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U2AF1 MUTATION PROMOTES TUMORIGENICITY THROUGH FACILITATING AUTOPHAGY FLUX MEDIATED BY FOXO3A ACTIVATION IN MYELODYSPLASTIC SYNDROMES
Author(s): ,
Yuqian Zhu
Affiliations:
Hematology,Shanghai Sixth People's Hospital,Shanghai,China
,
Feng Xu
Affiliations:
Hematology,Shanghai Sixth People's Hospital,Shanghai,China
,
Chunkang Chang
Affiliations:
Hematology,Shanghai Sixth People’s Hospital,Shanghai,China
,
Qi He
Affiliations:
Hematology,Shanghai Sixth People's Hospital,Shanghai,China
Lingyun Wu
Affiliations:
Hematology,Shanghai Sixth people's Hospital,Shanghai,China
EHA Library. Wu L. 06/09/21; 324291; PB1614
Lingyun Wu
Lingyun Wu
Contributions
Abstract

Abstract: PB1614

Type: Publication Only

Session title: Myelodysplastic syndromes - Biology & Translational Research

Background
Mutations in the U2 small nuclear RNA auxiliary factor 1 (U2AF1) gene are the common feature of a major subset in myelodysplastic syndromes (MDS). However, the genetic landscape and molecular pathogenesis of oncogenic U2AF1S34F mutation in MDS are not totally understood.

Aims
To explore the molecular pathogenesis of oncogenic U2AF1S34F mutation in MDS, we carried out the current study. 

Methods
We performed comprehensive analysis for prognostic significance of U2AF1 mutations in acute myeloid leukemia (AML) cohort based on The Cancer Genome Atlas (TCGA) database. Functional analysis of U2AF1S34F mutation was performed in vitro. Differentially expressed genes (DEGs) and significantly enriched pathways were identified by RNA-sequencing. The forkhead box protein O3a (FOXO3a) was investigated to mediate the function of U2AF1S34F mutation in cell models using lentivirus. Chromatin immunoprecipitation, immunoblotting analyses and immunofluorescence assays were also conducted. 

Results
U2AF1 mutations were associated with poor prognosis in MDS and AML samples, which significantly inhibited cell proliferation and induced cellular apoptosis in cell models. Our data identified that U2AF1-mutant cell lines undergo FOXO3a-dependent apoptosis and NLRP3 inflammasome activation, which induces pyroptotic cell death. Particularly, an increase in the level of FOXO3a promoted the progression of MDS in association with restored autophagy program leading to NLRP3 inflammasome activation in response to U2AF1S34F mutation. Based on the result that U2AF1S34F mutation promoted the transcriptional activity of Bim through up-regulating FOXO3a with transactivation of cell cycle regulators p21Cip1 and p27Kip1, FoxO3a, a potentially cancer-associated transcription factor, was identified as the key molecule on which these pathways converge. death. Particularly, an increase in the level of FOXO3a promoted the progression of MDS in association with restored autophagy program leading to NLRP3 inflammasome activation in response to U2AF1S34F mutation. Based on the result that U2AF1S34F mutation promoted the transcriptional activity of Bim through up-regulating FOXO3a with transactivation of cell cycle regulators p21Cip1 and p27Kip1, FoxO3a, a potentially cancer-associated transcription factor, was identified as the key molecule on which these pathways converge.

Conclusion
Overall, our studies provide new insights that U2AF1S34F mutation functions the crucial roles in mediating MDS disease progression via FOXO3a activation, and demonstrate novel targets of U2AF1 mutations to the pathogenesis of MDS.

Keyword(s):

Abstract: PB1614

Type: Publication Only

Session title: Myelodysplastic syndromes - Biology & Translational Research

Background
Mutations in the U2 small nuclear RNA auxiliary factor 1 (U2AF1) gene are the common feature of a major subset in myelodysplastic syndromes (MDS). However, the genetic landscape and molecular pathogenesis of oncogenic U2AF1S34F mutation in MDS are not totally understood.

Aims
To explore the molecular pathogenesis of oncogenic U2AF1S34F mutation in MDS, we carried out the current study. 

Methods
We performed comprehensive analysis for prognostic significance of U2AF1 mutations in acute myeloid leukemia (AML) cohort based on The Cancer Genome Atlas (TCGA) database. Functional analysis of U2AF1S34F mutation was performed in vitro. Differentially expressed genes (DEGs) and significantly enriched pathways were identified by RNA-sequencing. The forkhead box protein O3a (FOXO3a) was investigated to mediate the function of U2AF1S34F mutation in cell models using lentivirus. Chromatin immunoprecipitation, immunoblotting analyses and immunofluorescence assays were also conducted. 

Results
U2AF1 mutations were associated with poor prognosis in MDS and AML samples, which significantly inhibited cell proliferation and induced cellular apoptosis in cell models. Our data identified that U2AF1-mutant cell lines undergo FOXO3a-dependent apoptosis and NLRP3 inflammasome activation, which induces pyroptotic cell death. Particularly, an increase in the level of FOXO3a promoted the progression of MDS in association with restored autophagy program leading to NLRP3 inflammasome activation in response to U2AF1S34F mutation. Based on the result that U2AF1S34F mutation promoted the transcriptional activity of Bim through up-regulating FOXO3a with transactivation of cell cycle regulators p21Cip1 and p27Kip1, FoxO3a, a potentially cancer-associated transcription factor, was identified as the key molecule on which these pathways converge. death. Particularly, an increase in the level of FOXO3a promoted the progression of MDS in association with restored autophagy program leading to NLRP3 inflammasome activation in response to U2AF1S34F mutation. Based on the result that U2AF1S34F mutation promoted the transcriptional activity of Bim through up-regulating FOXO3a with transactivation of cell cycle regulators p21Cip1 and p27Kip1, FoxO3a, a potentially cancer-associated transcription factor, was identified as the key molecule on which these pathways converge.

Conclusion
Overall, our studies provide new insights that U2AF1S34F mutation functions the crucial roles in mediating MDS disease progression via FOXO3a activation, and demonstrate novel targets of U2AF1 mutations to the pathogenesis of MDS.

Keyword(s):

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