Chromatin Perturbation Promotes Susceptibility to Hypomethylating Agents

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Hypomethylating agents (HMAs) are used for haematological malignancies but their precise molecular mechanisms of action (MOA) remain debated.
• Understanding MOA is crucial for designing effective combination therapies.

Purpose of the Study:

• To elucidate the molecular mechanisms of hypomethylating agents (HMAs) in cancer treatment.
• To identify novel targets for combination therapies in acute myeloid leukaemia (AML).

Main Methods:

• Investigated the role of deubiquitinating enzyme USP48 in DNA demethylation and histone modification.
• Assessed the effect of USP48 loss on cellular response to DNMT1 inhibition.
• Analyzed USP48 localization at DNA damage sites and its function in deubiquitinating histone variants.

Main Results:

• USP48 was identified as a key regulator of posttranslational histone modification during DNA demethylation.
• Loss of USP48 selectively enhanced cellular sensitivity to DNMT1 inhibition, inducing rapid cell death.
• USP48 deubiquitinates H2A variants and DNA damage repair proteins, increasing chromatin accessibility upon HMA treatment.

Conclusions:

• USP48 acts as a posttranslational histone modifier impacting chromatin stability and DNA damage response.
• Targeting USP48 in combination with HMAs presents a promising therapeutic strategy for acute myeloid leukaemia (AML).