Adenosine Activates AMPK to Phosphorylate Bcl-XL Responsible for Mitochondrial Damage and DIABLO Release in HuH-7 Cells

Cellular Physiology and Biochemistry

关键词: Adenosine;    AMPK;    Bcl-XL;    Phosphorylation;    Mitochondria;    DIABLO;    Apoptosis;    HuH-7 cell;   

DOI  :  10.1159/000325207

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background/Aims Accumulating evidence has pointed to AMP-activated protein kinase (AMPK) as an inducer of apoptosis in a variety of cancer cells. The present study aimed at understanding AMPK signals for adenosine-induced HuH-7 cell apoptosis. Methods Cell viability, AMPK activity, mitochondrial membrane potentials, phosphorylation of Bcl-X_L, in situ DIABLO mobilizations, and caspase-3 activity were monitored in HuH-7 cells. Plasmid DNAs for DIABLO-GFP, mutant Bcl-X_L, dominant negative mutant AMPKα2 and the siRNAs to silence the AMPKα1 or AMPKα2 targeted gene were constructed and transfected. Results Adenosine or the AMPK activator AICAR induced apoptosis in HuH-7 cells, and no synergistic effect was obtained with co-treatment. Adenosine activated AMPK, to phosphorylate Bcl-X_L. Adenosine or AICAR disrupted mitochondrial membrane potentials, and the effect was inhibited by knocking-down AMPKα1 and/or AMPKα2, expressing dominant negative mutant AMPKα2 or mutant Bcl-X_L lacking Ser/Thr phosphorylation sites. AICAR stimulated DIABLO release from the mitochondria, and the release was suppressed by expressing the mutant Bcl-X_L. AICAR activated caspase-3, which was also inhibited by expressing the mutant Bcl-X_L. Conclusion Adenosine activates AMPK, to disrupt mitochondrial membrane potentials through Bcl-X_L phosphorylation, allowing DIABLO release from the mitochondria, as a factor for caspase-3 activation to induce HuH-7 cell apoptosis.

【 授权许可】

CC BY-NC-ND