BCL6 mediates Chemoresistance in Acute Myeloid Leukemia
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ABSTRACT:
PROVIDER: PRJNA549958 | ENA |
REPOSITORIES: ENA
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Project description:BCL6 is a transcription repressor that plays a crucial role in germinal center formation and lymphomagenesis. However, its role in myeloid malignancies remains unclear. Here, we explored the role of BCL6 in acute myeloid leukemia (AML). Heterogeneous levels of BCL6 were found across AML cell lines and primary AML samples. Cells with higher levels of BCL6 were indeed sensitive to treatment with BCL6 inhibitors. Gene expression profiling of AML cells treated with BCL6 inhibitor revealed a subset of target genes that are common with lymphoma cells. Ex vivo treatment of primary AML cells with BCL6 peptide inhibitor (BPI) induced apoptosis and decrease colony forming capacity which correlated with the levels of BCL6 expression . Importantly, inhibition of BCL6 in primary AML cells with either BPI or BCL6 siRNA resulted in significant reduction of leukemia initiating capacity using immunodeficient mice, suggesting ablation of leukemia stem cells (LSC). Such anti-LSC activity was also observed as downregulation of LSC gene signatures using gene expression analyses of cells treated with a BCL6 inhibitor. Importantly, treatment with cytarabine (AraC) induced BCL6 expression, and the levels of BCL6 induction were correlated with resistance to AraC. Treatment of AML primary derived xenografts (PDX) revealed that when AraC was combined with BCL6 inhibitor, inhibition of BCL6 significantly potentiated the efficacy of AraC and improved cytotoxic effects by interfering with the leukemia initiating capacity of AML cells. This suggests that pharmacological inhibition of BCL6 might provide a novel therapeutic strategy for ablation of LSCs and overcome chemoresistance in AML.
2020-08-01 | GSE133112 | GEO
Project description:Introduction Our previous study demonstrated that myc, mitochondrial oxidative phosphorylation, mTOR, and stemness were independently responsible for chemoresistance in AML. The current study aimed to further identify the potential mechanisms of chemoresistance of the “7+3” induction in AML using a single-cell RNA sequencing (scRNA-seq) approach. Methods Thirteen untreated de novo AML patients were enrolled and stratified into the complete remission (CR) (n = 8) and the non-CR (n = 5) groups. We used scRNA-seq to analyze the genetic profiles of 28950 AML cells from these 13 patients. A previously published bulk RNA-seq dataset validated our results. Results Chemoresistant AML cells had more premature accumulation in early hematopoiesis. The hematopoietic stem cell-like cells from the non-CR group expressed more leukemic stem cell markers (CD9, CD82, IL3RA and, IL1RAP) than those from the CR group. Besides, chemoresistant progenitor cells had impaired myeloid differentiation due to early hematopoiesis arrest. Importantly, the AML cells analyzed by the scRNA-seq and bulk RNA-seq honored comparable myeloid lineage cell fraction, which internally validated our results. Using the TCGA database, our analysis demonstrated that AML patients with a higher expression of chemoresistant genetic markers (IL3RA and IL1RAP had a worse overall survival (p < 0.01 for IL3RA; p < 0.05 for IL1RAP).
2023-03-01 | GSE198681 | GEO
Project description:Chemotherapy-resistant cancer recurrence is a major cause of mortality. In acute myeloid leukemia (AML), chemorefractory relapses result from the complex interplay between altered genetic, epigenetic and transcriptional states in leukemic cells. We developed an experimental model system using in vitro lineage tracing coupled with exome, transcriptome and in vivo functional readouts to assess the AML population dynamics and associated molecular determinants underpinning chemoresistance development. We found that combining standard chemotherapeutic regimens with low doses of DNA methyltransferase inhibitors (DNMTi, hypomethylating drugs) prevents chemoresistant relapses. Mechanistically, DNMTi suppressed the outgrowth of a pre-determined set of chemoresistant AML clones with stemness properties, instead favoring the expansion of rarer and unfit chemosensitive clones. Importantly, we confirmed the capacity of DNMTi combination to suppress stemness-dependent chemoresistance development in both xenotransplantation models and primary AML patient samples. Together, these results support the potential of DNMTi combination treatment to circumvent the development of chemorefractory AML relapses.
2019-07-19 | GSE134506 | GEO
Project description:To identify differences in the gene regulation between BCL6+/+ and BCL6-/- CML cells a gene expression analysis has been performed. We investigated the gene expression pattern in BCL6+/+ cells in the presence or absence of Imatinib and a combination of Imatinib and RI-BPI (a novel retro-inverso BCL6 peptide inhibitor). In BCL6-/- CML cells, we investigated the gene expression pattern in the presence or absence of Imatinib. BCR-ABL1 transformed myeloid cells from BCL6+/+ mice were cultured in the presence or absence of 10µM Imatinib or 10µM Imatinib and 20µM RI-BPI for 16 hours. BCR-ABL1 transformed myeloid cells from BCL6-/- mice were cultured in the presence or absence of 10µM Imatinib. Two samples for each condition were processed.
2011-08-23 | E-GEOD-24813 | biostudies-arrayexpress
Project description:We identified the BCL6 protooncogene as a critical downstream effector of FoxO3A in self-renewal signaling of CML-initiating cells. BCL6 represses Arf and p53 in CML cells and is required for leukemia stem cell maintenance, colony formation and initiation of leukemia in transplant recipients. Importantly, peptide inhibition of BCL6 in human CML cells compromises colony formation and leukemia-initiation in xenotransplanted mouse recipients. These findings identify peptide-inhibition of BCL6 as a novel strategy to eradicate leukemia-initiating cells in CML. Identification of BCL6 binding sites in human CML cell line JURL-MK1
2011-09-15 | E-GEOD-26085 | biostudies-arrayexpress
Project description:Resistance to chemotherapy is one of the primary obstacles in acute myeloid leukemia (AML) therapy. Micro-RNA-23a (miR-23a) is frequently deregulated in AML and has been linked to chemoresistance in solid cancers. We, therefore, studied its role in chemoresistance to cytarabine (AraC), which forms the backbone of all cytostatic AML treatments. Initially, we assessed AraC sensitivity in three AML cell lines following miR-23a overexpression/knockdown using MTT-cell viability and soft-agar colony-formation assays. Overexpression of miR-23a decreased the sensitivity to AraC, whereas its knockdown had the opposite effect. Analysis of clinical data revealed that high miR-23a expression correlated with relapsed/refractory (R/R) AML disease stages, the leukemic stem cell compartment, as well as with inferior overall survival (OS) and event-free survival (EFS) in AraC-treated patients. Mechanistically, we demonstrate that miR-23a targets and downregulates topoisomerase-2-beta (TOP2B), and that TOP2B knockdown mediates AraC chemoresistance as well. Likewise, low TOP2B expression also correlated with R/R-AML disease stages and inferior EFS/OS. In conclusion, we show that increased expression of miR-23a mediates chemoresistance to AraC in AML and that it correlates with an inferior outcome in AraC-treated AML patients. We further demonstrate that miR-23a causes the downregulation of TOP2B, which is likely to mediate its effects on AraC sensitivity.
| S-EPMC7072365 | biostudies-literature
Project description:Gilteritinib-induced upregulation of S100A9 is mediated through BCL6 in Acute Myeloid Leukemia
| PRJNA743665 | ENA
Project description:Using microarrays, we compared the changes in levels of gene expression between wildtype and Bcl6 KO macrophages in the absence or presence of LPS. Total RNA was obtained from WT and Bcl6 KO unstimulated and LPS-stimulated primary bone marrow-derived macrophages
2010-11-24 | E-GEOD-24792 | biostudies-arrayexpress
Project description:We identified the BCL6 protooncogene as a critical downstream effector of FoxO3A in self-renewal signaling of CML-initiating cells. BCL6 represses Arf and p53 in CML cells and is required for leukemia stem cell maintenance, colony formation and initiation of leukemia in transplant recipients. Importantly, peptide inhibition of BCL6 in human CML cells compromises colony formation and leukemia-initiation in xenotransplanted mouse recipients. These findings identify peptide-inhibition of BCL6 as a novel strategy to eradicate leukemia-initiating cells in CML.
2011-09-15 | GSE26085 | GEO
Project description:The aim of our research project is to identify microRNAs involved in chemoresistance in acute myeloid leukemia patients. We performed small RNA-sequencing on baseline bone marrow samples and compared chemoresistant versus chemosensitive patient samples.
2021-02-11 | E-MTAB-8775 | biostudies-arrayexpress