Harold Spielberg Research Fund

MDS develops due to genomic and epigenetic changes involving oncogenes and tumor suppressor genes. Unlike irreversible genomic damage, epigenetic changes are reversible with targeted therapy. Dr. Mukherji’s research is focusing on TET2, which is one of the most frequently mutated genes identified in patients with myelodysplastic syndromes (MDS). Results from recent studies have established that mutation in the TET2 tumor suppressor gene is one of the fundamental causes of MDS, as well as related myeloid malignancies (MDS-MPN and sAML). The protein product of the normal TET2 genes initiates the demethylation of 5-methylcytosine residues in the DNA, predominantly present in the regulatory regions of genes. In patients with TET2 mutations, progressive cytosine methylations in these regulatory regions cause epigenetic silencing of genes. This ultimately leads to the development of MDS, as well as related myeloid malignancies.

During the first year of the grant, he and his colleagues have made significant progress in developing a library of clinical samples which can be used to observe and rescue the activity of some TET2 clinical mutations. The second year of the study will focus on the potential of this research for targeting therapies for MDS based on these mutations.

Our long term goal is to understand the molecules and mechanisms that regulate normal generation of blood cellular components as well as malignant cell transformation, as a necessary prerequisite of discovering factors that could fine-tune blood cell differentiation or restore normal bone marrow function. Towards this aim, we have begun to analyze a myelodysplastic syndromes (MDS)-associated protein and a large panel of disease-causing mutants. We found some of the mutations, which are associated with the most severe diseases in humans, caused significant decrease in the protein’s DNA binding activity, while the activities of the other mutant proteins were not significantly different from wild type protein. More interestingly, the catalytic domain of wild type protein was observed to unfold in a single-step, highly cooperative manner; in contrast, most of mutant proteins were significantly more prone to thermal denaturation and aggregation. These results are significant because they will have significant impacts on design of mutant-specific rescue drugs: for instance, second-site suppressor or chaperone strategy often used for rescuing mutant function can be implemented for rescue of destabilized protein mutant. On the other hand, the forthcoming protein three-dimensional structure can be instantly applied to structure-based drug design or in silico screening of mutanttargeting compounds.