Aging and brain free cholesterol concentration on amyloid-ß peptide accumulation in guinea pigs.

Alzheimer's disease is a complex multifactorial neurodegenerative disorder wherein age is a major risk factor. The appropriateness of the Hartley guinea pig (GP), which displays high sequence homologies of its amyloid-ß (Aß40 and Aß42) peptides, Mdr1 and APP (amyloid precursor protein) and similarity in lipid handling to humans, was appraised among 9-40 weeks old guinea pigs. Protein expression levels of P-gp (Abcb1) and Cyp46a1 (24(S)-hydroxylase) for Aß40, and Aß42 efflux and cholesterol metabolism, respectively, were decreased with age, whereas those for Lrp1 (low-density lipoprotein receptor related protein 1), Rage (receptor for advanced glycation endproducts) for Aß efflux and influx, respectively, and Abca1 (the ATP binding cassette subfamily A member 1) for cholesterol efflux, were unchanged among the ages examined. There was a strong, negative correlation of the brain Aß peptide concentrations and Abca1 protein expression levels with free cholesterol. The correlation of Aß peptide concentrations with Cyp46a1 was, however, not significant, and concentrations of the 24(S)-hydroxycholesterol metabolite revealed a decreasing trend from 20 weeks old toward 40 weeks old guinea pigs. The composite data suggest a role for free cholesterol on brain Aß accumulation. The decreases in P-gp and Lrp1 protein levels should further exacerbate the accumulation of Aß peptides in guinea pig brain.

Clinical utility of measuring CD4+ T follicular cells in patients with immune dysregulation.

Mechanistic studies of autoimmune disorders have identified circulating T follicular helper (cTfh) cells as drivers of autoimmunity. However, the quantification of cTfh cells is not yet used in clinical practice due to the lack of age-stratified normal ranges and the unknown sensitivity and specificity of this test for autoimmunity. We enrolled 238 healthy participants and 130 patients with common and rare disorders of autoimmunity or autoinflammation. Patients with infections, active malignancy, or any history of transplantation were excluded. In 238 healthy controls, median cTfh percentages (range 4.8%-6.2%) were comparable among age groups, sexes, races, and ethnicities, apart from a significantly lower percentages in children less than 1 year of age (median 2.1%, CI: 0.4%-6.8, p < 0.0001). Among 130 patients with over 40 immune regulatory disorders, a cTfh percentage exceeding 12% had 88% sensitivity and 94% specificity for differentiating disorders with adaptive immune cell dysregulation from those with predominantly innate cell defects. This threshold had a sensitivity of 86% and specificity of 100% for active autoimmunity and normalized with effective treatment. cTfh percentages exceeding 12% distinguish autoimmunity from autoinflammation, thereby differentiating two endotypes of immune dysregulation with overlapping symptoms and different therapies.

Erratum: Non-homeostatic body weight regulation through a brainstem-restricted receptor for GDF15.

This corrects the article DOI: 10.1038/nature24042.

Non-homeostatic body weight regulation through a brainstem-restricted receptor for GDF15.

Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure. In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand. Recent studies have identified brain areas outside the hypothalamus that are activated under these 'non-homeostatic' conditions, but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptor for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the 'emergency circuit' that shapes feeding responses to stressful conditions. GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases. By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.

Black Race and Public Insurance Are Predictive of Inappropriate Evaluation of Iron Deficiency Anemia and Diarrhea.

BACKGROUND AND AIMS: Socioeconomic status, race, and insurance can impact healthcare delivery and utilization in several chronic disease states. The primary aim of our study was to determine whether race and insurance status are predictors of having an appropriate workup for celiac disease and inflammatory bowel disease (IBD) when presenting with iron deficiency anemia (IDA) and chronic diarrhea. METHODS: Medical records of patients seen at the University of Chicago Medical Center between January 1, 2006, and September 20, 2017, were reviewed. Patients with two separate encounters within 6 months associated with the diagnosis codes for both IDA and chronic diarrhea were identified. Patients without a diagnosis code for IBD and celiac disease were further grouped as those that had an "appropriate" workup and those that did not. Factors associated with the appropriate evaluation were analyzed by univariate and multivariate logistic regression. RESULTS: In total, 899,701 records were searched. A total of 83 patients fit inclusion into the study (8 IBD, 3 CD, 72 neither IBD or CD). Black race was associated with a 91% decreased odds of having the appropriate workup on univariate (OR 0.090, 95%CI 0.017-0.475, p = 0.005) and age-adjusted multivariate analysis (OR 0.095, 95% CI 0.017-0.527, p = 0.007). Public insurance status was significantly associated with a 90% decreased odds of appropriate workup on univariate (OR 0.102, 95% CI 0.024-0.438, p = 0.002) and age-adjusted multivariate analysis (OR 0.104, 95% CI 0.021-0.513, p = 0.005). CONCLUSIONS: Black race and public insurance were significantly associated with not having an appropriate workup for IBD and celiac disease when presenting with iron deficiency and chronic diarrhea.

Hypomorphic variants in AK2 reveal the contribution of mitochondrial function to B-cell activation.

BACKGROUND: The gene AK2 encodes the phosphotransferase adenylate kinase 2 (AK2). Human variants in AK2 cause reticular dysgenesis, a severe combined immunodeficiency with agranulocytosis, lymphopenia, and sensorineural deafness that requires hematopoietic stem cell transplantation for survival. OBJECTIVE: We investigated the mechanisms underlying recurrent sinopulmonary infections and hypogammaglobulinemia in 15 patients, ranging from 3 to 34 years of age, from 9 kindreds. Only 2 patients, both of whom had mildly impaired T-cell proliferation, each had a single clinically significant opportunistic infection. METHODS: Patient cells were studied with next-generation DNA sequencing, tandem mass spectrometry, and assays of lymphocyte and mitochondrial function. RESULTS: We identified 2 different homozygous variants in AK2. AK2G100S and AK2A182D permit residual protein expression, enzymatic activity, and normal numbers of neutrophils and lymphocytes. All but 1 patient had intact hearing. The patients' B cells had severely impaired proliferation and in vitro immunoglobulin secretion. With activation, the patients' B cells exhibited defective mitochondrial respiration and impaired regulation of mitochondrial membrane potential and quality. Although activated T cells from the patients with opportunistic infections demonstrated impaired mitochondrial function, the mitochondrial quality in T cells was preserved. Consistent with the capacity of activated T cells to utilize nonmitochondrial metabolism, these findings revealed a less strict cellular dependence of T-cell function on AK2 activity. Chemical inhibition of ATP synthesis in control T and B cells similarly demonstrated the greater dependency of B cells on mitochondrial function. CONCLUSIONS: Our patients demonstrate the in vivo sequelae of the cell-specific requirements for the functions of AK2 and mitochondria, particularly in B-cell activation and antibody production.

Endoscopic ultrasound acquired portal venous circulating tumor cells predict progression free survival and overall survival in patients with pancreaticobiliary cancers.

BACKGROUND AND AIMS: Despite recent advances, patients with pancreaticobiliary cancers have a poor prognosis. We previously demonstrated the efficacy of endoscopic ultrasound (EUS) guided acquisition of portal vein (PV) blood for enumeration of circulating tumor cells (CTCs). The aim of this study was to assess PV-CTCs as potential biomarkers for the assessment of progression-free (PFS) and overall survival (OS) in patients with pancreaticobiliary cancers. METHODS: 17 patients with biopsy-proven pancreaticobiliary malignancy were enrolled. CTCs were enumerated from both peripheral and PV blood. All patients were followed until death. PFS and OS were evaluated with the log-rank test and summarized with the use of Kaplan-Meier methods. Unadjusted and adjusted Cox-proportional hazards models were fitted to study the relationship between PV-CTCs and PFS and OS. RESULTS: After 3.5 years of follow-up, all patients had expired. PV-CTCs were detected in all patients (median PV-CTCs 62.0/7.5 mL (interquartile range [IQR] 17-132). The mean PFS in patients with PV-CTCs <185/7.5 mL was significantly longer than patients with PV-CTCs ≥185/7.5 mL (43.3 weeks vs. 12.8 weeks, log-rank p = 0.002). The mean OS in patients with PV-CTCs <185/7.5 mL was significantly longer than patients with PV-CTCs ≥185/7.5 mL (75.8 weeks vs. 29.5 weeks, log-rank p = 0.021). In an adjusted Cox-proportional hazards model, PV-CTCs were significant predictors of both PFS and OS (HR 1.004, p = 0.037; HR 1.004, p = 0.044 respectively). CONCLUSION: In this pilot and feasibility study, EUS-acquired PV-CTCs predicted PFS and OS. Our findings suggest that PV-CTCs can help provide important prognostic data for both providers and patients.

Off-Label Teduglutide Therapy in Non-intestinal Failure Patients with Chronic Malabsorption.

BACKGROUND: Teduglutide, a glucagon-like peptide 2 analog, has demonstrated efficacy in treating adult patients with short bowel syndrome (SBS) and dependence on parenteral nutrition (PN), but its role in chronic malabsorptive states that do not necessitate PN remains uncertain. AIMS: To evaluate teduglutide use beyond its approved indications and to discuss the results of this adjunctive treatment in patients resistant to established therapy. RESULTS: This series reports four patients treated with teduglutide off-label. The first case had Crohn's disease (CD) with persistent colocutaneous fistulae that demonstrated complete closure after 8 months of teduglutide therapy. The second case involved a PN-dependent CD patient with persistent fistulae and intra-abdominal abscesses who weaned off PN and had a significant improvement in her nutritional status after 3 months of teduglutide therapy. The third case had CD complicated by severe malnutrition and previous PN-associated line infections, but by 9 months of teduglutide therapy, she gained 5 kg and no longer required re-initiation of PN. The fourth case had a high-output diverting ileostomy with resultant impaired healing of a stage IV decubitus ulcer, and after 2 months of therapy, the patient's pre-albumin increased by 250% and the ulcer had decreased by 40% in size. CONCLUSION: The use of teduglutide might be broadened to include patients with functional SBS not meeting strict criteria for intestinal failure. Further studies should evaluate the efficacy of teduglutide in patients who may require short-term small intestine rehabilitation or who have chronically impaired absorptive capacity not yet requiring PN.

Omecamtiv Mecarbil, a Cardiac Myosin Activator, Increases Ca2+ Sensitivity in Myofilaments With a Dilated Cardiomyopathy Mutant Tropomyosin E54K.

Apart from transplant, there are no satisfactory therapies for the severe depression in contractility in familial dilated cardiomyopathy (DCM). Current heart failure treatments that act by increasing contractility involve signaling cascades that alter calcium homeostasis and induce arrhythmias. Omecamtiv mecarbil is a promising new inotropic agent developed for heart failure that may circumvent such limitations. Omecamtiv is a direct cardiac myosin activator that promotes and prolongs the strong myosin-actin binding conformation to increase the duration of systolic elastance. We tested the effect of omecamtiv on Ca(2+) sensitivity of myofilaments of a DCM mouse model containing a tropomyosin E54K mutation. We compared tension and ATPase activity of detergent-extracted myofilaments with and without treatment with 316 nM omecamtiv at varying pCa values. When transgenic myofilaments were treated with omecamtiv, the pCa50 for activation of tension increased from 5.70 ± 0.02 to 5.82 ± 0.02 and ATPase activity increased from 5.73 ± 0.06 to 6.07 ± 0.04. This significant leftward shift restored Ca(2+) sensitivity to levels no longer significantly different from controls. Proteomic studies lacked changes in sarcomeric protein phosphorylation. Our data demonstrate that omecamtiv can potentially augment cardiac contractility in DCM by increasing Ca(2+) sensitivity. The use of direct myosin activators addresses functional defects without incurring the adverse side effects of Ca(2+)-dependent treatments.

Clinical utility of bronchoalveolar lavage and respiratory tract biopsies in diagnosis and management of suspected invasive respiratory fungal infections in children.

BACKGROUND: Bronchoscopy with bronchoalveolar lavage (BAL) and respiratory tract biopsies are important tools for diagnosing fungal infections in children with cancer and hematopoietic stem cell transplant (HSCT) recipients. Our objective was to evaluate the impact of BAL and respiratory tract biopsies on the management of suspected fungal infections in oncology and HSCT patients. PROCEDURE: We retrospectively reviewed the medical records of oncology and HSCT patients with possible, probable, or proven fungal infection of the respiratory tract and determined whether BAL or biopsy following computed tomography (CT) prompted a change in management. RESULTS: Among 101 patients (0.5-29 years of age), 24 underwent a BAL and 31 had biopsies (27 lung and 4 sinus). The remaining 46 patients had CT scans only. Of these, there were radiographic findings suggestive of a fungal infection in 38 patients (83%). Thirty of these 38 patients (79%) had a change in management. BAL provided a diagnosis in 6 of 24 patients (25%). There was a change in management in 2 of the 6 (33%). Respiratory tract biopsy provided a diagnosis in 12 of 31 patients (39%). Biopsy results led to a change in management in 4 of the 12 patients (33%). Significant postoperative morbidity attributed to biopsy occurred in 3 of 31 patients (10%); 2 patients had pneumothorax requiring chest tube and intubation and a patient had prolonged intubation. CONCLUSION: BAL and biopsy in children with an oncological diagnosis or those undergoing HSCT only infrequently lead to changes in management in the era of empiric therapy with broad-spectrum anti-fungal agents.

Playing three-dimensional video games boosts stereo vision.

Playing two-dimensional video games has been shown to result in improvements in a range of visual and cognitive tasks, and these improvements appear to generalize widely1,2,3,4,5,6. Here we report that young adults with healthy vision, surprisingly, showed a dramatic improvement in stereo vision after playing three-dimensional, but not two-dimensional, video games for a relatively short period of time. Intriguingly, neither group showed any significant improvement in binocular contrast sensitivity. This dissociation suggests that the visual enhancement was specific to genuine stereoscopic processing, not indirectly resulting from enhanced contrast processing, and required engaging in a disparity cue-rich three-dimensional environment.

Antitumor Activity of a Novel LAIR1 Antagonist in Combination with Anti-PD1 to Treat Collagen-Rich Solid Tumors.

We recently reported that resistance to PD-1 blockade in a refractory lung cancer-derived model involved increased collagen deposition and the collagen-binding inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR1). Thus, we hypothesized that LAIR1 and collagen cooperated to suppress therapeutic response. In this study, we report that LAIR1 is associated with tumor stroma and is highly expressed by intratumoral myeloid cells in both human tumors and mouse models of cancer. Stroma-associated myeloid cells exhibit a suppressive phenotype and correlate with LAIR1 expression in human cancer. NGM438, a novel humanized LAIR1 antagonist mAb, elicits myeloid inflammation and allogeneic T-cell responses by binding to LAIR1 and blocking collagen engagement. Furthermore, a mouse-reactive NGM438 surrogate antibody sensitized refractory KP mouse lung tumors to anti-PD-1 therapy and resulted in increased intratumoral CD8+ T-cell content and inflammatory gene expression. These data place LAIR1 at the intersection of stroma and suppressive myeloid cells and support the notion that blockade of the LAIR1/collagen axis can potentially address resistance to checkpoint inhibitor therapy in the clinic.

ILT2 and ILT4 Drive Myeloid Suppression via Both Overlapping and Distinct Mechanisms.

Solid tumors are dense three-dimensional (3D) multicellular structures that enable efficient receptor-ligand trans interactions via close cell-cell contact. Immunoglobulin-like transcript (ILT)2 and ILT4 are related immune-suppressive receptors that play a role in the inhibition of myeloid cells within the tumor microenvironment. The relative contribution of ILT2 and ILT4 to immune inhibition in the context of solid tumor tissue has not been fully explored. We present evidence that both ILT2 and ILT4 contribute to myeloid inhibition. We found that although ILT2 inhibits myeloid cell activation in the context of trans-engagement by MHC-I, ILT4 efficiently inhibits myeloid cells in the presence of either cis- or trans-engagement. In a 3D spheroid tumor model, dual ILT2/ILT4 blockade was required for the optimal activation of myeloid cells, including the secretion of CXCL9 and CCL5, upregulation of CD86 on dendritic cells, and downregulation of CD163 on macrophages. Humanized mouse tumor models showed increased immune activation and cytolytic T-cell activity with combined ILT2 and ILT4 blockade, including evidence of the generation of immune niches, which have been shown to correlate with clinical response to immune-checkpoint blockade. In a human tumor explant histoculture system, dual ILT2/ILT4 blockade increased CXCL9 secretion, downregulated CD163 expression, and increased the expression of M1 macrophage, IFNγ, and cytolytic T-cell gene signatures. Thus, we have revealed distinct contributions of ILT2 and ILT4 to myeloid cell biology and provide proof-of-concept data supporting the combined blockade of ILT2 and ILT4 to therapeutically induce optimal myeloid cell reprogramming in the tumor microenvironment.

Clinical utility of measuring CD4 + T follicular cells in patients with immune dysregulation.

Mechanistic studies of autoimmune disorders have identified circulating T follicular helper (cTfh) cells as drivers of autoimmunity. However, the quantification of cTfh cells is not yet used in clinical practice due to the lack of age-stratified normal ranges and the unknown sensitivity and specificity of this test for autoimmunity. We enrolled 238 healthy participants and 130 patients with common and rare disorders of autoimmunity or autoinflammation. Patients with infections, active malignancy, or any history of transplantation were excluded. In 238 healthy controls, median cTfh percentages (range 4.8% - 6.2%) were comparable among age groups, sexes, races, and ethnicities, apart from a significantly lower percentages in children less than 1 year of age (median 2.1%, CI: 0.4% - 6.8, p< 0.0001). Among 130 patients with over 40 immune regulatory disorders, a cTfh percentage exceeding 12% had 88% sensitivity and 94% specificity for differentiating disorders with adaptive immune cell dysregulation from those with predominantly innate cell defects. This threshold had a sensitivity of 86% and specificity of 100% for active autoimmunity and normalized with effective treatment. cTfh percentages exceeding 12% distinguish autoimmunity from autoinflammation, thereby differentiating two endotypes of immune dysregulation with overlapping symptoms and different therapies.

Exploring the translation process for multilingual implementation research studies: a collaborative autoethnography.

INTRODUCTION: In an increasingly globalised and interconnected world, evidence to evaluate complex interventions may be generated in multiple languages. However, despite its influence in shaping the evidence base, there is little literature explicitly connecting the translation process to the goals and processes of implementation research. This study aims to explore the processes and experience of an international implementation research team conducting a process evaluation of a complex intervention in Tibet Autonomous Region, China. METHODS: This study uses a collaborative autoethnographic approach to explore the translation process from Chinese or Tibetan to English of key stakeholder interview transcripts. In this approach, multiple researchers and translators contributed their reflections, and conducted joint analysis through dialogue, reflection and with consideration of multiple perspectives. Seven researchers involved with the translation process contributed their perspectives through in-depth interviews or written reflections and jointly analysed the resulting data. RESULTS: We describe the translation process, synthesise key challenges including developing a 'voice' and tone as a translator, conveying the depth of idioms across languages, and distance from the study context. We further offer lessons learnt including the importance of word banks with unified translations of words and phrases created iteratively during the translation process, the need to collaborate between translators and the introspective work necessary for translators to explore their positionality and reflexivity during the work. We then offer a summary of these learnings for other implementation research teams. CONCLUSION: Our findings emphasise that in order to ensure rigour in their work, implementation research teams using qualitative data should make concerted effort to consider both the translation process as well as its outcomes. Given the numerous multinational or multilingual implementation research studies using qualitative methods, there is a need for further consideration and reflection on the translation process.

The Fibronectin-ILT3 Interaction Functions as a Stromal Checkpoint that Suppresses Myeloid Cells.

Suppressive myeloid cells inhibit antitumor immunity by preventing T-cell responses. Immunoglobulin-like transcript 3 (ILT3; also known as LILRB4) is highly expressed on tumor-associated myeloid cells and promotes their suppressive phenotype. However, the ligand that engages ILT3 within the tumor microenvironment and renders tumor-associated myeloid cells suppressive is unknown. Using a screening approach, we identified fibronectin as a functional ligand for ILT3. The interaction of fibronectin with ILT3 polarized myeloid cells toward a suppressive state, and these effects were reversed with an ILT3-specific antibody that blocked the interaction of ILT3 with fibronectin. Furthermore, ex vivo treatment of human tumor explants with anti-ILT3 reprogrammed tumor-associated myeloid cells toward a stimulatory phenotype. Thus, the ILT3-fibronectin interaction represents a "stromal checkpoint" through which the extracellular matrix actively suppresses myeloid cells. By blocking this interaction, tumor-associated myeloid cells may acquire a stimulatory phenotype, potentially resulting in increased antitumor T-cell responses.

Novel immunocompetent murine tumor model for evaluation of conditionally replication-competent (oncolytic) murine adenoviral vectors.

Oncolytic adenoviral vectors that express immunostimulatory transgenes are currently being evaluated in clinic. Preclinical testing of these vectors has thus far been limited to immunodeficient xenograft tumor models since human adenoviruses do not replicate effectively in murine tumor cells. The effect of the immunostimulatory transgene on overall virus potency can therefore not be readily assessed in these models. Here, a model is described that allows the effective testing of mouse armed oncolytic adenovirus (MAV) vectors in immunocompetent syngeneic tumor models. These studies demonstrate that the MAV vectors have a high level of cytotoxicity in a wide range of murine tumor cells. The murine oncolytic viruses were successfully armed with murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) by a novel method which resulted in vectors with a high level of tumor-specific transgene expression. The mGM-CSF-armed MAV vectors showed an improved level of antitumor potency and induced a systemic antitumor immune response that was greater than that induced by unarmed parental vectors in immunocompetent syngeneic tumor models. Thus, the oncolytic MAV-1 system described here provides a murine homolog model for the testing of murine armed oncolytic adenovirus vectors in immunocompetent animals. The model allows evaluation of the impact of virus replication and the host immune response on overall virus potency and enables the generation of translational data that will be important for guiding the clinical development of these viruses.

Anti-programmed death-1 synergizes with granulocyte macrophage colony-stimulating factor--secreting tumor cell immunotherapy providing therapeutic benefit to mice with established tumors.

PURPOSE: The purpose of the present study was to evaluate granulocyte macrophage colony-stimulating factor (GM-CSF)-secreting tumor cell immunotherapy, which is known to stimulate potent and long-lasting antigen-specific immune responses, in combination with PD-1 blockade, which has been shown to augment cellular immune responses. EXPERIMENTAL DESIGN: Survival studies were done in the B16 melanoma and CT26 colon carcinoma tumor models. Immune monitoring studies were done in the B16 model. GM-CSF-secreting tumor cell immunotherapy was administered s.c. and the anti-PD-1 antibody was administered i.p. RESULTS: The studies reported here show that combining PD-1 blockade with GM-CSF-secreting tumor cell immunotherapy prolonged the survival of tumor-bearing animals compared with animals treated with either therapy alone. Prolonged survival correlated with strong antigen-specific T-cell responses detected by tetramer staining and an in vivo CTL assay, higher secretion levels of proinflammatory cytokines by splenocytes, and the persistence of functional CD8+ T cells in the tumor microenvironment. Furthermore, in the biweekly multiple treatment setting, repeated antigen-specific T-cell expansion was only observed following administration of the cellular immunotherapy with the PD-1 blockade and not when the cellular immunotherapy or PD-1 blockade was used as monotherapy. CONCLUSION: The combination of PD-1 blockade with GM-CSF-secreting tumor cell immunotherapy leads to significantly improved antitumor responses by augmenting the tumor-reactive T-cell responses induced by the cellular immunotherapy. Readministration of the cellular immunotherapy with the anti-PD-1 antibody in subsequent immunotherapy cycles was required to reactivate these T-cell responses.

Antibody-mediated inhibition of GDF15-GFRAL activity reverses cancer cachexia in mice.

Cancer cachexia is a highly prevalent condition associated with poor quality of life and reduced survival1. Tumor-induced perturbations in the endocrine, immune and nervous systems drive anorexia and catabolic changes in adipose tissue and skeletal muscle, hallmarks of cancer cachexia2-4. However, the molecular mechanisms driving cachexia remain poorly defined, and there are currently no approved drugs for the condition. Elevation in circulating growth differentiation factor 15 (GDF15) correlates with cachexia and reduced survival in patients with cancer5-8, and a GDNF family receptor alpha like (GFRAL)-Ret proto-oncogene (RET) signaling complex in brainstem neurons that mediates GDF15-induced weight loss in mice has recently been described9-12. Here we report a therapeutic antagonistic monoclonal antibody, 3P10, that targets GFRAL and inhibits RET signaling by preventing the GDF15-driven interaction of RET with GFRAL on the cell surface. Treatment with 3P10 reverses excessive lipid oxidation in tumor-bearing mice and prevents cancer cachexia, even under calorie-restricted conditions. Mechanistically, activation of the GFRAL-RET pathway induces expression of genes involved in lipid metabolism in adipose tissues, and both peripheral chemical sympathectomy and loss of adipose triglyceride lipase protect mice from GDF15-induced weight loss. These data uncover a peripheral sympathetic axis by which GDF15 elicits a lipolytic response in adipose tissue independently of anorexia, leading to reduced adipose and muscle mass and function in tumor-bearing mice.

Allogeneic GM-CSF-secreting tumor cell immunotherapies generate potent anti-tumor responses comparable to autologous tumor cell immunotherapies.

Clinical studies of cell-based immunotherapies have included both patient-specific (autologous) and non-patient-specific (allogeneic) approaches. Major concerns in using allogeneic immunotherapies are that the induced immune responses may be predominantly directed against the allogeneic HLA molecules of the cellular immunotherapy and not against its potential tumor antigens and that only the allogeneic responses will be enhanced when the immunotherapies are combined with immune checkpoint regulators in an effort to enhance overall immunotherapy potency. To evaluate these possibilities, studies were performed using the GM-CSF-secreting B16F1 cell line as autologous immunotherapy (Auto) and the same cell line modified to over-express the MHC molecule K(d) to generate an immunotherapy that expresses an allogeneic component (Allo) when injected into C57/Bl6 mice. The goal was to compare the specific anti-tumor immune responses induced by these two immunotherapies, which share an identical antigen repertoire, with the exception of the allogeneic MHC class I molecule expressed by the Allo cells, and have identical GM-CSF-secretion levels. Both immunotherapies provided similar therapeutic benefit to tumor-bearing animals with a trend towards a more pronounced tumor growth delay in animals injected with the Allo immunotherapy. This correlated with a significant increase in the number of activated DCs and T-cells in the DLN of Allo-treated animals. In addition, persistent infiltration of effector CD8(+) T-cells was detected in the tumors of animals treated with the Allo immunotherapy, which correlated with a trend towards a greater antigen-specific T-cell response in these animals. When combined with the immune checkpoint regulator anti-PD-1, tumor-specific and allogeneic immune responses were equally enhanced. Thus, the ability of an allogeneic tumor cell immunotherapy to induce a therapeutic anti-tumor immune response is comparable, if not superior, to an autologous tumor cell immunotherapy and its anti-tumor potency can be enhanced when combined with immunomodulatory compounds.