Inhibition of apoptosis in human tumour cells by okadaic acid
Article first published online: 4 FEB 2005
Copyright © 1992 Wiley-Liss, Inc.
Journal of Cellular Physiology
Volume 153, Issue 3, pages 550–556, December 1992
How to Cite
Song, Q., Baxter, G. D., Kovacs, E. M., Findik, D. and Lavin, M. F. (1992), Inhibition of apoptosis in human tumour cells by okadaic acid. J. Cell. Physiol., 153: 550–556. doi: 10.1002/jcp.1041530316
- Issue published online: 4 FEB 2005
- Article first published online: 4 FEB 2005
- Manuscript Accepted: 1 JUL 1992
- Manuscript Received: 31 DEC 1991
Gamma-radiation, tetrandrine, bistratene A, and cisplatin were all found to induce pronounced morphological changes characteristic of apoptosis and extensive DNA fragmentation in the human BM13674 cell line 8 h after treatment. Apoptosis induced in BM13674 cells by these diverse agents was markedly inhibited by 1 μM okadaic acid, a tumour promoter that inhibits protein phosphatases 1 and 2A. This compound also inhibited the appearance of apoptosis in fresh human leukaemia cells that had been exposed to gamma-radiation. The inhibition of apoptosis was confirmed using fluorescence microscopy and DNA gel electrophoresis. Dephosphorylation of a limited number of proteins was shown to be associated with apoptosis and okadaic acid prevented these dephosphorylations. Previous studies on the BM13674 cell line showed that an inhibitor of protein synthesis failed to prevent apoptosis in these cells. The present data provides further support that posttranslational modification of proteins, in particular, phosphorylation/dephosphorylation status, plays an important role in inhibition/activation of programmed cell death in different human cells after exposure to several cytotoxic agents. © 1992 Wiley-Liss, Inc.