The type of DNA damage response after Decitabine treatment depends on the level of DNMT activity
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ABSTRACT: Decitabine and Azacytidine are considered as epigenetic drugs that induce DNA-methyltransferase (DNMT)-DNA crosslinks, resulting in DNA-hypomethylation and -damage. Although they are already applied against myeloid cancers, important aspects of their mode of action remain unknown, highly limiting their clinical potential. Using a combinatorial approach, we reveal that the efficacy profile of both compounds primarily depends on the level of induced DNA-damage. Under low DNMT-activity, only Decitabine has a substantial impact. Conversely, when DNMT-activity is high, toxicity and cellular response to both compounds are dramatically increased, but do not primarily depend on DNA-hypomethylation or RNA-associated processes. By investigating proteome dynamics on chromatin, we show that Decitabine induces a strictly DNMT-dependent multifaceted DNA-damage response based on chromatin-recruitment, but not expression level changes of repair-associated proteins. The choice of DNA-repair pathway herby depends on the severity of Decitabine-induced DNA-lesions. While under moderate DNMT-activity, mismatch (MMR), base-excision (BER) and Fanconi anemia-dependent DNA-repair combined with homologous recombination are activated in response to Decitabine, high DNMT-activity and therefore immense replication stress, induce activation of MMR and BER followed by non-homologous end-joining.
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Embryo, Early Embryonic Cell
SUBMITTER: Franziska Traube
LAB HEAD: Franziska Traube
PROVIDER: PXD045353 | Pride | 2024-06-19
REPOSITORIES: Pride
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