Tumor-derived lactic acid modulates dendritic cell activation and antigen expression.

The tumor milieu can influence dendritic cell (DC) differentiation. We analyzed DC differentiation in a 3-dimensional tumor model and propose a new mechanism of DC modulation by the tumor environment. Monocytes were cultured in the presence of IL-4 and GM-CSF within multicellular tumor spheroids (MCTSs) generated from different tumor cell lines. Monocytes invaded the MCTSs and differentiated into tumor-associated dendritic cells (TADCs). The antigen expression was altered on TADCs independent of the culture conditions (immature/mature DCs, Langerhans cells) and IL-12 secretion was reduced. Supernatants of MCTSs could partially transfer the suppressive effect. Conditioned media from urotheli…

Tumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A-specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A-specific CTLs revealed a high cytolytic activity against allogeneic Melan-A-expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of the codin…

Blockade of PD-L1 (B7-H1) augments human tumor-specific T cell responsesin vitro

Human tumors frequently escape immune destruction, despite the presence of cytotoxic T cells (CTL) recognizing tumor-associated antigens (TAA). We have previously shown that programmed death ligand-1 (PD-L1), a recently identified ligand of the B7 superfamily, is expressed on murine tumors and can inhibit antitumor immune responses. To evaluate the clinical relevance of our animal model findings, we examined human tumors and tumor-specific T cells. We found PD-L1 to be constitutively expressed on human renal cell carcinoma (RCC) cell lines and upregulated on human melanoma cell lines upon exposure to interferon-gamma. Similarly, we found binding of anti-PD-L1 monoclonal antibody (mAb) on fr…

Tumor-Derived Lactic Acid Modulates Dendritic Cell Activation and Differentiation.

Abstract The tumor milieu can influence DC differentiation in vivo and in vitro. We analyzed DC differentiation in a 3-dimensional tumor model and propose a new mechanism of DC modulation by the tumor environment. Monocytes were cultured in the presence of IL-4 and GM-CSF within multicellular tumor spheroids (MCTS) generated from urothelial carcinoma (J82, UMUC3) and melanoma cell lines (MelIm, Mel108). Monocytes invaded the tumor spheroids and differentiated into tumor-associated dendritic cells (TADC) that displayed an altered phenotype compared to DC generated without tumor contact. The expression of CD1a was reduced on TADC whereas CD80, CD86 and CD16 were upregulated. In addition, TADC…

Is first-line single-agent mitoxantrone in the treatment of high-risk metastatic breast cancer patients as effective as combination chemotherapy? No difference in survival but higher quality of life were found in a multicenter randomized trial.

BACKGROUND: To determine whether patients with high-risk metastatic breast cancer draw benefit from combination chemotherapy as first-line treatment. PATIENTS AND METHODS: A total of 260 women with measurable metastatic breast cancer fulfilling high-risk criteria, previously untreated with chemotherapy for their metastatic disease, were randomized to receive either mitoxantrone 12 mg/m(2) or the combination of fluorouracil 500 mg/m(2), epirubicin 50 mg/m(2) and cyclophosphamide 500 mg/m(2) (FEC) every 3 weeks. Treatment was continued until complete remission plus two cycles, or until disease progression. In the case of partial remission or stable disease, treatment was stopped after 12 cycl…

High frequency of functionally active Melan-a-specific T cells in a patient with progressive immunoproteasome-deficient melanoma.

AbstractTumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A–specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A–specific CTLs revealed a high cytolytic activity against allogeneic Melan-A–expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of t…

A case of Waldenstroem's disease with a monoclonal IgM antiphospholipid antibody

The antiphospholipid syndrome (APS) was described in 1983 as a clinical entity characterized by venous and arterial thrombosis, thrombocytopenia, and recurrent fetal loss. The serological markers of APS are antiphospholipid antibodies (APLA) directed mainly against anionic phospholipids, usually cardiolipin but also phosphatidylserine. Some APLA exhibit lupus anticoagulant activity. Monoclonal gammopathy sometimes occurs with the presence of autoantibodies. In this paper, we describe a patient with the diagnosis of immunocytoma with an IgM, kappa paraprotein with apparent specificity against anionic phospholipids, and lupus anticoagulant activity, but no clinical signs of APS. We describe i…