Document Type
Article
Publication Date
2-12-2024
Manuscript Version
vor
Abstract
The 5-azacytidine (AZA) and decitabine (DEC) are noncytotoxic, differentiation-inducing therapies approved for treatment of myelodysplastic syndrome, acute myeloid leukemias (AML), and under evaluation as maintenance therapy for AML postallogeneic hematopoietic stem cell transplant and to treat hemoglobinapathies. Malignant cell cytoreduction is thought to occur by S-phase specific depletion of the key epigenetic regulator, DNA methyltransferase 1 (DNMT1) that, in the case of cancers, thereby releases terminal-differentiation programs. DNMT1-targeting can also elevate expression of immune function genes (HLA-DR, MICA, MICB) to stimulate graft versus leukemia effects. In vivo, there is a large inter-individual variability in DEC and 5-AZA activity because of pharmacogenetic factors, and an assay to quantify the molecular pharmacodynamic effect of DNMT1-depletion is a logical step toward individualized or personalized therapy. We developed and analytically validated a flow cytometric assay for DNMT1 epitope levels in blood and bone marrow cell subpopulations defined by immunophenotype and cell cycle state. Wild type (WT) and DNMT1 knock out (DKO) HC116 cells were used to select and optimize a highly specific DNMT1 monoclonal antibody. Methodologic validation of the assay consisted of cytometry and matching immunoblots of HC116-WT and -DKO cells and peripheral blood mononuclear cells; flow cytometry of H116-WT treated with DEC, and patient samples before and after treatment with 5-AZA. Analysis of patient samples demonstrated assay reproducibility, variation in patient DNMT1 levels prior to treatment, and DNMT1 depletion posttherapy. A flow-cytometry assay has been developed that in the research setting of clinical trials can inform studies of DEC or 5-AZA treatment to achieve targeted molecular pharmacodynamic effects and better understand treatment-resistance/failure.
Keywords
biomarkers, hypomethylation, pharmacodynamics
Publication Title
Cytometry Part B - Clinical Cytometry
Rights
© 2024 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals LLC on behalf of International Clinical Cytometry Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Woost, P. G., William, B. M., Cooper, B. W., Ueda Oshima, M., Otegbeye, F., De Lima, M. J., Wald, D., Mahfouz, R. Z., Saunthararajah, Y., Stefan, T., & Jacobberger, J. W. (2024). Flow cytometry of DNMT1 as a biomarker of hypomethylating therapies. Cytometry Part B: Clinical Cytometry, 106(1), 11–24. https://doi.org/10.1002/cyto.b.22158