BCL7A is silenced by hypermethylation to promote acute myeloid leukemia
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE226604 | GEO | 2023/04/07
REPOSITORIES: GEO
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Project description:BackgroundRecent massive sequencing studies have revealed that SWI/SNF complexes are among the most frequently altered functional entities in solid tumors. However, the role of SWI/SNF in acute myeloid leukemia is poorly understood. To date, SWI/SNF complexes are thought to be oncogenic in AML or, at least, necessary to support leukemogenesis. However, mutation patterns in SWI/SNF genes in AML are consistent with a tumor suppressor role. Here, we study the SWI/SNF subunit BCL7A, which has been found to be recurrently mutated in lymphomas, but whose role in acute myeloid malignancies is currently unknown.MethodsData mining and bioinformatic approaches were used to study the mutational status of BCL7A and the correlation between BCL7A expression and promoter hypermethylation. Methylation-specific PCR, bisulfite sequencing, and 5-aza-2'-deoxycytidine treatment assays were used to determine if BCL7A expression was silenced due to promoter hypermethylation. Cell competition assays after BCL7A expression restoration were used to assess the role of BCL7A in AML cell line models. Differential expression analysis was performed to determine pathways and genes altered after BCL7A expression restoration. To establish the role of BCL7A in tumor development in vivo, tumor growth was compared between BCL7A-expressing and non-expressing mouse xenografts using in vivo fluorescence imaging.ResultsBCL7A expression was inversely correlated with promoter methylation in three external cohorts: TCGA-LAML (N = 160), TARGET-AML (N = 188), and Glass et al. (2017) (N = 111). The AML-derived cell line NB4 silenced the BCL7A expression via promoter hypermethylation. Ectopic BCL7A expression in AML cells decreased their competitive ability compared to control cells. Additionally, restoration of BCL7A expression reduced tumor growth in an NB4 mouse xenograft model. Also, differential expression analysis found that BCL7A restoration altered cell cycle pathways and modified significantly the expression of genes like HMGCS1, H1-0, and IRF7 which can help to explain its tumor suppressor role in AML.ConclusionsBCL7A expression is silenced in AML by promoter methylation. In addition, restoration of BCL7A expression exerts tumor suppressor activity in AML cell lines and xenograft models.
| S-EPMC10026484 | biostudies-literature
Project description:BCL7A is silenced by hypermethylation to promote acute myeloid leukemia
| PRJNA940796 | ENA
Project description:Mutations in genes encoding the various subunits of the SWI/SNF chromatin remodeling complex are frequently observed in different human cancers. In diffuse large B-cell lymphoma (DLBCL), genetic changes in BCL7A, a subunit of the SWI/SNF complex, have been recently reported but the functional role of such genetic changes remains unknown. BCL7A mutations concentrate at the first exon and the most frequently mutated hotspot is the splice donor site of the first intron. By using in vitro and in vivo analyses, we show that restoration of BCL7A drives a tumor suppressor-like phenotype. Further, we found that splice site mutations block the tumor suppressor phenotype and prevent BCL7A from binding to the SWI/SNF complex. Finally, we identified that the SWI/SNF complex accumulates mutations in a third of DLBCL tumors, especially in the GCB subtype. These discoveries highlight the tumor suppressor role of BCL7A mutations in DLBCL, and suggest that the SWI/SNF complex is involved in DLBCL pathogenesis.
2020-10-21 | PXD014795 | Pride
Project description:Mutations in genes encoding the various subunits of the SWI/SNF chromatin remodeling complex are frequently observed in different human cancers. In diffuse large B-cell lymphoma (DLBCL), genetic changes in BCL7A, a subunit of the SWI/SNF complex, have been recently reported but the functional role of such genetic changes remains unknown. BCL7A mutations concentrate at the first exon and the most frequently mutated hotspot is the splice donor site of the first intron. By using in vitro and in vivo analyses, we show that restoration of BCL7A drives a tumor suppressor-like phenotype. Further, we found that splice site mutations block the tumor suppressor phenotype and prevent BCL7A from binding to the SWI/SNF complex. Finally, we identified that the SWI/SNF complex accumulates mutations in a third of DLBCL tumors, especially in the GCB subtype. These discoveries highlight the tumor suppressor role of BCL7A mutations in DLBCL, and suggest that the SWI/SNF complex is involved in DLBCL pathogenesis.
2020-11-20 | GSE149277 | GEO
Project description:Purpose：Examination of global gene expression of 14-day-old WT, bcl7a(brip3), bcl7b(brip4), bcl7a bcl7b(brip3 brip4), bcl7a bcl7b brm-3(brip3 brip4 brm-3) and bcl7a bcl7b brm-1(brip3 brip4 brm-1) seedlings under short day condition. Methods: Total RNA was extracted from 14-day-old Arabidopsis seedlings under short-day conditions using TRIzol reagent (Invitrogen) following the manufacturer's instructions. RNAs from three biological replicates was sequenced. separately at Novogene, using Illumina Hiseq X-Ten (Sequencing method: Hiseq-PE150). The paired-end RNA-seq reads were quantified by Salmon(Patro et al., 2017) (v1.5.1) with parameters -k 31 and --type quasi. Salmon index was generated using AtRTD2.fa as the reference transcriptome. The gene quantification files of all samples were used as inputs (TPM values) for differential gene expression analysis by DESeq2(Love et al., 2014) v3.10. To analyze differential gene expression in all samples, we used “parametric” Fit type, “ratio” method for estimate Size Factors and Wald significance test function provided by DESeq2. Conclusions: Our study represents the first detailed analysis of bcl7a(brip3), bcl7b(brip4), bcl7a bcl7b(brip3 brip4), bcl7a bcl7b brm-3(brip3 brip4 brm-3) and bcl7a bcl7b brm-1(brip3 brip4 brm-1) transcriptomes, with biologic replicates, generated by RNA-seq technology.
2024-01-03 | GSE215151 | GEO
Project description:DNA methylation patterns are frequently dysregulated in cancer, although little is known of the mechanisms through which specific gene sets become aberrantly methylated. The ecotropic viral integration site 1 (EVI1) locus encodes a DNA binding zinc-finger transcription factor that is aberrantly expressed in a subset of acute myeloid leukemia (AML) patients with poor outcome. We find that the promoter DNA methylation signature of EVI1 AML blast cells differs from those of normal CD34(+) bone marrow cells and other AMLs. This signature contained 294 differentially methylated genes, of which 238 (81%) were coordinately hypermethylated. An unbiased motif analysis revealed an overrepresentation of EVI1 binding sites among these aberrantly hypermethylated loci. EVI1 was capable of binding to these promoters in 2 different EVI1-expressing cell lines, whereas no binding was observed in an EVI1-negative cell line. Furthermore, EVI1 was observed to interact with DNA methyl transferases 3A and 3B. Among the EVI1 AML cases, 2 subgroups were recognized, of which 1 contained AMLs with many more methylated genes, which was associated with significantly higher levels of EVI1 than in the cases of the other subgroup. Our data point to a role for EVI1 in directing aberrant promoter DNA methylation patterning in EVI1 AMLs.
| S-EPMC3037746 | biostudies-literature
Project description:Nuclear localization of non-phosphorylated, active beta-catenin is a measure of Wnt pathway activation and is associated with adverse outcome in patients with acute myeloid leukemia (AML). While genetic alterations of the Wnt pathway are infrequent in AML, inhibitors of this pathway are silenced by promoter methylation in other malignanices. Leukemia cell lines were examined for Wnt pathway inhibitor methylation and total beta-catenin levels, and had frequent methylation of Wnt inhibitors and upregulated beta-catenin by Western blot and immunofluorescence. One hundred sixty-nine AML samples were examined for methylation of Wnt inhibitor genes. Diagnostic samples from 72 patients with normal cytogenetics who received standard high-dose induction chemotherapy were evaluated for associations between methylation and event-free or overall survival. Extensive methylation of Wnt pathway inhibitor genes was observed in cell lines, and 89% of primary AML samples had at least one methylated gene: DKK1 (16%), DKK3 (8%), RUNX3 (27%), sFRP1 (34%), sFRP2 (66%), sFRP4 (9%), sFRP5 (54%), SOX17 (29%), and WIF1 (32%). In contrast to epithelial tumors, methylation of APC (2%) and RASSF1A (0%) was rare. In patients with AML with normal cytogenetics, sFRP2 and sFRP5 methylation at the time of diagnosis was associated with an increased risk of relapse, and sFRP2 methylation was associated with an increased risk for death. In patients with AML: (a) there is a high frequency of Wnt pathway inhibitor methylation; (b) Wnt pathway inhibitor methylation is distinct from that observed in epithelial malignancies; and (c) methylation of sFRP2 and sFRP5 may predict adverse clinical outcome in patients with normal karyotype AML.
| S-EPMC4000011 | biostudies-literature
Project description:In acute myeloid leukemia (AML) DNA hypermethylation of gene promoters is frequently observed and often correlates with a block of differentiation. Treatment of AML patients with DNA methyltransferase inhibitors results in global hypomethylation of genes and, thereby, can lead to a reactivation of the differentiation capability. Unfortunately, after termination of treatment both hypermethylation and differentiation block return in most cases. Here, we apply, for the first time, a computational model of epigenetic regulation of transcription to: i) provide a mechanistic understanding of the DNA (de-) methylation process in AML and; ii) improve DNA demethylation treatment strategies. By in silico simulation, we analyze promoter hypermethylation scenarios referring to DNMT dysfunction, decreased H3K4me3 and increased H3K27me3 modification activity, and accelerated cell proliferation. We quantify differences between these scenarios with respect to gene repression and activation. Moreover, we compare the scenarios regarding their response to DNMT inhibitor treatment alone and in combination with inhibitors of H3K27me3 histone methyltransferases and of H3K4me3 histone demethylases. We find that the different hypermethylation scenarios respond specifically to therapy, suggesting that failure of remission originates in patient-specific deregulation. We observe that inappropriate demethylation therapy can result even in enforced deregulation. As an example, our results suggest that application of high DNMT inhibitor concentration can induce unwanted global gene activation if hypermethylation originates in increased H3K27me3 modification. Our results underline the importance of a personalized therapy requiring knowledge about the patient-specific mechanism of epigenetic deregulation.
| S-EPMC5788435 | biostudies-literature
Project description:Mammalian SWI/SNF/BAF chromatin remodeling complexes influence cell lineage determination. While the contribution of mammalian SWI/SNF/BAF complexes in neural progenitor cell (NPC) proliferation and differentiation has been reported, little is known about the transcriptional profiles that determine neurogenesis or gliogenesis. Here we report that BCL7A is a modulator of the SWI/SNF/BAF complex and stimulates the genome-wide occupancy of the ATPase BRG1. We demonstrate that BCL7A is dispensable for SWI/SNF/BAF complex integrity, whereas it is essential to regulate Notch/Wnt pathway and mitochondrial bioenergetics in differentiating NPCs. Together, our findings uncover the unique mechanistic contribution of BCL7A-containing SWI/SNF/BAF complex in mitochondria-driven NPC commitment, thereby providing a better understanding of the cell-intrinsic transcriptional processes that connect metabolism, neuronal morphogenesis and cognitive flexibility.
2022-10-15 | GSE210759 | GEO
Project description:Mammalian SWI/SNF/BAF chromatin remodeling complexes influence cell lineage determination. While the contribution of mammalian SWI/SNF/BAF complexes in neural progenitor cell (NPC) proliferation and differentiation has been reported, little is known about the transcriptional profiles that determine neurogenesis or gliogenesis. Here we report that BCL7A is a modulator of the SWI/SNF/BAF complex and stimulates the genome-wide occupancy of the ATPase BRG1. We demonstrate that BCL7A is dispensable for SWI/SNF/BAF complex integrity, whereas it is essential to regulate Notch/Wnt pathway and mitochondrial bioenergetics in differentiating NPCs. Together, our findings uncover the unique mechanistic contribution of BCL7A-containing SWI/SNF/BAF complex in mitochondria-driven NPC commitment, thereby providing a better understanding of the cell-intrinsic transcriptional processes that connect metabolism, neuronal morphogenesis and cognitive flexibility.
2022-10-15 | GSE210757 | GEO