Title : Silibinin activates p53-caspase 2 pathway and causes caspase-mediated cleavage of Cip1/p21 in apoptosis induction in bladder transitional-cell papilloma RT4 cells: evidence for a regulatory loop between p53 and caspase 2.

Pub. Date : 2006 Nov

PMID : 16777994






8 Functional Relationships(s)
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1 Silibinin activates p53-caspase 2 pathway and causes caspase-mediated cleavage of Cip1/p21 in apoptosis induction in bladder transitional-cell papilloma RT4 cells: evidence for a regulatory loop between p53 and caspase 2. Silybin tumor protein p53 Homo sapiens
2 Silibinin activates p53-caspase 2 pathway and causes caspase-mediated cleavage of Cip1/p21 in apoptosis induction in bladder transitional-cell papilloma RT4 cells: evidence for a regulatory loop between p53 and caspase 2. Silybin tumor protein p53 Homo sapiens
3 Here, we studied the mechanisms involved in silibinin-induced apoptosis of RT4 cells having intact p53. Silybin tumor protein p53 Homo sapiens
4 Silibinin increased p53 protein level together with its increased phosphorylation at serine 15, activated caspase cascade and caused Bid cleavage for apoptosis. Silybin tumor protein p53 Homo sapiens
5 Silibinin-caused p53 activation was mediated via ATM-Chk2 pathway, which in turn induced caspase 2-mediated apoptosis. Silybin tumor protein p53 Homo sapiens
6 Pifithrin-alpha, a p53 inhibitor, reversed silibinin-induced caspase activation including caspase 2; however, caspase 2 inhibitor also reversed p53 phosphorylation suggesting a bidirectional regulation between them. Silybin tumor protein p53 Homo sapiens
7 Further, silibinin caused a rapid translocation of p53 and Bid into mitochondria leading to increased permeabilization of mitochondrial membrane and cytochrome c release into the cytosol. Silybin tumor protein p53 Homo sapiens
8 Together, these results suggested the novel mechanisms for apoptosis induction by silibinin involving p53-caspase 2 activation and caspase-mediated cleavage of Cip1/p21. Silybin tumor protein p53 Homo sapiens