cedrelone and Leukemia--Erythroblastic--Acute

MAPK/ERK kinases transmit signals from many growth factors/kinase receptors during normal cell growth/differentiation, and their dysregulation is a hallmark of diverse types of cancers. A plethora of drugs were developed to block this kinase pathway for clinical application. With the exception of a recently identified agent, EQW, most of these inhibitors target upstream factors but not ERK1/2; no activator of ERK1/2 is currently available.. A library of compounds isolated from medicinal plants of China was screened for anti-cancer activities. Three limonoid compounds, termed A1541-43, originally isolated from the plant Melia azedarach, exhibiting strong anti-leukemic activity. The anti-neoplastic activity and the biological target of these compounds were explored using various methods, including western blotting, flow cytometry, molecular docking and animal model for leukemia.. Compounds A1541-43, exhibiting potent anti-leukemic activity, was shown to induce ERK1/2 phosphorylation. In contrast, the natural product Cedrelone, which shares structural similarities with A1541-43, functions as a potent inhibitor of ERK1/2. We provided evidence that A1541-43 and Cedrelone specifically target ERK1/2, but not the upstream MAPK/ERK pathway. Computational docking analysis predicts that compounds A1541-43 bind a region in ERK1/2 that is distinct from that to which Cedrelone and EQW bind. Interestingly, both A1541-43, which act as ERK1/2 agonists, and Cedrelone, which inhibit these kinases, exerted strong anti-proliferative activity against multiple leukemic cell lines, and induced robust apoptosis as well as erythroid and megakaryocytic differentiation in erythroleukemic cell lines. These compounds also suppressed tumor progression in a mouse model of erythroleukemia.. This study identifies for the first time activators of ERK1/2 with therapeutic potential for the treatment of cancers driven by dysregulation of the MAPK/ERK pathway and possibly for other disorders.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Binding Sites; Cell Cycle Checkpoints; Cell Differentiation; Disease Models, Animal; Disease Progression; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Female; Humans; K562 Cells; Leukemia, Erythroblastic, Acute; Limonins; Male; MAP Kinase Signaling System; Melia azedarach; Mice; Mice, Inbred BALB C; Mitogen-Activated Protein Kinase Kinases; Molecular Docking Simulation; Plant Leaves; Signal Transduction; Survival Rate