Time-dependent onset of Interferon-alpha2b-induced apoptosis in isolated hepatocytes from preneoplastic rat livers.
We have already demonstrated that interferon alfa-2b (IFN-alpha2b) induces apoptosis in isolated hepatocytes from preneoplastic rat livers via the secretion of transforming growth factor beta(1) (TGF-beta(1)), and this process is accompanied by caspase-3 activation. The aim of this study was to further investigate the mechanism of this activation. Isolated hepatocytes from preneoplastic livers induced DNA fragmentation in response to IFN-alpha2b, which was completely blocked when anti-TGF-beta(1) was added to the culture media. IFN-alpha2b mediated radical oxygen species (ROS) production that preceded the loss of mitochondrial transmembrane potential (DeltaPsi), release of cytochrome c, and activation of caspase-3. Bax levels increased in a time-dependent fashion, and Bcl-x(L) was down-regulated in the early hours of IFN-alpha2b treatment. The delayed translocation of Bid into the mitochondria was in concordance with late caspase-8 activation. In conclusion, endogenous TGF-beta(1) secreted under IFN-alpha2b stimulus seems to induce cytochrome c release through a mechanism related to Bcl-2 family members and loss of mitochondrial DeltaPsi. Bax protein could be responsible of the release of cytochrome c during the initial hours of IFN-alpha2b-induced apoptosis via TGF-beta(1). Activated Bid by caspases could amplificate the mitochondrial events, enhancing the release of cytochrome c.
Alvarez
María de Luján
Mde L
Instituto de Fisiología Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, 2000 Rosario, Argentina.
Quiroga
Ariel D
AD
Ronco
María Teresa
MT
Parody
Juan Pablo
JP
Ochoa
J Elena
JE
Monti
Juan A
JA
Carnovale
Cristina E
CE
Carrillo
María Cristina
MC
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D022781:Hepatocytes / Q000166:cytology* / Q000378:metabolism; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000494:pharmacology*; D008099:Liver / Q000166:cytology*; D008113:Liver Neoplasms / Q000378:metabolism*; D008297:Male; D053078:Membrane Potential, Mitochondrial; D011230:Precancerous Conditions / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
D017304:Annexin A5; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1; D045304:Cytochromes c; D053148:Caspase 3; D053181:Caspase 8