HLA-G/LILRBs: A Cancer Immunotherapy Challenge.

Despite some success, many patients do not benefit from immunotherapy. New strategies to improve clinical efficacy include identification of novel immune-checkpoint (IC) targets or a combination of immunotherapy with antiangiogenic treatments. Here, we propose the therapeutic use of IC, HLA-G/LILRB, and explore its enhanced synergistic antitumor activity when combined with antiangiogenic therapies

The Notch Delta-4 ligand helps to maintain the quiescence and the short-term reconstitutive potential of Haematopoietic Progenitor Cells through activation of a key gene network: Delta-4/Notch pathway retains the HPCs potential

International audienceUnderstanding the role of Notch and its ligands within the different bone marrow niches could shed light on the mechanisms regulating haematopoietic progenitor cells (HPCs) maintenance and self renewal. Here, we report that murine bone marrow HPCs activation by the vascular Notch Delta4 ligand maintains a significant proportion of cells specifically in the G0 state. Furthermore, Delta4/Notch pathway limits significantly the loss of the in vivo short-term reconstitutive potential upon transplantation of Delta-4 activated HPCs into lethally irradiated recipient mice. Both effects are directly correlated with the decrease of cell cycle genes transcription such as CYCLIN-D1, − D2, and -D3, and the upregulation of stemness related genes transcription such as BMI1, GATA2, HOXB4 and C-MYC. In addition, the transcriptional screening also highlights new downstream post-transcriptional factors, named PUMILIO1 and − 2, as part of the stem signature associated with the Delta4/Notch signalling pathway

The immune-checkpoint HLA-G/ILT4 is involved in the regulation of VEGF expression in clear cell renal cell carcinoma

Background: Clear cell renal cell carcinoma (ccRCC), the most aggressive renal cancer, is characterized by early lymph node metastases and bad prognosis. Most therapies targeting advanced or metastatic ccRCC are based, as first-line treatment, on the administration of the vascular endothelial growth factor (VEGF) neutralizing antibody termed Bevacizumab. Despite proven benefits, the expected results were not obtained for the majority of patients. The possibility that an intricate interplay between angiogenesis and immune-checkpoints might exist lead us to evaluate tumor angiogenesis, by means of VEGF expression together with the immune checkpoint HLA-G/ILT4. Methods: Tumor specimens were obtained from patients from two separate cohorts: One from "Evita Pueblo"Hospital from Berazategui, (Buenos Aires, Argentina) and the second includes patients surgically operated at the Urology Department of Saint-Louis Hospital (Paris, France) with a confirmed ccRCC diagnosis. Immunohistochemistry was performed with specific antibodies directed against HLA-G, VEGF-A, VEGF-C, D240, CD34, ILT4 and Ca-IX. In addition, gene expression levels were measured in a cell line derived from a ccRCC patient by semi-quantitative RT-PCR. Results: Our results show that the highly vascularized tumors of ccRCC patients express high levels of VEGF and the immune-checkpoint HLA-G. In addition, ILT4, one of the HLA-G receptors, was detected on macrophages surrounding tumor cells, suggesting the generation of an immune-tolerant microenvironment that might favor tumorigenesis. Notably, RT-qPCR analysis provided the first evidence on the transcriptional relationship between HLA-G/ILT4 and the VEGF family. Namely, in the presence of HLA-G or ILT4, the levels of VEGF-A are diminished whereas those of VEGF-C are increased. Conclusions: In an effort to find new therapeutic molecules and fight against metastasis dissemination associated with the poor survival rates of ccRCC patients, these findings provide the rationale for co-targeting angiogenesis and the immune checkpoint HLA-G.Fil: García, Marcela. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; ArgentinaFil: Palma, Maria Belen. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia. Laboratorio de Biología del Desarrollo Celular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Verine, Jerome. Ap-hp, Saint-louis Hospital; Francia. Research Division in Hematology and Immunology; FranciaFil: Miriuka, Santiago Gabriel. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia. Laboratorio de Biología del Desarrollo Celular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Inda, Ana María. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; ArgentinaFil: Errecalde, Ana Lia. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; ArgentinaFil: Desgrandchamps, François. Saint-louis Hospital; FranciaFil: Carosella, Edgardo Delfino. Universite de Paris; FranciaFil: Tronik Le Roux, Diana. Universite de Paris; Franci

HLA-G gene editing in tumor cell lines as a novel alternative in cancer immunotherapy

Cancer immunotherapies based mainly on the blockade of immune-checkpoint (IC) molecules by anti-IC antibodies offer new alternatives for treatment in oncological diseases. However, a considerable proportion of patients remain unresponsive to them. Hence, the development of novel clinical immunotherapeutic approaches and/or targets are crucial.W In this context, targeting the immune-checkpoint HLA-G/ILT2/ILT4 has caused great interest since it is abnormally expressed in several malignancies generating a tolerogenic microenvironment. Here, we used CRISPR/Cas9 gene editing to block the HLA-G expression in two tumor cell lines expressing HLA-G, including a renal cell carcinoma (RCC7) and a choriocarcinoma (JEG-3). Different sgRNA/Cas9 plasmids targeting HLA-G exon 1 and 2 were transfected in both cell lines. Downregulation of HLA-G was reached to different degrees, including complete silencing. Most importantly, HLA-G − cells triggered a higher in vitro response of immune cells with respect to HLA-G + wild type cells. Altogether, we demonstrated for the first time the HLA-G downregulation through gene editing. We propose this approach as a first step to develop novel clinical immunotherapeutic approaches in cancer.Fil: Palma, Maria Belen. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Tronik Le Roux, Diana. Saint-Louis Hospital; Francia. Universite de Paris 1 - Pantheon Sorbonne.; FranciaFil: Amin, Guadalupe. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castañeda, Sheila Lucia. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Möbbs, Alan Miqueas. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scarafia, Maria Agustina. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: la Greca, Alejandro Damián. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Daouya, Marina. Hôpital Saint-louis; Francia. Universite de Paris 1 - Pantheon Sorbonne.; FranciaFil: Poras, Isabelle. Hôpital Saint-louis; Francia. Universite de Paris 1 - Pantheon Sorbonne.; FranciaFil: Inda, Ana María. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Moro, Lucía Natalia. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carosella, Edgardo Delfino. Hôpital Saint-louis; Francia. Universite de Paris 1 - Pantheon Sorbonne.; FranciaFil: García, Marcela Nilda. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Departamento de Ciencias Morfológicas. Cátedra de Citología y Embriología A; ArgentinaFil: Miriuka, Santiago Gabriel. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The immune-checkpoint HLA-G/ILT4 is involved in the regulation of VEGF expression in clear cell renal cell carcinoma

Background: Clear cell renal cell carcinoma (ccRCC), the most aggressive renal cancer, is characterized by early lymph node metastases and bad prognosis. Most therapies targeting advanced or metastatic ccRCC are based, as first-line treatment, on the administration of the vascular endothelial growth factor (VEGF) neutralizing antibody termed Bevacizumab. Despite proven benefits, the expected results were not obtained for the majority of patients. The possibility that an intricate interplay between angiogenesis and immune-checkpoints might exist lead us to evaluate tumor angiogenesis, by means of VEGF expression together with the immune checkpoint HLA-G/ILT4. Methods: Tumor specimens were obtained from patients from two separate cohorts: One from “Evita Pueblo” Hospital from Berazategui, (Buenos Aires, Argentina) and the second includes patients surgically operated at the Urology Department of Saint-Louis Hospital (Paris, France) with a confirmed ccRCC diagnosis. Immunohistochemistry was performed with specific antibodies directed against HLA-G, VEGF-A, VEGF-C, D240, CD34, ILT4 and Ca-IX. In addition, gene expression levels were measured in a cell line derived from a ccRCC patient by semi-quantitative RT-PCR. Results: Our results show that the highly vascularized tumors of ccRCC patients express high levels of VEGF and the immune-checkpoint HLA-G. In addition, ILT4, one of the HLA-G receptors, was detected on macrophages surrounding tumor cells, suggesting the generation of an immune-tolerant microenvironment that might favor tumorigenesis. Notably, RT-qPCR analysis provided the first evidence on the transcriptional relationship between HLA-G/ILT4 and the VEGF family. Namely, in the presence of HLA-G or ILT4, the levels of VEGF-A are diminished whereas those of VEGF-C are increased. Conclusions: In an effort to find new therapeutic molecules and fight against metastasis dissemination associated with the poor survival rates of ccRCC patients, these findings provide the rationale for co-targeting angiogenesis and the immune checkpoint HLA-G.Facultad de Ciencias Médica

Mise au point d'une stratégie de marquage cellulaire par des codes-barres moléculaires en vue d'optimiser l'utilisation des cellules souches hématopoïétiques en thérapies génique et cellulaire

De par leurs propriétés d autorenouvellement et de multipotentialité, les cellules souches hématopoïétiques (CSH) présentent un intérêt médical majeur et sont au cœur de nombreuses thérapies génique et cellulaire. Cependant, leur utilisation en clinique est encore limitée par leur rareté, leur hétérogénéité fonctionnelle, et leur perte durant l étape de manipulation in vitro qui précède la transplantation.Dans ce contexte, nous avons mis au point une stratégie de marquage cellulaire par des codes-barres moléculaires afin d évaluer simultanément et quantitativement les capacités de repopulation des CSH in vivo. Cette stratégie nous a permis de cribler 1200 composés chimiques afin d identifier des molécules capables (1) d améliorer l efficacité de transduction des CSH par un vecteur lentiviral, (2) de maintenir voire d expandre, lors de l étape de culture in vitro, les CSH capables de repopulation à long terme. Plusieurs molécules candidates sont en cours de validation.Par ailleurs, grâce au marquage par des codes-barres, nous avons révélé l hétérogénéité des CSH en comparant leur capacité d autorenouvellement, la taille de la descendance qu elles génèrent et leur capacité de différenciation. Notre technique nous a permis non seulement de confirmer l existence de CSH biaisées vers le lignage myéloïde ou vers le lignage lymphoïde, mais aussi de quantifier leur fréquence.L application de cette stratégie à un autre système cellulaire nous a permis d étudier l influence de facteurs environnementaux et génétiques sur la croissance cellulaire de populations exprimant différentiellement l -synucléine, une protéine impliquée dans la maladie de Parkinson et certains cancers.Considerable hope is placed on the use of hematopoietic stem cells (HSC) in engineered gene- and cell- based therapy protocols. Their clinical utilization is, however to some extent, limited by their scarce representation, their heterogeneity and their loss during the ex vivo manipulation procedure. Within this context, we developed a barcode tagging strategy to simultaneously evaluate in vivo the repopulating capacity of HSC cultured in vitro. Barcode deconvolution demonstrated that our strategy constitute a powerful tool for tracking HSC quantitatively even using several dozens of different conditions. Using this strategy, we screened 1200 chemical compounds in order to identify molecules acting (1) on HSC transduction efficiency using a lentiviral vector, (2) on maintenance or even amplification during the in vitro culture step of long-term repopulating HSC. Several candidate molecules are currently under validation. In addition, using this barcoding strategy, we reveal heterogeneous behaviour of HSC examining their proliferation capacity, self-renewal ability and their differentiation lineage option. Our technique allowed us not only to confirm the occurrence of myeloid- and lymphoid-biased HSC, but also to quantify their frequency.We apply this strategy to another cell system to address the effect of different genetic and environmental factors on proliferation of cells expressing -synuclein, a protein involved in Parkinson disease and some cancers.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Réponse des cellules souches hématoïétiques aux radiations ionisantes

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

Mixture model on the variance for the differential analysis of gene expression data

In microarray experiments, accurate estimation of the gene variance is a key step in the identification of differentially expressed genes. Variance models go from the too stringent homoscedastic assumption to the overparameterized model assuming a specific variance for each gene. Between these two extremes there is some room for intermediate models. We propose a method that identifies clusters of genes with equal variance. We use a mixture model on the gene variance distribution. A test statistic for ranking and detecting differentially expressed genes is proposed. The method is illustrated with publicly available complementary deoxyribonucleic acid microarray experiments, an unpublished data set and further simulation studies. Copyright 2005 Royal Statistical Society.

Transcriptome Characterization Uncovers the Molecular Response of Hematopoietic Cells to Ionizing Radiation

International audienceIonizing radiation causes rapid and acute suppression of hematopoietic cells that manifests as the hematopoietic syndrome. However, the roles of molecules and regulatory pathways induced in vivo by irradiation of different hematopoietic cells have not been completely elaborated. Using a strategy that combined different microarray bioinformatics tools, we identified gene networks that might be involved in the early response of hematopoietic cells radiation response in vivo. The grouping of similar time-ordered gene expression profiles using quality threshold clustering enabled the successful identification of common binding sites for 56 transcription factors that may be involved in the regulation of the early radiation response. We also identified novel genes that are responsive to the transformation-related protein 53; all of these genes were biologically validated in p53-transgenic null mice. Extension of the analysis to purified bone marrow cells including highly purified long-term hematopoietic stem cells, combined with functional classification, provided evidence of gene expression modifications that were largely unknown in this primitive population. Our methodology proved particularly useful for analyzing the transcriptional regulation of the complex ionizing radiation response of hematopoietic cells. Our data may help to elucidate the molecular mechanisms involved in tissue radiosensitivity and to identify potential targets for improving treatment in radiation emergencies