Targeting R-loop-associated ATR response in myelodysplastic syndrome.
Ontology highlight
ABSTRACT:
SUBMITTER: Nguyen HD
PROVIDER: S-EPMC6498995 | biostudies-literature | 2019 Apr
REPOSITORIES: biostudies-literature
Publications
Targeting R-loop-associated ATR response in myelodysplastic syndrome.
Nguyen Hai Dang HD Zou Lee L Graubert Timothy A TA
Oncotarget 20190405 27
Similar Datasets
Project description:Heterozygous somatic mutations in spliceosome genes (U2AF1, SF3B1, ZRSR2, or SRSF2) occur in >50% of patients with myelodysplastic syndrome (MDS). These mutations occur early in disease development, suggesting that they contribute to MDS pathogenesis and may represent a unique genetic vulnerability for targeted therapy. Here, we show that RNA splicing perturbation by expression of the U2AF1(S34F) mutant causes accumulation of R loops, a transcription intermediate containing RNA:DNA hybrids and displaced single-stranded DNA, and elicits an ATR response. ATR inhibitors (ATRi) induced DNA damage and cell death in U2AF1(S34F)-expressing cells, and these effects of ATRi were enhanced by splicing modulating compounds. Moreover, ATRi-induced DNA damage was suppressed by overexpression of RNaseH1, an enzyme that specifically removes the RNA in RNA:DNA hybrids, suggesting that the ATRi sensitivity of U2AF1(S34F)-expressing cells arises from R loops. Taken together, our results demonstrate that ATR may represent a novel therapeutic target in patients with MDS carrying the U2AF1(S34F) mutation and potentially other malignancies harboring spliceosome mutations.Significance: This study provides preclinical evidence that patients with MDS or other myeloid malignancies driven by spliceosome mutations may benefit from ATR inhibition to exploit the R loop-associated vulnerability induced by perturbations in splicing. Cancer Res; 78(18); 5363-74. ©2018 AACR.
| S-EPMC6139047 | biostudies-literature
Project description:Myelodysplastic Syndromes (MDS) result from expansion of defective hematopoietic stem/progenitor clones. There is an urgent need to develop targeted therapies capable of eliminating the defective MDS clones. We identified that IRAK1, an immune modulating kinase, is overexpressed and hyperactivated in MDS. MDS-propagating clones treated with a small-molecule IRAK1 inhibitor (IRAK1/4-Inh) exhibited impaired expansion and increased apoptosis, which coincided with TRAF6/NF-M-NM-:B inhibition. Suppression of IRAK1, either by RNAi or with IRAK1/4-Inh, is selectively detrimental to MDS clones as normal CD34+ cells are preserved. Based on conclusions derived from an integrative gene expression analysis, we combined IRAK1 and BCL2 inhibitors and found that co-treatment collaboratively and selectively eliminated MDS clones. In summary, these findings implicate IRAK1 as a drugable target in MDS. MDSL cells were transduced with lentivirus encoding shRNA targeting human IRAK1 and a negative control (pLKO) for 2.5 days. GFP positive cells were sorted for RNA extraction, labeling, and hybridization. A total of four samples were included, and two groups are assigned. Two replicates are for each group. Comparison comprises mRNA expression profile of TRAF6 knockdown (shT6) v.s. control vector (pLKO). Additionally, MDSL cells were treated with either DMSO or IRAK inhibitor for 24hrs. Cells were subjected to RNA extraction, labeling, and hybridization. A total of four samples were included, and two groups are assigned.
2013-04-25 | E-GEOD-46346 | biostudies-arrayexpress
Project description:Myelodysplastic syndromes (MDSs) arise from a defective hematopoietic stem/progenitor cell. Consequently, there is an urgent need to develop targeted therapies capable of eliminating the MDS-initiating clones. We identified that IRAK1, an immune-modulating kinase, is overexpressed and hyperactivated in MDSs. MDS clones treated with a small molecule IRAK1 inhibitor (IRAK1/4-Inh) exhibited impaired expansion and increased apoptosis, which coincided with TRAF6/NF-?B inhibition. Suppression of IRAK1, either by RNAi or with IRAK1/4-Inh, is detrimental to MDS cells, while sparing normal CD34(+) cells. Based on an integrative gene expression analysis, we combined IRAK1 and BCL2 inhibitors and found that cotreatment more effectively eliminated MDS clones. In summary, these findings implicate IRAK1 as a drugable target in MDSs.
| S-EPMC3711103 | biostudies-literature
Project description:Myelodysplastic syndrome (MDS) is a group of hematopoietic disorders with limited treatment options. Anemia is a common symptom in MDS, and although erythropoiesis-stimulating agents such as erythropoietin, lenalidomide, and luspatercept are available to treat anemia, many MDS patients do not respond to these first-line therapies. Therefore, alternative drug development strategies are needed to improve therapeutic efficacy. Splicing modulators to correct splicing-related defects have shown promising results in clinical trials. Targeting differentiation of early erythroid progenitors to increase the erythroid output in MDS is another novel approach, which has shown encouraging results at the pre-clinical stage. Together, these therapeutic strategies provide new avenues to target MDS symptoms untreatable previously.
| S-EPMC8487963 | biostudies-literature
Project description:Unscheduled R-loops are a major source of replication stress and DNA damage. R-loop-induced replication defects are sensed and suppressed by ATR kinase, whereas it is not known whether R-loop itself is actively involved in ATR activation and, if so, how this is achieved. Here, we report that the nuclear form of RNA-editing enzyme ADAR1 promotes ATR activation and resolves genome-wide R-loops, a process that requires its double-stranded RNA-binding domains. Mechanistically, ADAR1 interacts with TOPBP1 and facilitates its loading on perturbed replication forks by enhancing the association of TOPBP1 with RAD9 of the 9-1-1 complex. When replication is inhibited, DNA-RNA hybrid competes with TOPBP1 for ADAR1 binding to promote the translocation of ADAR1 from damaged fork to accumulate at R-loop region. There, ADAR1 recruits RNA helicases DHX9 and DDX21 to unwind R-loops, simultaneously allowing TOPBP1 to stimulate ATR more efficiently. Collectively, we propose that the tempo-spatially regulated assembly of ADAR1-nucleated protein complexes link R-loop clearance and ATR activation, while R-loops crosstalk with blocked replication forks by transposing ADAR1 to finetune ATR activity and safeguard the genome.
| S-EPMC10681745 | biostudies-literature
Project description:Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders characterized by dysplasia, ineffective hematopoiesis, and predisposition to secondary acute myeloid leukemias (sAML). Azacitidine (AZA) is the standard care for high-risk MDS patients not eligible for allogenic bone marrow transplantation. However, only half of the patients respond to AZA and eventually all patients relapse. Response-predicting biomarkers and combinatorial drugs targets enhancing therapy response and its duration are needed. Here, we have taken a dual approach. First, we have evaluated genes encoding chromatin regulators for their capacity to modulate AZA response. We were able to validate several genes, whose genetic inhibition affected the cellular AZA response, including 4 genes encoding components of Imitation SWItch chromatin remodeling complex pointing toward a specific function and co-vulnerability. Second, we have used a classical cohort analysis approach measuring the expression of a gene panel in bone marrow samples from 36 MDS patients subsequently receiving AZA. The gene panel included the identified AZA modulators, genes known to be involved in AZA metabolism and previously identified candidate modulators. In addition to confirming a number of previously made observations, we were able to identify several new associations, such as NSUN3 that correlated with increased overall survival. Taken together, we have identified a number of genes associated with AZA response in vitro and in patients. These groups of genes are largely nonoverlapping suggesting that different gene sets need to be exploited for the development of combinatorial drug targets and response-predicting biomarkers.
| S-EPMC9605795 | biostudies-literature
Project description:Aberrant T-cell function is implicated in the pathogenesis of myelodysplastic syndrome (MDS). Monitoring the T-cell receptor (TCR) repertoire can provide insights into T-cell adaptive immunity. Previous studies found skewed TCR repertoires in MDS compared to healthy patients; however these studies that leverage mRNA-based spectratyping have limitations. Furthermore, evaluating the TCR repertoire in context of hypomethylating agents (HMAs) treatment can provide insights into the dynamics of T-cell mediated responses in MDS. We conducted immunosequencing of the CDR3 regions of TCRβ chains in bone marrows of 11 MDS patients prior to treatment (n=11 bone marrows prior to treatment), and in at least 2 timepoints for each patient following treatment (n=26 bone marrow aspirates post-treatment) with (HMA), alongside analyzing bone marrows from 4 healthy donors as controls. TCR repertoires in MDS patients were more clonal and less diverse than healthy donors. However, unlike previous reports, we did not observe significant skewness in CDR3 length or spectratyping. The global metrics of TCR profiling including richness, clonality, overlaps were not significantly changed in responders or non-responders following treatment with HMAs. However, we found an emergence of novel clonotypes in MDS patients who responded to treatment, while non-responders had a higher frequency of contracted clonotypes following treatment. By applying GLIPH2 for antigen prediction, we found rare TCR specificity clusters shared by TCR clonotypes from different patients at pre- or following treatment. Our data show clear differences in TCR repertoires of MDS compared with healthy patients and that novel TCR clonotype emergence in response to HMA therapy was correlated with response. This suggests that response to HMA therapy may be partially driven by T-cell mediated immunity and that the immune-based therapies, which target the adaptive immune system, may play a significant role in select patients with MDS.
| S-EPMC8072464 | biostudies-literature
Project description:Myelodysplastic Syndromes (MDS) result from expansion of defective hematopoietic stem/progenitor clones. There is an urgent need to develop targeted therapies capable of eliminating the defective MDS clones. We identified that IRAK1, an immune modulating kinase, is overexpressed and hyperactivated in MDS. MDS-propagating clones treated with a small-molecule IRAK1 inhibitor (IRAK1/4-Inh) exhibited impaired expansion and increased apoptosis, which coincided with TRAF6/NF-κB inhibition. Suppression of IRAK1, either by RNAi or with IRAK1/4-Inh, is selectively detrimental to MDS clones as normal CD34+ cells are preserved. Based on conclusions derived from an integrative gene expression analysis, we combined IRAK1 and BCL2 inhibitors and found that co-treatment collaboratively and selectively eliminated MDS clones. In summary, these findings implicate IRAK1 as a drugable target in MDS.
2013-04-25 | GSE46346 | GEO
Project description: Not available
| S-EPMC4947000 | biostudies-literature
Project description:Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders and characterized by dysplasia, ineffective hematopoiesis and predisposition to secondary acute myeloid leukemia (sAML). Azacitidine (AZA) is the standard care for high-risk MDS patients not eligible for allogenic bone marrow transplantation. However, only half of the patients respond and all patients eventually relapse. Response predicting biomarkers and combinatorial drugs targets enhancing response and its duration are needed. Here, we have taken a dual approach. First, we have evaluated genes encoding chromatin regulators for their capacity to modulate AZA response. We were able to validate several genes, whose genetic inhibition affected the cellular AZA response, including four genes encoding components of ISWI chromatin remodelling complex pointing towards a specific function and co-vulnerability. Second, we have used a classical cohort analysis approach measuring the association of expression of a gene panel in bone marrow samples collected at diagnosis of 36 MDS patients. The gene panel included the identified AZA modulators, genes known to be involved in AZA metabolism and previously identified candidate modulators. In addition to confirming a number of previously made observations, we were able to identify several new associations, such as SMARCA5 as positive indicator for AZA response, or NSUN3 that correlated with increased overall survival. Taken together we have identified a number of genes associated with AZA response in vitro and in patients. These groups of genes are largely non-overlapping suggesting that different gene sets need to be exploited for the development of combinatorial drug targets and response-predicting biomarkers.
2022-11-02 | GSE208736 | GEO