Dual inhibition of tubulin and DNMT by the novel letermovir derivative H62 blocks leukemia.

Leukemia therapy, especially myelogenous leukemias, is often challenged by an aggressive nature, high relapse rate due to dormant stem cells, side effects, and drug resistance. Microtubules-targeting agents are often used as first-line therapy for various cancers, including hematological malignancies. However, limitations such as immunosuppression, drug resistance, and cytotoxicity hinder effectiveness. Therefore, developing novel microtubules-targeting agents that overcome these limitations warrants a more effective treatment strategy for leukemias. Herein, we developed several letermovir derivatives, among them H62, which display vigorous anti-proliferative activity against various blood cancer cell lines, especially erythroleukemia. H62 inhibited growth by inducing G2/M cell cycle arrest, erythroid differentiation, and apoptosis, associated with intracellular Reactive Oxygen Species (ROS) accumulation in erythroleukemic cells. In a model of erythroleukemia induced in BALB/c mice by Friend virus, H62 strongly inhibited erythroleukemogenesis, while displaying limited cytotoxicity. Mechanistically, H62 binds to β-tubulin, inhibiting microtubules polymerization and disrupting microtubules integrity. RNA-seq analysis also demonstrated effects on various genes characteristic of epigenomic reprogramming. Indeed, H62 inhibited DNA Methyltransferase (DNMT) activity by binding to DNMT1 with high affinity, resulting in changes in the expression of genes associated with cell survival and proliferation. Additionally, H62, like the DNMT inhibitor 5-Azacytidine, suppressed β-tubulin in leukemic cells. These results suggest that the H62 compound possesses unique dual DNMT and microtubules-inhibitory activity through binding to DNMT and β-tubulin, making it a potent candidate for the treatment of myelogenous leukemias, including erythroleukemia with an unfavorable prognosis.