title: Growth inhibition and induction of apoptosis in NB4 promyelocytic leukemia cells by trypsin inhibitor from sweet potato storage roots.
abstract: The objective of this study was to investigate the antiproliferative effect and the mechanism of trypsin inhibitor (TI) from sweet potato [Ipomoea batatas (L.) Lam. 'Tainong 57'] storage roots on NB4 promyelocytic leukemia cells. The results showed that TI inhibited cellular growth of NB4 promyelocytic leukemia cells in a time-dependent and dose-dependent manner, and treatment for 72 h induced a marked inhibition of cellular growth, showing an IC50 of 57.1 +/- 8.26 microg/mL. TI caused cell cycle arrest at the G1 phase as determined by flow cytometric analysis and apoptosis as shown by DNA laddering. TI-induced cell apoptosis involved p53, Bcl-2, Bax, and cytochrome c protein in NB4 cells. P53 and Bax proteins were accumulated, and antiapoptotic molecule Bcl-2 was decreased in the tested cells in a time-dependent manner during TI treatment. TI also induced a substantial release of cytochrome c from the mitochondria into the cytosol. Hence, TI induced apoptosis in NB4 cells through a mitochondria-dependent pathway, which was associated with the activation of caspase-3 and -8. These results demonstrated that TI induces NB4 cell apoptosis through the inhibition of cell growth and the activation of the pathway of caspase-3 and -8 cascades.
authors.affiliation: Institute of Chinese Pharmaceutical Sciences and Department of Physiology, School of Medicine, China Medical University, Taichung 404, Taiwan.
authors.forename: Guan-Jhong
authors.initials: GJ
authors.lastname: Huang
authors.forename: Ming-Jyh
authors.initials: MJ
authors.lastname: Sheu
authors.forename: Hsien-Jung
authors.initials: HJ
authors.lastname: Chen
authors.forename: Yuan-Shiun
authors.initials: YS
authors.lastname: Chang
authors.forename: Yaw-Huei
authors.initials: YH
authors.lastname: Lin
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000032:analysis; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D053938:DNA Fragmentation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D027723:Ipomoea batatas / Q000737:chemistry*; D015473:Leukemia, Promyelocytic, Acute; D035281:Plant Tubers / Q000737:chemistry*; D014361:Trypsin Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D018797:Cell Cycle Proteins; D014361:Trypsin Inhibitors; D020169:Caspases