Adoptive cell therapy of solid tumors with reprogrammed T cells can be considered the “next generation” of cancer hallmarks. CAR-T cells fail to be as effective as in liquid tumors for the inability to reach and survive in the microenvironment surrounding the neoplastic foci. The intricate net of cross-interactions occurring between tumor components, stromal and immune cells leads to an ineffective anergic status favoring the evasion from the host’s defenses. Our goal is hereby to trace the road imposed by solid tumors to CAR-T cells, highlighting pitfalls and strategies to be developed and refined to possibly overcome these hurdles.

Background: Despite the efficacy of immune checkpoint inhibitors (ICIs) only the 20-30% of treated patients present long term benefits. The metabolic changes occurring in the gut microbiota metabolome are herein proposed as a factor potentially influencing the response to immunotherapy. Methods: The metabolomic profiling of gut microbiota was characterized in 11 patients affected by non-small cell lung cancer (NSCLC) treated with nivolumab in second-line treatment with anti-PD-1 nivolumab. The metabolomics analyses were performed by GC-MS/SPME and 1 H-NMR in order to detect volatile and non-volatile metabolites. Metabolomic data were processed by statistical profiling and chemometric analyses. Results: Four out of 11 patients (36%) presented early progression, while the remaining 7 out of 11 (64%) presented disease progression after 12 months. 2-Pentanone (ketone) and tridecane (alkane) were significantly associated with early progression, and on the contrary short chain fatty acids (SCFAs) (i.e., propionate, butyrate), lysine and nicotinic acid were significantly associated with long-term beneficial effects. Conclusions: Our preliminary data suggest a significant role of gut microbiota metabolic pathways in affecting response to immunotherapy. The metabolic approach could be a promising strategy to contribute to the personalized management of cancer patients by the identification of microbiota-linked "indicators" of early progressor and long responder patients.

Dendritic cells (DCs) sense the microenvironment through several types of receptors recognizing pathogen-associated molecular patterns. In particular, C-type lectins, expressed by distinct subsets of DCs, recognize and internalize specific carbohydrate antigen in a Ca 2+ -dependent manner. Targeting of these receptors is becoming an efficient strategy of delivering antigens in DC-based anticancer immunotherapy. Here we investigated the role of the macrophage galactose type C-lectin receptor (MGL), expressed by immature DCs (iDCs), as a molecular target for α-N-acetylgalactosamine (GalNAc or Tn)-carrying tumor-associated antigens to improve DC performance. MGL expressed by ex vivo-generated iDCs from healthy donors was engaged by a 60-mer MUC1 9Tn -glycopeptide as a Tn-carrying tumor-associated antigen, and an anti-MGL antibody, as a specific MGL binder. We demonstrated that MGL engagement induced homotrimers and homodimers, triggering the phosphorylation of extracellular signal-regulated kinase 1,2 (ERK1,2) and nuclear factor-κB activation. Analysis of DC phenotype and function demonstrated that MGL engagement improved DC performance as antigen-presenting cells, promoting the upregulation of maturation markers, a decrease in phagocytosis, an enhancement of motility, and most importantly an increase in antigen-specific CD8 + T-cell activation. These results demonstrate that the targeting of MGL receptor on human DCs has an adjuvant effect and that this strategy can be used to design novel anticancer vaccines. Keywords: C-type lectins · Dendritic cells · Macrophage galactose-type C-type lectin (MGL) · MUC1 · Tn-tumor associated antigens IntroductionDendritic cells (DCs), as professional antigen-presenting cells (APCs), sense the microenvironment through different types of Correspondence: Prof. Marianna Nuti e-mail: marianna.nuti@uniroma1.it receptors to scan local environmental changes and eliminate incoming pathogens [1]. They play an essential role in the uptake of self-or pathogen-associated antigens, thus, steering and directing the immune response. After activation, DCs migrate to the draining lymph nodes, where they initiate specific immunity * These authors contributed equally to this work. The most important molecules from the CLR family include macrophage galactose type C-lectin (MGL), dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), the mannose receptor, DEC205, and Dectin-1. These receptors are able to trigger distinct signaling pathways that modulate DC functions through the expression of specific molecules and cytokines, determining the polarization of T cells [4]. These properties make this C-type lectin family an optimal tool for DC targeting in cancer vaccination. Human MGL (hMGL) is a type II C-type lectin, expressed in vitro by macrophages and monocyte derived DCs and in vivo by DCs of skin and lymph nodes [5,6]. Its carbohydrate recognition domains contain a QPD sequence that is responsible for recognition of α-or β-N-acetylgalactosamine (GalNAc, Tn) res...

BackgroundImmune checkpoint inhibitors have revolutionized the treatment paradigm of highly lethal malignancies like advanced non-small cell lung cancer (NSCLC), demonstrating long-term tumour control and extended patient survival. Unfortunately, only 25–30% of patients experience a durable benefit, while the vast majority demonstrate primary or acquired resistance. Recently, indoleamine 2,3-dioxygenase (IDO) activity has been proposed as a possible mechanism of resistance to anti-PD-1 treatment leading to an immunosuppressive microenvironment.MethodsPre-treatment serum concentrations of tryptophan (trp) and kynurenine (kyn) were measured by high-performance liquid chromatography tandem mass spectrometry in NSCLC patients treated with second-line nivolumab. The IDO activity was expressed with kyn/trp ratio. The associations between kyn/trp ratio and early progression, performance status (PS), age, sex, brain metastases, pleural effusion, progression free survival (PFS) and overall survival (OS) were analyzed using Spearman test and Mann–Whitney test.ResultsTwenty-six NSCLC patients were included in our study; 14 of them (54%) presented early progression (< 3 months) to nivolumab treatment. The median value of kyn/trp ratio was 0.06 µg/ml and the median value of quinolinic acid was 68.45 ng/ml. A significant correlation between early progression and higher kyn/trp ratio and quinolinic acid concentration was observed (p = 0.017 and p = 0.005, respectively). Patients presenting lower values of kyn/trp ratio and quinolinic acid levels showed longer PFS (median PFS not reached versus 3 months; HR: 0.3; p = 0.018) and OS (median OS not reached vs 3 months; HR: 0.18; p = 0.0005).ConclusionIDO activity, expressed as kyn/trp ratio, is associated with response to immunotherapy; in particular, higher kyn/trp ratio could predict resistance to anti-PD-1 treatment. These preliminary results suggest the possibility of using anti-PD-1 plus IDO inhibitor in those patients with high level of kyn/trp ratio.

BackgroundImmune checkpoint inhibitors, targeting the molecules CTLA-4, PD-1 and PD-L1, showed efficacy against several type of cancers and are currently used in clinical practice. An important biological variable that influences innate and adaptive immunity is the sex, acting through genetic, hormonal and environmental factors. The overall differences between sexes could be crucial to evaluate the response to ICIs.Materials and methodsWe performed a meta-analysis of Phase II-III Clinical Trials published up to June 2017 in which anti-CTLA-4, anti-PD-1 and anti-PD-L1 were studied. We extracted the OS and PFS HR differentiated by sex from subgroups analysis of each trial. We analyzed the three classes of drugs separately.ResultsWe selected 36 Phase II-III Clinical Trials, 9 of which reported results for OS and 6 for PFS. We analyzed 2 Clinical Trials for OS with anti-CTLA-4, including 1178 patients, observing a benefit for males vs females (HR 0.65, 95% CI 0.55-0.77 vs HR 0.79, 95% CI 0.65-0.96, p 0.078).Not statistically significant results were observed with anti-PD-1 neither for OS (males vs females: HR 0.72, 95% CI 0.64-0.83 vs HR 0.81, 95% CI 0.70-0.94, p 0.285) neither for PFS (males vs females: HR 0.66, 95% CI 0.52-0.82 vs HR 0.85, 95% CI 0.66-1.09, p 0.158). We cannot perform a meta-analysis for anti-PD-L1 due to the lack of data.ConclusionsDifferent mechanisms could be involved in sex differences with regard to immunotherapy. These differences could be relevant to identify immunological targets in order to draw studies exploring novel combinations of immunotherapy agents.

C-type lectin receptors (CLRs) on antigen-presenting cells (APCs) facilitate uptake of carbohydrate antigens for antigen presentation, modulating the immune response in infection, homeostasis, autoimmunity, allergy, and cancer. In this review, we focus on the role of the macrophage galactose type C-type lectin (MGL) in the immune response against self-antigens, pathogens, and tumor associated antigens (TAA). MGL is a CLR exclusively expressed by dendritic cells (DCs) and activated macrophages (MØs), able to recognize terminal GalNAc residues, including the sialylated and nonsialylated Tn antigens. We discuss the effects on DC function induced throughout the engagement of MGL, highlighting the importance of the antigen structure in the modulation of immune response. Indeed modifying Tn-density, the length, and steric structure of the Tn-antigens can result in generating immunogens that can efficiently bind to MGL, strongly activate DCs, mimic the effects of a danger signal, and achieve an efficient presentation in HLA classes I and II compartments.

Background The advent of immune checkpoint inhibitors (ICIs) has considerably expanded the armamentarium against non-small cell lung cancer (NSCLC) contributing to reshaping treatment paradigms in the advanced disease setting. While promising tissue- and plasma-based biomarkers are under investigation, no reliable predictive factor is currently available to aid in treatment selection. Methods Patients with stage IIIB–IV NSCLC receiving nivolumab at Sant’Andrea Hospital and Regina Elena National Cancer Institute from June 2016 to July 2017 were enrolled onto this study. Major clinicopathological parameters were retrieved and correlated with patients’ survival outcomes in order to assess their prognostic value and build a useful tool to assist in the decision making process. Results A total of 102 patients were included in this study. The median age was 69 years (range 44–85 years), 69 (68%) were male and 52% had ECOG PS 0. Loco-regional/distant lymph nodes were the most commonly involved site of metastasis (71%), followed by lung parenchyma (67%) and bone (26%). Overall survival (OS) in the whole patients’ population was 83.6%, 63.2% and 46.9% at 3, 6 and 12 months, respectively; while progression-free survival (PFS) was 66.5%, 44.4% and 26.4% at 3, 6 and 12 months, respectively. At univariate analysis, age ≥ 69 years ( P = 0.057), ECOG PS ( P < 0.001), the presence of liver ( P < 0.001), lung ( P = 0.017) metastases, lymph nodes only involvement (P = 0.0145) were significantly associated with OS and ECOG PS ( P < 0.001) and liver metastases ( P < 0.001), retained statistical significance at multivariate analysis. A prognostic nomogram based on three variables (liver and lung metastases and ECOG PS) was built to assign survival probability at 3, 6, and 12 months after nivolumab treatment commencement. Conclusion We developed a nomogram based on easily available and inexpensive clinical factors showing a good performance in predicting individual OS probability among NSCLC patients treated with nivolumab. This prognostic device could be valuable to clinicians in more accurately driving treatment decision in daily practice as well as enrollment onto clinical trials.

Immune Checkpoint Inhibitors (ICIs) are improving the survival of cancer patients, however only the 20-30% of treated patients present clinical benefits. Toxicity represents the major cause of reduced dosage, delayed drug administration and therapy discontinuation. Hence in the context of multiple treatment possibilities, the identification of predictive markers of response and toxicity is a challenging approach for drug selection in order to obtain the best clinical benefit while minimizing the side effects. The loss of the protective function of intestinal barriers that interacts with the environment measured as increased intestinal permeability and the changes occurring in the microbiota composition have been proposed as a mechanism potentially explaining the pathogenesis of immune related toxicity.In this review we discuss the new perspectives on the involvement of PD-1 and PDL-1 in the cross talk between gut microbiota and immune fitness and how gut microbiota impacts on the efficacy of anti-PD-1 and anti-PDL-1 treatments in cancer.