Mizue Terai

Interleukin 10 in the tumor microenvironment: a target for anticancer immunotherapy

IL-10 is an immunomodulatory cytokine that is frequently upregulated in various types of cancer. The biological role of IL-10 in cancer is quite complex; however, the presence of IL-10 in advanced metastases and the positive correlation between serum IL-10 levels and progression of disease indicates a critical role of IL-10 in the tumor microenvironment. IL-10 has been shown to directly affect the function of antigen-presenting cells by inhibiting the expression of MHC and costimulatory molecules, which in turn induces immune suppression or tolerance. Additionally, IL-10 downregulates the expression of Th1 cytokines and induces T-regulatory responses. Taken together, a combination of IL-10 antagonism and immunostimulatory treatments such as cancer vaccines, Toll-like receptor agonists, Th1 cytokines, and chemokines would be a logical approach to enhance an antitumor immune response.

Immunoembolization of Malignant Liver Tumors, Including Uveal Melanoma, Using Granulocyte-Macrophage Colony-Stimulating Factor

PURPOSE We conducted a phase I study to investigate the feasibility and safety of immunoembolization with granulocyte-macrophage colony-stimulating factor (GM-CSF; sargramostim) for malignant liver tumors, predominantly hepatic metastases from patients with primary uveal melanoma. PATIENTS AND METHODS Thirty-nine patients with surgically unresectable malignant liver tumors, including 34 patients with primary uveal melanoma, were enrolled. Hepatic artery embolization accompanied an infusion of dose-escalated GM-CSF (25 to 2,000 microg) given every 4 weeks. Primary end points included dose-limiting toxicity and maximum tolerated dose (MTD). Patients who completed two cycles of treatments were monitored for hepatic antitumor response. Survival rates of patients were also monitored. RESULTS MTD was not reached up to the dose level of 2,000 microg, and there were no treatment-related deaths. Thirty-one assessable patients with uveal melanoma demonstrated two complete responses, eight partial responses, and 10 occurrences of stable disease in their hepatic metastases. The median overall survival of intent-to-treat patients who had metastatic uveal melanoma was 14.4 months. Multivariate analyses indicated that female sex, high doses of GM-CSF (> or = 1,500 microg), and regression of hepatic metastases (complete and partial responses) were correlated to longer overall survival. Moreover, high doses of GM-CSF were associated with prolonged progression-free survival in extrahepatic sites. CONCLUSION Immunoembolization with GM-CSF is safe and feasible in patients with hepatic metastasis from primary uveal melanoma. Encouraging preliminary efficacy and safety results warrant additional clinical study in metastatic uveal melanoma.

High-Dose Immunoembolization: Survival Benefit in Patients with Hepatic Metastases from Uveal Melanoma

PURPOSE To retrospectively evaluate prognostic factors for survival in patients with uveal melanoma who received chemoembolization (CE) with 1,3-bis (2-chloroethyl)-1-nitrosourea or immunoembolization (IE) with granulocyte-macrophage colony-stimulating factor (GM-CSF) for hepatic metastases. MATERIALS AND METHODS Fifty-three consecutive patients with uveal melanoma were treated by using CE or IE in clinical trials approved by the Institutional Review Board. Prognostic factors associated with overall survival (OS) and progression-free survival (PFS) in the liver and extrahepatic (systemic) organs were retrospectively evaluated. Covariates of age, sex, preexisting extrahepatic metastases, liver enzyme levels, tumor volume, radiologic response in hepatic metastases, and treatment type were analyzed. RESULTS Compared with CE, high-dose (>or=1500 microg of GM-CSF) IE resulted in significantly better OS (20.4 vs 9.8 months, P = .005) and systemic PFS (12.4 vs 4.8 months, P = .001) at univariate analysis. Overall, women outlived men (14.4 vs 9.8 months, P = .01). Patients who achieved regression of hepatic metastases after embolization lived much longer than did those who did not achieve regression (27.2 vs 9.9 months, P < .001). At multivariate analysis, prolonged OS was confirmed for women, patients who underwent high-dose IE, younger patients (age < 60 years), and patients with regression of hepatic metastases. Independent predictors of longer systemic PFS included high-dose IE, younger age, and regression of hepatic metastases. No covariate predicted liver PFS except for hepatic response. CONCLUSION Treatment with high-dose IE prolonged survival of patients with uveal melanoma who received embolization of hepatic metastases and possibly delayed progression of extrahepatic metastases.

Combination of monocyte-derived dendritic cells and activated T cells which express CD40 ligand: a new approach to cancer immunotherapy.

Interactions between dendritic cells (DCs) and activated T cells are critically important for the establishment of an effective immune response. To develop the basis for a new DC-based cancer vaccine, we investigated cell-to-cell interactions between human monocyte-derived DCs and autologous T cells that are activated to express the CD40 ligand (CD40L). Peripheral blood monocytes were cultured in the presence of granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin 4 (IL-4) to induce differentiation of DCs. Activated T cells (ATs) consisted of autologous peripheral blood lymphocytes that had been activated with phytohemagglutinin (PHA) and then stimulated with calcium ionophore to up-regulate expression of CD40L. Coculture of these DCs and ATs induced significant production of interleukin 12 (IL-12) and also enhanced the production of interferon γ (IFN-γ). The production of IL-12 was blocked by an anti-CD40L antibody or by separation of the DC and AT fractions by a permeable membrane. Furthermore, coculture of DCs and ATs induced DCs to upregulate CD83 expression and stimulated migration of DCs toward the macrophage inflammatory protein 3-β (MIP-3β). ATs also migrated toward the MIP-3β. These results suggest a combination of DCs and ATs as a potentially effective therapeutic strategy.

Interleukin 6 mediates production of interleukin 10 in metastatic melanoma

We previously reported that substantial amounts of IL-10, an immunomodulatory cytokine, are produced by cell suspensions of fresh human metastatic melanoma tissues. Production diminished with continuous culturing of cells, which suggests a pivotal interactive role between melanoma cells and the tumor microenvironment. In this study, we found that the culture media obtained from LPS-stimulated peripheral blood mononuclear cells induced IL-10 production by metastatic melanoma cells. Of the multiple cytokines present in the conditioned culture media, IL-6 was identified as the inducer of IL-10 production. A neutralizing antibody against IL-6 completely blocked the conditioned medium-induced IL-10 production. Metastatic melanoma cells that constitutively produce low amount of IL-10 increased IL-10 production in response to recombinant human IL-6 in a dose-dependent fashion. The response to exogenously added IL-6 was less significant in melanoma cells that produced high amounts of IL-6, probably due to pre-existing autocrine stimulation of IL-10 by endogenous IL-6. On the other hand, metastatic melanoma cells that do not constitutively produce IL-10 protein did not respond to exogenous IL-6. In IL-6-responsive melanoma cells, IL-6 increased STAT3 phosphorylation and inhibition of STAT3 signaling using siRNA or inhibitors for JAKs diminished IL-6-induced IL-10 production. In addition, inhibition of MEK and PI3K, but not mTOR, interfered with IL-10 production. Taken together, the data suggest that blocking of these signals leading to IL-10 production is a potential strategy to enhance an anti-melanoma immune response in metastatic melanoma.

Paracrine effect of NRG1 and HGF drives resistance to MEK inhibitors in metastatic uveal melanoma

Uveal melanoma patients with metastatic disease usually die within one year, emphasizing an urgent need to develop new treatment strategies for this cancer. MEK inhibitors improve survival in cutaneous melanoma patients but show only modest efficacy in metastatic uveal melanoma patients. In this study, we screened for growth factors that elicited resistance in newly characterized metastatic uveal melanoma cell lines to clinical-grade MEK inhibitors, trametinib and selumetinib. We show that neuregulin 1 (NRG1) and hepatocyte growth factor (HGF) provide resistance to MEK inhibition. Mechanistically, trametinib enhances the responsiveness to NRG1 and sustained HGF-mediated activation of AKT. Individually targeting ERBB3 and cMET, the receptors for NRG1 and HGF, respectively, overcome resistance to trametinib provided by these growth factors and by conditioned medium from fibroblasts that produce NRG1 and HGF. Inhibition of AKT also effectively reverses the protective effect of NRG1 and HGF in trametinib-treated cells. Uveal melanoma xenografts growing in the liver in vivo and a subset of liver metastases of uveal melanoma patients express activated forms of ERBB2 (the coreceptor for ERBB3) and cMET. Together, these results provide preclinical evidence for the use of MEK inhibitors in combination with clinical-grade anti-ERBB3 or anti-cMET monoclonal antibodies in metastatic uveal melanoma.

Human interleukin 10 receptor 1/IgG1-Fc fusion proteins: immunoadhesins for human IL-10 with therapeutic potential.

Interleukin 10 (IL-10) is produced by various types of human cancer, including malignant melanoma, and plays an important role in negative regulation of cell-mediated immune responses against tumors. We have developed chimeric molecules (immunoadhesins), combining the extracellular domain of human interleukin 10 receptor 1 (IL-10R1) with the Fc regions of human IgG1 heavy chain and investigated their capability of blocking the biological activities of human IL-10. Monomeric and dimeric immunoadhesins (IL-10R1/IgG1) constructs were tested for capturing human IL-10 and blocking its biological activities. Plasmid vectors that contained the IL-10 immunoadhesin constructs were directly transfected into human melanoma cell lines. Transfection of plasmid vectors into melanoma cell lines resulted in capturing of exogenously added as well as endogeneously produced IL-10. The supernatants obtained from an IL-10 non-producing melanoma cell line transfected with monomeric IL-10 immunoadhesin plasmids most efficiently captured exogenously added IL-10, compared to those obtained with the dimeric IL-10R1/IgG1 plasmid vector. Transfection of IL-10-producing melanoma cells with the monomeric IL-10 immunoadhesin plasmids totally captured endogenously produced IL-10 and enhanced T cell responses against allogeneic melanoma cells. Furthermore, purified monomeric IL-10 immunoadhesin protein showed IL-10 capturing efficacy compatible with that of IL-10-specific monoclonal antibodies. Collectively, these studies indicate that IL-10 immunoadhesins, especially in monomeric form, are potent inhibitors of biological activities of IL-10 and suggest that these molecules, alone or in conjunctions with other immunotherapeutic approaches, can be utilized for the immuno-targeting of IL-10 producing tumors.

Arterial Blood, Rather Than Venous Blood, is a Better Source for Circulating Melanoma Cells

Background CTCs provide prognostic information and their application is under investigation in multiple tumor types. Of the multiple variables inherent in any such process, none is more important to outcome than the appropriateness of the sample source. To address this question, we investigated CTCs in paired peripheral venous and arterial blood specimens obtained from stage IV uveal melanoma patients. Methods Blood specimens were obtained from both common femoral arteries and antecubital veins in 17 uveal melanoma patients with multiple hepatic metastases for CTC measurements. Finding CTCs were detectable with greater frequency (100%) and in larger numbers (median 5, range 1 to 168) in all arterial blood specimens than in venous samples (52.9%; median 1, range 0 to 8). Patients with hepatic as well as extra-hepatic metastasis showed higher number of arterial CTCs, compared to patients with liver-only metastasis (p = 0.003). There was no significant association between the number of arterial CTCs and the tumor burden within the liver in patients who had liver-only metastases. Interpretation Our data indicate that arterial blood specimens might be a better source of circulating uveal melanoma cells. Although less conveniently processed, perhaps arterial blood should be evaluated as sample source for measurement of CTCs.

Co-targeting HGF-cMET signaling with MEK inhibitors in metastatic uveal melanoma

Patients with metastatic uveal melanoma usually die within 1 year of diagnosis, emphasizing an urgent need to develop new treatment strategies. The liver is the most common site of metastasis. Mitogen-activated protein kinase kinase (MEK) inhibitors improve survival in V600 BRAF–mutated cutaneous melanoma patients but have limited efficacy in patients with uveal melanoma. Our previous work showed that hepatocyte growth factor (HGF) signaling elicits resistance to MEK inhibitors in metastatic uveal melanoma. In this study, we demonstrate that expression of two BH3-only family proteins, Bim-EL and Bmf, contributes to HGF-mediated resistance to MEK inhibitors. Targeting HGF/cMET signaling with LY2875358, a neutralizing and internalizing anti-cMET bivalent antibody, and LY2801653, a dual cMET/RON inhibitor, overcomes resistance to trametinib provided by exogenous HGF and by conditioned medium from primary hepatic stellate cells. We further determined that activation of PI3Kα/γ/δ isoforms mediates the resistance to MEK inhibitors by HGF. Combination of LY2801653 with trametinib decreases AKT phosphorylation and promotes proapoptotic PARP cleavage in metastatic uveal melanoma explants. Together, our data support the notion that selectively blocking cMET signaling or PI3K isoforms in metastatic uveal melanoma may break the intrinsic resistance to MEK inhibitors provided by factors from stromal cells in the liver. Mol Cancer Ther; 16(3); 516–28. ©2017 AACR.

Ladarixin, a dual CXCR1/2 inhibitor, attenuates experimental melanomas harboring different molecular defects by affecting malignant cells and tumor microenvironment

CXCR1 and CXCR2 chemokine receptors and their ligands (CXCL1/2/3/7/8) play an important role in tumor progression. Tested to date CXCR1/2 antagonists and chemokine-targeted antibodies were reported to affect malignant cells in vitro and in animal models. Yet, redundancy of chemotactic signals and toxicity hinder further clinical development of these approaches. In this pre-clinical study we investigated the capacity of a novel small molecule dual CXCR1/2 inhibitor, Ladarixin (LDX), to attenuate progression of experimental human melanomas. Our data showed that LDX-mediated inhibition of CXCR1/2 abrogated motility and induced apoptosis in cultured cutaneous and uveal melanoma cells and xenografts independently of the molecular defects associated with the malignant phenotype. These effects were mediated by the inhibition of AKT and NF-kB signaling pathways. Moreover, systemic treatment of melanoma-bearing mice with LDX also polarized intratumoral macrophages to M1 phenotype, abrogated intratumoral de novo angiogenesis and inhibited melanoma self-renewal. Collectively, these studies outlined the pre-requisites of the successful CXCR1/2 inhibition on malignant cells and demonstrated multifactorial effects of Ladarixin on cutaneous and uveal melanomas, suggesting therapeutic utility of LDX in treatment of various melanoma types.