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Silibinin induces apoptosis via calpain-dependent AIF nuclear translocation in U87MG human glioma cell death.

Jeong JC, Shin WY, Kim TH, Kwon CH, Kim JH, Kim YK, Kim KH - J. Exp. Clin. Cancer Res. (2011)

Bottom Line: Silibinin caused ROS generation and its effect was inhibited by calpain inhibitor, the general PKC inhibitor GF 109203X, the specific PKCδ inhibitor rottlerin, and catalase.Silibinin induced AIF nuclear translocation and its effect was prevented by calpain inhibitor.Transfection of vector expressing microRNA of AIF prevented the silibinin-induced cell death.

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Affiliation: Department of Oriental Medicine, Dongguk University, Kyung Ju, 780-714, Korea.

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Role of calpain in silibinin-induced cell death. (A) Cells were exposed to 30 μM silibinin for 36 h in the presence of various concentrations of calpain inhibitor (Z-CHO). Cell viability was estimated by MTT assay. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone. (B) Cells were exposed to 30 μM silibinin for 24 h in the presence of 2 mM EGTA and 0.5 μM Z-CHO. Calpain activity was measured by calpain assay kit. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone.
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Figure 1: Role of calpain in silibinin-induced cell death. (A) Cells were exposed to 30 μM silibinin for 36 h in the presence of various concentrations of calpain inhibitor (Z-CHO). Cell viability was estimated by MTT assay. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone. (B) Cells were exposed to 30 μM silibinin for 24 h in the presence of 2 mM EGTA and 0.5 μM Z-CHO. Calpain activity was measured by calpain assay kit. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone.

Mentions: Calpains are cytosolic Ca2+-activated neutral cysteine proteases and ubiquitously distributed in all animal cells, which play a critical role in regulating cell viability [11,12]. Accumulating evidence suggests that calpain activation may contribute to cell death in certain cell types including thymocytes, monocytes, cardiomyocytes, and neuronal cells [13]. Since our previous study showed that the calpain inhibitor Z-Leu-Leu-CHO at 0.5 μM significantly protected effectively against the silibinin-induced cell death [8], we observed in the present study the dose-dependency of the inhibitor effect. The results showed that the calpain inhibitor exerted protective effect against the silibinin-induced cell death in a dose-dependent manner with maximum potency at 0.5-1 μM (Figure 1A). Silibinin also induced calpain activation, which was blocked by EGTA and calpain inhibitor (Figure 1B). These results indicate that calpain activation plays a critical role in the silibinin-induced cell death in human glioma cells.


Silibinin induces apoptosis via calpain-dependent AIF nuclear translocation in U87MG human glioma cell death.

Jeong JC, Shin WY, Kim TH, Kwon CH, Kim JH, Kim YK, Kim KH - J. Exp. Clin. Cancer Res. (2011)

Role of calpain in silibinin-induced cell death. (A) Cells were exposed to 30 μM silibinin for 36 h in the presence of various concentrations of calpain inhibitor (Z-CHO). Cell viability was estimated by MTT assay. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone. (B) Cells were exposed to 30 μM silibinin for 24 h in the presence of 2 mM EGTA and 0.5 μM Z-CHO. Calpain activity was measured by calpain assay kit. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108340&req=5

Figure 1: Role of calpain in silibinin-induced cell death. (A) Cells were exposed to 30 μM silibinin for 36 h in the presence of various concentrations of calpain inhibitor (Z-CHO). Cell viability was estimated by MTT assay. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone. (B) Cells were exposed to 30 μM silibinin for 24 h in the presence of 2 mM EGTA and 0.5 μM Z-CHO. Calpain activity was measured by calpain assay kit. Data are mean ± SEM of four independent experiments performed in duplicate. *p < 0.05 compared with silibinin alone.
Mentions: Calpains are cytosolic Ca2+-activated neutral cysteine proteases and ubiquitously distributed in all animal cells, which play a critical role in regulating cell viability [11,12]. Accumulating evidence suggests that calpain activation may contribute to cell death in certain cell types including thymocytes, monocytes, cardiomyocytes, and neuronal cells [13]. Since our previous study showed that the calpain inhibitor Z-Leu-Leu-CHO at 0.5 μM significantly protected effectively against the silibinin-induced cell death [8], we observed in the present study the dose-dependency of the inhibitor effect. The results showed that the calpain inhibitor exerted protective effect against the silibinin-induced cell death in a dose-dependent manner with maximum potency at 0.5-1 μM (Figure 1A). Silibinin also induced calpain activation, which was blocked by EGTA and calpain inhibitor (Figure 1B). These results indicate that calpain activation plays a critical role in the silibinin-induced cell death in human glioma cells.

Bottom Line: Silibinin caused ROS generation and its effect was inhibited by calpain inhibitor, the general PKC inhibitor GF 109203X, the specific PKCδ inhibitor rottlerin, and catalase.Silibinin induced AIF nuclear translocation and its effect was prevented by calpain inhibitor.Transfection of vector expressing microRNA of AIF prevented the silibinin-induced cell death.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Oriental Medicine, Dongguk University, Kyung Ju, 780-714, Korea.

Show MeSH
Related in: MedlinePlus