Search results for "Tumor immunology"
showing 10 items of 21 documents
Chemotherapy Sensitizes Colon Cancer Initiating Cells to Vγ9Vδ2 T Cell-Mediated Cytotoxicity
2013
Colon cancer comprises a small population of cancer initiating stem cells (CIC) that is responsible for tumor maintenance and resistance to anti-cancer therapies, possibly allowing for tumor recapitulation once treatment stops. Combinations of immune-based therapies with chemotherapy and other anti-tumor agents may be of significant clinical benefit in the treatment of colon cancer. However, cellular immune-based therapies have not been experimented yet in the population of colon CICs. Here, we demonstrate that treatment with low concentrations of commonly used chemotherapeutic agents, 5- fluorouracyl and doxorubicin, sensitize colon CICs to Vc9Vd2 T cell cytotoxicity. Vc9Vd2 T cell cytotox…
Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.
2013
Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation…
Characterization of Human γδ T Lymphocytes Infiltrating Primary Malignant Melanomas
2012
T lymphocytes are often induced naturally in melanoma patients and infiltrate tumors. Given that gamma delta T cells mediate antigen-specific killing of tumor cells, we studied the representation and the in vitro cytokine production and cytotoxic activity of tumor infiltrating gamma delta T cells from 74 patients with primary melanoma. We found that gamma delta T cells represent the major lymphocyte population infiltrating melanoma, and both V delta 1(+) and V delta 2(+) cells are involved. The majority of melanoma-infiltrating gamma delta cells showed effector memory and terminally-differentiated phenotypes and, accordingly, polyclonal gamma delta T cell lines obtained from tumor-infiltrat…
Bleomycin Exerts Ambivalent Antitumor Immune Effect by Triggering Both Immunogenic Cell Death and Proliferation of Regulatory T Cells
2013
International audience; Bleomycin (BLM) is an anticancer drug currently used for the treatment of testis cancer and Hodgkin lymphoma. This drug triggers cancer cell death via its capacity to generate radical oxygen species (ROS). However, the putative contribution of anticancer immune responses to the efficacy of BLM has not been evaluated. We make here the observation that BLM induces immunogenic cell death. In particular, BLM is able to induce ROS-mediated reticulum stress and autophagy, which result in the surface exposure of chaperones, including calreticulin and ERp57, and liberation of HMBG1 and ATP. BLM induces anti-tumor immunity which relies on calreticulin, CD8(+) T cells and inte…
Role of tumor-infiltrating lymphocytes in patients with solid tumors: Can a drop dig a stone?
2019
International audience; In recent years, multiple strategies for eliciting anti-tumor immunity have been developed in different clinical studies. Currently, immunotherapy was clinically validated as effective treatment option for many tumors such as melanoma, non-small cell lung cancer (NSCLC) and renal cell carcinoma (RCC). Some surface receptors of immune cells, called immune checkpoint receptors, may inhibit activity of proinflammatory lymphocytes, following binding with specific ligands. Cancer cells exploit these mechanisms to inactivate tumor-infiltrating lymphocytes (TILs) to escape from immunosurveillance. Among the different tumor-infiltrating immune cell populations, including leu…
MiR-29b antagonizes the pro-inflammatory tumor-promoting activity of multiple myeloma-educated dendritic cells
2017
Dendritic cells (DCs) have a key role in regulating tumor immunity, tumor cell growth and drug resistance. We hypothesized that multiple myeloma (MM) cells might recruit and reprogram DCs to a tumor-permissive phenotype by changes within their microRNA (miRNA) network. By analyzing six different miRNA-profiling data sets, miR-29b was identified as the only miRNA upregulated in normal mature DCs and significantly downregulated in tumor-associated DCs. This finding was validated in primary DCs co-cultured in vitro with MM cell lines and in primary bone marrow DCs from MM patients. In DCs co-cultured with MM cells, enforced expression of miR-29b counteracted pro-inflammatory pathways, includin…
Plasmacytoid dendritic cells are inefficient in activation of human regulatory T cells
2011
BACKGROUND: Dendritic cells (DC) play a key role in initiation and regulation of immune responses. Plasmacytoid DC (pDC), a small subset of DC, characterized as type-I interferon producing cells, are critically involved in anti-viral immune responses, but also mediate tolerance by induction of regulatory T cells (Treg). In this study, we compared the capacity of human pDC and conventional DC (cDC) to modulate T cell activity in presence of Foxp3(+) Treg. PRINCIPAL FINDINGS: In coculture of T effector cells (Teff) and Treg, activated cDC overcome Treg anergy, abrogate their suppressive function and induce Teff proliferation. In contrast, pDC do not break Treg anergy but induce Teff prolifera…
Dataset related to article "Tumor-Derived Prostaglandin E2 Promotes p50 NF-κB-Dependent Differentiation of Monocytic MDSCs"
2021
This record contains data related to article: ""Tumor-Derived Prostaglandin E2 Promotes p50 NF-κB-Dependent Differentiation of Monocytic MDSCs". Myeloid-derived suppressor cells (MDSC) include immature monocytic (M-MDSC) and granulocytic (PMN-MDSC) cells that share the ability to suppress adaptive immunity and to hinder the effectiveness of anticancer treatments. Of note, in response to IFNγ, M-MDSCs release the tumor-promoting and immunosuppressive molecule nitric oxide (NO), whereas macrophages largely express antitumor properties. Investigating these opposing activities, we found that tumor-derived prostaglandin E2 (PGE2) induces nuclear accumulation of p50 NF-…
Editorial: Understanding Gamma Delta T Cell Multifunctionality - Towards Immunotherapeutic Applications.
2020
Introduction: gd T cells have been characterized by the expression of a gd T cell receptor (TCR).When the gd TCR and the corresponding ab TCR were first discovered it was assumed that the corresponding cell types were likely to be functionally very similar. However, some 30 years later, we have realized that they are not. Unlike ab T cells, gd T cells (i) sense target antigens independent of MHC molecules; (ii) display NK-cell like innate reactivities, including killing of infected cells as well as microbes; (iii) are able to take up large particulates, including bacteria, and (iv) can act as professional antigen presenting cells. The “stress sensing” abilities of gd T cells have led to a g…
Role of Type I and II Interferons in Colorectal Cancer and Melanoma
2017
Cancer can be considered an aberrant organ with a hierarchical composition of different cell populations. The tumor microenvironment, including the immune cells and related cytokines, is crucial during all the steps of tumor development. In particular, type I and II interferons are involved in a plethora of mechanisms that regulate immune responses in cancer, thus balancing immune escape versus immune surveillance. Interferons are involved in both the direct and indirect regulation of cancer cell proliferation and metastatic potential. The mutational background of genes involved in interferons signaling could serve as a prognostic biomarker and a powerful tool to screen cancer patients elig…