RESUMO
Tumor immunosuppression is a limiting factor for successful cancer therapy. The lipid sphingosine-1-phosphate (S1P), which signals through 5 distinct G protein-coupled receptors (S1PR1-5), has emerged as an important regulator of carcinogenesis. However, the utility of targeting S1P in tumors is hindered by S1P's impact on immune cell trafficking. Here, we report that ablation of the immune cell-specific receptor S1PR4, which plays a minor role in immune cell trafficking, delayed tumor development and improved therapy success in murine models of mammary and colitis-associated colorectal cancer through increased CD8+ T cell abundance. Transcriptome analysis revealed that S1PR4 affected proliferation and survival of CD8+ T cells in a cell-intrinsic manner via the expression of Pik3ap1 and Lta4h. Accordingly, PIK3AP1 expression was connected to increased CD8+ T cell proliferation and clinical parameters in human breast and colon cancer. Our data indicate a so-far-unappreciated tumor-promoting role of S1P by restricting CD8+ T cell expansion via S1PR4.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Neoplasias Mamárias Experimentais/terapia , Receptores de Esfingosina-1-Fosfato/deficiência , Receptores de Esfingosina-1-Fosfato/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Proliferação de Células/genética , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Colite/complicações , Colite/imunologia , Colite/patologia , Neoplasias do Colo/etiologia , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Progressão da Doença , Feminino , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Esfingosina-1-Fosfato/genética , Microambiente Tumoral/genética , Microambiente Tumoral/imunologiaRESUMO
In solid tumors, tumor-associated macrophages (TAMs) commonly accumulate within hypoxic areas. Adaptations to such environments evoke transcriptional changes by the hypoxia-inducible factors (HIFs). While HIF-1α is ubiquitously expressed, HIF-2α appears tissue-specific with consequences of HIF-2α expression in TAMs only being poorly characterized. An E0771 allograft breast tumor model revealed faster tumor growth in myeloid HIF-2α knockout (HIF-2αLysM-/- ) compared with wildtype (wt) mice. In an RNA-sequencing approach of FACS sorted wt and HIF-2α LysM-/- TAMs, serine protease inhibitor, Kunitz type-1 ( Spint1) emerged as a promising candidate for HIF-2α-dependent regulation. We validated reduced Spint1 messenger RNA expression and concomitant Spint1 protein secretion under hypoxia in HIF-2α-deficient bone marrow-derived macrophages (BMDMs) compared with wt BMDMs. In line with the physiological function of Spint1 as an inhibitor of hepatocyte growth factor (HGF) activation, supernatants of hypoxic HIF-2α knockout BMDMs, not containing Spint1, were able to release proliferative properties of inactive pro-HGF on breast tumor cells. In contrast, hypoxic wt BMDM supernatants containing abundant Spint1 amounts failed to do so. We propose that Spint1 contributes to the tumor-suppressive function of HIF-2α in TAMs in breast tumor development.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Neoplasias/genética , Proteínas Secretadas Inibidoras de Proteinases/genética , Microambiente Tumoral/genética , Aloenxertos , Animais , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/genética , Fator de Crescimento de Hepatócito/genética , Humanos , Macrófagos/metabolismo , Macrófagos/patologia , Glicoproteínas de Membrana/genética , Camundongos , Neoplasias/patologia , RNA MensageiroRESUMO
Yersinia enterocolitica is a food-borne, gastro-intestinal pathogen with world-wide distribution. Only 11 serotypes have been isolated from patients, with O:3, O:9, O:8 and O:5,27 being the serotypes most commonly associated with human yersiniosis. Serotype is an important characteristic of Y. enterocolitica strains, allowing differentiation for epidemiology, diagnosis and phylogeny studies. Conventional serotyping, performed by slide agglutination, is a tedious and laborious procedure whose interpretation tends to be subjective, leading to poor reproducibility. Here we present a PCR-based typing scheme for molecular identification and patho-serotyping of Y. enterocolitica. Genome-wide comparison of Y. enterocolitica sequences allowed analysis of the O-antigen gene clusters of different serotypes, uncovering their formerly unknown genomic locations, and selection of targets for serotype-specific amplification. Two multiplex PCRs and one additional PCR were designed and tested on various reference strains and isolates from different origins. Our genotypic assay proved to be highly specific for identification of Y. enterocolitica species, discrimination between virulent and non-virulent strains, distinguishing the main human-related serotypes, and typing of conventionally untypeable strains. This genotyping scheme could be applied in microbiology laboratories as an alternative or complementary method to the traditional phenotypic assays, providing data for epidemiological studies.
