The Italian Network for Tumor Bio-Immunotherapy (NIBIT) Foundation: ongoing and prospective activities in immuno-oncology.

The ongoing revolution in cancer immunotherapy stems from the knowledge that distinct immune-checkpoints regulate the physiological crosstalk between and among immune cells by delivering inhibitory or activating signals. These notions, and the availability of mAb directed to diverse immune-checkpoint molecules, have led to a significant clinical improvement in cancer treatment. In this scenario, further achievements are undoubtedly to be expected from the contribution of novel, proof-of-principle clinical trials designed to explore the therapeutic efficacy of new immunotherapy-based combinations and treatment sequences. Along these lines, the clinical translation of pre-clinical evidence generated by non-profit research entities is likely to provide a significant contribution to gaining new insights that will further boost the field of cancer immunotherapy. To pursue this goal, and to provide comprehensive educational programs in immune-oncology (I-O), several national and global networks have been revitalized or newly established in recent years. This rapidly evolving scenario led the Board of Directors of the Italian Network of Tumor Bio-Immunotherapy (NIBIT) to establish the NIBIT Foundation. This Focused Research Review summarizes the main ongoing and prospective I-O activities of the NIBIT Foundation.

Fighting breast cancer stem cells through the immune-targeting of the xCT cystine-glutamate antiporter.

Tumor relapse and metastatic spreading act as major hindrances to achieve complete cure of breast cancer. Evidence suggests that cancer stem cells (CSC) would function as a reservoir for the local and distant recurrence of the disease, due to their resistance to radio- and chemotherapy and their ability to regenerate the tumor. Therefore, the identification of appropriate molecular targets expressed by CSC may be critical in the development of more effective therapies. Our studies focused on the identification of mammary CSC antigens and on the development of CSC-targeting vaccines. We compared the transcriptional profile of CSC-enriched tumorspheres from an Her2+ breast cancer cell line with that of the more differentiated parental cells. Among the molecules strongly upregulated in tumorspheres we selected the transmembrane amino-acid antiporter xCT. In this review, we summarize the results we obtained with different xCT-targeting vaccines. We show that, despite xCT being a self-antigen, vaccination was able to induce a humoral immune response that delayed primary tumor growth and strongly impaired pulmonary metastasis formation in mice challenged with tumorsphere-derived cells. Moreover, immunotargeting of xCT was able to increase CSC chemosensitivity to doxorubicin, suggesting that it may act as an adjuvant to chemotherapy. In conclusion, our approach based on the comparison of the transcriptome of tumorspheres and parental cells allowed us to identify a novel CSC-related target and to develop preclinical therapeutic approaches able to impact on CSC biology, and therefore, hampering tumor growth and dissemination.

Immune checkpoint blockade therapy of mesothelioma: a clinical and radiological challenge.

Treatment of malignant pleural mesothelioma (MPM) represents a highly unmet medical need. Here, we discuss the results and therapeutic potential of first- and second-generation immunomodulatory antibodies targeting distinct immune checkpoints for the treatment of MPM, as well as their prospective therapeutic role in combination strategies. We also discuss the role of appropriate radiological criteria of response for MPM and the potential need of ad hoc criteria of disease evaluation in MPM patients undergoing treatment with immunotherapeutic agents.

T cell responses to tumor: how dominant assumptions on immune activity led to a neglect of pathological functions, and how evolutionary considerations can help identify testable hypotheses for improving immunotherapy.

Cancer immunotherapy is based on the premise that activated, pro-inflammatory T cell responses to tumor will mostly combat tumor growth. Nowadays accepted as largely valid, this hypothesis has been formed as a result of extensive theoretical and experimental argumentation on the inherent function of the immune system and the nature of the immunological self, dating back to the foundations of immunology. These arguments have also been affected by how current working hypotheses were set by researchers, an issue that has been the focus of study by medical anthropologists. As a result of these processes, cancer immunotherapy has developed into a truly promising anti-cancer strategy, with very substantial benefits in clinical outcomes. However, as immunotherapy still has large margins for improvement, a more thorough examination of both the historical background and evolutionary context of current assumptions for how the immune system responds to cancer can help reveal novel, testable questions. We describe how attempting to answer some of these questions experimentally, such as identifying the contributors of tumor-associated fibrosis, has led to potentially useful insights on how to improve immunotherapy.

Defective HLA class I antigen processing machinery in cancer.

Malignant transformation of cells is frequently associated with defective HLA class I antigen processing machinery (APM) component expression. This abnormality may have functional relevance, since it may have a negative impact on tumor cell recognition by cognate T cells. Furthermore, HLA class I APM abnormalities appear to have clinical significance, since they are associated with poor prognosis in several malignant diseases and may play a role in the resistance to immune checkpoint inhibitor-based immunotherapy. In this paper, we have reviewed the literature describing abnormalities in HLA class I APM component expression in many types of cancer. These abnormalities have been reported in all types of cancer analyzed with a frequency ranging between a minimum of 35.8% in renal cancer and a maximum of 87.9% in thyroid cancer for HLA class I heavy chains. In addition, we have described the molecular mechanisms underlying defects in HLA class I APM component expression and function by malignant cells. Lastly, we have discussed the clinical significance of HLA class I APM component abnormalities in malignant tumors.

Transcriptomic analysis of the tumor microenvironment to guide prognosis and immunotherapies.

Tumors are highly heterogeneous tissues where malignant cells are surrounded by and interact with a complex tumor microenvironment (TME), notably composed of a wide variety of immune cells, as well as vessels and fibroblasts. As the dialectical influence between tumor cells and their TME is known to be clinically crucial, we need tools that allow us to study the cellular composition of the microenvironment. In this focused research review, we report MCP-counter, a methodology based on transcriptomic markers that assesses the proportion of several immune and stromal cell populations in the TME from transcriptomic data, and we highlight how it can provide a way to decipher the complex mechanisms at play in tumors. In several malignancies, MCP-counter scores have been used to show various prognostic impacts of the TME, which we also show to be linked with the mutational burden of tumors. We also compared established molecular classifications of colorectal cancer and clear-cell renal cell carcinoma with the output of MCP-counter, and show that molecular subgroups have different TME profiles, and that these profiles are consistent within a given subgroup. Finally, we provide insights as to how knowing the TME composition may shape patient care in the near future.

The non-small cell lung cancer immune landscape: emerging complexity, prognostic relevance and prospective significance in the context of immunotherapy.

Immunotherapy of non-small cell lung cancer (NSCLC), by immune checkpoint inhibitors, has profoundly improved the clinical management of advanced disease. However, only a fraction of patients respond and no effective predictive factors have been defined. Here, we discuss the prospects for identification of such predictors of response to immunotherapy, by fostering an in-depth analysis of the immune landscape of NSCLC. The emerging picture, from several recent studies, is that the immune contexture of NSCLC lesions is a complex and heterogeneous feature, as documented by analysis for frequency, phenotype and spatial distribution of innate and adaptive immune cells, and by characterization of functional status of inhibitory receptor+ T cells. The complexity of the immune landscape of NSCLC stems from the interaction of several factors, including tumor histology, molecular subtype, main oncogenic drivers, nonsynonymous mutational load, tumor aneuploidy, clonal heterogeneity and tumor evolution, as well as the process of epithelial-mesenchymal transition. All these factors contribute to shape NSCLC immune profiles that have clear prognostic significance. An integrated analysis of the immune and molecular profile of the neoplastic lesions may allow to define the potential predictive role of the immune landscape for response to immunotherapy.

Cholesterol metabolites and tumor microenvironment: the road towards clinical translation.

Targeting the tumor microenvironment focusing on immune cells has recently become a standard of care for some tumors. Indeed, antibodies blocking immune checkpoints (e.g., anti-CTLA-4 and anti-PD1 mAbs) have been approved by regulatory agencies for the treatment of some solid tumors based upon successes in many clinical trials. Although tumor metabolism has always attracted the attention of tumor biologists, only recently have oncologists renewed their interest in this field of tumor biology research. This has highlighted the possibility to pharmacologically target rate-limiting enzymes along key metabolic pathways of tumor cells, such as lipogenesis and aerobic glycolysis. Altered tumor metabolism has also been shown to influence the functionality of the tumor microenvironment as a whole, particularly the immune cell component of thereof. Cholesterol, oxysterols and Liver X receptors (LXRs) have been investigated in different tumor models. Recent in vitro and in vivo results point to their involvement in tumor and immune cell biology, thus making the LXR/oxysterol axis a possible target for novel antitumor strategies. Indeed, the possibility to target both tumor cell metabolism (i.e., cholesterol metabolism) and tumor-infiltrating immune cell dysfunctions induced by oxysterols might result in a synergistic antitumor effect generating long-lasting memory responses. This review will focus on the role of cholesterol metabolism with particular emphasis on the role of the LXR/oxysterol axis in the tumor microenvironment, discussing mechanisms of action, pros and cons, and strategies to develop antitumor therapies based on the modulation of this axis.

Immunotherapy with dendritic cells loaded with glioblastoma stem cells: from preclinical to clinical studies.

Different approaches have been explored to raise effective antitumor responses against glioblastoma (GBM), the deadliest of primary brain tumors. In many clinical studies, cancer vaccines have been based on dendritic cells (DCs) loaded with peptides, representing one or more specific tumor antigens or whole lysates as a source of multiple antigens. Randomized clinical trials using DCs are ongoing, and results of efficacy are not yet available. Such strategies are feasible and safe; however, immune-suppressive microenvironment, absence of appropriate specific epitopes to target, and cancer immunoediting can limit their efficacy. The aim of this review is to describe how the definition of novel and more specific targets may increase considerably the possibility of successful DC immunotherapy. By proposing to target glioblastoma stem-like cells (GSCs), the immune response will be pointed to eradicating factors and pathways highly relevant to GBM biology. Preclinical observations on efficacy, and preliminary results of immunotherapy trials, encourage exploring the clinical efficacy of DC immunotherapy in GBM patients using high-purity, GSC-loaded DC vaccines.

Developments in cancer vaccines for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) accounts for about 6 % of all new cancers diagnosed worldwide and represents one of the leading causes of cancer-related death globally in men and women, respectively. The overall prognosis for HCC patients is poor, especially in the majority of patients with more advanced stage of disease. Indeed, in such cases immunotherapeutic strategies may represent a novel and effective tool. A few immunotherapy trials conducted for HCC have provided divergent results, urging the scientific community to explore additional paths to improve efficacy of immunotherapeutic approaches. The "Cancer Vaccine development for Hepatocellular Carcinoma"-HEPAVAC Consortium has been funded by the EU within the FP7 with the goal of developing a novel therapeutic peptide-based cancer vaccine strategy for HCC including both "off-the-shelf" and personalized antigens. This will be one of the very few vaccine trials for HCC and the first multi-epitope, multi-target and multi-HLA allele therapeutic cancer vaccine for such a frequent and aggressive disease with a hitherto high unmet medical need. Feasibility, safety and biological efficacy will be evaluated in a randomized, controlled European multicenter phase I/II clinical trial.