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Background Immunotherapeutic early-phase clinical trials (ieCTs) increasingly adopt large expansion cohorts exploring novel agents across different tumor types. High-grade glioma (HGG) patients are usually excluded from these trials. Methods Data of patients with recurrent HGGs treated within multicohort ieCTs between February 2014 and August 2019 (experimental group, EG) at our Phase I Unit were retrospectively reviewed and compared to a matched control group (CG) of patients treated with standard therapies. We retrospectively evaluated clinical, laboratory, and molecular parameters through univariate and multivariate analysis. A prospective characterization of circulating leukocyte subpopulations was performed in the latest twenty patients enrolled in the EG, with a statistical significance cutoff of P < .1. Results Thirty HGG patients were treated into six ieCTs. Fifteen patients received monotherapies (anti-PD-1, anti-CSF-1R, anti-TGFβ, anti-cereblon), fifteen patients combination regimens (anti-PD-L1 + anti-CD38, anti-PD-1 + anti-CSF-1R). In the EG, median progression-free survival and overall survival (OS) from treatment initiation were 1.8 and 8.6 months; twelve patients survived more than 12 months, and two of them more than 6 years. Univariate analysis identified O6-methylguanine DNA methyltransferase (MGMT) promoter methylation and total protein value at six weeks as significantly correlated with a better outcome. Decreased circulating neutrophils and increased conventional dendritic cells levels lead to significantly better OS. Conclusions A subgroup of EG patients achieved remarkably durable disease control. MGMT promoter methylation identifies patients who benefit more from immunotherapy. Monitoring dynamic changes of innate immune cell populations may help to predict clinical outcomes.

Aims The pathogenetic mechanisms underlying unprovoked venous thromboembolism (uVTE) are largely unknown. In this study, we investigated the molecular mechanisms involved in uVTE pathogenesis by using ex vivo expanded endothelial colony-forming cells (ECFCs), which represent a valuable non-invasive tool for the assessment of endothelial function. Methods and results We isolated and expanded ECFCs from the peripheral blood of uVTE patients and observed that these cells underwent earlier senescence and showed lower growth rate compared with ECFCs obtained from healthy donors. Through microarray expression profiling, we demonstrated that 2905 genes were differentially expressed between patients and controls. Among them, the anti-angiogenic cytokine TNF superfamily member 15 (TNFSF15) and its death-receptor TNFRSF25 were up-regulated in uVTE ECFCs, and this finding was validated by RT-qPCR. TNFSF15 up-regulation was confirmed at the protein level in ECFC supernatants, and the in vivo relevance of these findings was further corroborated by demonstrating that also the plasmatic levels of TNFSF15 are increased in uVTE patients. After proving that exogenous TNFSF15 exerts pro-apoptotic and anti-proliferative activity on control ECFCs, we demonstrated through blocking experiments that TNFSF15 up-regulation contributes to impaired survival and proliferation of uVTE ECFCs. Conclusion By providing evidence that TNFSF15 impairs ECFC functions crucial to endothelial repair, and that uVTE patients have increased TNFSF15 levels both ex vivo and in vivo, the results of this study suggest that pathologic up-regulation of TNFSF15–TNFRSF25 axis may contribute to uVTE pathogenesis, and may represent the target for novel therapeutic strategies aimed at preventing recurrences in uVTE patients.

International audience; Human Vδ2 cells are innate-like γδ T effectors performing potent immune surveillance against tumors. The constitutive expression of NKG2A identifies a subset of Vδ2 T cells licensed with an intrinsic hyper-responsiveness against cancer. Indeed, the transcriptomic profiles of NKG2A+ and NKG2A- cells characterize two distinct "intralineages" of Vδ2 T lymphocytes that appear early during development, keep their phenotypes, and show self-renewal capabilities in adult life. The hyper-responsiveness of NKG2A+ Vδ2 T cells is counterbalanced by the inhibitory signaling delivered by human leukocyte antigen E (HLA-E) expressed on malignant cells as a tumor-escape mechanism. However, either masking or knocking out NKG2A restores the capacity of Vδ2 T cells to exert the highest effector functions even against HLA-E+ tumors. This is highly relevant in the clinic, as the different degrees of engagement of the NKG2A-HLA-E checkpoint in hepatocellular carcinoma, glioblastoma, and non-small cell lung cancer directly impact patients' overall survival. These findings open avenues for developing combined cellular and immunologic anticancer therapies.

Dendritic cells (DCs) play a crucial role in the complex interplay between tumor cells and the immune system. During the elimination phase of cancer immunoediting, immunostimulatory DCs are critical for the control of tumor growth. During the escape phase, regulatory DCs sustain tumor tolerance and contribute to the development of the immunosuppressive tumor microenvironment that characterizes this phase. Moreover, increasing evidence indicates that DCs are also critical for the success of cancer immunotherapy. Hence, there is increasing need to fully characterize DC subsets and their activatory/inhibitory profile in cancer patients. In this review, we describe the role played by different DC subsets in the different phases of cancer immunoediting, the function exerted by different activatory and inhibitory molecules expressed on DC surface, and the cytokines produced by distinct DC subsets, in order to provide an overview on the DC features that may be useful to be assessed when dealing with the flow cytometric characterization of DCs in cancer patients. © 2020 International Society for Advancement of Cytometry.

Endothelial colony-forming cells (ECFCs), a unique endothelial stem cell population, are highly increased in the blood of Kaposi sarcoma (KS) patients. KS-derived ECFCs (KS-ECFCs) are also endowed with increased proliferative and vasculogenic potential, thus suggesting that they may be precursors of KS spindle cells. However, the mechanisms underlying the increased proliferative activity of KS-ECFCs remain poorly understood. Sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) are metabolically interconnected sphingoid mediators crucial to cell proliferation. Here, we investigated the metabolism, release, and proliferative effects of S1P and C1P in KS-ECFCs compared with control ECFCs (Ct-ECFCs). Metabolic studies by cell labeling, chromatographic analyses, and digital autoradiography revealed that S1P and C1P biosynthesis and S1P secretion are all efficient processes in KS-ECFCs, more efficient in KS-ECFCs than Ct-ECFCs. Quantitative PCR analyses demonstrated a significantly higher ceramide kinase and sphingosine kinase-2 expression in KS-ECFCs. Notably, also the expression of S1P1 and S1P3 receptors was augmented in KS-ECFCs. Accordingly, treatment with exogenous C1P or S1P induced a significant, concentration-dependent stimulation of KS-ECFC proliferation, but was almost completely ineffective in Ct-ECFCs. Hence, we identified C1P and S1P as autocrine/paracrine proliferative signals in KS-ECFCs. A better understanding of the mechanisms that enhance S1P/C1P formation in KS-ECFCs may yield effective therapeutic modalities.

Glioma is the most common primary brain cancer, and half of patients present a diagnosis of glioblastoma (GBM), its most aggressive and lethal form. Conventional therapies, including surgery, radiotherapy, and chemotherapy, have not resulted in major ameliorations in GBM survival outcome, which remains extremely poor. Recent immunotherapy improvements for other tumors, coupled with growing knowledge of the complex interactions between malignant glioma cells and the immune system, led to an exponential increase in glioma immunotherapy research. However, immunotherapeutic strategies in GBM have not yet reached their full potential, mainly due to the limited understanding of the strong immunosuppressive microenvironment (TME) characterizing this tumor. Glioma-associated macrophages and microglia (GAMs) are key drivers of the local immunosuppression promoting tumor progression and its resistance to immunomodulating therapeutic strategies. Together with other myeloid cells, such as dendritic cells and neutrophils, GAMs actively shape glioma TME, modulate anti-tumoral immune response and support angiogenesis, tumor cell invasion and proliferation. In this review, we discuss the role of myeloid cells in the complex TME of glioma and the available clinical data on therapeutic strategies focusing on approaches that affect myeloid cells activity in GBM.

Simple Summary The reciprocal crosstalk between dendritic cells (DCs) and natural killer (NK) cells plays a pivotal role in regulating immune defense against viruses and tumors. The Th-cell polarizing ability, cytokine-producing capacity, chemokine expression, and migration of DCs are regulated by activated NK cells. Conversely, the effector functions including lysis and cytokine production, proliferation, and migration of NK cells are influenced by close interactions with activated DCs. In this review, we explore the impact of DC–NK cell crosstalk and its therapeutic potential in immune control of liver malignances. Abstract Natural killer (NK) and dendritic cells (DCs) are innate immune cells that play a crucial role in anti-tumor immunity. NK cells kill tumor cells through direct cytotoxicity and cytokine secretion. DCs are needed for the activation of adaptive immune responses against tumor cells. Both NK cells and DCs are subdivided in several subsets endowed with specialized effector functions. Crosstalk between NK cells and DCs leads to the reciprocal control of their activation and polarization of immune responses. In this review, we describe the role of NK cells and DCs in liver cancer, focusing on the mechanisms involved in their reciprocal control and activation. In this context, intrahepatic NK cells and DCs present unique immunological features, due to the constant exposure to non-self-circulating antigens. These interactions might play a fundamental role in the pathology of primary liver cancer, namely hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Additionally, the implications of these immune changes are relevant from the perspective of improving the cancer immunotherapy strategies in HCC and ICC patients.

Kaposi's sarcoma (KS) is characterized by hyperproliferation of spindle cells that have an endothelial origin and assume their characteristic features upon infection with human herpesvirus-8, the causative agent for KS. The multifocal nature of KS suggests that spindle cells derive from circulating HHV8-infected precursors that yet lack identification. We investigated whether endothelial colony-forming cells (ECFCs) obtained from KS patients may be putative precursors of spindle cells by assessing whether their in vitro behavior may evoke the in vivo behavior of KS spindle cells. We isolated and cultured ECFCs from the blood of 83 patients with classic KS and compared them with ECFCs obtained from 86 healthy donors. ECFCs were highly increased in the blood of classic KS patients; they showed higher proliferative and vasculogenic potential and higher production of IL-6 than control ECFCs. Similarly to spindle cells in KS lesions, a variable proportion of cells within each ECFC colony expressed the human herpesvirus-8 latency-associated nuclear antigen. ECFCs obtained from classic KS patients evoked KS spindle cell behavior, thus supporting the hypothesis that ECFCs may be putative precursors of spindle cells. ECFCs can therefore represent a noninvasive tool for studying KS and screening drug activity, thus possibly guiding personalized care for KS patients.