Involvement of tumor necrosis factor receptor-associated protein 1 (TRAP1) in apoptosis induced by beta-hydroxyisovalerylshikonin.
beta-Hydroxyisovalerylshikonin (beta-HIVS), a compound isolated from the traditional oriental medicinal herb Lithospermum radix, is an ATP non-competitive inhibitor of protein-tyrosine kinases, such as v-Src and EGFR, and it induces apoptosis in various lines of human tumor cells. However, the way in which beta-HIVS induces apoptosis remains to be clarified. In this study, we performed cDNA array analysis and found that beta-HIVS suppressed the expression of the gene for tumor necrosis factor receptor-associated protein 1 (TRAP1), which is a member of the heat-shock family of proteins. When human leukemia HL60 cells and human lung cancer DMS114 cells were treated with beta-HIVS, the amount of TRAP1 in mitochondria decreased in a time-dependent manner during apoptosis. A similar reduction in the level of TRAP1 was also observed upon exposure of cells to VP16. Treatment of DMS114 cells with TRAP1-specific siRNA sensitized the cells to beta-HIVS-induced apoptosis. Moreover, the reduction in the level of expression of TRAP1 by TRAP1-specific siRNA enhanced the release of cytochrome c from mitochondria when DMS114 cells were treated with either beta-HIVS or VP16. The suppression of the level of TRAP1 by either beta-HIVS or VP16 was blocked by N-acetyl-cysteine, indicating the involvement of reactive oxygen species (ROS) in the regulation of the expression of TRAP1. These results suggest that suppression of the expression of TRAP1 in mitochondria might play an important role in the induction of apoptosis caused via formation of ROS.
Laboratory of Biological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo 142-8555, Japan. masuda@pharm.showa-u.ac.jp
Yutaka
Y
Masuda
Genryu
G
Shima
Toshihiro
T
Aiuchi
Masayo
M
Horie
Kouichi
K
Hori
Shigeo
S
Nakajo
Sachiko
S
Kajimoto
Toshiko
T
Shibayama-Imazu
Kazuyasu
K
Nakaya
D000111:Acetylcysteine / Q000737:chemistry / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D016923:Cell Death; D002460:Cell Line; D045744:Cell Line, Tumor; D004396:Coloring Agents / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D018922:HL-60 Cells; D018841:HSP90 Heat-Shock Proteins / Q000502:physiology*; D006801:Humans; D020014:K562 Cells; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D009285:Naphthoquinones / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D010957:Plasmids / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D004396:Coloring Agents; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D018841:HSP90 Heat-Shock Proteins; D009285:Naphthoquinones; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C092306:TRAP1 protein, human; C118460:beta-hydroxyisovalerylshikonin; D005047:Etoposide; D045304:Cytochromes c; D000111:Acetylcysteine