Glioblastomas (GBM) are brain tumors which display a bad prognosis despite conventional treatment associating surgical resection and subsequent radio-chemotherapy. These tumors are defined by an abundant and abnormal vascularization as well as by an important cellular heterogeneity. GBM notably contain a subpopulation of GBM stem-like cells (GSC) which contribute to tumor aggressiveness, resistance, and recurrence. Moreover, GSC directly take part in the formation of new vessels via their transdifferentiation into tumor derived endothelial cells (TDEC). Considering the importance of the vascularization in the GBM, we postulate that radiation could enhance the transdifferentiation of GSC into TDEC. Here, we show that ionizing radiation potentiates endothelial features of TDEC obtained from 3 patient-derived primocultures of GSC. Indeed, TDEC obtained from irradiated GSC (TDEC IR+) migrate more towards VEGF, form more pseudotubes in Matrigel in vitro and develop more functional blood vessel in Matrigel plugs implanted in Nude mice than TDEC obtained from non-irradiated GSC. Transcriptomic analysis allows us to highlight an overexpression of Tie2 in TDEC IR+ which is associated with the activation of AKT signaling pathway. All radiation-induced effects on TDEC IR+ were abolished by using a Tie2 kinase inhibitor, confirming the role of Tie2 signaling pathway in this process. Finally, the number of Tie2+ vessels is increased in recurrent GBM compared with matched untreated tumors. In conclusion, we show that irradiation potentiates proangiogenic features of TDEC throught Tie2/AKT signaling pathway. New therapeutic stategies associating standard teatment and an inhibitor of Tie2 signaling pathway should be considered for forthcoming trials.
Ionizing radiation induces endothelial transdifferentiation of glioblastoma stem-like cells through the Tie2 signaling pathway.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Targeted resequencing identifies PTCH1 as a major contributor to ocular developmental anomalies and extends the SOX2 regulatory network.
Specimen part, Time
View SamplesSOX2 is the main gene involved in anophthalmia. In order to identify genes regulated by SOX2 transcription factors (genes that could be good candidates to also be involved in ocular development), we studied transcriptomic profiles of murine genetically modified stem cells overexpressing the RAX gene (CCE-Rx cells) after transfection by a siRNA against SOX2 or a scramble siRNA.
Targeted resequencing identifies PTCH1 as a major contributor to ocular developmental anomalies and extends the SOX2 regulatory network.
Specimen part, Time
View SamplesAfter 5 days in culture with 2ng/ml of IL7, Pax5-/- transduced pro-B cells with PAX5A or PAX5B cDNA were sorted according to their EGFP positivity and total RNA was extracted.
No associated publication
Specimen part
View SamplesWe produced and analyzed the transcriptomic profiles of agressive plasmablastic lymphomas to describe their "immune escape" profile, depending on their viral status (HIV, EBV, ...). We used microarrays to compare the global gene expression profile between EBV+ and EBV- PL subtypes. This analysis unveiled the interest of treating EBV+ PL patients by immune checkpoint blockade strategies.
No associated publication
Specimen part
View SamplesExhaustion markers are expressed by T lymphocytes in Follicular Lymphoma (FL). Through these, TIM-3 has been recently identified as a poor pronostic factor when expressed by FL CD4+ T cells.
Impaired functional responses in follicular lymphoma CD8<sup>+</sup>TIM-3<sup>+</sup> T lymphocytes following TCR engagement.
Specimen part, Subject
View SamplesMyeloproliferative neoplasms are frequently associated with aberrant constitutive tyrosine kinase (TK) activity resulting from point mutations or chimaeric fusion genes, such as BCR ABL1 or JAK2 V617F. We report here for the first time in hematological malignancies, two novel fusion genes involving the TK RET, BCR-RET and FGFR1OP-RET, in chronic myelo monocytic leukemia (CMML) cases. The two RET fusion genes lead to the aberrant activation of RET, are able to transform hematopoietic cells and skew the hematopoietic differentiation program towards the monocytic/macrophage lineage. We also report that the BCR-RET fusion protein is insensitive to Imatinib but sensitive to Sorafenib in vivo. CMML is an hematopoietic malignancy associated with the frequent activation of the RAS pathway. The RET fusion genes seems to constitutively mimic the same signaling pathway than RAS mutations. Overall, the RET fusion genes behaviors in the monocytic lineage underlie the role of the normal RET TK activity during the physiological monocytic differentiation.
RET fusion genes are associated with chronic myelomonocytic leukemia and enhance monocytic differentiation.
Cell line
View SamplesSickle cell disease (SCD) is caused by a pathogenic hemoglobin (Hb) mutation, yet patients can have dramatically variable clinical manifestations. Here we address the genetic basis of this clinical heterogeneity. Using a systems genetics approach, we performed whole blood gene expression analysis and eQTL analysis on different clinical phenotypes in SCD patients.
Genomic architecture of sickle cell disease in West African children.
Sex, Age
View SamplesSteroid hormones regulate essential physiological processes and inadequate levels are associated with various pathological conditions. In testosterone-producing Leydig cells, steroidogenesis is strongly stimulated by LH via its receptor leading to increased cAMP production and expression of the steroidogenic acute regulatory (STAR) protein, which is essential for the initiation of steroidogenesis. Leydig cell steroidogenesis then passively decreases following the rapid degradation of cAMP into AMP by phosphodiesterases. In this study, we show that AMP-activated protein kinase (AMPK) is activated following cAMP breakdown in MA-10 and MLTC-1 Leydig cells. Activated AMPK then actively inhibits cAMP-induced steroidogenesis by repressing the expression of key regulators of steroidogenesis including Star and Nr4a1. Similar results were obtained in Y-1 adrenal cells and in the constitutive steroidogenic cell line R2C. Our data identify AMPK as an active repressor of steroid hormone biosynthesis in steroidogenic cells that is essential to preserve cellular energy and prevent excess steroid production.
A cell-autonomous molecular cascade initiated by AMP-activated protein kinase represses steroidogenesis.
Specimen part, Treatment
View SamplesWe have previously shown that Il1a-knockout (KO) mice exhibit rapid (at day 1) and persistent improvements in locomotion associated with reduced lesion volume compared with Il1b-KO mice and C57BL/6 controls after traumatic spinal cord injury (SCI). To investigate the mechanism by which Il1a mediates its detrimental effect, we analyzed the transcriptome of the injured spinal cord of Il1a-KO, Il1b-KO and C57BL/6 mice at 24 hours after SCI using GeneChip microarrays.
IL-1α Gene Deletion Protects Oligodendrocytes after Spinal Cord Injury through Upregulation of the Survival Factor Tox3.
Specimen part
View Samples