Synthesis of Novel Indirubin Derivatives and Their Effects on the Proliferation, Cell Cycle and Apoptosis in Acute Myeloblastic Leukemia HL-60 Cells

Acute myelogenous leukemia is a malignant disease of the hemopoietic tissue, which causes great harm to human health, and there is no therapeutic drugs with low toxicity and high efficiency. Indirubin is the active constituent of the traditional chinese medicine qingdai, which has potential anti-leukemia activity. However, poor water solubility and low bioavailability have limited its clinical treatment. To improve the water solubility and anti-leukemia activity of indirubin, hydrophilic amino side chain was linked to the indirubin, and five novel indirubin derivatives were synthesized, which were identified by HRMS, H-1 NMR and C-13 NMR. Meanwhile, the effects of target molecules on the proliferation of acute myeloblastic leukemia HL-60 cells were evaluated using CCK-8 assay. The results showed that four derivatives displayed potent antiproliferative activity against HL-60 cells. Notably, N-1-(2-dimethylaminoethyl)indirubin (5a) exhibited the best anticacner activity with an IC50 value of (3.564 +/- 0.211) mu mol/L. Flow cytometry and Hoechst 33342 staining indicated that compound 5a could significantly trigger cell cycle arrest and induce apoptosis of HL-60 cells. Finally, compound 5a could regulate the levels of cell cycle arrest- and apoptosis-related proteins. Together, these findings revealed that compound 5a maybe be a promising lead candidate for the treatment of leukemia.