Induction of apoptosis in hepatocellular carcinoma Smmc-7721 cells by vitamin K(2) is associated with p53 and independent of the intrinsic apoptotic pathway.

Abstract

Vitamin K(2) (VK(2)) can exert cell growth inhibitory effects in various human cancer cells. In this study, we investigated the cell growth inhibitory effects of VK(2) in hepatocellular carcinoma Smmc-7721 cells and the mechanisms involved. We found that VK(2)-inhibited cell proliferation in Smmc-7721 cells in a dose-dependent manner, and the IC50 of VK(2) in Smmc-7721 cells was 9.73 microM at 24 h. The data from flow cytometric analyses, DNA fragmentation assays, and caspase 3 activity assays revealed that apoptosis was the determining factor in VK(2) activity. Furthermore, a significant increase in p53 phosphorylation and protein level was exhibited in apoptotic cells treated with VK(2), although there were no changes in p53 mRNA expression. Bax expression was unaffected by VK(2) in Smmc-7721 cells. In addition, our study showed that caspase 3 was activated by caspase 8, not caspase 9, in Smmc-7721 cells treated with VK(2). In summary, these data suggested that VK(2) can inhibit the growth of Smmc-7721 cells by induction of apoptosis involving caspase 8 activation and p53. This apoptotic process was not mediated by the intrinsic apoptotic pathway.

• Authors: Lu Li, Zhiling Qi, Jin Qian, Fuyong Bi, Jun Lv, Lei Xu, Ling Zhang, Hongyu Chen, Renbing Jia
• Journal: Molecular and cellular biochemistry (Mol Cell Biochem) Vol. 342 Issue 1-2 Pg. 125-31 (Sep 2010) ISSN: 1573-4919 [Electronic] Netherlands
• PMID: 20449638 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Messenger
• TP53 protein, human
• Tumor Suppressor Protein p53
• Vitamins
• bcl-2-Associated X Protein
• Vitamin K 2
• Caspase 3
• Caspase 8
• Caspase 9

Topics

• Apoptosis (drug effects)
• Blotting, Western
• Carcinoma, Hepatocellular (drug therapy, metabolism, pathology)
• Caspase 3 (metabolism)
• Caspase 8 (metabolism)
• Caspase 9 (metabolism)
• Cell Proliferation (drug effects)
• Enzyme Activation (drug effects)
• Flow Cytometry
• Humans
• Liver Neoplasms (drug therapy, metabolism, pathology)
• RNA, Messenger (genetics)
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction (drug effects)
• Tumor Cells, Cultured
• Tumor Suppressor Protein p53 (genetics, metabolism)
• Vitamin K 2 (pharmacology)
• Vitamins (pharmacology)
• bcl-2-Associated X Protein (genetics, metabolism)