Involvement of Akt in mitochondria-dependent apoptosis induced by a cdc25 phosphatase inhibitor naphthoquinone analog

• Published in: FEBS letters 2003-12, Vol.555 (2), p.217-222
• Main Authors: Kim, Hae Jong, Kang, Seung Koo, Mun, Jung Yee, Chun, Young Jin, Choi, Kyung Hee, Kim, Mie Young
• Format: Article
• Language: English
• Subjects: Akt; Amino Acid Chloromethyl Ketones - pharmacology; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Bad; bcl-2-Associated X Protein; bcl-Associated Death Protein; BH3 Interacting Domain Death Agonist Protein; Carrier Proteins - metabolism; Caspase Inhibitors; Caspases - metabolism; cdc25 Phosphatases - antagonists & inhibitors; Cytochrome c; Cytochromes c - metabolism; DEVD-pNA, N-acetyl-Asp-Glu-Val-Asp-p-nitroanilide; Enzyme Activation - drug effects; Enzyme Inhibitors - pharmacology; FITC, fluorescein isothiocyanate; HL-60 Cells; Humans; IETD-pNA, N-acetyl-Ile-Glu-Thr-Asp-p-nitroanilide; Immunoblotting; LEHD-pNA, N-acetyl-Leu-Glu-His-Asp-p-nitroanilide; Mitochondria - metabolism; Naphthoquinone analog; Naphthoquinones - antagonists & inhibitors; Naphthoquinones - pharmacology; Protein-Serine-Threonine Kinases - metabolism; Protein-Serine-Threonine Kinases - pharmacology; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins - pharmacology; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2 - metabolism; Signal Transduction; zVAD-fmk, z-Val-Ala-Asp(OMe)-fluoromethylketone
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(03)01238-9

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.