1. Vitamin K analog (compound 5) induces apoptosis in human hepatocellular carcinoma independent of the caspase pathway
- Author
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Yukiko Saitou, Tomoyuki Kawakita, Brian I. Carr, Hidekazu Inoue, Kazushi Sugimoto, Naoyuki Enokimura, Norihiko Yamamoto, Hiroshi Okano, Katsuya Shiraki, and Takeshi Nakano
- Subjects
Cancer Research ,Carcinoma, Hepatocellular ,Vitamin K ,education ,bcl-X Protein ,Apoptosis ,X-Linked Inhibitor of Apoptosis Protein ,TNF-Related Apoptosis-Inducing Ligand ,chemistry.chemical_compound ,Tumor Cells, Cultured ,Humans ,Pharmacology (medical) ,Viability assay ,DAPI ,Fragmentation (cell biology) ,Enzyme Inhibitors ,Caspase ,Pharmacology ,Membrane Glycoproteins ,biology ,Cell growth ,Tumor Necrosis Factor-alpha ,Liver Neoplasms ,Molecular biology ,Caspase Inhibitors ,XIAP ,Oncology ,chemistry ,Proto-Oncogene Proteins c-bcl-2 ,Cell culture ,Caspases ,biology.protein ,Tumor Suppressor Protein p53 ,Apoptosis Regulatory Proteins ,Signal Transduction - Abstract
A systemic vitamin K analog, compound 5 (Cpd 5), possesses the ability to inhibit cell growth of tumor cells. Therefore, we investigated the effect of Cpd 5 in human hepatocellular carcinoma (HCC) cell lines and evaluatedits role in apoptosis. Human HCC cell lines were cultured and treated with Cpd 5. Apoptosis was assessed using DAPI staining and Annexin-V membrane staining. The expression of caspases, XIAP and Bcl-x L was also investigated. Cpd 5 decreased cell viability in a dose-dependent manner in two HCC cells (HLE and SK-Hep1) containing mutant p53, but not in the HepG2 cell line, which contained wild-type p53. Cpd 5-treated HLE and SK-Hep1 cells showed typical apoptotic features, nuclear condensation and nuclear fragmentation upon DAPI staining. Positive membranous staining for Annexin-V was also seen in these cells. Both caspase-8 and caspase-3 activities were up-regulated slightly. Pro-caspase-8 protein levels decreased slightly in both cells. Although the expression of Bcl-x L was not influenced by Cpd 5, that of XIAP decreased in HLE cells. However, the pan-caspase inhibitor, zVAD, could not significantly prevent Cpd 5-induced apoptosis and Cpd 5 could not augment TRAIL-induced apoptosis. These results demonstrate that Cpd 5 induced apoptosis in human HCC cell lines, mainly independently of caspase activities. This may contribute to its highly potent cytotoxicity toward HCC cells.
- Published
- 2005