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Styrylpyrone Derivative (SPD) induces apoptosis in a caspase-7-dependent manner in the human breast cancer cell line MCF-7.

Lee AT, Azimahtol HL, Tan AN - Cancer Cell Int. (2003)

Bottom Line: RESULTS: We found that the intrinsic apoptotic pathway was invoked, with the accumulation of cytosolic cytochrome c and processing of the initiator caspase-9.To confirm that apoptosis was induced following caspase-7 activation, the caspase inhibitor Ac-DEVD-CHO was used.CONCLUSIONS: Taken together, these results suggest SPD as a potent antiproliferative agent on MCF-7 cells by inducing apoptosis in a caspase-7-dependent manner.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biosciences & Biotechnology, Faculty of Science & Technology, National University of Malaysia, 43600 Bangi, Selangor, MALAYSIA. alvinlee@email.com

ABSTRACT
BACKGROUND: Styrylpyrone derivative (SPD) is a plant-derived pharmacologically active compound extracted from Goniothalamus sp. Previously, we have reported that SPD inhibited the proliferation of MCF-7 human breast cancer cells by inducing apoptotic cell death, while having minimal effects on non-malignant cells. Here, we attempt to further elucidate the mode of action of SPD. RESULTS: We found that the intrinsic apoptotic pathway was invoked, with the accumulation of cytosolic cytochrome c and processing of the initiator caspase-9. Cleaved products of procaspase-8 were not detected. Next, the executioner caspase-7 was cleaved and activated in response to SPD treatment. To confirm that apoptosis was induced following caspase-7 activation, the caspase inhibitor Ac-DEVD-CHO was used. Pre-incubation of cells with this inhibitor reversed apoptosis levels and caspase-7 activity in SPD-treated cells to untreated levels. CONCLUSIONS: Taken together, these results suggest SPD as a potent antiproliferative agent on MCF-7 cells by inducing apoptosis in a caspase-7-dependent manner.

No MeSH data available.


Related in: MedlinePlus

Activation of caspase-7 after SPD-treatment. The activity of caspase-7 was measured with a Colorimetric Assay Kit (Chemicon) that recognizes cleavage of the sequence DEVD by active caspase-7. Caspase-7 activity increased when cells were treated with SPD, indicating the catalytic activation of this executioner caspase. When MCF-7 cells were incubated with the caspase-7 inhibitor, DEVD-CHO, prior to SPD treatment, caspase-7 DEVDase activity diminished.
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Figure 4: Activation of caspase-7 after SPD-treatment. The activity of caspase-7 was measured with a Colorimetric Assay Kit (Chemicon) that recognizes cleavage of the sequence DEVD by active caspase-7. Caspase-7 activity increased when cells were treated with SPD, indicating the catalytic activation of this executioner caspase. When MCF-7 cells were incubated with the caspase-7 inhibitor, DEVD-CHO, prior to SPD treatment, caspase-7 DEVDase activity diminished.

Mentions: The role of the initiator caspase-9 is to generate the active forms of executioner caspase-3 and -7 by limited proteolysis, and thereby transmit the apoptotic signal to the execution phase. Here, we used the caspase-3-deficient MCF-7 cell line. As with previous reports [32,33], caspase-3 activity was not detected (data not shown). Immunoblot analyses of lysates obtained from MCF-7 cells treated with SPD at 10-6 M found that caspase-7 was cleaved to the 17-kDa fragment required for its activation (Figure 3). When the activity of caspase-7 was assayed, SPD-treated cells showed increase in activity compared to untreated controls (Figure 4). To confirm that the SPD-induced apoptotic cell death was due to the involvement of caspase-7, cells were also treated with SPD in the presence of the specific inhibitor of caspase-7, Ac-DEVD-CHO [34]. SPD-treated cells preincubated with the inhibitor exhibited repressed caspase-7 DEVDase activity. Also, preincubation of MCF-7 cells with this inhibitor at 50 μM to 100 μM inhibited apoptosis and brought apoptotic levels down to the level similar to controls (Figure 5), thus purporting an apoptotic pathway dependent on caspase-7.


Styrylpyrone Derivative (SPD) induces apoptosis in a caspase-7-dependent manner in the human breast cancer cell line MCF-7.

Lee AT, Azimahtol HL, Tan AN - Cancer Cell Int. (2003)

Activation of caspase-7 after SPD-treatment. The activity of caspase-7 was measured with a Colorimetric Assay Kit (Chemicon) that recognizes cleavage of the sequence DEVD by active caspase-7. Caspase-7 activity increased when cells were treated with SPD, indicating the catalytic activation of this executioner caspase. When MCF-7 cells were incubated with the caspase-7 inhibitor, DEVD-CHO, prior to SPD treatment, caspase-7 DEVDase activity diminished.
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Related In: Results  -  Collection

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Figure 4: Activation of caspase-7 after SPD-treatment. The activity of caspase-7 was measured with a Colorimetric Assay Kit (Chemicon) that recognizes cleavage of the sequence DEVD by active caspase-7. Caspase-7 activity increased when cells were treated with SPD, indicating the catalytic activation of this executioner caspase. When MCF-7 cells were incubated with the caspase-7 inhibitor, DEVD-CHO, prior to SPD treatment, caspase-7 DEVDase activity diminished.
Mentions: The role of the initiator caspase-9 is to generate the active forms of executioner caspase-3 and -7 by limited proteolysis, and thereby transmit the apoptotic signal to the execution phase. Here, we used the caspase-3-deficient MCF-7 cell line. As with previous reports [32,33], caspase-3 activity was not detected (data not shown). Immunoblot analyses of lysates obtained from MCF-7 cells treated with SPD at 10-6 M found that caspase-7 was cleaved to the 17-kDa fragment required for its activation (Figure 3). When the activity of caspase-7 was assayed, SPD-treated cells showed increase in activity compared to untreated controls (Figure 4). To confirm that the SPD-induced apoptotic cell death was due to the involvement of caspase-7, cells were also treated with SPD in the presence of the specific inhibitor of caspase-7, Ac-DEVD-CHO [34]. SPD-treated cells preincubated with the inhibitor exhibited repressed caspase-7 DEVDase activity. Also, preincubation of MCF-7 cells with this inhibitor at 50 μM to 100 μM inhibited apoptosis and brought apoptotic levels down to the level similar to controls (Figure 5), thus purporting an apoptotic pathway dependent on caspase-7.

Bottom Line: RESULTS: We found that the intrinsic apoptotic pathway was invoked, with the accumulation of cytosolic cytochrome c and processing of the initiator caspase-9.To confirm that apoptosis was induced following caspase-7 activation, the caspase inhibitor Ac-DEVD-CHO was used.CONCLUSIONS: Taken together, these results suggest SPD as a potent antiproliferative agent on MCF-7 cells by inducing apoptosis in a caspase-7-dependent manner.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biosciences & Biotechnology, Faculty of Science & Technology, National University of Malaysia, 43600 Bangi, Selangor, MALAYSIA. alvinlee@email.com

ABSTRACT
BACKGROUND: Styrylpyrone derivative (SPD) is a plant-derived pharmacologically active compound extracted from Goniothalamus sp. Previously, we have reported that SPD inhibited the proliferation of MCF-7 human breast cancer cells by inducing apoptotic cell death, while having minimal effects on non-malignant cells. Here, we attempt to further elucidate the mode of action of SPD. RESULTS: We found that the intrinsic apoptotic pathway was invoked, with the accumulation of cytosolic cytochrome c and processing of the initiator caspase-9. Cleaved products of procaspase-8 were not detected. Next, the executioner caspase-7 was cleaved and activated in response to SPD treatment. To confirm that apoptosis was induced following caspase-7 activation, the caspase inhibitor Ac-DEVD-CHO was used. Pre-incubation of cells with this inhibitor reversed apoptosis levels and caspase-7 activity in SPD-treated cells to untreated levels. CONCLUSIONS: Taken together, these results suggest SPD as a potent antiproliferative agent on MCF-7 cells by inducing apoptosis in a caspase-7-dependent manner.

No MeSH data available.


Related in: MedlinePlus