title: Synergistic Apoptosis-Inducing Antileukemic Effects of Arsenic Trioxide and Mucuna macrocarpa Stem Extract in Human Leukemic Cells via a Reactive Oxygen Species-Dependent Mechanism.
abstract: The objective of this study was to examine the potential of enhancing the antileukemic activity of arsenic trioxide (ATO) by combining it with a folk remedy, crude methanolic extract of Mucuna macrocarpa (CMEMM). Human leukemia cells HL-60, Jurkat, and Molt-3 were treated with various doses of ATO, CMEMM, and combinations thereof for 24 and 48 h. Results indicated that the combination of 2.5 μM ATO and 50 μg/mL CMEMM synergistically inhibited cell proliferation in HL-60 and Jurkat cell lines. Apoptosis triggered by ATO/CMEMM treatment was confirmed by accumulation of cells in the sub-G(1) phase in cell cycle analyses, characteristic apoptotic nuclear fragmentation, and increased percentage of annexin V-positive apoptotic cells. Such combination treatments also led to elevation of reactive oxygen species (ROS). The antioxidants N-acetyl cysteine (NAC), butylated hydroxytoluene, and α-tocopherol prevented cells from ATO/CMEMM-induced apoptosis. The ATO/CMEMM-induced activation of caspase-3 and caspase-9 can be blocked by NAC. In summary, these results suggest that ATO/CMEMM combination treatment exerts synergistic apoptosis-inducing effects in human leukemic cells through a ROS-dependent mechanism and may provide a promising antileukemic approach in the future.
authors.affiliation: Graduate Institute of Chinese Pharmaceutical Sciences, China Medical University, Taichung 404, Taiwan.
authors.forename: Kuan-Hung
authors.initials: KH
authors.lastname: Lu
authors.forename: Hui-Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Min-Li
authors.initials: ML
authors.lastname: Huang
authors.forename: Shang-Chih
authors.initials: SC
authors.lastname: Lai
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Ho
authors.forename: Yuan-Shiun
authors.initials: YS
authors.lastname: Chang
authors.forename: Chin-Wen
authors.initials: CW
authors.lastname: Chi