Abstract
Brefeldin A (BFA) has recently been shown to induce apoptosis in human tumor cells in a p53-independent fashion. In this study, BFA-induced apoptosis was analyzed in the human Jurkat T-cell line. Apoptosis occurred 8 h after treatment with BFA and at concentrations as low as 10 ng/ml and increased with the duration of BFA exposure. Forskolin, an inhibitor of BFA- induced deaggregation of the Golgi-microtubular complex in some cell lines, failed to reverse BFA-mediated apoptosis. Further study of the mechanism of BFA-induced apoptosis was conducted by using a series of peptide protease inhibitors. Complete inhibition of cell death was achieved with benzyloxycarbonyl-Val-Ala-Asp-fluromethylketone, a peptide inhibitor of the caspase protease family, and Z-Asp-Glu-Val-Asp-FMK, a specific inhibitor of caspase-3. Both Acetyl-Tyr-Val-Ala-Asp-chloromethylketone and Acetyl-Tyr- Val-Ala-Asp-aldehyde, selective caspase-1 (interleukin-1β converting enzyme) inhibitors, exerted only partial protection of cells from apoptosis at higher concentrations. Z-Phe-Ala-FMK, a cysteine protease inhibitor lacking aspartate at the P1 position, did not have any impact on BFA-induced apoptosis. Furthermore, Jurkat cells transfected with the proto-oncoprotein Bcl-2, which is able to block various apoptotic conditions, showed remarkable resistance to the apoptotic effect of BFA. Thus, the data indicate that BFA- induced apoptosis requires caspase(s) activation, primarily the activation of caspase-3, and is inhibited by overexpression of Bcl-2.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 57-68 |
| Number of pages | 12 |
| Journal | Experimental Cell Research |
| Volume | 245 |
| Issue number | 1 |
| DOIs | |
| State | Published - Nov 25 1998 |
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ASJC Scopus subject areas
- Cell Biology
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Brefeldin A-mediated apoptosis requires the activation of caspases and is inhibited by Bcl-2. / Guo, Hua; Tittle, Thomas V.; Allen, Hamish; Maziarz, Richard.
In: Experimental Cell Research, Vol. 245, No. 1, 25.11.1998, p. 57-68.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Brefeldin A-mediated apoptosis requires the activation of caspases and is inhibited by Bcl-2
AU - Guo, Hua
AU - Tittle, Thomas V.
AU - Allen, Hamish
AU - Maziarz, Richard
PY - 1998/11/25
Y1 - 1998/11/25
N2 - Brefeldin A (BFA) has recently been shown to induce apoptosis in human tumor cells in a p53-independent fashion. In this study, BFA-induced apoptosis was analyzed in the human Jurkat T-cell line. Apoptosis occurred 8 h after treatment with BFA and at concentrations as low as 10 ng/ml and increased with the duration of BFA exposure. Forskolin, an inhibitor of BFA- induced deaggregation of the Golgi-microtubular complex in some cell lines, failed to reverse BFA-mediated apoptosis. Further study of the mechanism of BFA-induced apoptosis was conducted by using a series of peptide protease inhibitors. Complete inhibition of cell death was achieved with benzyloxycarbonyl-Val-Ala-Asp-fluromethylketone, a peptide inhibitor of the caspase protease family, and Z-Asp-Glu-Val-Asp-FMK, a specific inhibitor of caspase-3. Both Acetyl-Tyr-Val-Ala-Asp-chloromethylketone and Acetyl-Tyr- Val-Ala-Asp-aldehyde, selective caspase-1 (interleukin-1β converting enzyme) inhibitors, exerted only partial protection of cells from apoptosis at higher concentrations. Z-Phe-Ala-FMK, a cysteine protease inhibitor lacking aspartate at the P1 position, did not have any impact on BFA-induced apoptosis. Furthermore, Jurkat cells transfected with the proto-oncoprotein Bcl-2, which is able to block various apoptotic conditions, showed remarkable resistance to the apoptotic effect of BFA. Thus, the data indicate that BFA- induced apoptosis requires caspase(s) activation, primarily the activation of caspase-3, and is inhibited by overexpression of Bcl-2.
AB - Brefeldin A (BFA) has recently been shown to induce apoptosis in human tumor cells in a p53-independent fashion. In this study, BFA-induced apoptosis was analyzed in the human Jurkat T-cell line. Apoptosis occurred 8 h after treatment with BFA and at concentrations as low as 10 ng/ml and increased with the duration of BFA exposure. Forskolin, an inhibitor of BFA- induced deaggregation of the Golgi-microtubular complex in some cell lines, failed to reverse BFA-mediated apoptosis. Further study of the mechanism of BFA-induced apoptosis was conducted by using a series of peptide protease inhibitors. Complete inhibition of cell death was achieved with benzyloxycarbonyl-Val-Ala-Asp-fluromethylketone, a peptide inhibitor of the caspase protease family, and Z-Asp-Glu-Val-Asp-FMK, a specific inhibitor of caspase-3. Both Acetyl-Tyr-Val-Ala-Asp-chloromethylketone and Acetyl-Tyr- Val-Ala-Asp-aldehyde, selective caspase-1 (interleukin-1β converting enzyme) inhibitors, exerted only partial protection of cells from apoptosis at higher concentrations. Z-Phe-Ala-FMK, a cysteine protease inhibitor lacking aspartate at the P1 position, did not have any impact on BFA-induced apoptosis. Furthermore, Jurkat cells transfected with the proto-oncoprotein Bcl-2, which is able to block various apoptotic conditions, showed remarkable resistance to the apoptotic effect of BFA. Thus, the data indicate that BFA- induced apoptosis requires caspase(s) activation, primarily the activation of caspase-3, and is inhibited by overexpression of Bcl-2.
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U2 - 10.1006/excr.1998.4235
DO - 10.1006/excr.1998.4235
M3 - Article
VL - 245
SP - 57
EP - 68
JO - Experimental Cell Research
JF - Experimental Cell Research
SN - 0014-4827
IS - 1
ER -