A Novel Methoxybenzyl 5-Nitroacridone Derivative Effectively Triggers G1 Cell Cycle Arrest in Chronic Myelogenous Leukemia K562 Cells by Inhibiting CDK4/6-Mediated Phosphorylation of Rb.

Chronic myeloid leukemia (CML) is a malignant tumor caused by the abnormal proliferation of hematopoietic stem cells. Among a new series of acridone derivatives previously synthesized, it was found that the methoxybenzyl 5-nitroacridone derivative has nanomolar cytotoxicity in vitro against human chronic myelogenous leukemia K562 cells. In order to further explore the possible anti-leukemia mechanism of action of on K562 cells, a metabolomics and molecular biology study was introduced. It was thus found that most of the metabolic pathways of the G1 phase of K562 cells were affected after treatment. In addition, a concentration-dependent accumulation of cells in the G1 phase was observed by cell cycle analysis. Western blot analysis showed that significantly down-regulated the phosphorylation level of retinoblastoma-associated protein (Rb) in a concentration-dependent manner, upon 48 h treatment. In addition, induced K562 cells apoptosis, through both mitochondria-mediated and exogenous apoptotic pathways. Taken together, these results indicate that effectively triggers G1 cell cycle arrest and induces cell apoptosis in K562 cells, by inhibiting the CDK4/6-mediated phosphorylation of Rb. Furthermore, the possible binding interactions between and CDK4/6 protein were clarified by homology modeling and molecular docking. In order to verify the inhibitory activity of against other chronic myeloid leukemia cells, KCL-22 cells and K562 adriamycin-resistant cells (K562/ADR) were selected for the MTT assay. It is worth noting that showed significant anti-proliferative activity against these cell lines after 48 h/72 h treatment. Therefore, this study provides new mechanistic information and guidance for the development of new acridones for application in the treatment of CML.