Qinwan Huang,1 Lin Wang,1 Qian Ran,1 Jin Wang,1 Chengqiang Wang,2 Hui He,2 Li Li,2 Hongyi Qi21College of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, People's Republic of China; 2College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, People's Republic of ChinaPurpose: This study aims to observe the effects of notopterol on the apoptosis and differentiation of HL-60 cells and to explore the underlying molecular mechanisms.Methods: Cell

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... ty was assessed using sulforhodamine B assay. Cell proliferation was determined by the trypan blue dye exclusion test. Colony-forming units were assayed in methylcellulose. Apoptosis assays were carried out by annexin V-fluorescein isothiocyanate(FITC)/propidium iodide (PI) double staining, Hoechst 33342 staining, mitochondrial membrane potential, and Western blot. Wright–Giemsa staining, nitroblue tetrazolium (NBT) reduction assay, CD11b and CD14 and Western blot were detected for induction of differentiation. In addition, cell-cycle phase distribution was analyzed by flow cytometry and Western blot. The combination therapy of notopterol and all-trans retinoic acid (ATRA) on HL-60 cells was examined.Results: Notopterol obviously inhibited the growth of HL-60 cells with an IC50 value of 40.32 μM and remarkably reduced the number of colonies by 10, 20, and 40 μM. In addtion, notopterol induced the percentage of apoptotic HL-60 cells, reduced the mitochondrial membrane potential, decreased the protein expresstion of Bcl-2 and Mcl-1, and increased the expression of Bax, cleavage of caspase 9, caspase 3, and PARP. As for cell differentiation, notopterol clearly induced chromatin condensation; increased the nucleocytoplasmic ratio, nitroblue tetrazolium-positive cells, expression of CD14 and CD11b, and protein expression of c-Jun and Jun B, and decreased c-myc. Furthermore, notopterol induced the G0/G1 cell-cycle arrest as determined using flow cytometry, which may be related to the regulation of cell-cycle-related proteins p53 [...]