL tumors following a variety of therapies, including PD-1 blockade. These results implicate CTLA-4:CD86 interactions as a component of the immunologically privileged niche surrounding HRS cells and raise the possibility that patients with cHL refractory to PD-1 blockade may benefit from CTLA-4 blockade.

Genomic analyses of PMBL reveal new drivers and mechanisms of sensitivity to PD-1 blockade.

Primary mediastinal large B-cell lymphomas (PMBLs) are aggressive tumors that typically present as large mediastinal masses in young women. PMBLs share clinical, transcriptional, and molecular features with classical Hodgkin lymphoma (cHL), including constitutive activation of nuclear factor κB (NF-κB), JAK/STAT signaling, and programmed cell death protein 1 (PD-1)-mediated immune evasion. The demonstrated efficacy of PD-1 blockade in relapsed/refractory PMBLs led to recent approval by the US Food and Drug Administration and underscored the importance of characterizing targetable genetic vulnerabilities in this disease. Here, we report a comprehensive analysis of recurrent genetic alterations -somatic mutations, somatic copy number alterations, and structural variants-in a cohort of 37 newly diagnosed PMBLs. We identified a median of 9 genetic drivers per PMBL, including known and newly identified components of the JAK/STAT and NF-κB signaling pathways and frequent B2M alterations that limit major histocompatibility complex class I expression, as in cHL. PMBL also exhibited frequent, newly identified driver mutations in ZNF217 and an additional epigenetic modifier, EZH2. The majority of these alterations were clonal, which supports their role as early drivers. In PMBL, we identified several previously uncharacterized molecular features that may increase sensitivity to PD-1 blockade, including high tumor mutational burden, microsatellite instability, and an apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC) mutational signature. The shared genetic features between PMBL and cHL provide a framework for analyzing the mechanism of action of PD-1 blockade in these related lymphoid malignancies.

Pembrolizumab in Relapsed or Refractory Primary Mediastinal Large B-Cell Lymphoma.

PURPOSE: Patients with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) have a poor prognosis, and their treatment represents an urgent and unmet need. Because PMBCL is associated with genetic aberrations at 9p24 and overexpression of programmed cell death-1 (PD-1) ligands (PD-L1), it is hypothesized to be susceptible to PD-1 blockade. METHODS: In the phase IB KEYNOTE-013 (ClinicalTrials.gov identifier: NCT01953692) and phase II KEYNOTE-170 (ClinicalTrials.gov identifier: NCT02576990) studies, adults with rrPMBCL received pembrolizumab for up to 2 years or until disease progression or unacceptable toxicity. The primary end points were safety and objective response rate in KEYNOTE-013 and objective response rate in KEYNOTE-170. Secondary end points included duration of response, progression-free survival, overall survival, and safety. Exploratory end points included association between biomarkers and pembrolizumab activity. RESULTS: The objective response rate was 48% (7 complete responses; 33%) among 21 patients in KEYNOTE-013 and 45% (7 complete responses; 13%) among 53 patients in KEYNOTE-170. After a median follow-up time of 29.1 months in KEYNOTE-013 and 12.5 months in KEYNOTE-170, the median duration of response was not reached in either study. No patient with complete response experienced progression, including 2 patients with complete response for at least 1 year off therapy. Treatment-related adverse events occurred in 24% of patients in KEYNOTE-013 and 23% of patients in KEYNOTE-170. There were no treatment-related deaths. Among 42 evaluable patients, the magnitude of the 9p24 gene abnormality was associated with PD-L1 expression, which was itself significantly associated with progression-free survival. CONCLUSION: Pembrolizumab is associated with high response rate, durable activity, and a manageable safety profile in patients with rrPMBCL.

Metabolic Diversity in Human Non-Small Cell Lung Cancer Cells.

Intermediary metabolism in cancer cells is regulated by diverse cell-autonomous processes, including signal transduction and gene expression patterns, arising from specific oncogenotypes and cell lineages. Although it is well established that metabolic reprogramming is a hallmark of cancer, we lack a full view of the diversity of metabolic programs in cancer cells and an unbiased assessment of the associations between metabolic pathway preferences and other cell-autonomous processes. Here, we quantified metabolic features, mostly from the 13C enrichment of molecules from central carbon metabolism, in over 80 non-small cell lung cancer (NSCLC) cell lines cultured under identical conditions. Because these cell lines were extensively annotated for oncogenotype, gene expression, protein expression, and therapeutic sensitivity, the resulting database enables the user to uncover new relationships between metabolism and these orthogonal processes.