FoxO3a modulation and promotion of apoptosis by interferon-α2b in rat preneoplastic liver
Article first published online: 23 DEC 2013
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Volume 34, Issue 10, pages 1566–1577, November 2014
How to Cite
Liver Int. 2014; 34: 1566–1577
- Issue published online: 13 OCT 2014
- Article first published online: 23 DEC 2013
- Accepted manuscript online: 29 NOV 2013 09:20AM EST
- Manuscript Accepted: 21 NOV 2013
- Manuscript Received: 4 JAN 2013
- Agencia Nacional de Promoción Científica y Tecnológica. Grant Number: PICT 05-38068
- Consejo Nacional de Investigaciones Científicas y Técnicas. Grant Number: 1246 2009-2011
- Instituto Nacional del Cáncer. Grant Number: 8
- MAPK ;
- oxidative stress;
- PUMA ;
FoxO3a, a member of the FOXO family of transcription factors, is expressed in adult liver and modulates the expression of genes involved in apoptosis. FoxO3a is post-translationally regulated, negatively by PI3K/Akt and MAPK/Erk and positively by oxidative stress/JNK pathways. In previous works, we have demonstrated that interferon-α2b (IFN-α2b) induces apoptosis of hepatic preneoplastic foci through the production of reactive oxygen species (ROS).
To investigate the post-translational signal events triggered by the oxidative stress induced by IFN-α2b and the modulation of FoxO3a transcriptional activity during these events in rat preneoplastic liver.
Adult male Wistar rats were subjected to a two-phase model of hepatocarcinogenesis. A group of animals received IFN-α2b and another group received IFN-α2b and ascorbic acid (ASC), by intraperitoneal injection. Lipid peroxidation, immunohistochemistry, immunoblotting, co-immunoprecipitation and sqRT-PCR assays were performed to explore the role of ROS, JNK, Akt, Erk, FoxO3a, β-catenin and PUMA in the IFN-α2b-mediated apoptotic mechanism.
In vivo IFN-α2b treatment induced endogenous production of ROS which activated JNK. IFN-α2b blocked the activation of Akt and Erk, avoiding FoxO3a activity repression. Activated JNK was responsible for the nuclear translocation and transcriptional activity of FoxO3a which positively modulated the expression of PUMA, a proapoptotic player. In addition, nuclear FoxO3a competed for the nuclear β-catenin associated to TCF, inhibiting the canonical Wnt signalling pathway.
The data presented here propose a model in which in vivo IFN-α2b treatment induces nuclear translocation and transcriptional activity of FoxO3a, triggering the mitochondrial apoptotic pathway in hepatic preneoplastic foci.