ABSTRACT
MLL/KMT2A amplifications and translocations are prevalent in infant, adult, and therapy-induced leukemia. However, the molecular contributor(s) to these alterations are unclear. Here, we demonstrate that histone H3 lysine 9 mono- and di-methylation (H3K9me1/2) balance at the MLL/KMT2A locus regulates these amplifications and rearrangements. This balance is controlled by the crosstalk between lysine demethylase KDM3B and methyltransferase G9a/EHMT2. KDM3B depletion increases H3K9me1/2 levels and reduces CTCF occupancy at the MLL/KMT2A locus, in turn promoting amplification and rearrangements. Depleting CTCF is also sufficient to generate these focal alterations. Furthermore, the chemotherapy doxorubicin (Dox), which associates with therapy-induced leukemia and promotes MLL/KMT2A amplifications and rearrangements, suppresses KDM3B and CTCF protein levels. KDM3B and CTCF overexpression rescues Dox-induced MLL/KMT2A alterations. G9a inhibition in human cells or mice also suppresses MLL/KMT2A events accompanying Dox treatment. Therefore, MLL/KMT2A amplifications and rearrangements are controlled by epigenetic regulators that are tractable drug targets, which has clinical implications.
Subject(s)
Epigenesis, Genetic , Myeloid-Lymphoid Leukemia Protein , Adult , Animals , Humans , Infant , Mice , Doxorubicin/pharmacology , Gene Rearrangement , Histocompatibility Antigens , Histone-Lysine N-Methyltransferase/genetics , Histone-Lysine N-Methyltransferase/metabolism , Jumonji Domain-Containing Histone Demethylases/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Leukemia/metabolism , Lysine/metabolism , Myeloid-Lymphoid Leukemia Protein/genetics , Translocation, GeneticABSTRACT
Two series of novel pyridoxine-based azaheterocyclic analogs of feruloyl methane (Dehydrozingerone, DZG) were synthesized, and their biological activity against a panel of tumor and normal cell lines was evaluated in vitro. The most active compounds possessed expressed cytotoxic activity, which was comparable to cytotoxic activity of doxorubicin and significantly higher than that of DZG, and a remarkable selectivity for the studied cancer cell lines as compared to the normal cells. The leading compound and DZG initiated arrest of the cell cycle in the G2/M phase, preventing normal division and further transition of daughter cells to the G0/G1 phase. Similar to DZG, but with higher efficiency, the leading compound was able to inhibit migration activity and, therefore, invasiveness of tumor cells. It also increased concentration of reactive oxygen species in tumor cells, induced depolarization of mitochondrial membranes and initiated apoptosis accompanied by disruption of integrity of cytoplasmic cell membranes. By contrast to DZG, the leading compound did not possess antioxidant properties. The obtained data make the described chemotype a promising starting point for the development of new anticancer agents.
