Differential regulation of phosphatidylserine externalization and DNA fragmentation by caspases in anticancer drug-induced apoptosis of rat mammary adenocarcinoma MTLn3 cells

Citation
M. Huigsloot et al., Differential regulation of phosphatidylserine externalization and DNA fragmentation by caspases in anticancer drug-induced apoptosis of rat mammary adenocarcinoma MTLn3 cells, BIOCH PHARM, 62(8), 2001, pp. 1087-1097
Citations number
53
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pharmacology & Toxicology
Journal title
BIOCHEMICAL PHARMACOLOGY
ISSN journal
0006-2952 → ACNP
Volume
62
Issue
8
Year of publication
2001
Pages
1087 - 1097
Database
ISI
SICI code
0006-2952(20011015)62:8<1087:DROPEA>2.0.ZU;2-P
Abstract
Caspase activation is a central event in the execution phase of apoptosis a nd is associated with phosphatidylserine (PS) externalization and DNA fragm entation. We investigated the role of caspase activity in anticancer drug-i nduced PS externalization and DNA fragmentation in MTLn3 cells. Caspase act ivation (DEVD-AMC cleavage) occurred in a time- and concentration-dependent manner after exposure to doxorubicin, in association with cleavage of poly (ADP) ribose polymerase and protein kinase C delta, two caspase-3 substrate s. Caspase activation was closely followed by oligonucleosomal DNA fragment ation and PS externalization as determined by flow cytometric analysis. Sim ilar observations were made for etoposide and cisplatin. Inhibition of casp ases with zVAD-fmk inhibited almost completely doxorubicin-induced DNA frag mentation as well as proteolysis of protein kinase C delta. In contrast, PS externalization induced by doxorubicin was only partly affected by caspase inhibition. Flow cytometric cell sorting demonstrated that DNA fragmentati on in the remaining PS positive cells after doxorubicin treatment in the pr esence of zVAD-fmk was fully blocked. In conclusion, these data indicate th at while DNA fragmentation in anticancer drug-induced apoptosis of MTLn3 ce lls is fully dependent on caspase activity, PS externalization is controlle d by both caspase-dependent and caspase-independent pathways. (C) 2001 Else vier Science Inc. All rights reserved.