Increased Stability of Nucleophosmin/B23 in Anti-Apoptotic Effect of Ras during Serum Deprivation
- 1Graduate Institute of Pharmacology, National Yang Ming University, Taiwan, Republic of China (C.C.C.); and 2Cancer Biochemistry Laboratory, Department of Pharmacology, College of Medicine, Chang Gung University, Taiwan, Republic of China (B.Y.M.Y.)
Abstract
We obtained evidence that increased stability of nucleophosmin/B23 is involved in antiapoptotic effect of ras during serum deprivation. Nucleophosmin/B23 in serum-deprived (0% serum) NIH-3T3 cells was found to be highly unstable with a half-life less than 4 h. In contrast, nucleophosmin/B23 in serum-deprived ras-transformed (RAS-3T3) cells was as stable as that in serum-supplemented NIH-3T3 or RAS-3T3 cells. Treatment of RAS-3T3 cells with nucleophosmin/B23 antisense oligomer significantly potentiated the apoptosis induced by serum deprivation. Much less caspase-3 activity was noted in the lysate derived from serum-deprived RAS-3T3 cells compared with that in the lysate of serum-deprived NIH-3T3 cells. Cell permeable caspase-3 inhibitor added in the medium blocked the decrease of nucleophosmin/B23 and apoptosis induced by serum deprivation in NIH-3T3 cells. The inhibitor, on the other hand, promoted significant decrease of nucleolin/C23 in NIH-3T3 cells during serum deprivation. Unlike nucleolin/C23, down-regulation of nucleophosmin/B23 was thus not proliferation-dependent but caspase-3- and apoptosis-dependent. Our results indicate important relationships among ras, nucleophosmin/B23, activation of caspase-3, and induction of apoptosis.
Footnotes
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Send reprint requests to: Dr. Benjamin Y. M. Yung, Cancer Biochemistry Laboratory, Department of Pharmacology, College of Medicine, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-San, Tao-Yuan 333, Taiwan, Republic of China. E-mail: byung{at}mail.cgu.edu.tw
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This work was supported by Chang Gung Memorial Hospital Research Funding Grant CMRP 753 and National Science Council (R.O.C.) Grant NSC 89–2320-B182–023 and National Research Institute of Health Council (R.O.C.) Grant NHRI-GT-EX89S935L.
- Abbreviations:
- RA
- retinoic acid
- MAb
- monoclonal antibody
- DMEM
- Dulbecco's modified Eagle's medium
- PAGE
- polyacrylamide gel electrophoresis
- TBST
- Tris-buffered saline/Tween 20
- PVDF
- polyvinylidene difluoride
- CHAPS
- 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid
- MAPK
- mitogen-activated protein kinase
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- Received July 14, 2000.
- Accepted October 17, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
