Anna Passarelli

Avβ3 integrin: Pathogenetic role in osteotropic tumors

The interplay of cancer cells and accessory cells within the microenvironment drives signals regulating the proliferation, migration and skeleton colonization. Osteotropism of tumor cells depends on chemokine activation, production of soluble factors and defective gene expression that cooperate within the metastatic niche to the bone resorbing functions of osteoclasts. Adhesion of cancer cells to the extracellular matrix is regulated by integrins as αvβ3 that enhances their invasiveness, pro-tumor angiogenesis and skeleton invasion. Therefore, αvβ3 signaling is implicated in enhancing osteotropism of breast and prostate cancers as well as of multiple myeloma. Targeting of αvβ3 has been adopted to restrain the tumor progression in several cancer models leading to improvement of overall survival as effect of the reduction of both tumor burden and osteotropism by malignant cells. Here, we review both the role of αvβ3 in malignant osteoclastogenesis and its potential targeting to restrain the bone colonization by skeleton invading cancers.

The immune escape in melanoma: role of the impaired dendritic cell function.

Melanoma is an immunogenic cancer that overcomes the control of the immune system through the production of tolerogenic cytokines and growth factors in the microenvironment. In melanoma, dendritic cells (DC) show severe alterations in maturation, cross-priming and antigenic presentation, while other accessory cells infiltrating the tumor milieu also suppress DCs through the activation of the STAT pathway by IL-10 and IL-6. Novel immunotherapy strategies blocking cytotoxic T-lymphocyte antigen (CTLA-4) are successful in advanced disease, while melanoma cells carrying the BRAFV600E mutation further reinforce the immune suppression by activating MAPKs. Here, we review the major mechanisms involved in the cross-talk between melanoma cells and the immune system as well as the issue of defects in DCs in relation to novel studies aimed at restoring their anti-tumor activity.

Serum exosomes as predictors of clinical response to ipilimumab in metastatic melanoma

ABSTRACT Immunotherapy is effective in metastatic melanoma (MM) but most studies failed in discovering a biomarker predictive of clinical response. Exosomes (Exo) from melanoma cells are detectable in sera of MM patients similarly to those produced by immune cells that control the tumor progression. Here, we investigated by flow-cytometry the levels of Exo from both T-cells and dendritic cells (DCs) in 59 patients with MM treated with IPI and the relative expression of PD-1, CD28 and ICOS as well as CD80 and CD86. We found a significant increment of PD-1 and CD28 expression in patients achieving a clinical response reflected by improvement of both PFS and OS. Furthermore, MM patients receiving IPI who showed extended PFS underwent increased expression of CD80 and CD86 on DC-derived Exo at the end of treatment. These results suggest a possible association of both PD-1 and CD28 up-regulation on immune cell-derived Exo in patients with better clinical response to IPI.

Immune‑related adverse events during anticancer immunotherapy: Pathogenesis and management (Review)

Immunotherapy is one of the most recent systemic treatments to emerge for use in oncology, and is based on the blocking of inhibitory immune checkpoints to potentiate the immune response to cancer. The anti-cytotoxic T lymphocyte-associated antigen-4 antibody ipilimumab and anti-programmed cell death protein 1 antibodies, including nivolumab and pembrolizumab, are currently available and widely used, and other immune-inhibiting antibodies are now under intensive investigation. These antibodies have shown efficacy in a growing number of tumor types, following initial observations of their notable effects in melanoma treatment. Despite the efficacy of these antibodies, their novel mechanisms of action are also associated with a new class of side effects called immune-related adverse events (IRAEs). These side effects do not share a common pathophysiology with other anticancer treatments and, therefore, they often require specific therapies. When detected early and correctly treated, IRAEs are reversible; however, they can become severe and life-threatening if underestimated or inappropriately treated. This review aims to revisit the pathogenesis of IRAEs, with attention to gastrointestinal manifestations, since these are common and potentially dangerous complications of immunotherapy and represent a major cause of treatment discontinuation. Recommendations and guidelines for the management of IRAEs are also presented, in order to provide a clear and applicable algorithm for use by clinicians.

Exosomes in melanoma: a role in tumor progression, metastasis and impaired immune system activity

Exosomes (Exo) are small vesicles produced by melanoma cells and the accessory cells of the tumor microenvironment. They emerge via both classical and direct pathways and actively participate in tumor colonisation of distant tissues. The proteins, nucleic acids, cytokines and growth factors engulfed by Exo are transferred to recipient cells, where they drive numerous functions required for the tumor escape from immune system control and tumor progression. By positively or negatively modulating immune cell properties, Exo provoke immune suppression and, in turn, defective dendritic cell (DC) functions. Together, these effects limit the cytotoxicity of T-cells and expand both T-regulatory and myeloid-derived suppressor populations. They also hinder perforin and granzyme production by natural killer cells. Finally, Exo also control the organotropism of melanoma cells. The distinct phenotypic properties of Exo can be exploited both for diagnostic purposes and in the early identification of melanoma patients likely to respond to immunotherapy. The potential therapeutic application of Exo derived from DCs has been demonstrated in vaccination trials, which showed an increase in anti-melanoma activity with respect to circulating tumor cells. However, additional studies are required before Exo can be effectively used in diagnostic and therapeutic applications in melanoma.

Immune system and melanoma biology: a balance between immunosurveillance and immune escape

Melanoma is one of the most immunogenic tumors and its relationship with host immune system is currently under investigation. Many immunomodulatory mechanisms, favoring melanomagenesis and progression, have been described to interfere with the disablement of melanoma recognition and attack by immune cells resulting in immune resistance and immunosuppression. This knowledge produced therapeutic advantages, such as immunotherapy, aiming to overcome the immune evasion. Here, we review the current advances in cancer immunoediting and focus on melanoma immunology, which involves a dynamic interplay between melanoma and immune system, as well as on effects of “targeted therapies” on tumor microenvironment for combination strategies.

Dendritic cell-derived exosomes (Dex) are potential biomarkers of response to Ipilimumab in metastatic melanoma

Background Chemotherapy and vaccination with tumor-loaded dendritic cells (DCs) show poor impact on overall survival (OS) in metastatic melanoma. Ipilimumab (IPI) improves OS throughout the blockade of CTLA4-mediated inhibitory signals in T-cells and restores the efficiency of the antigenic cross-priming by mature (m) DCs. However, variation of immune cells to evaluate the response to IPI does not reflect the T-cell activation and is a modest predictor of clinical response. Recent studies in human and experimental melanoma demonstrated that mDCs release endomysial microvescicles namely dexosomes (Dex) showing a functional anti-melanoma activity as well as an antigenic profile resembling that of circulating mDCs including CD40, CD80 and CD86 co-stimulatory molecules. This research is aimed to identify an early biomarker of T-cell activation for predicting the clinical response in IPItreated melanoma patients.

Adverse drug reactions after intravenous rituximab infusion are more common in hematologic malignancies than in autoimmune disorders and can be predicted by the combination of few clinical and laboratory parameters: results from a retrospective, multicenter study of 374 patients

Abstract Rituximab is an effective treatment for CD20 + B-cell malignancies and autoimmune disorders. However, adverse drug reactions (ADRs) may occur after rituximab infusion, causing, in rare cases, its discontinuation. In this multicenter, retrospective study, among 374 patients treated with rituximab i.v., 23.5% experienced ADRs. Mean follow-up was 20.6 months (range 8–135). Overall, ADRs were significantly more frequent in non-Hodgkin lymphomas (NHL) and chronic lymphocytic leukemias (25–35.9%), than in autoimmune diseases (9.4–17.5%) (p < .0001). Grade 3–4 toxicity was observed in eight patients (2.1%), and in four of them (1% of all patients) definitive drug discontinuation was necessary. Interestingly, three groups of patients with different risk of developing ADR were identified, according to a predictive heat-map developed combining four parameters (splenomegaly, history of allergy, hemoglobin levels and gender) selected by multivariate analysis. This model may be useful in identifying patients at higher risk of ADRs, needing appropriate preventing therapies.

Circulating dendritic cell levels identify high-risk stage II-III melanoma patients: a potential role as additional prognostic marker

Background Melanoma is an immunogenic cancer that overcomes the immune surveillance through the production of tolerogenic cytokines and growth factors within microenvironment. Melanoma-derived dendritic cells (DCs) show altered maturation, cross-priming and antigenic presentation and their major defect concerns the activation of the STAT pathway. The prognostic criteria to define melanoma at high-risk of relapse/recurrence include the Breslow depth, the Clark level and number of mitosis. Sentinel lymph node (SLN) characterization is a prognostic factor in melanoma, although false negative occurs in approximately 5% of patients. We investigated the potential prognostic role of DC number variation in relation to clinical stage, and suggest their role as early predictor of high risk melanomas.