Everolimus restrains the IL-17A-dependent osteoclast-like transdifferentiation of dendritic cells in multiple myeloma

Immune System Evasion as Hallmark of Melanoma Progression: The Role of Dendritic Cells

Melanoma is an immunogenic tumor whose relationship with immune cells resident in the microenvironment significantly influences cancer cell proliferation, progression, and metastasis. During melanomagenesis, both immune and melanoma cells undergo the immunoediting process that includes interconnected phases as elimination, equilibrium, and escape or immune evasion. In this context, dendritic cells (DCs) are active players that indirectly counteract the proliferation of melanoma cells. Moreover, DC maturation, migration, and cross-priming as well as their functional interplay with cytotoxic T-cells through ligands of immune checkpoint receptors result impaired. A number of signals propagated by highly proliferating melanoma cells and accessory cells as T-cells, natural killer cells (NKs), tumor-associated macrophages (TAMs), T-regulatory cells (T-regs), myeloid-derived suppressor cells (MDSCs), and endothelial cells participate to create an immunosuppressive milieu that results engulfed of tolerogenic factors and interleukins (IL) as IL-6 and IL-10. To underline the role of the immune infiltrate in blocking the melanoma progression, it has been described that the composition, density, and distribution of cytotoxic T-cells in the surrounding stroma is predictive of responsiveness to immunotherapy. Here, we review the major mechanisms implicated in melanoma progression, focusing on the role of DCs.

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

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.