Clinical Predictors of Survival in Patients With BRAFV600-Mutated Metastatic Melanoma Treated With Combined BRAF and MEK Inhibitors After Immune Checkpoint Inhibitors.

Prospective and between trial comparisons indicate that first-line treatment with immune checkpoint inhibitors improves survival outcomes compared to first-line therapy with combined BRAF and MEK inhibitors in metastatic melanoma containing BRAFV600E/K mutations. Long-term outcomes for BRAF/MEK inhibition after progression on immunotherapy have not been reported. Moreover, clinical variables associated with outcome from treatment with combined BRAF/MEK inhibition were previously identified in the first-line setting but have not been investigated when targeted therapies are administered after progression on immune therapy. We performed a retrospective single institution analysis of 40 metastatic melanoma patients receiving combined BRAF/MEK inhibitors after progression on an anti-PD-1 or ipilimumab plus nivolumab to assess response rate by RECIST 1.1, progression-free and overall survival (PFS and OS). Pretreatment clinical variables were analyzed for association with OS. Ipilimumab/nivolumab was the first-line immunotherapy regimen in 39 patients (97.5%), and BRAFV600E/K mutations were present in 33 (83%) and 7 (17%) patients, respectively. The median OS from start of BRAF/MEK inhibitors was 20.3 months (1.73-106.4+, 95% CI of median 13.3-30.7). Clinical characteristics associated with worse survival prior to starting BRAF/MEK inhibitors included age > 60 years (median OS 14 vs. 28 months; HR 2.5; 95% CI 0.91-6.87, P = .023), ECOG-PS > 2 (median OS 7 vs. 33 months; HR 2.89; 95% CI 0.78-10.76, P = .018), and presence of bone metastases (median OS 9 vs. 52 months; HR 3.17; 95% CI 1.33-7.54, P = .002). These associations with shorter survival maintained their significance on multivariate analysis. If confirmed in larger cohorts, the identified prognostic variables can be used for stratification of patients in future randomized trials.

Causal identification of single-cell experimental perturbation effects with CINEMA-OT.

Recent advancements in single-cell technologies allow characterization of experimental perturbations at single-cell resolution. While methods have been developed to analyze such experiments, the application of a strict causal framework has not yet been explored for the inference of treatment effects at the single-cell level. Here we present a causal-inference-based approach to single-cell perturbation analysis, termed CINEMA-OT (causal independent effect module attribution + optimal transport). CINEMA-OT separates confounding sources of variation from perturbation effects to obtain an optimal transport matching that reflects counterfactual cell pairs. These cell pairs represent causal perturbation responses permitting a number of novel analyses, such as individual treatment-effect analysis, response clustering, attribution analysis, and synergy analysis. We benchmark CINEMA-OT on an array of treatment-effect estimation tasks for several simulated and real datasets and show that it outperforms other single-cell perturbation analysis methods. Finally, we perform CINEMA-OT analysis of two newly generated datasets: (1) rhinovirus and cigarette-smoke-exposed airway organoids, and (2) combinatorial cytokine stimulation of immune cells. In these experiments, CINEMA-OT reveals potential mechanisms by which cigarette-smoke exposure dulls the airway antiviral response, as well as the logic that governs chemokine secretion and peripheral immune cell recruitment.

FGF-21 Conducts a Liver-Brain-Kidney Axis to Promote Renal Cell Carcinoma.

Metabolic homeostasis is one of the most exquisitely tuned systems in mammalian physiology. Metabolic homeostasis requires multiple redundant systems to cooperate to maintain blood glucose concentrations in a narrow range, despite a multitude of physiological and pathophysiological pressures. Cancer is one of the canonical pathophysiological settings in which metabolism plays a key role. In this study, we utilized REnal Gluconeogenesis Analytical Leads (REGAL), a liquid chromatography-mass spectrometry/mass spectrometry-based stable isotope tracer method that we developed to show that in conditions of metabolic stress, the fasting hepatokine fibroblast growth factor-21 (FGF-21)1,2 coordinates a liver-brain-kidney axis to promote renal gluconeogenesis. FGF-21 promotes renal gluconeogenesis by enhancing ß2 adrenergic receptor (Adrb2)-driven, adipose triglyceride lipase (ATGL)-mediated intrarenal lipolysis. Further, we show that this liver-brain-kidney axis promotes gluconeogenesis in the renal parenchyma in mice and humans with renal cell carcinoma (RCC). This increased gluconeogenesis is, in turn, associated with accelerated RCC progression. We identify Adrb2 blockade as a new class of therapy for RCC in mice, with confirmatory data in human patients. In summary, these data reveal a new metabolic function of FGF-21 in driving renal gluconeogenesis, and demonstrate that inhibition of renal gluconeogenesis by FGF-21 antagonism deserves attention as a new therapeutic approach to RCC.

A Phase I Study of APX005M and Cabiralizumab with or without Nivolumab in Patients with Melanoma, Kidney Cancer, or Non-Small Cell Lung Cancer Resistant to Anti-PD-1/PD-L1.

PURPOSE: PD-1/PD-L1 inhibitors are approved for multiple tumor types. However, resistance poses substantial clinical challenges. PATIENTS AND METHODS: We conducted a phase I trial of CD40 agonist APX005M (sotigalimab) and CSF1R inhibitor cabiralizumab with or without nivolumab using a 3+3 dose-escalation design (NCT03502330). Patients were enrolled from June 2018 to April 2019. Eligibility included patients with biopsy-proven advanced melanoma, non-small cell lung cancer (NSCLC), or renal cell carcinoma (RCC) who progressed on anti-PD-1/PD-L1. APX005M was dose escalated (0.03, 0.1, or 0.3 mg/kg i.v.) with a fixed dose of cabiralizumab with or without nivolumab every 2 weeks until disease progression or intolerable toxicity. RESULTS: Twenty-six patients (12 melanoma, 1 NSCLC, and 13 RCC) were enrolled in six cohorts, 17 on nivolumab-containing regimens. Median duration of follow-up was 21.3 months. The most common treatment-related adverse events were asymptomatic elevations of lactate dehydrogenase (n = 26), creatine kinase (n = 25), aspartate aminotransferase (n = 25), and alanine aminotransferase (n = 19); periorbital edema (n = 17); and fatigue (n = 13). One dose-limiting toxicity (acute respiratory distress syndrome) occurred in cohort 2. The recommended phase 2 dose was APX005M 0.3 mg/kg, cabiralizumab 4 mg/kg, and nivolumab 240 mg every 2 weeks. Median days on treatment were 66 (range, 23-443). Median cycles were 4.5 (range, 2-21). One patient had unconfirmed partial response (4%), 8 stable disease (31%), 16 disease progression (62%), and 1 unevaluable (4%). Pro-inflammatory cytokines were upregulated 4 hours post-infusion. CD40 and MCSF increased after therapy. CONCLUSIONS: This first in-human study of patients with anti-PD-1/PD-L1-resistant tumors treated with dual macrophage-polarizing therapy, with or without nivolumab demonstrated safety and pharmacodynamic activity. Optimization of the dosing frequency and sequence of this combination is warranted.

Tumor regression mediated by oncogene withdrawal or erlotinib stimulates infiltration of inflammatory immune cells in EGFR mutant lung tumors.

BACKGROUND: Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitors (TKIs) like erlotinib are effective for treating patients with EGFR mutant lung cancer; however, drug resistance inevitably emerges. Approaches to combine immunotherapies and targeted therapies to overcome or delay drug resistance have been hindered by limited knowledge of the effect of erlotinib on tumor-infiltrating immune cells. METHODS: Using mouse models, we studied the immunological profile of mutant EGFR-driven lung tumors before and after erlotinib treatment. RESULTS: We found that erlotinib triggered the recruitment of inflammatory T cells into the lungs and increased maturation of alveolar macrophages. Interestingly, this phenotype could be recapitulated by tumor regression mediated by deprivation of the EGFR oncogene indicating that tumor regression alone was sufficient for these immunostimulatory effects. We also found that further efforts to boost the function and abundance of inflammatory cells, by combining erlotinib treatment with anti-PD-1 and/or a CD40 agonist, did not improve survival in an EGFR-driven mouse model. CONCLUSIONS: Our findings lay the foundation for understanding the effects of TKIs on the tumor microenvironment and highlight the importance of investigating targeted and immuno-therapy combination strategies to treat EGFR mutant lung cancer.

B cell depletion or absence does not impede anti-tumor activity of PD-1 inhibitors.

BACKGROUND: PD-1 inhibitors are approved for multiple malignancies and function by stimulating T cells. However, the role of B cells in the anti-tumor activity of these drugs is unknown, as is their activity in patients who have received B cell depleting drugs or with immunoglobulin deficiencies. METHODS: We studied B cell content in 40 melanomas from patients treated with pembrolizumab or nivolumab and assessed the association with response to therapy. Murine MC38 colon cancer and YUMMER1.7 melanoma models were used to determine whether concomitant anti-CD20 antibody injections diminish the anti-tumor effects of anti-PD-1. Results were validated in muMT mice, which lack B cells. RESULTS: B cells were sparse in most melanomas and B cell content was not associated with response to anti-PD-1 or overall survival. Employing MC38 and YUMMER1.7 models, we demonstrated that anti-CD20 antibodies reduce tumor-infiltrating B cells yet had no effect on tumor growth, response to PD-1 inhibition, or survival. In muMT mice, T-cell dependent tumor rejection and anti-PD-1 responses were no different than in wildtype C57BL/6 J mice. CONCLUSIONS: The degree of tumor infiltrating B cell content is not associated with response to anti-PD-1 inhibitors in melanoma. PD-1 inhibitors cause tumor shrinkage in murine cancer models even when B cells are absent or are depleted. PD-1 inhibitors are likely to be active in patients with impaired B cell function, such as patients undergoing B cell depletion with drugs including rituximab for conditions such as B cell malignancies or autoimmune disorders.

Uncoupling Hepatic Oxidative Phosphorylation Reduces Tumor Growth in Two Murine Models of Colon Cancer.

Obesity is associated with colon cancer pathogenesis, but the underlying mechanism is actively debated. Here, we confirm that diet-induced obesity promotes tumor growth in two murine colon cancer models and show that this effect is reversed by an orally administered controlled-release mitochondrial protonophore (CRMP) that acts as a liver-specific uncoupler of oxidative phosphorylation. This agent lowered circulating insulin, and the reduction of tumor growth was abrogated by an insulin infusion raising plasma insulin to the level of high-fat-fed mice. We also demonstrate that hyperinsulinemia increases glucose uptake and oxidation in vivo in tumors and that CRMP reverses these effects. This study provides evidence that perturbations of whole-organism energy balance or hepatic energy metabolism can influence neoplastic growth. Furthermore, the data show that glucose uptake and utilization by cancers in vivo are not necessarily constitutively high but rather may vary according to the hormonal milieu.

Myeloid-targeted immunotherapies act in synergy to induce inflammation and antitumor immunity.

Eliciting effective antitumor immune responses in patients who fail checkpoint inhibitor therapy is a critical challenge in cancer immunotherapy, and in such patients, tumor-associated myeloid cells and macrophages (TAMs) are promising therapeutic targets. We demonstrate in an autochthonous, poorly immunogenic mouse model of melanoma that combination therapy with an agonistic anti-CD40 mAb and CSF-1R inhibitor potently suppressed tumor growth. Microwell assays to measure multiplex protein secretion by single cells identified that untreated tumors have distinct TAM subpopulations secreting MMP9 or cosecreting CCL17/22, characteristic of an M2-like state. Combination therapy reduced the frequency of these subsets, while simultaneously inducing a separate polyfunctional inflammatory TAM subset cosecreting TNF-α, IL-6, and IL-12. Tumor suppression by this combined therapy was partially dependent on T cells, and on TNF-α and IFN-γ. Together, this study demonstrates the potential for targeting TAMs to convert a "cold" into an "inflamed" tumor microenvironment capable of eliciting protective T cell responses.

IL-7 plays a critical role for the homeostasis of allergen-specific memory CD4 T cells in the lung and airways.

Memory T cells respond rapidly to repeated antigen exposure and can maintain their population for extended periods through self-renewal. These characteristics of memory T cells have mainly been studied during viral infections, whereas their existence and functions in allergic diseases have been studied incompletely. Since allergic patients can suffer repeated relapses caused by intermittent allergen exposure, we hypothesized that allergen- specific memory Th2 cells are present and the factors necessary for the maintenance of these cells are provided by the lung and airways. Using a murine model of airway inflammation, we found that allergen-specific CD4 T cells survived longer than 70 days in the lung and airways in an IL-7 dependent fashion. These T cells showing homeostatic proliferation were largely found in the mediastinal lymph node (mLN), rather than the airways; however, cells residing in the lung and airways developed recall responses successfully. We also found that CD4 T cells exhibited differential phenotypes in the mLN and in the lung. Altogether, we believe that allergen-specific memory T cells reside and function in the lung and airways, while their numbers are replenished through homeostatic turnover in the mLNs. Furthermore, we determined that IL-7 signaling is important for the homeostasis of these cells.

UV-induced somatic mutations elicit a functional T cell response in the YUMMER1.7 mouse melanoma model.

Human melanomas exhibit relatively high somatic mutation burden compared to other malignancies. These somatic mutations may produce neoantigens that are recognized by the immune system, leading to an antitumor response. By irradiating a parental mouse melanoma cell line carrying three driver mutations with UVB and expanding a single-cell clone, we generated a mutagenized model that exhibits high somatic mutation burden. When inoculated at low cell numbers in immunocompetent C57BL/6J mice, YUMMER1.7 (Yale University Mouse Melanoma Exposed to Radiation) regresses after a brief period of growth. This regression phenotype is dependent on T cells as YUMMER1.7 tumors grow significantly faster in immunodeficient Rag1-/- mice and C57BL/6J mice depleted of CD4 and CD8 T cells. Interestingly, regression can be overcome by injecting higher cell numbers of YUMMER1.7, which results in tumors that grow without effective rejection. Mice that have previously rejected YUMMER1.7 tumors develop immunity against higher doses of YUMMER1.7 tumor challenge. In addition, escaping YUMMER1.7 tumors are sensitive to anti-CTLA-4 and anti-PD-1 therapy, establishing a new model for the evaluation of immune checkpoint inhibition and antitumor immune responses.

CCR7 expression alters memory CD8 T-cell homeostasis by regulating occupancy in IL-7- and IL-15-dependent niches.

C-C receptor 7 (CCR7) is important to allow T cells and dendritic cells to migrate toward CCL19- and CCL21-producing cells in the T-cell zone of the spleen and lymph nodes. The role of this chemokine receptor in regulating the homeostasis of effector and memory T cells during acute viral infection is poorly defined, however. In this study, we show that CCR7 expression alters memory CD8 T-cell homeostasis following lymphocytic choriomeningitis virus infection. Greater numbers of CCR7-deficient memory T cells were formed and maintained compared with CCR7-sufficient memory T cells, especially in the lung and bone marrow. The CCR7-deficient memory T cells also displayed enhanced rates of homeostatic turnover, which may stem from increased exposure to IL-15 as a consequence of reduced exposure to IL-7, because removal of IL-15, but not of IL-7, normalized the numbers of CCR7-sufficient and CCR7-deficient memory CD8 T cells. This result suggests that IL-15 is the predominant cytokine supporting augmentation of the CCR7(-/-) memory CD8 T-cell pool. Taken together, these data suggest that CCR7 biases memory CD8 T cells toward IL-7-dependent niches over IL-15-dependent niches, which provides insight into the homeostatic regulation of different memory T-cell subsets.

Prostaglandin E2 and programmed cell death 1 signaling coordinately impair CTL function and survival during chronic viral infection.

More than 10% of the world's population is chronically infected with HIV, hepatitis C virus (HCV) or hepatitis B virus (HBV), all of which can cause severe disease and death. These viruses persist in part because continuous antigenic stimulation causes the deterioration of virus-specific cytotoxic T lymphocyte (CTL) function and survival. Additionally, antiviral CTLs autonomously suppress their responses to limit immunopathology by upregulating inhibitory receptors such as programmed cell death 1 (PD-1). Identification and blockade of the pathways that induce CTL dysfunction may facilitate the clearance of chronic viral infections. We found that the prostaglandin E2 (PGE2) receptors EP2 and EP4 were upregulated on virus-specific CTLs during chronic lymphocytic choriomeningitis virus (LCMV) infection and suppressed CTL survival and function. We show that the combined blockade of PGE2 and PD-1 signaling was therapeutic in terms of improving viral control and augmenting the numbers of functional virus-specific CTLs. Thus, PGE2 inhibition is both an independent candidate therapeutic target and a promising adjunct therapy to PD-1 blockade for the treatment of HIV and other chronic viral infections.

Hepatic acetyl CoA links adipose tissue inflammation to hepatic insulin resistance and type 2 diabetes.

Impaired insulin-mediated suppression of hepatic glucose production (HGP) plays a major role in the pathogenesis of type 2 diabetes (T2D), yet the molecular mechanism by which this occurs remains unknown. Using a novel in vivo metabolomics approach, we show that the major mechanism by which insulin suppresses HGP is through reductions in hepatic acetyl CoA by suppression of lipolysis in white adipose tissue (WAT) leading to reductions in pyruvate carboxylase flux. This mechanism was confirmed in mice and rats with genetic ablation of insulin signaling and mice lacking adipose triglyceride lipase. Insulin's ability to suppress hepatic acetyl CoA, PC activity, and lipolysis was lost in high-fat-fed rats, a phenomenon reversible by IL-6 neutralization and inducible by IL-6 infusion. Taken together, these data identify WAT-derived hepatic acetyl CoA as the main regulator of HGP by insulin and link it to inflammation-induced hepatic insulin resistance associated with obesity and T2D.

The transcription factor FoxO1 sustains expression of the inhibitory receptor PD-1 and survival of antiviral CD8(+) T cells during chronic infection.

Protein kinase B (also known as AKT) and the mechanistic target of rapamycin (mTOR) are central regulators of T cell differentiation, proliferation, metabolism, and survival. Here, we show that during chronic murine lymphocytic choriomeningitis virus infection, activation of AKT and mTOR are impaired in antiviral cytotoxic T lymphocytes (CTLs), resulting in enhanced activity of the transcription factor FoxO1. Blockade of inhibitory receptor programmed cell death protein 1 (PD-1) in vivo increased mTOR activity in virus-specific CTLs, and its therapeutic effects were abrogated by the mTOR inhibitor rapamycin. FoxO1 functioned as a transcriptional activator of PD-1 that promoted the differentiation of terminally exhausted CTLs. Importantly, FoxO1-null CTLs failed to persist and control chronic viral infection. Collectively, this study shows that CTLs adapt to persistent infection through a positive feedback pathway (PD-1?FoxO1?PD-1) that functions to both desensitize virus-specific CTLs to antigen and support their survival during chronic viral infection.

Chronic viral infection promotes sustained Th1-derived immunoregulatory IL-10 via BLIMP-1.

During the course of many chronic viral infections, the antiviral T cell response becomes attenuated through a process that is regulated in part by the host. While elevated expression of the immunosuppressive cytokine IL-10 is involved in the suppression of viral-specific T cell responses, the relevant cellular sources of IL-10, as well as the pathways responsible for IL-10 induction, remain unclear. In this study, we traced IL-10 production over the course of chronic lymphocytic choriomeningitis virus (LCMV) infection in an IL-10 reporter mouse line. Using this model, we demonstrated that virus-specific T cells with reduced inflammatory function, particularly Th1 cells, display elevated and sustained IL-10 expression during chronic LCMV infection. Furthermore, ablation of IL-10 from the T cell compartment partially restored T cell function and reduced viral loads in LCMV-infected animals. We found that viral persistence is needed for sustained IL-10 production by Th1 cells and that the transcription factor BLIMP-1 is required for IL-10 expression by Th1 cells. Restimulation of Th1 cells from LCMV-infected mice promoted BLIMP-1 and subsequent IL-10 expression, suggesting that constant antigen exposure likely induces the BLIMP-1/IL-10 pathway during chronic viral infection. Together, these data indicate that effector T cells self-limit their responsiveness during persistent viral infection via an IL-10-dependent negative feedback loop.