title: Involvement of Akt in mitochondria-dependent apoptosis induced by a cdc25 phosphatase inhibitor naphthoquinone analog.
abstract: Vitamin K-related analogs induce growth inhibition via a cell cycle arrest through cdc25A phosphatase inhibition in various cancer cell lines. We report that 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (DDN), a naphthoquinone analog, induces mitochondria-dependent apoptosis in human promyelocytic leukemia HL-60 cells. DDN induced cytochrome c release, Bax translocation, cleavage of Bid and Bad, and activation of caspase-3, -8, -9 upon the induction of apoptosis. Cleavage of Bid, the caspase-8 substrate, was inhibited by the broad caspase inhibitor z-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD-fmk), whereas cytochrome c release was not affected, suggesting that activation of caspase-8 and subsequent Bid cleavage occur downstream of cytochrome c release. DDN inhibited the activation of Akt detected by decreasing level of phosphorylation. Overexpression of constitutively active Akt protected cells from DDN-induced apoptosis, while dominant negative Akt moderately enhanced cell death. Furthermore, Akt prevented release of cytochrome c and cleavage of Bad in DDN-treated HL-60 cells. Taken together, DDN-induced apoptosis is associated with mitochondrial signaling which involves cytochrome c release via a mechanism inhibited by Akt.
authors.affiliation: Division of Biochemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, South Korea.
authors.forename: Hae Jong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Seung Koo
authors.initials: SK
authors.lastname: Kang
authors.forename: Jung Yee
authors.initials: JY
authors.lastname: Mun
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Chun
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Choi
authors.forename: Mie Young
authors.initials: MY
authors.lastname: Kim
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D015151:Immunoblotting; D008928:Mitochondria / Q000378:metabolism*; D009285:Naphthoquinones / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000378:metabolism* / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D020687:cdc25 Phosphatases / Q000037:antagonists & inhibitors*
chemical_list: C462781:2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone; D000590:Amino Acid Chloromethyl Ketones; C494819:BAD protein, human; C494826:BAX protein, human; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D009285:Naphthoquinones; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D045304:Cytochromes c; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020687:cdc25 Phosphatases; D020169:Caspases