Cancer cell CCR2 orchestrates suppression of the adaptive immune response.

C-C chemokine receptor type 2 (CCR2) is expressed on monocytes and facilitates their recruitment to tumors. Though breast cancer cells also express CCR2, its functions in these cells are unclear. We found that Ccr2 deletion in cancer cells led to reduced tumor growth and approximately twofold longer survival in an orthotopic, isograft breast cancer mouse model. Deletion of Ccr2 in cancer cells resulted in multiple alterations associated with better immune control: increased infiltration and activation of cytotoxic T lymphocytes (CTLs) and CD103+ cross-presenting dendritic cells (DCs), as well as up-regulation of MHC class I and down-regulation of checkpoint regulator PD-L1 on the cancer cells. Pharmacological or genetic targeting of CCR2 increased cancer cell sensitivity to CTLs and enabled the cancer cells to induce DC maturation toward the CD103+ subtype. Consistently, Ccr2-/- cancer cells did not induce immune suppression in Batf3-/- mice lacking CD103+ DCs. Our results establish that CCR2 signaling in cancer cells can orchestrate suppression of the immune response

Cancer cell CCR2 orchestrates suppression of the adaptive immune response

ABSTRACT C-C chemokine receptor type 2 (CCR2) is expressed on monocytes and facilitates their recruitment to tumors. Although breast cancer cells also express CCR2, its functions in these cells are unclear. We found that Ccr2 deletion in cancer cells led to reduced tumor growth and ∼2-fold longer survival in an orthotopic isograft breast cancer mouse model. Deletion of Ccr2 in cancer cells resulted in multiple alterations associated with better immune control: increased infiltration and activation of cytotoxic T lymphocytes (CTLs) and CD103+ cross-presenting dendritic cells (DCs), as well as upregulation of MHC class I and downregulation of checkpoint regulator PD-L1 on the cancer cells. Pharmacological inhibition of CCR2 increased cancer cell sensitivity to CTLs and enabled cancer cells to induce DC maturation toward the CD103+ subtype. Consistently, Ccr2 -/- cancer cells did not induce immune suppression in Batf3 -/- mice lacking the CD103+ DC subtype. Our results establish that CCR2 signaling in cancer cells can orchestrate suppression of the immune response. Summary C-C chemokine receptor type 2 (CCR2) expressed on monocytes facilitates their recruitment to tumors. Here, CCR2 signaling in cancer cells is shown to suppress immune control of tumors, in part by reducing CD103+ dendritic cell recruitment

Inflammasome Deletion Promotes Anti-tumor NK Cell Function in an IL-1/IL-18 Independent Way in Murine Invasive Breast Cancer

International audienc

An in vivo avian model of human melanoma to perform rapid and robust preclinical studies

Abstract Metastatic melanoma patients carrying a BRAF V600 mutation can be treated with BRAF inhibitors (BRAFi), in combination with MEK inhibitors (MEKi), but innate and acquired resistance invariably occurs. Resistance can involve transcriptional- and epigenetic-based phenotypic adaptations, as yet unpredictable. Predicting patient response to targeted therapies is crucial to guide clinical decision. We describe here the development of a highly efficient patient-derived xenograft model adapted to patient melanoma biopsies, using the avian embryo as a host (AVI-PDX ™ ). In this in vivo paradigm, we depict a fast and reproducible tumor engraftment of patient samples within the embryonic skin, preserving key molecular and phenotypic features. We show that sensitivity and resistance to BRAFi/MEKi targeted therapies can be reliably modeled in these AVI-PDX ™ , as well as synergies with other drugs, such as HDACi. We further provide proof-of-concept that the AVI-PDX ™ models the diversity of responses of melanoma patients to BRAFi/MEKi, within days, hence positioning it as a valuable tool for the design of personalized medicine assays and for the evaluation of novel combination strategies

Antibody response in children with multisystem inflammatory syndrome related to COVID-19 (MIS-C) compared to children with uncomplicated COVID-19.

To comprehensively analyze the quality of the antibody response between children with Multisystem inflammatory syndrome (MIS-C) and age-matched controls at one month after SARS-CoV-2 exposure, and infected in the same time-period.info:eu-repo/semantics/publishe

Sphingolipid paracrine signaling impairs keratinocyte adhesion to promote melanoma invasion

International audienceMelanoma is the deadliest form of skin cancer due to its propensity to metastasize. It arises from melanocytes, which are attached to keratinocytes within the basal epidermis. Here, we hypothesize that, in addition to melanocyte-intrinsic modifications, dysregulation of keratinocyte functions could initiate early-stage melanoma cell invasion. We identified the lysolipid sphingosine 1-phosphate (S1P) as a tumor paracrine signal from melanoma cells that modifies the keratinocyte transcriptome and reduces their adhesive properties, leading to tumor invasion. Mechanistically, tumor cell-derived S1P reduced E-cadherin expression in keratinocytes via S1P receptor dependent Snail and Slug activation. All of these effects were blocked by S1P2/3 antagonists. Importantly, we showed that epidermal E-cadherin expression was inversely correlated with the expression of the S1P-producing enzyme in neighboring tumors and the Breslow thickness in patients with early-stage melanoma. These findings support the notion that E-cadherin loss in the epidermis initiates the metastatic cascade in melanoma