Lymphocyte NK | EPFL Graph Search

vignette|Lymphocyte NK humain Les cellules tueuses naturelles, ou lymphocytes NK, pour Natural Killer, sont des cellules du système immunitaire inné cytotoxique qui n'éliminent pas directement les agents infectieux notamment en raison de leurs récepteurs invariants. Les cellules NK représentent environ 5 à 16 % des lymphocytes humains Ce sont des cellules provenant de la lignée lymphocytaire proche des cellules des lymphocytes T, mais ne possédant pas de récepteur membranaire aux antigènes comme les lymphocytes. Ce sont de grands lymphocytes granuleux (par opposition aux « petits lymphocytes »), non T (CD3-) non B (CD19-), caractérisés chez l'humain par les marqueurs CD56, CD16 et NK. Les récepteurs du lymphocyte NK sont synthétisés au cours du développement et de la maturation de la cellule puis ceux-ci ne subiront plus de changement. Les cellules NK utilisent des récepteurs inhibiteurs (récepteur tueur d'immunoglobuline et Ly49) pour se développer, mûrir et reconnaître le « soi » du « non-soi ». Les cellules tueuses naturelles éliminent les cellules dont la fonction est altérée, comme les cellules tumorales ou les cellules infectées par un virus. Par exemple, les cellules tueuses naturelles peuvent reconnaître les cellules n'exprimant plus le CMH de classe I. Cette situation est observée durant une infection virale, certains virus pouvant induire la diminution du CMH de classe I pour éviter la reconnaissance par d'autres cellules immunitaires comme les lymphocytes T CD8. Découvertes dans les années 1960, ces cellules tirent leur nom du fait qu'elles n'ont pas besoin de l'activation d'un lymphocyte CD4+ pour avoir une action cytotoxique. L'existence de lymphocytes cytotoxiques naturels ou lymphocytes NK (sigle de l'anglais Natural Killer, signifiant « tueur naturel ») aussi appelés cellules tueuses naturelles ayant des propriétés anti-tumorales intrinsèques et innées a été découverte lors d'expérience avec des lymphocytes T.

A Manganese Phosphate Nanocluster Activates the cGAS‐STING Pathway for Enhanced Cancer Immunotherapy

Li Tang, Yugang Guo, Yuqing Xie, Min Gao, Armand Kurum, Kewen Lei, Yu Zhao, Xiaomeng Hu, Simon Bart M. Van Herck

Targeting the stimulator of interferon genes (STING) pathway with cyclic dinucleotides (CDNs), the natural STING agonists, is a promising immunotherapeutic strategy for cancer. However, the clinical application of natural CDNs as therapeutics is greatly hindered by their intrinsic properties including negative charges, small molecular weight, and high susceptibility to enzymatic degradation. Mn2+ ions have been recently discovered to directly activate the cyclic GMP-AMP (cGAMP) synthase (cGAS) and augment cGAMP-STING binding affinity. Here, a PEGylated manganese(II) phosphate (MnP-PEG) nanocluster is developed with high biocompatibility and potent capacity to stimulate the cGAS-STING pathway. MnP-PEG nanoclusters activate the immature bone marrow-derived dendritic cells (DCs) leading to 57.3- and 13.3-fold higher production of interferon β and interleukin-6 than free cGAMP, respectively. The potent STING activation capacity is likely due to the efficient cellular internalization of MnP-PEG nanoclusters by DCs and acid-triggered release of Mn2+ ions in the endolysosomes. Intratumoral administration of MnP-PEG nanoclusters markedly enhances tumor infiltration as well as maturation of DCs and macrophages, and promotes activation and cytotoxicity of T cells and natural killer cells in the tumor. MnP-PEG nanocluster in combination with a checkpoint inhibitor leads to significant tumor regression in the B16F10 murine melanoma model without any overt toxicities.

2021

Elucidating the role of lymphatic vessels within the tumor microenvironment of breast cancer

Ingrid Maria van Mier

Breast cancer is the most common cancer in women worldwide, with an estimated 1.7 million newly diagnosed cases in 2012. Despite the many clinical manifestations, metastatic disease is the main cause of death, and is responsible for 90% of all breast cancer-related deaths. Aggressive carcinomas of the breast preferentially spread via the lymphogenous route, and often co-opt and actively remodel the lymphatic vasculature in order to invade and metastasize to their draining lymph nodes (LNs) and, ultimately, to distant organs. Indeed, expression of vascular endothelial growth factor (VEGF)-C, the principal lymphangiogenic growth factor, by the tumor or recruited ancillary cells has been shown to correlate both with LN and distant metastasis, and shorter overall survival (OS), and LN status represents an important prognostic factor for patients diagnosed with breast cancer. Although traditionally considered as passive conduits that solely mediate tumor cell escape, more recent research aimed at discerning the interactions between the developing tumor and its associated lymphatic vessels has revealed that the lymphatic vasculature actively promotes lymphogenous metastasis of invasive tumor cells. Likewise, collaborative interactions between tumor cells and a multitude of other tissue-resident and recruited ancillary cells, which together constitute the tumor microenvironment, not only coercively contribute to tumor growth, progression and metastasis, but also suggest that interactions among primed stromal cells themselves may be important in the process of metastatic dissemination as well. Notably, expansion of tumor-associated lymphatic vessels in the tumor periphery leads to increased lymphatic drainage from the tumor to the tumor-draining LN, and interstitial flow-induced mechanical changes may alter tensional homeostasis within the tumor through stimulation of local fibroblasts that remodel and stiffen the extracellular matrix (ECM). Furthermore, VEGF-C-induced remodeling of the tumor-associated lymphatic vasculature has been shown to directly suppress the anti-tumor immune response, thereby promoting tolerance to the nascent tumor. Thus, to explore whether tumor-associated lymphatic vessels promote tumor metastasis not only via interactions with the incipient tumor, but also through cross-talk with the surrounding stromal cells, the different components of the tumor microenvironment, specifically tensional homeostasis and anti-tumor immunity, were evaluated upon modulation of lymphatic vessel growth in various experimental models of breast cancer. Accordingly, inhibition of VEGFR-3-mediated signaling upon administration of an antagonistic antibody in a genetically engineered preclinical mouse model specifically reduced the number of lymphatic endothelial cells (LECs) in the tumor, whereas conversely, orthotopic inoculation of a stable murine breast cancer cell line with enhanced expression of VEGF-C induced an expansion of the lymphatic endothelium. Although either experimental approach affected either regional or distant metastatic dissemination of the primary tumor to LN or the lungs, respectively, these effects did not seem to be mediated by interactions of the tumor-associated lymphatic vasculature with the tumor microenvironment in these particular experimental models.

EPFL2017

Elucidating the role of lymphatic vessels within the tumor microenvironment of breast cancer

Ingrid Maria van Mier

EPFL2017