[Regulation of arsenic trioxide-inducing apoptosis]
1Institute of Hematology, Peoples' Hospital, Beijing Medical University, Beijing 100044.
Zhonghua Xue Ye Xue Za Zhi = Zhonghua Xueyexue Zazhi
|October 17, 2001
Summary
Arsenic trioxide (As2O3) induces apoptosis by interacting with intracellular thiol (-SH) groups and activating caspases. Retinoic acid (RA) effects on As2O3-induced apoptosis vary by cell type.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Apoptosis is a critical cellular process involved in development and disease.
- Arsenic trioxide (As2O3) is a chemotherapeutic agent known to induce apoptosis.
- The precise mechanisms of As2O3-induced apoptosis, including the roles of intracellular thiols and caspases, require further elucidation.
Purpose of the Study:
- To investigate the interplay between intracellular thiol (-SH) groups, caspases, retinoic acid (RA), and As2O3-induced apoptosis.
- To determine the influence of thiol compounds and caspase inhibitors on As2O3-induced apoptosis in leukemia cell lines.
- To examine the synergistic or antagonistic effects of RA in combination with As2O3 on apoptosis.
Main Methods:
- In vitro studies were conducted using NB4 and HL-60 leukemia cell lines.
- The effects of N-acetylcysteine (NAC), buthionine sulfoximine (BSO), and other thiol compounds on As2O3-induced apoptosis were assessed.
- Caspase inhibitors, including Z-VAD.fmk and Y-VAD.fmk, were used to probe caspase activation pathways.
- The combined effects of retinoic acid (RA) and As2O3 on apoptosis were evaluated in different cell types.
Main Results:
- N-acetylcysteine (NAC) completely inhibited As2O3-induced apoptosis, while buthionine sulfoximine (BSO) potentiated it; other thiols had no significant effect.
- The broad-spectrum caspase inhibitor Z-VAD.fmk blocked As2O3-induced apoptosis, whereas the caspase-3 inhibitor Y-VAD.fmk did not.
- Retinoic acid (RA) exhibited synergistic effects with As2O3 in HL-60 cells but antagonistic effects in NB4 cells.
Conclusions:
- As2O3 induces apoptosis by binding to intracellular thiol (-SH) groups, altering signal transduction pathways, and selectively activating caspases.
- The modulatory effect of retinoic acid (RA) on As2O3-induced apoptosis is cell-type dependent, highlighting the complexity of apoptotic regulation.
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