Abstract
We have studied the effect of tri-phenyl tin benzimadazolethiolcopper chloride (TPT-CuCl2), a novel bimetallic compound, on the regulation of apoptosis in HeLa cells, MCF-7 cells, and in vivo Wistar rat model. TPT-CuCl2 induces significant apoptosis in HeLa cell line characterized by DNA fragmentation and chromosome condensation. Comet assay revealed that TPT-CuCl2 targets and causes severe damage to the DNA. Treatment of HeLa cells with TPT-CuCl2 rescues the accumulation of p53 from the suppression of human papilloma virus E6, resulting in a dramatic up-regulation of Bax and Bak and down-regulation of the antiapoptotic factor Survivin. Apoptotic induction by TPT-CuCl2 was shown to mediate in a p53-depedent manner; loss of p53 impairs the release of cytochrome c and Smac/DIABLO from mitochondria to cytosol. Moreover, we have shown that TPT-CuCl2 induced-apoptosis was through an intrinsic mitochondrial pathway, which was inhibited by viral oncoprotein E1B19K. Caspase-3 was found to be indispensable in TPT-CuCl2-triggered apoptosis signaling pathway, because caspase-3 deficient cell line MCF-7 was resistant to TPT-CuCl2. Furthermore, in vivo studies using C6 glioblastoma xenograft rat model revealed that TPT-CuCl2 exhibits significant antiproliferative activity against tumor development with minimal cytotoxicity toward normal physiological function of the experimental rats. These findings imply the attractiveness of TPT-CuCl2 as a drug candidate for further development.
Footnotes
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This research was funded by the Key Project (KSCX2-2-01-004) from the Chinese Academy of Sciences, grants from National Natural Science Foundation of China (90208027, 30370308, and 30121001), and a 973 grant (2002CB713702) from the Ministry of Science and Technology of China.
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doi:10.1124/jpet.104.069104.
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ABBREVIATIONS: HPV, human papilloma virus; mAb, monoclonal antibody; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; PBS, phosphate-buffered saline; TPT-CuCl2, tri-phenyl tin benzimidazolethiol copper chloride; TUNEL, terminal deoxynucleotidyl transferase dUTP nick-end labeling; RT-PCR, reverse transcription-polymerase chain reaction; TBS, Tris-buffered saline; PI, propidium iodide; FACS, fluorescence-activated cell sorting; FITC, fluorescein isothiocyanate; GFP, green fluorescent protein; Smac/DIABLO, second mitochondria-derived activator of caspases; PARP-1, poly(ADP-ribose) polymerase-1; ALT, alanine aminotransferase; RBC, red blood cell.
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↵1 N.H. and D.Z. contributed equally to this work.
- Received March 26, 2004.
- Accepted May 27, 2004.
- The American Society for Pharmacology and Experimental Therapeutics
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