DNMT3A R882 mutations promote anthacyline resistance through impaired DNA-damage sensing
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE72883 | GEO | 2016/11/14
SECONDARY ACCESSION(S): PRJNA295441
REPOSITORIES: GEO
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Project description:Although the majority of acute myeloid leukemia (AML) patients initially respond to chemotherapy, most of them subsequently relapse due to persistent, chemoresistant disease. However, the mechanistic basis by which AML cells persist during chemotherapy has not been fully delineated. Recurrent somatic mutations in the DNA methyltransferase 3A gene (DNMT3A), most frequently at arginine 882 (DNMT3Amut), are commonly observed in AML patients, and are also detected in elderly subjects with clonal hematopoiesis in the absence of leukemic transformation. DNMT3Amut AML patients have an inferior outcome when treated with standard dose daunorubicin-based induction chemotherapy, suggesting that DNMT3Amut AML cells can persist following chemotherapy and drive relapse. DNMT3Amut cells show impaired nucleosome eviction and chromatin remodeling in response to DNA damage in the setting of anthracycline exposure. This defect leads to an inability to sense and repair DNA damage, which results in the accumulation of single-stranded DNA breaks and increased mutagenesis. Our studies identify a critical role for DNMT3A R882 mutations in driving AML chemoresistance, and highlight the importance of chromatin remodeling in the response to cytotoxic chemotherapy.
2016-11-14 | GSE86827 | GEO
Project description:Although the majority of acute myeloid leukemia (AML) patients initially respond to chemotherapy, most of them subsequently relapse due to persistent, chemoresistant disease. However, the mechanistic basis by which AML cells persist during chemotherapy has not been fully delineated. Recurrent somatic mutations in the DNA methyltransferase 3A gene (DNMT3A), most frequently at arginine 882 (DNMT3Amut), are commonly observed in AML patients, and are also detected in elderly subjects with clonal hematopoiesis in the absence of leukemic transformation. DNMT3Amut AML patients have an inferior outcome when treated with standard dose daunorubicin-based induction chemotherapy, suggesting that DNMT3Amut AML cells can persist following chemotherapy and drive relapse. DNMT3Amut cells show impaired nucleosome eviction and chromatin remodeling in response to DNA damage in the setting of anthracycline exposure. This defect leads to an inability to sense and repair DNA damage, which results in the accumulation of single-stranded DNA breaks and increased mutagenesis. Our studies identify a critical role for DNMT3A R882 mutations in driving AML chemoresistance, and highlight the importance of chromatin remodeling in the response to cytotoxic chemotherapy.
2016-11-14 | GSE72882 | GEO
Project description:Although the majority of acute myeloid leukemia (AML) patients initially respond to chemotherapy, most of them subsequently relapse due to persistent, chemoresistant disease. However, the mechanistic basis by which AML cells persist during chemotherapy has not been fully delineated. Recurrent somatic mutations in the DNA methyltransferase 3A gene (DNMT3A), most frequently at arginine 882 (DNMT3Amut), are commonly observed in AML patients, and are also detected in elderly subjects with clonal hematopoiesis in the absence of leukemic transformation. DNMT3Amut AML patients have an inferior outcome when treated with standard dose daunorubicin-based induction chemotherapy, suggesting that DNMT3Amut AML cells can persist following chemotherapy and drive relapse. DNMT3Amut cells show impaired nucleosome eviction and chromatin remodeling in response to DNA damage in the setting of anthracycline exposure. This defect leads to an inability to sense and repair DNA damage, which results in the accumulation of single-stranded DNA breaks and increased mutagenesis. Our studies identify a critical role for DNMT3A R882 mutations in driving AML chemoresistance, and highlight the importance of chromatin remodeling in the response to cytotoxic chemotherapy.
2016-11-14 | GSE72737 | GEO
Project description:DNMT3A R882 mutations promote anthacyline resistance through impaired DNA-damage sensing
| PRJNA295441 | ENA
Project description:Although the majority of patients with acute myeloid leukemia (AML) initially respond to chemotherapy, many of them subsequently relapse, and the mechanistic basis for AML persistence following chemotherapy has not been determined. Recurrent somatic mutations in DNA methyltransferase 3A (DNMT3A), most frequently at arginine 882 (DNMT3AR882), have been observed in AML and in individuals with clonal hematopoiesis in the absence of leukemic transformation. Patients with DNMT3AR882 AML have an inferior outcome when treated with standard-dose daunorubicin-based induction chemotherapy, suggesting that DNMT3AR882 cells persist and drive relapse. We found that Dnmt3a mutations induced hematopoietic stem cell expansion, cooperated with mutations in the FMS-like tyrosine kinase 3 gene (Flt3ITD) and the nucleophosmin gene (Npm1c) to induce AML in vivo, and promoted resistance to anthracycline chemotherapy. In patients with AML, the presence of DNMT3AR882 mutations predicts minimal residual disease, underscoring their role in AML chemoresistance. DNMT3AR882 cells showed impaired nucleosome eviction and chromatin remodeling in response to anthracycline treatment, which resulted from attenuated recruitment of histone chaperone SPT-16 following anthracycline exposure. This defect led to an inability to sense and repair DNA torsional stress, which resulted in increased mutagenesis. Our findings identify a crucial role for DNMT3AR882 mutations in driving AML chemoresistance and highlight the importance of chromatin remodeling in response to cytotoxic chemotherapy.
| S-EPMC5359771 | biostudies-literature
Project description:Somatic DNMT3A mutations at R882 are frequently observed in AML patients including the very abundant R882H, but also R882C, R882P and R882S. Using deep enzymology, we show here that DNMT3A-R882H has more than 70-fold altered flanking sequence preferences when compared with wildtype DNMT3A. The R882H flanking sequence preferences mainly differ on the 3' side of the CpG site, where they resemble DNMT3B, while 5' flanking sequence preferences resemble wildtype DNMT3A, indicating that R882H behaves like a DNMT3A/DNMT3B chimera. Investigation of the activity and flanking sequence preferences of other mutations of R882 revealed that they cause similar effects. Bioinformatic analyses of genomic methylation patterns focusing on flanking sequence effects after expression of wildtype DNMT3A and R882H in human cells revealed that genomic methylation patterns reflect the details of the altered flanking sequence preferences of R882H. Concordantly, R882H specific hypermethylation in AML patients was strongly correlated with the R882H flanking sequence preferences. R882H specific DNA hypermethylation events in AML patients were accompanied by R882H specific mis-regulation of several genes with strong cancer connection, which are potential downstream targets of R882H. In conclusion, our data provide novel and detailed mechanistic understanding of the pathogenic mechanism of the DNMT3A R882H somatic cancer mutation.
| S-EPMC6868496 | biostudies-literature
Project description:DNA methyltransferase 3A (DNMT3A) is mutated in various myeloid neoplasms including acute myeloid leukemia (AML), especially at the Arg882 and associated with inferior outcomes. Here, we report that the DNMT3A-Arg882His/Cys (R882H/C) mutations led to inactivation of apoptosis through DNA damage signaling following the impairment of differentiation of myeloid leukemia cells. Gene expression profiling analysis revealed aberrant expression of several cell-cycle and apoptosis-related genes, and the DNA methylation assay identified both hypo- and hypermethylation features in different regions throughout the whole genome of DNMT3A mutants-transduced myeloid cells. We found that DNMT3A-R882H/C mutations upregulated the expression of an antioxidant protein, pyroxiredoxin-2 (PRDX2), at the mRNA and protein levels with decreased accumulation of reactive oxygen species (ROS). Augmentation of ROS generation by ROS accumulating agent or by knockdown of PRDX2 from myeloid cells effectively increased drug sensitivity and apoptosis as a consequence of reduced cell proliferation. DNMT3A-R882C/H mutations decreased apoptosis induction in part by increasing the antioxidant capacity of the cell owing to upregulation of PRDX2. Molecularly, both DNMT3A-WT and R882H/C mutants interacted with PRDX2; and R882C/H mutation-induced hypomethylation increased PRDX2 expression which enhanced cell proliferation and growth with impairment of apoptosis, thereby contributing to leukemogenesis.
| S-EPMC6153424 | biostudies-literature
Project description:EGFR signaling has been implicated in hypoxia-associated resistance to radiation or chemotherapy. Non-small cell lung carcinomas (NSCLC) with activating L858R or ?E746-E750 EGFR mutations exhibit elevated EGFR activity and downstream signaling. Here, relative to wild-type (WT) EGFR, mutant (MT) EGFR expression significantly increases radiosensitivity in hypoxic cells. Gene expression profiling in human bronchial epithelial cells (HBEC) revealed that MT-EGFR expression elevated transcripts related to cell cycle and replication in aerobic and hypoxic conditions and downregulated RAD50, a critical component of nonhomologous end joining and homologous recombination DNA repair pathways. NSCLCs and HBEC with MT-EGFR revealed elevated basal and hypoxia-induced ?-H2AX-associated DNA lesions that were coincident with replication protein A in the S-phase nuclei. DNA fiber analysis showed that, relative to WT-EGFR, MT-EGFR NSCLCs harbored significantly higher levels of stalled replication forks and decreased fork velocities in aerobic and hypoxic conditions. EGFR blockade by cetuximab significantly increased radiosensitivity in hypoxic cells, recapitulating MT-EGFR expression and closely resembling synthetic lethality of PARP inhibition.Implications: This study demonstrates that within an altered DNA damage response of hypoxic NSCLC cells, mutant EGFR expression, or EGFR blockade by cetuximab exerts a synthetic lethality effect and significantly compromises radiation resistance in hypoxic tumor cells. Mol Cancer Res; 15(11); 1503-16. ©2017 AACR.
| S-EPMC5668182 | biostudies-literature
Project description:Somatic mutations of DNMT3A gene have recently been reported in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We examined the entire coding sequences of DNMT3A gene by high-resolution melting analysis and sequencing in Chinese patients with myeloid malignancies. R882 mutations were found in 12/182 AML and in 4/51 MDS, but not in either 79 chronic myeloid leukemia (CML), or 57 myeloproliferative neoplasms (MPNs), or 4 chronic monomyelocytic leukemia. No other DNMT3A mutations were detected in all patients. R882 mutations were associated with old age and more frequently present in monoblastic leukemia (M4 and M5, 7/52) compared to other subtypes (5/130). Furthermore, 14/16 (86.6%) R882 mutations were observed in patients with normal karyotypes. The overall survival of mutated MDS patients was shorter than those without mutation (median 9 and 25 months, respectively). We conclude that DNMT3A R882 mutations are recurrent molecular aberrations in AML and MDS, and may be an adverse prognostic event in MDS.
| S-EPMC3204995 | biostudies-literature
Project description:Background: DNA methyltransferase 3A (DNMT3A) plays a unique role in hematopoiesis and acute myeloid leukemia (AML) pathogenesis. While the influences of DNMT3A mutation subtypes are still under debate. Purpose: Exploration of the clinical and molecular differences between AML patients carrying DNMT3A R882 mutations and DNMT3A frameshift mutations. Methods: Next generation of sequencing (NGS) and clinical data of 118 AML patients in our center were analyzed and compared. NGS, mRNA and miRNA profiling and clinical data from 12 patients in TCGA database were integrative analyzed. Results: Among all patients enrolled, 113 patients were positive for the variants of interest. Overall, a total of 295 variants were discovered, among which 24 DNMT3A mutations were detected, including 1 non-sense, 20 missense, 3 frameshift mutations. And 7 DNMT3A R882 mutations (3 R882H, 2 R882C, and 2 R882P) were found. Clinical analysis from our cohort and TCGA database indicated that patients carrying DNMT3A R882 mutation exhibited significantly higher levels of peripheral blood hemoglobin and non-significantly inferior prognosis compared with patients with DNMT3A frameshift mutations. Integrative analysis indicated that miR-10b, miR-143, and miR-30a were significantly decreased in the DNMT3A R882 group. High miR-143 expression is significantly associated with better prognosis in AML patients with DNMT3A mutations. Conclusion: Different molecular and clinical characteristics existed between patients with DNMT3A variant subtypes. The distinct microRNA expression pattern for DNMT3A R882 AML patients might not only act as markers to predict disease prognosis, but also could be further investigated to develop novel therapeutic targets for patients with DNMT3A mutations.
| S-EPMC6821681 | biostudies-literature