Project description:LC-MS data and DIA-NN search files relating to: PU.1 Eviction at Lymphocyte-Specific Chromatin Domains Mediates Glucocorticoid Response in Acute Lymphoblastic Leukemia.
Abstract: The epigenetic landscape plays a critical role in the onset and evolution of various malignancies, but its therapeutic utility remains underutilized. Glucocorticoids are an essential part of many multi-agent treatment regimens for lymphoid malignancies. However, the emergence of glucocorticoid resistance is a significant barrier to cure, which is in part due to epigenetic alterations, including aberrant chromatin accessibility and hypermethylation at lymphocyte-specific glucocorticoid-response elements (GREs). To gain a deeper understanding of regulatory mechanisms leading to these epigenetic alterations, we conducted a multi-omics study, including chromosome conformation capture sequencing (HiC), to examine changes in the 3D genome structure following the in vivo treatment of acute lymphoblastic leukemia (ALL) patient-derived xenografts (PDXs) with glucocorticoid. We found that glucocorticoid treatment led to distinct patterns of topologically associated domains (TADs) in glucocorticoid sensitive compared to resistant PDXs. Furthermore, we show that these TADs were primed by the development-related pioneer transcription factor PU.1, which extensively interacts with the glucocorticoid receptor (GR) exclusively in glucocorticoid-sensitive ALL PDXs. An integrative analysis of rapid immunoprecipitation mass spectrometry of endogenous protein (RIME) and ChIP-seq revealed that PU.1 binding was associated with lymphocyte-specific activation of GREs and GRE-interacting super-enhancers. The PU.1-associated TADs modulated epigenetic marks, and particularly the eviction of PU.1 promoted GR binding and the expression of signature genes, including BIM, ZBTB16 and RASA1, mediating glucocorticoid-induced apoptosis in ALL. These findings were phenocopied using a PU.1 inhibitor DB2313 to restore glucocorticoid sensitivity in ALL. Taken together, this study identified a new epigenetic pathway integrating PU.1 priming and PU.1-GR interaction which ultimately leads to PU.1 eviction in ALL. This pathway provides the first link between the activity of a lineage-specific transcription factor and epigenetic modulators mediating the response to glucocorticoids and thus offers a new avenue to translate fundamental epigenetic research into the clinic.
Project description:Drug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer. Experiment Overall Design: primary acute lymphoblastic leukemia samples were determined to be sensitive or resistant to in vitro treatment with glucocorticoids. Samples were then hybrized to affymetrix microarrays
Project description:Gene expression data of glucocorticoid resistant and sensitive acute lymphoblastic leukemia cell lines for the article: Expression, regulation and function of phosphofructo-kinase/fructose-biphosphatases (PFKFBs) in glucocorticoid-induced apoptosis of acute lymphoblastic leukemia cells Glucocorticoids (GCs) cause apoptosis and cell cycle arrest in lymphoid cells and constitute a central component in the therapy of lymphoid malignancies, most notably childhood acute lymphoblastic leukemia (ALL). PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-2), a kinase controlling glucose metabolism, was identified by us previously as GC response gene in expression profiling analyses performed in children with ALL during initial systemic GC mono-therapy. Since deregulation of glucose metabolism has been implicated in apoptosis induction, this gene and its relatives PFKFB1, 3, and 4 were further analyzed. Expression analyses in additional ALL children, non-leukemic individuals and leukemic cell lines confirmed frequent PFKFB2 induction by GC in most systems sensitive to GC-induced apoptosis, particularly in T-ALL cells. The 3 other family members, in contrast, were not or weakly expressed (PFKFB1 and 4) or not induced by GC (PFKFB3). Conditional PFKFB2 over-expression in the CCRF-CEM T-ALL in vitro model revealed that its 2 splice variants (15A and 15B) did not have any detectable effect on survival or cell cycle progression. Moreover, neither PFKFB2 splice variant significantly affected sensitivity to, or kinetics of, GC-induced apoptosis. Our data suggest that, at least in the model system investigated, PFKFB2 is not an essential upstream regulator of the anti-leukemic effects of GC. Generation of the GC sensitive and resistant clones is described in Parson et al. FASEB J 2005 (Pubmed id 15637111). In brief GC sensitive clones were generated by limiting dilution subcloning from the GC sensitive T-ALL cell line CCRF-CEM-C7H2. To generate GC resistant clones the CCRF-CEM-C7H2 cell line was clutured in the presence of 10E-7 M dexametasone. Gene expression profiles of glucocorticoid (GC) resistant and sensitive T-ALL cells during GC treatment and corresponding control samples (cells treated with carrier control). GC induced regulation of PFKFB2 was determined in the various cell lines based on the expression intensities of the corresponding probe sets in GC treated and control samples.
Project description:Glucocorticoids (GCs) cause apoptosis in lymphoid lineage cells and are therefore widely used in the therapy of lymphoid malignancies. The molecular mechanisms of the anti-leukemic GC effects are, however, poorly understood. We have previously defined a list of GC-regulated candidate genes by Affymetrix-based whole genome comparative expression profiling in children with acute lymphoblastic leukemia (ALL) during systemic GC monotherapy and in experimental systems of GC-induced apoptosis. ZBTB16, a Zink finger and BOZ-domain containing transcriptional repressor, was one of the most promising candidates derived from this screen. To investigate its possible role in GC-induced apoptosis and cell cycle arrest, we performed conditional over-expression experiments in CCRF-CEM childhood ALL cells. Transgenic ZBTB16 alone had no detectable effect on survival, however, it reduced sensitivity to GC-induced apoptosis. This protective effect was not seen when apoptosis was induced by antibodies against Fas/CD95 or 3 different chemotherapeutics. To address the molecular mechanism underlying this protective effect, we performed whole genome expression profiling in cells with conditional ZBTB16 expression. Surprisingly, ZBTB16 induction did not significantly alter the expression profile, however, it interfered with the regulation of several GC response genes. One of them, BCL2L11/Bim, has previously been shown to be responsible for cell death induction in CCRF-CEM cells. Thus, ZBTB16´s protective effect can be attributed to interference with transcriptional regulation of apoptotic genes, at least in the investigated model system.
Project description:Glucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we used a systems biology approach, based on the reverse engineering of signaling regulatory networks, which identified the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Indeed, activation of AKT1 in T-ALL lymphoblasts impairs glucocorticoid-induced apoptosis. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein at position S134 and blocks glucocorticoid-induced NR3C1 translocation to the nucleus. Consistently, inhibition of AKT1 with MK-2206 increases the response of T-ALL cells to glucocorticoid therapy both in T-ALL cell lines and in primary patient samples thus effectively reversing glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of ATK1 inhibitors and glucocorticoids, in combination, for the treatment of T-ALL. This study includes 228 T-ALL samples of which 117 samples are re-analysis of GSE26713.
Project description:Glucocorticoids are critical components of combination chemotherapy regimens in pediatric acute lymphoblastic leukemia (ALL). However, the signaling pathways regulating apoptosis in glucocorticoid-treated lymphoid cells remain unclear. In this study, pediatric ALL patient-derived xenograft inherently sensitive to glucocorticoids were exposed to dexamethasone in vivo. Whole-genome GR binding sites and histone acetylation status were detected using chromatin immunoprecipitation sequencing analyses. This provided a global understanding of dexamethasone-induced DNA modulations in ALL cells in vivo, which is likely to be important in the understanding of mechanisms of glucocorticoid response in lymphoid malignancies.
Project description:Article title: Expression, regulation and function of phosphofructo-kinase/fructose-biphosphatases (PFKFBs) in glucocorticoid-induced apoptosis of acute lymphoblastic leukemia cells. Glucocorticoids (GCs) cause apoptosis and cell cycle arrest in lymphoid cells and constitute a central component in the therapy of lymphoid malignancies, most notably childhood acute lymphoblastic leukemia (ALL). PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-2), a kinase controlling glucose metabolism, was identified by us previously as a GC response gene in expression profiling analyses performed in children with ALL during initial systemic GC mono-therapy. Since deregulation of glucose metabolism has been implicated in apoptosis induction, this gene and its relatives PFKFB1, 3, and 4 were further analyzed. Expression analyses in additional ALL children, non-leukemic individuals and leukemic cell lines confirmed frequent PFKFB2 induction by GC in most systems sensitive to GC-induced apoptosis, particularly in T-ALL cells. The 3 other family members, in contrast, were not or weakly expressed (PFKFB1 and 4) or not induced by GC (PFKFB3). Conditional PFKFB2 over-expression in the CCRF-CEM T-ALL in vitro model revealed that its 2 splice variants (15A and 15B) did not have any detectable effect on survival or cell cycle progression. Moreover, neither PFKFB2 splice variant significantly affected sensitivity to, or kinetics of, GC-induced apoptosis. Our data suggest that, at least in the model system investigated, PFKFB2 is not an essential upstream regulator of the anti-leukemic effects of GC. Gene expression profiles of 4 non-leukemic individuals (1 healthy and 3 with epilepsy) were generated from mononuclear cells isolated from peripheral blood samples before, and after 2, 6, and 24 hours of in-vivo glucocorticoid treatment.
Project description:Glucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we used a systems biology approach, based on the reverse engineering of signaling regulatory networks, which identified the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Indeed, activation of AKT1 in T-ALL lymphoblasts impairs glucocorticoid-induced apoptosis. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein at position S134 and blocks glucocorticoid-induced NR3C1 translocation to the nucleus. Consistently, inhibition of AKT1 with MK-2206 increases the response of T-ALL cells to glucocorticoid therapy both in T-ALL cell lines and in primary patient samples thus effectively reversing glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of ATK1 inhibitors and glucocorticoids, in combination, for the treatment of T-ALL.
Project description:Glucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we identify the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein and blocks glucocorticoid-induced NR3C1 transcription by inhibiting glucocorticoid-induced NT3C1 translocation to the nucleus. Consistently, pharmacologic inhibition of AKT1 increases the response of T-ALL cells to glucocorticoid therapy and effectively reverses glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of AKT1 inhibitors and glucocorticoids in combination for the treatment of T-ALL. Gene Expression Analysis of DND41 cell lines infected with shPTEN or shLUC and treated with 1M-BM-5M Dexamethasone vs DMSO for 24h, in triplicate.
Project description:Glucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we identify the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein and blocks glucocorticoid-induced NR3C1 transcription by inhibiting glucocorticoid-induced NT3C1 translocation to the nucleus. Consistently, pharmacologic inhibition of AKT1 increases the response of T-ALL cells to glucocorticoid therapy and effectively reverses glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of AKT1 inhibitors and glucocorticoids in combination for the treatment of T-ALL.