Author ORCID Identifier

0000-0001-6357-8449

Defense Date

2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Human and Molecular Genetics

First Advisor

Gordon D. Ginder

Second Advisor

Joyce Lloyd

Third Advisor

Joseph Landry

Fourth Advisor

Senthil Radhakrishnan

Fifth Advisor

Tomasz Kordula

Abstract

Depletion of the ATPase component of the Nucleosome Remodeling and Deacetylase (NuRD) complex, CHD4, reduces acute myeloid leukemia (AML) cell survival. This study identified other NuRD components, as potential therapeutic targets for disrupting protein-protein interactions within NuRD. In addition to AML, we established that T-cell Acute Lymphoblastic Leukemia (T-ALL) cell lines responded similarly to CHD4 depletion.

Greater than 90% depletion of either MBD2 or MBD3 (the mutually exclusive two DNA binding NuRD paralogues) – was unremarkable, but complete depletion of MBD3 increased apoptosis and genotoxic sensitivity. Combined depletion of MBD-NuRD proteins augmented apoptosis observed with complete MBD3 depletion - indicating redundancy of MBD2 and MBD3. This effect was ‘rescued’ by add-back of wild-type, but not mutant MBD2.

The mutually exclusive GATAD2A and GATAD2B NuRD paralogues, that connect CHD4 to MBD2/3, through the CR1 domain of GATAD2 and the coiled CC domain of MBD2/3, were next interrogated. GATAD2A depletion was unremarkable, but GATAD2B depletion reduced cell survival (increased apoptosis, reduced cell proliferation and colony forming ability) in cell lines and primary AML samples, but not in CD34+ hematopoietic stem cells. Additionally, the relative transcript levels of GATAD2B and c-Myc were significantly correlated.

Next, we showed that a CR1 penetrating peptide dislodges GATAD2B and CHD4 from NuRD in cell lysates. Cell lines and primary samples treated with the peptide showed significantly increased apoptosis, but normal CD34+ progenitors. We conclude that targeting the coiled-coil interaction between MBD proteins and the GATAD2B-CHD4 chromatin remodeling subcomplex of NuRD may be a promising therapeutic strategy in acute leukemia.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

4-13-2020

Available for download on Saturday, April 12, 2025

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