FBXO11 is a candidate tumor suppressor in the leukemic transformation of myelodysplastic syndrome
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE156708 | GEO | 2020/08/24
REPOSITORIES: GEO
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Project description:FBXO11 is a candidate tumor suppressor in the leukemic transformation of myelodysplastic syndrome
| PRJNA658804 | ENA
Project description:Myelodysplastic syndrome (MDS) is a heterogeneous myeloid malignancy characterized by blood cell morphological dysplasia, ineffective clonal hematopoiesis, and risk of transformation to secondary acute myeloid leukemia (sAML). A number of genetic abnormalities have been identified in MDS and sAML, but sensitive sequencing methods can detect these mutations in nearly all healthy individuals by 60 years of age. To discover novel cellular pathways that accelerate MDS and sAML, we performed a CRISPR/Cas9 screen in the human MDS-L cell line. We report here that loss of the F-Box protein FBXO11, a component of the SCF ubiquitin ligase complex, confers cytokine independent growth to MDS-L cells, suggesting a tumor suppressor role for FBXO11 in myeloid malignancies. Putative FBXO11 substrates are enriched for proteins with functions in RNA metabolism and, of note, spliceosome mutations that are commonly found in MDS/sAML are rare in patients with low FBXO11 expression. We also reveal that loss of FBXO11 leads to significant changes in transcriptional pathways influencing leukocyte proliferation, differentiation, and apoptosis. Last, we find that FBXO11 expression is reduced in patients with secondary AML. We conclude that loss of FBXO11 is a mechanism for disease transformation of MDS into AML, and may represent a future therapeutic target.
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Project description:Transfer RNA (tRNA)-derived fragments (tRF) are emerging small noncoding (nc) RNAs that, while commonly altered in cancer, have poorly defined roles in tumorigenesis. Here we show that pseudouridylation (Ψ) of a stem-cell-enriched tRF subtype, mTOG, selectively inhibits malignant protein synthesis programs, thereby promoting engraftment and differentiation of myelodysplastic syndrome (MDS) hematopoietic stem and progenitor cells (HSPC). Building on evidence that mTOG-Ψ target the polyadenylate-binding protein cytoplasmic 1 (PABPC1), we employed HDX-MS to reveal critical interactions between mTOG and functional RNA-recognition motif (RRM) domains in PABPC1. Mechanistically, this hinders the recruitment of the translational co-activator PABPC1-interacting protein 1 (PAIP1) and strongly represses translation of transcripts sharing 5’UTR pyrimidine-enriched sequences (PES), including 5’ terminal oligopyrimidine tracts (TOP) that encode protein machinery components, and are frequently altered in cancer. Significantly, mTOG dysregulation leads to aberrantly increased 5’PES mRNA translation in malignant MDS-HSPC and is clinically associated with leukemic transformation and reduced patient survival. Taken together, these results define a critical role for tRF and Ψ in difficult-to-treat subsets of MDS characterized by high risk of progression to acute myeloid leukemia.
2021-12-20 | PXD023122 | Pride
Project description:Transcriptional profiling of mouse 4T1 breast cancer cells stably tranduced with pLEX-MCS based lentivirus. Three groups were compared, Vector cells, SNAIL expressing cells; and SNAIL+FBXO11 expressing cells. SNAIL expression induced strong EMT phenotype while SNAIL/FBXO11 reversed cells back to epithelial cells.
2014-12-01 | GSE50887 | GEO
Project description:Transcriptional profiling of mouse HMLEN breast cancer cells (HMLE cells transformed with -Neu oncogene) stably tranduced with pLEX-MCS based lentivirus. Three groups were compared, Vector cells, SNAIL expressing cells; and SNAIL+FBXO11 expressing cells. SNAIL expression induced strong EMT phenotype while SNAIL/FBXO11 reversed cells back to epithelial cells.
2014-12-01 | GSE50888 | GEO
Project description:BCL6 is a key oncogene in lymphoma pathogenesis. The expression of BCL6 in lymphoid cells can be deregulated by several mechanisms, including chromosomal translocations, somatic mutations in the promoter regulatory regions or reduced proteasome-mediated degradation. FBXO11 was recently identified as a major ubiquitin ligase involved in the degradation of BCL6 and is frequently inactivated in diffuse large B-cell lymphoma (DLBCL). In this work, we found that FBXO11 is frequently mutated in Burkitt lymphoma (BL) but rarely mutated in other BCL6-positive lymphomas, such as follicular lymphoma (FL). All mutations tested impaired FBXO11 mediated BCL6 degradation and FBXO11 knock-out completely stabilized BCL6 levels in human BL cell lines. Conditional deletion of one copy or both copies of FBXO11 in c-Myc-driven B cell lymphoma in mice accelerated lymphomagenesis, genetically confirming that FBXO11 is a haplo-insufficient oncosuppressor in lymphoma. In both FBOX11 WT and deficient BL mouse and human cell lines, blockade of BCL6 via a specific degrader or BCL6 inhibitors, impaired lymphoma growth in vitro and in vivo, an effect further enhanced by co-inhibition of c-Myc activity. Overall these findings not only establish FBXO11 as one of the most frequently mutated genes in BL, but also elucidate its biological functions in lymphomagenesis and thereby identify BCL6 as a specific therapeutic target in BL.
2021-12-31 | GSE159303 | GEO
Project description:The histone mark H3K27me3 and its reader/writer Polycomb repressive complex 2 (PRC2) mediate widespread transcriptional repression in stem and progenitor cells. Mechanisms that regulate this activity are critical for tissue development but poorly understood. Here we show that the E3 ubiquitin ligase FBXO11 relieves PRC2-mediated repression during erythroid maturation by targeting its newly identified substrate BAHD1, an H3K27me3 reader that recruits transcriptional co-repressors. Erythroblasts lacking FBXO11 are developmentally delayed, with reduced expression of maturation-associated genes, most of which harbor bivalent histone marks (activating H3K4me3 and repressive H3K27me3), bind BAHD1, and fail to recruit the erythroid transcription factor GATA1. The BAHD1 complex interacts physically with PRC2 and depletion of either component restores FBXO11-deficient erythroid gene expression. Previous studies showed that FBXO11 promotes B-cell development and inhibits lymphomagenesis by degrading the transcriptional repressor BCL6. We show that in aggressive B-cell lymphoma lines, depletion of FBXO11 causes the accumulation of both BCL6 and BAHD1, and that suppression of BAHD1 slows cell expansion. Our studies identify BAHD1 as a novel effector of PRC2-mediated repression and reveal how a single E3 ubiquitin ligase eliminates PRC2 repression at developmentally poised bivalent genes during erythropoiesis. The FBXO11-BAHD1 regulatory axis may function in other developmental pathways, including B-lymphopoiesis and lymphomagenesis.
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Project description:Control of oxidative stress in the bone marrow (BM) is key for maintaining the balance between self-renewal, proliferation, and differentiation of hematopoietic cells. Breakdown of this regulation can lead to diseases characterized by BM failure such as the myelodysplastic syndromes (MDS). To better understand the role of oxidative stress in MDS development, we compared protein carbonylation as an oxidative stress marker in BM of patients with MDS and control subjects, and also patients with MDS under treatment with the iron chelator deferasirox.
2019-10-30 | PXD013609 | Pride
Project description:Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell (HSC) malignancies characterized by ineffective hematopoiesis with increased incidence in elderly individuals. Genetic alterations do not fully explain the molecular pathogenesis of the disease, indicating that other types of lesions may play a role in its development. In this work, we analyzed the transcriptional lesions of human HSCs, demonstrating how aging and MDS are characterized by a complex transcriptional rewiring that manifests as diverse linear and non-linear transcriptional dynamisms. While aging-associated lesions seemed to predispose elderly HSCs to myeloid transformation, disease-specific alterations may be involved in triggering MDS development. Among MDS-specific lesions, we detected the overexpression of the transcription factor (TF) DDIT3. Exogenous upregulation of DDIT3 in human healthy HSCs induced an MDS-like transcriptional state, and a delay in erythropoiesis, with an accumulation of cells in early stages of erythroid differentiation, as determined by single-cell RNA-sequencing. Increased DDIT3 expression was associated with downregulation of transcription factors required for normal erythropoiesis, such as KLF1, TAL1 or SOX6, and with a failure in the activation of their erythroid transcriptional programs. Finally, DDIT3 knockdown in CD34+ cells from MDS patients was able to restore erythropoiesis, as demonstrated by immunophenotypic and transcriptional profiling. These results demonstrate that DDIT3 may be a driver of MDS transformation, and a potential therapeutic target to restore the inefficient erythropoiesis characterizing these patients.
2022-11-10 | GSE183325 | GEO
Project description:Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell (HSC) malignancies characterized by ineffective hematopoiesis with increased incidence in elderly individuals. Genetic alterations do not fully explain the molecular pathogenesis of the disease, indicating that other types of lesions may play a role in its development. In this work, we analyzed the transcriptional lesions of human HSCs, demonstrating how aging and MDS are characterized by a complex transcriptional rewiring that manifests as diverse linear and non-linear transcriptional dynamisms. While aging-associated lesions seemed to predispose elderly HSCs to myeloid transformation, disease-specific alterations may be involved in triggering MDS development. Among MDS-specific lesions, we detected the overexpression of the transcription factor (TF) DDIT3. Exogenous upregulation of DDIT3 in human healthy HSCs induced an MDS-like transcriptional state, and a delay in erythropoiesis, with an accumulation of cells in early stages of erythroid differentiation, as determined by single-cell RNA-sequencing. Increased DDIT3 expression was associated with downregulation of transcription factors required for normal erythropoiesis, such as KLF1, TAL1 or SOX6, and with a failure in the activation of their erythroid transcriptional programs. Finally, DDIT3 knockdown in CD34+ cells from MDS patients was able to restore erythropoiesis, as demonstrated by immunophenotypic and transcriptional profiling. These results demonstrate that DDIT3 may be a driver of MDS transformation, and a potential therapeutic target to restore the inefficient erythropoiesis characterizing these patients.
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