Kim Hae Jong, Kang Seung Koo, Mun Jung Yee, Chun Young Jin, Choi Kyung Hee, Kim Mie Young
Division of Biochemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, South Korea.
FEBS Lett. 2003 Dec 4;555(2):217-22. 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.
维生素K相关类似物通过抑制多种癌细胞系中的细胞周期蛋白磷酸酶cdc25A，使细胞周期停滞，从而抑制细胞生长。我们报道了萘醌类似物2,3-二氯-5,8-二羟基-1,4-萘醌（DDN）可诱导人早幼粒细胞白血病HL-60细胞发生线粒体依赖性凋亡。DDN诱导凋亡时，会导致细胞色素c释放、Bax易位、Bid和Bad裂解以及半胱天冬酶-3、-8、-9激活。半胱天冬酶-8底物Bid的裂解受到广谱半胱天冬酶抑制剂z-Val-Ala-Asp(OMe)-氟甲基酮（zVAD-fmk）的抑制，而细胞色素c释放不受影响，这表明半胱天冬酶-8的激活以及随后的Bid裂解发生在细胞色素c释放的下游。DDN通过降低磷酸化水平抑制Akt的激活。持续激活的Akt过表达可保护细胞免受DDN诱导的凋亡，而显性负性Akt则适度增强细胞死亡。此外，Akt可阻止DDN处理的HL-60细胞中细胞色素c的释放和Bad的裂解。综上所述，DDN诱导的凋亡与线粒体信号传导有关，该信号传导涉及细胞色素c通过一种受Akt抑制的机制释放。
