Benzodiazepines compromise the outcome of cancer immunotherapy.

Acyl CoA binding protein (ACBP, which is encoded by diazepam binding inhibitor, DBI) acts on the gamma-amino butyric acid (GABA) receptor type A via a specific binding site that is shared by diazepam and other benzodiazepines. Both ACBP/DBI and benzodiazepines act as positive allosteric modulators, hence increasing GABA effects on this receptor. Recently, we found that ACBP/DBI acts as an endogenous immunosuppressor, meaning that its antibody-mediated neutralization has immunostimulatory effects and enhances the efficacy of immunotherapy and chemoimmunotherapy in mouse models. Driven by these considerations, we investigated whether diazepam administration in mice would reverse the beneficial effects of ACBP/DBI neutralization on cancer chemoimmunotherapy. Indeed, diazepam abolished the therapeutic of anti-ACBP/DBI antibodies, supporting the idea that diazepam exerts immunosuppressive properties. Of note, treatment with benzodiazepines was associated with poor clinical responses to chemoimmunotherapy in patients with non-small cell lung cancer (NSCLC) as compared to individuals not receiving any psychotropic drugs. Medication with other psychotropic drugs than benzodiazepines did not compromise the outcome of chemoimmunotherapy, indicating that this immunosuppressive effect was benzodiazepine specific. We conclude that benzodiazepines may confer systemic immunosuppression. This hypothesis requires further epidemiological and clinical confirmation.

Elimination of cDC1 cells by regulatory T cells jeopardizes cancer immunotherapy.

Recent findings revealed that neoantigen-specific cytotoxic type 1 regulatory T (TR1) CD4 T cells can subvert cancer immunotherapy by killing type 1 conventional dendritic cells (cDC1s) that present tumor antigens bound to MHC class II. This underlines the importance of cDC1s for eliciting anticancer immunity but poses a novel clinical challenge.

Flow cytometry-assisted analysis of phenotypic maturation markers on an immortalized dendritic cell line.

Dendritic cells (DCs), and especially so conventional type I DCs (cDC1s), are fundamental regulators of anticancer immunity, largely reflecting their superior ability to engulf tumor-derived material and process it for cross-presentation on MHC Class I molecules to CD8+ cytotoxic T lymphocytes (CTLs). Thus, investigating key DC functions including (but not limited to) phagocytic capacity, expression of CTL-activating ligands on the cell surface, and cross-presentation efficacy is an important component of multiple immuno-oncology studies. Unfortunately, DCs are terminally differentiated cells, implying that they cannot be propagated indefinitely in vitro and hence must be generated ad hoc from circulating or bone marrow-derived precursors, which presents several limitations. Here, we propose a simple, cytofluorometric method to quantify phenotypic activation markers including CD80, CD86 and MHC class II molecules on the surface of a conditionally immortalized immature DC line that can be indefinitely propagated in vitro but also driven into maturation at will with a simple change in culture conditions. Upon appropriate scaling and automatization, this approach is compatible with high-throughput screening programs for the discovery of novel DC activators that do not suffer from batch variability and other limitations associated with the generation of fresh DCs.

Neutralization of the autophagy-repressive tissue hormone DBI/ACBP (diazepam binding inhibitor, acyl-CoA binding protein) enhances anticancer immunosurveillance.

The plasma concentration of the macroautophagy/autophagy inhibitor DBI/ACBP (diazepam binding inhibitor, acyl-CoA binding protein) increases with aging and body mass index (BMI). Both advanced age and obesity are among the most important risk factors for the development of cancer. We observed that patients with cancer predisposition syndromes due to mutations in BRCA1, BRCA2 and TP53 exhibit abnormally high plasma DBI/ACBP levels. Additionally, patients without known cancer predisposition syndromes also manifest higher DBI/ACBP levels before imminent cancer diagnosis (within 0-3 years) as compared to age and BMI-matched controls who remain cancer-free. Thus, supranormal plasma DBI/ACBP constitutes a risk factor for later cancer development. Mouse experimentation revealed that genetic or antibody-mediated DBI/ACBP inhibition can delay the development or progression of cancers. In the context of chemoimmunotherapy, DBI/ACBP neutralization enhances tumor infiltration by non-exhausted effector T cells but reduces infiltration by regulatory T cells. This resulted in better cancer control in models of breast cancer, non-small cell lung cancer and sarcoma. We conclude that DBI/ACBP constitutes an actionable autophagy checkpoint for improving cancer immunosurveillance. Abbreviation: BMI, body mass index; CTL, cytotoxic T lymphocyte; DBI, diazepam binding inhibitor, acyl-CoA binding protein; mAb, monoclonal antibody; NSCLC, non-small cell lung cancer; PDCD1/PD-1, programmed cell death 1; scRNA-seq, single-cell RNA sequencing; Treg, regulatory T cell.

Acyl CoA binding protein (ACBP): an autophagy checkpoint that can be targeted for improving cancer immunosurveillance.

Acyl CoA binding protein (ACBP) encoded by DBI is a tissue hormone that limits autophagy in multiple cell types, hence acting as an extracellular autophagy checkpoint. We recently reported in Molecular Cancer that monoclonal antibodies neutralizing ACBP improve immunosurveillance of breast and lung carcinomas. Moreover, ACBP neutralization improves the outcome of neoadjuvant chemoimmunotherapy with PD-1 blockade in preclinical models.

Acyl-coenzyme a binding protein (ACBP) - a risk factor for cancer diagnosis and an inhibitor of immunosurveillance.

BACKGROUND: The plasma concentrations of acyl coenzyme A binding protein (ACBP, also known as diazepam-binding inhibitor, DBI, or 'endozepine') increase with age and obesity, two parameters that are also amongst the most important risk factors for cancer. METHODS: We measured ACBP/DBI in the plasma from cancer-free individuals, high-risk patients like the carriers of TP53 or BRCA1/2 mutations, and non-syndromic healthy subjects who later developed cancer. In mice, the neutralization of ACBP/DBI was used in models of non-small cell lung cancer (NSCLC) and breast cancer development and as a combination treatment with chemoimmunotherapy (chemotherapy + PD-1 blockade) in the context of NSCLC and sarcomas. The anticancer T cell response upon ACBP/DBI neutralization was characterized by flow cytometry and single-cell RNA sequencing. RESULTS: Circulating levels of ACBP/DBI were higher in patients with genetic cancer predisposition (BRCA1/2 or TP53 germline mutations) than in matched controls. In non-syndromic cases, high ACBP/DBI levels were predictive of future cancer development, and especially elevated in patients who later developed lung cancer. In preclinical models, ACBP/DBI neutralization slowed down breast cancer and NSCLC development and enhanced the efficacy of chemoimmunotherapy in NSCLC and sarcoma models. When combined with chemoimmunotherapy, the neutralizing monoclonal antibody against ACBP/DBI reduced the frequency of regulatory T cells in the tumor bed, modulated the immune checkpoint profile, and increased activation markers. CONCLUSION: These findings suggest that ACBP/DBI acts as an endogenous immune suppressor. We conclude that elevation of ACBP/DBI constitutes a risk factor for the development of cancer and that ACBP/DBI is an actionable target for improving cancer immunosurveillance.

Long-distance microbial mechanisms impacting cancer immunosurveillance.

The intestinal microbiota determines immune responses against extraintestinal antigens, including tumor-associated antigens. Indeed, depletion or gross perturbation of the microbiota undermines the efficacy of cancer immunotherapy, thereby compromising the clinical outcome of cancer patients. In this review, we discuss the long-distance effects of the gut microbiota and the mechanisms governing antitumor immunity, such as the translocation of intestinal microbes into tumors, migration of leukocyte populations from the gut to the rest of the body, including tumors, as well as immunomodulatory microbial products and metabolites. The relationship between these pathways is incompletely understood, in particular the significance of the tumor microbiota with respect to the identification of host and/or microbial products that regulate the egress of bacteria and immunocytes toward tumor beds.

Obesity-Associated Colorectal Cancer.

Colorectal cancer (CRC) affects approximately 2 million people worldwide. Obesity is the major risk factor for CRC. In addition, obesity contributes to a chronic inflammatory stage that enhances tumor progression through the secretion of proinflammatory cytokines. In addition to an increased inflammatory response, obesity-associated cancer presents accrued molecular factors related to cancer characteristics, such as genome instability, sustained cell proliferation, telomere dysfunctions, angiogenesis, and microbial alteration, among others. Despite the evidence accumulated over the last few years, the treatments for obesity-associated CRC do not differ from the CRC treatments in normal-weight individuals. In this review, we summarize the current knowledge on obesity-associated cancer, including its epidemiology, risk factors, molecular factors, and current treatments. Finally, we enumerate possible new therapeutic targets that may improve the conditions of obese CRC patients. Obesity is key for the development of CRC, and treatments resulting in the reversal of obesity should be considered as a strategy for improving antineoplastic CRC therapies.

Acyl-CoA binding protein for the experimental treatment of anorexia.

Extracellular acyl-coenzyme A binding protein [ACBP encoded by diazepam binding inhibitor (DBI)] is a phylogenetically ancient appetite stimulator that is secreted in a nonconventional, autophagy-dependent fashion. Here, we show that low ACBP/DBI plasma concentrations are associated with poor prognosis in patients with anorexia nervosa, a frequent and often intractable eating disorder. In mice, anorexia induced by chronic restraint stress (CRS) is accompanied by a reduction in circulating ACBP/DBI concentrations. We engineered a chemical-genetic system for the secretion of ACBP/DBI through a biotin-activatable, autophagy-independent pathway. In transgenic mice expressing this system in hepatocytes, biotin-induced elevations in plasma ACBP/DBI concentrations prevented anorexia induced by CRS or chemotherapeutic agents including cisplatin, doxorubicin, and paclitaxel. ACBP/DBI reversed the CRS or cisplatin-induced increase in plasma lipocalin-2 concentrations and the hypothalamic activation of anorexigenic melanocortin 4 receptors, for which lipocalin-2 is an agonist. Daily intravenous injections of recombinant ACBP/DBI protein or subcutaneous implantation of osmotic pumps releasing recombinant ACBP/DBI mimicked the orexigenic effects of the chemical-genetic system. In conclusion, the supplementation of extracellular and peripheral ACBP/DBI might constitute a viable strategy for treating anorexia.

Targeted opening of the blood-brain barrier facilitates doxorubicin/anti-PD-1-based chemoimmunotherapy of glioblastoma.

Doxorubicin is a prototypical inducer of immunogenic cell death (ICD) that sensitizes to subsequent immunotherapy by PD-1 blockade. However, this systemic drug combination fails against glioblastoma, hidden behind the blood-brain barrier (BBB). A recent work delineates a biophysical method for BBB permeabilization that yields effective preclinical effects of chemoimmunotherapy.

Copper impairs the intestinal barrier integrity in Wilson disease.

In Wilson disease (WD), liver copper (Cu) excess, caused by mutations in the ATPase Cu transporting beta (ATP7B), has been extensively studied. In contrast, in the gastrointestinal tract, responsible for dietary Cu uptake, ATP7B malfunction is poorly explored. We therefore investigated gut biopsies from WD patients and compared intestines from two rodent WD models and from human ATP7B knock-out intestinal cells to their respective wild-type controls. We observed gastrointestinal (GI) inflammation in patients, rats and mice lacking ATP7B. Mitochondrial alterations and increased intestinal leakage were observed in WD rats, Atp7b-/- mice and human ATP7B KO Caco-2 cells. Proteome analyses of intestinal WD homogenates revealed profound alterations of energy and lipid metabolism. The intestinal damage in WD animals and human ATP7B KO cells did not correlate with absolute Cu elevations, but likely reflects intracellular Cu mislocalization. Importantly, Cu depletion by the high-affinity Cu chelator methanobactin (MB) restored enterocyte mitochondria, epithelial integrity, and resolved gut inflammation in WD rats and human WD enterocytes, plausibly via autophagy-related mechanisms. Thus, we report here before largely unrecognized intestinal damage in WD, occurring early on and comprising metabolic and structural tissue damage, mitochondrial dysfunction, and compromised intestinal barrier integrity and inflammation, that can be resolved by high-affinity Cu chelation treatment.

Custom scoring based on ecological topology of gut microbiota associated with cancer immunotherapy outcome.

The gut microbiota influences the clinical responses of cancer patients to immunecheckpoint inhibitors (ICIs). However, there is no consensus definition of detrimental dysbiosis. Based on metagenomics (MG) sequencing of 245 non-small cell lung cancer (NSCLC) patient feces, we constructed species-level co-abundance networks that were clustered into species-interacting groups (SIGs) correlating with overall survival. Thirty-seven and forty-five MG species (MGSs) were associated with resistance (SIG1) and response (SIG2) to ICIs, respectively. When combined with the quantification of Akkermansia species, this procedure allowed a person-based calculation of a topological score (TOPOSCORE) that was validated in an additional 254 NSCLC patients and in 216 genitourinary cancer patients. Finally, this TOPOSCORE was translated into a 21-bacterial probe set-based qPCR scoring that was validated in a prospective cohort of NSCLC patients as well as in colorectal and melanoma patients. This approach could represent a dynamic diagnosis tool for intestinal dysbiosis to guide personalized microbiota-centered interventions.

Aging and cancer.

Aging and cancer exhibit apparent links that we will examine in this review. The null hypothesis that aging and cancer coincide because both are driven by time, irrespective of the precise causes, can be confronted with the idea that aging and cancer share common mechanistic grounds that are referred to as 'hallmarks'. Indeed, several hallmarks of aging also contribute to carcinogenesis and tumor progression, but some of the molecular and cellular characteristics of aging may also reduce the probability of developing lethal cancer, perhaps explaining why very old age (> 90 years) is accompanied by a reduced incidence of neoplastic diseases. We will also discuss the possibility that the aging process itself causes cancer, meaning that the time-dependent degradation of cellular and supracellular functions that accompanies aging produces cancer as a byproduct or 'age-associated disease'. Conversely, cancer and its treatment may erode health and drive the aging process, as this has dramatically been documented for cancer survivors diagnosed during childhood, adolescence, and young adulthood. We conclude that aging and cancer are connected by common superior causes including endogenous and lifestyle factors, as well as by a bidirectional crosstalk, that together render old age not only a risk factor of cancer but also an important parameter that must be considered for therapeutic decisions.

Clinically relevant GABARAP deficiency abrogates bortezomib-induced immunogenic cell death in multiple myeloma.

Recently, it was revealed that the high-risk, poor-prognosis downregulation of GABA type A receptor-associated protein (GABARAP) causes a defect in both autophagy and surface exposure of calreticulin (CALR) in multiple myeloma (MM) cells responding to bortezomib. Hence, GABARAP-defective MM cells fail to undergo immunogenic cell death.

Immunogenic oncolysis by tigilanol tiglate.

Tigilanol tiglate is an oncolytic small molecule that is undergoing clinical trials. A recent study revealed the capacity of this pyroptosis inducer to elicit hallmarks of immunogenic cell death. In addition, intratumoral injection of tigilanol tiglate can sensitize subcutaneous cancers to subsequent immune checkpoint inhibitors targeting CTLA-4 alone or in combination with PD-1.

Tutorial: design, production and testing of oncolytic viruses for cancer immunotherapy.

Oncolytic viruses (OVs) represent a novel class of cancer immunotherapy agents that preferentially infect and kill cancer cells and promote protective antitumor immunity. Furthermore, OVs can be used in combination with established or upcoming immunotherapeutic agents, especially immune checkpoint inhibitors, to efficiently target a wide range of malignancies. The development of OV-based therapy involves three major steps before clinical evaluation: design, production and preclinical testing. OVs can be designed as natural or engineered strains and subsequently selected for their ability to kill a broad spectrum of cancer cells rather than normal, healthy cells. OV selection is further influenced by multiple factors, such as the availability of a specific viral platform, cancer cell permissivity, the need for genetic engineering to render the virus non-pathogenic and/or more effective and logistical considerations around the use of OVs within the laboratory or clinical setting. Selected OVs are then produced and tested for their anticancer potential by using syngeneic, xenograft or humanized preclinical models wherein immunocompromised and immunocompetent setups are used to elucidate their direct oncolytic ability as well as indirect immunotherapeutic potential in vivo. Finally, OVs demonstrating the desired anticancer potential progress toward translation in patients with cancer. This tutorial provides guidelines for the design, production and preclinical testing of OVs, emphasizing considerations specific to OV technology that determine their clinical utility as cancer immunotherapy agents.

Targeting immunogenic cell stress and death for cancer therapy.

Immunogenic cell death (ICD), which results from insufficient cellular adaptation to specific stressors, occupies a central position in the development of novel anticancer treatments. Several therapeutic strategies to elicit ICD - either as standalone approaches or as means to convert immunologically cold tumours that are insensitive to immunotherapy into hot and immunotherapy-sensitive lesions - are being actively pursued. However, the development of ICD-inducing treatments is hindered by various obstacles. Some of these relate to the intrinsic complexity of cancer cell biology, whereas others arise from the use of conventional therapeutic strategies that were developed according to immune-agnostic principles. Moreover, current discovery platforms for the development of novel ICD inducers suffer from limitations that must be addressed to improve bench-to-bedside translational efforts. An improved appreciation of the conceptual difference between key factors that discriminate distinct forms of cell death will assist the design of clinically viable ICD inducers.

Cancer and the Metaorganism.

SUMMARY: Pathogenic shifts in the gut microbiota are part of the "ecological" alterations that accompany tumor progression and compromise immunosurveillance. The future management of health and disease including cancer will rely on the diagnosis of such shifts and their therapeutic correction by general or personalized strategies, hence restoring metaorganismal homeostasis.