Strategies to reverse melanoma-induced T-cell dysfunction

Cancer risk and gammopathies in 2123 adults with Gaucher disease type 1 in the International Gaucher Group Gaucher Registry

There are numerous reports of cancers in Gaucher disease (GD) from mostly small single-center studies; however, precise risk estimates and cancer types involved have not been delineated. We conducted a study involving 2123 patients with GD type 1 (GD1) to assess the incidence of hematological malignancies, gammopathies, and solid tumors in an international observational study, the International Cooperative Gaucher Group Gaucher Registry (Clinicaltrials.gov: NCT00358943). Risk for cancer overall and for each type of malignancy was compared to the United States (US) population using the Surveillance, Epidemiology, and End Results database. Natural history of gammopathy was determined through assessing the progression from a diagnosis of monoclonal gammopathy of unknown significance (MGUS) to multiple myeloma (MM). Risk for hematological malignancies was more than four times higher than expected compared to the general population: non-Hodgkin lymphoma was approximately three times higher; MM was approximately nine times higher. Age-specific incidence rates of MGUS were unexpectedly high among younger patients. The 10-year cumulative incidence of MM after diagnosis of MGUS was 7.9%, comparable to the general population. Compared to the general US population, GD1 patients were at higher risk for solid malignancies of liver (2.9 times), kidney (2.8 times), melanoma (2.5 times), and breast (1.4 times). Colorectal, prostate, and lung cancer risks were lower than expected. These findings help advance care of patients with GD1 by supporting recommendations for individualized monitoring for malignancies and antecedents such as MGUS for MM and provoke important questions of the role of glucosylceramide and related sphingolipids in cancer biology.

The role of FoxP3+ regulatory T cells and IDO+ immune and tumor cells in malignant melanoma - an immunohistochemical study

BACKGROUND

FoxP3+ Regulatory T cells (Tregs) and indoleamine-2,3-dioxygenase (IDO) participate in the formation of an immunosuppressive tumor microenvironment (TME) in malignant cutaneous melanoma (CM). Recent studies have reported that IDO expression correlates with poor prognosis and greater Breslow's depth, but results concerning the role of FoxP3+ Tregs in CM have been controversial. Furthermore, the correlation between IDO and Tregs has not been substantially studied in CM, although IDO is known to be an important regulator of Tregs activity.

METHODS

We investigated the associations of FoxP3+ Tregs, IDO+ tumor cells and IDO+ stromal immune cells with tumor stage, prognostic factors and survival in CM. FoxP3 and IDO were immunohistochemically stained from 29 benign and 29 dysplastic nevi, 18 in situ -melanomas, 48 superficial and 62 deep melanomas and 67 lymph node metastases (LNMs) of CM. The number of FoxP3+ Tregs and IDO+ stromal immune cells, and the coverage and intensity of IDO+ tumor cells were analysed.

RESULTS

The number of FoxP3+ Tregs and IDO+ stromal immune cells were significantly higher in malignant melanomas compared with benign lesions. The increased expression of IDO in melanoma cells was associated with poor prognostic factors, such as recurrence, nodular growth pattern and increased mitotic count. Furthermore, the expression of IDO in melanoma cells was associated with reduced recurrence-free survival. We further showed that there was a positive correlation between IDO+ tumor cells and FoxP3+ Tregs.

CONCLUSIONS

These results indicate that IDO is strongly involved in melanoma progression. FoxP3+ Tregs also seems to contribute to the immunosuppressive TME in CM, but their significance in melanoma progression remains unclear. The positive association of FoxP3+ Tregs with IDO+ melanoma cells, but not with IDO+ stromal immune cells, indicates a complex interaction between IDO and Tregs in CM, which demands further studies.

T cell pathology in skin inflammation

Forming the outer body barrier, our skin is permanently exposed to pathogens and environmental hazards. Therefore, skin diseases are among the most common disorders. In many of them, the immune system plays a crucial pathogenetic role. For didactic and therapeutic reasons, classification of such immune-mediated skin diseases according to the underlying dominant immune mechanism rather than to their clinical manifestation appears to be reasonable. Immune-mediated skin diseases may be mediated mainly by T cells, by the humoral immune system, or by uncontrolled unspecific inflammation. According to the involved T cell subpopulation, T cell-mediated diseases may be further subdivided into T1 cell-dominated (e.g., vitiligo), T2 cell-dominated (e.g., acute atopic dermatitis), T17/T22 cell-dominated (e.g., psoriasis), and Treg cell-dominated (e.g., melanoma) responses. Moreover, T cell-dependent and -independent responses may occur simultaneously in selected diseases (e.g., hidradenitis suppurativa). The effector mechanisms of the respective T cell subpopulations determine the molecular changes in the local tissue cells, leading to specific microscopic and macroscopic skin alterations. In this article, we show how the increasing knowledge of the T cell biology has been comprehensively translated into the pathogenetic understanding of respective model skin diseases and, based thereon, has revolutionized their daily clinical management.

Cancer Stem Cell Vaccination With PD-L1 and CTLA-4 Blockades Enhances the Eradication of Melanoma Stem Cells in a Mouse Tumor Model

Immune checkpoint inhibitors and monoclonal antibodies reinvigorate cancer immunotherapy. However, these immunotherapies only benefit a subset of patients. We previously reported that ALDH tumor cells were highly enriched for cancer stem cells (CSCs), and ALDH CSC lysate-pulsed dendritic cell (CSC-DC) vaccine was shown to induce CSC-specific cytotoxic T lymphocytes. In this study, we investigated the CSC targeting effect of the CSC-DC vaccine combined with a dual blockade of programmed death-ligand 1 and cytotoxic T-lymphocyte-associated protein (CTLA-4) in B16-F10 murine melanoma tumor model. Our data showed that animals treated with the dual blockade of programmed death-ligand 1 and CTLA-4 and CSC-DC vaccine conferred significantly more tumor regression than the CSC-DC vaccine alone. Importantly, the triple combination treatment dramatically eliminated ALDH CSCs in vivo. We observed that CSC-DC vaccine in combination with anti-PD-L1 and anti-CTLA-4 administration resulted in ∼1.7-fold fewer PD-1CD8 T cells and ∼2.5-fold fewer CTLA-4CD8 T cells than the populations observed following the CSC-DC vaccination alone. Moreover, significant antitumor effects and dramatically eliminated ALDH CSCs following the triple combination treatment were accompanied by significantly enhanced T-cell expansion, suppressed transforming growth factor β secretion, enhanced IFN-γ secretion, and significantly enhanced host specific CD8 T-cell response against CSCs. Collectively, these data showed that administration of a-PD-L1 and a-CTLA-4 combined with CSC-DC vaccine may represent an effective immunotherapeutic strategy for cancer patients in clinical.

Comparative investigation of the effects of specific antigen‑sensitized DC‑CIK and DC‑CTL cells against B16 melanoma tumor cells

The use of personalized adoptive immunotherapy as a potential novel approach is promising in the treatment of tumors resistant to conventional therapies. In the present study, dendritic cell (DC)-cytokine-induced killer (CIK) and DC-cytotoxic lymphocyte (CTL) cells were cultured to examine their phenotype, proliferation and cytotoxicity against B16 melanoma tumor cells. In addition, comparative investigations of the effect of specific antigen-sensitized DC-CIK and DC-CTL cells against B16 melanoma tumor cells were performed in vitro and in vivo. The results showed that the phenotypes of the co-cultured cells were altered, and DCs promoted DC-CIK cell and DC-CTL cell differentiation and maturation in vitro. Lactate dehydrogenase cytotoxic analysis indicated that the cytotoxicity increased as the effector to target ratio increased between 10:1 and 40:1, and the cytotoxic effect towards B16 melanoma cells by DC-CTL cells was significantly higher, compared with that of DC-CIK cells. To further examine the antineoplastic efficacy of DC-CIK and DC-CTL cells in vivo, the present study performed tail-intravenous injection of DC-CIK cells and DC-CTL cells, which attenuated B16 melanoma cell-engrafted tumor growth, induced G₀/G₁ cell cycle arrest and accelerated cell apoptosis. Taken together, these results suggested that the use of DC-CTL or DC-CIK cell therapy as a personalized adoptive immunotherapy may regulate immune status and inhibit tumor growth in vivo. In addition, the experiments indicated that DC-CTL cells offer superior antineoplastic activity, compared with DC-CIK cells against B16 melanoma tumor cells.

Regulatory T cells in the immunotherapy of melanoma

Patients with melanoma are supposed to develop spontaneous immune responses against specific tumor antigens. However, several mechanisms contribute to the failure of tumor antigen-specific T cell responses, inducing immune escape. Importantly, immunosuppression mediated by regulatory T cells (Tregs) in tumor lesions is a dominant mechanism of tumor immune evasion. Based on this information, several therapies targeting Tregs such as cyclophosphamide, IL-2-based therapies, and antibodies against the surface molecular of Tregs have been developed. However, only some of these strategies showed clinical efficacy in patients with melanoma in spite of their success in shifting immune systems to antitumor responses in animal models. In the future, strategies specifically depleting local Tregs, inhibiting Treg migration to the tumor lesion, and Treg depletion in combination with other chemotherapies or immune modulation will hopefully bring benefits to melanoma patients.