Molecular Events Involved in Ochratoxin A Induced Mitochondrial Pathway of Apoptosis, Modulation by Bcl-2 Family Members Chayma Bouaziz, 1 Ossama Sharaf el dein, 2 Ce ´ cile Martel, 2 Emna El Golli, 1 Salwa Abid-Esseﬁ, 1 Catherine Brenner, 2 Christophe Lemaire, 2 Hassen Bacha 1 1 Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Rue Avicenne, Monastir 5000, Tunisia 2 Laboratoire de Ge ´ ne ´ tique et Biologie Cellulaire, CNRS UMR 8159, Universite ´ de Versaille/ SQY, 45 Avenue des Etats-Unis, Versailles 78035, France Received 22 July 2009; revised 3 February 2010; accepted 4 February 2010 ABSTRACT: In this study, we looked for the role of the mitochondrion in the cytotoxicity of ochratoxin A (OTA), which is one of the most abundant food-contaminating mycotoxins in the world. In different human carcinoma cell lines, OTA triggered a mitochondria-dependent apoptotic process, which is characterized by opening of the mitochondrial permeability transition pore (PTPC), loss of mitochondrial transmembrane potential (DC m ), increase in O 2 [chemp] – production, mitochondrial relocalization of Bax, release of cyto- chrome c, and caspase activation. However, studies performed on puriﬁed organelles suggested that OTA does not directly target the mitochondrion. In addition, we showed that mitochondrial alterations induced by this mycotoxin are favored by the proapoptotic protein Bax, but not Bak. These alterations are pre- vented by the antiapoptotic proteins, Bcl-2 and to a lesser degree by Bcl-X L . Taken together, these data indicate that although mitochondria, PTPC members and proteins of Bcl-2 family play a pivotal role in OTA-induced apoptosis, they do not constitute real targets to overcome its toxicity. # 2010 Wiley Periodicals, Inc. Environ Toxicol 26: 579–590, 2011. Keywords: ochratoxin A; mitochondria; apoptosis; PTPC; Bcl-2; ROS INTRODUCTION The ingestion of poisonous secondary metabolites of fungi, known as mycotoxins, may cause livestock and human dis- ease and death. Among these mycotoxins, ochratoxin A (OTA), produced primarily by Aspergillus ochraceus and Penicillium verrucosum (CAST, 2003), is one of the most abundant food-contaminating mycotoxins in the world. A signiﬁcant feature of OTA is its presence in a wide variety of commodities in varying amounts often at very high lev- els (CAST, 2003; Zaied et al., 2009). OTA may accumulate in tissues and ﬂuids of either humans or animals consuming contaminated food because of its slow elimination from the body. Moreover, the occurrence of OTA in house dust and other airborne particulates may be of signiﬁcance in human disease (Richard et al., 1999; Skaug et al., 2001). Although OTA is known for its numerous adverse effects in a variety of animal species such as teratogenicity (Wangikar et al., 2005), immunotoxicity (Creppy et al., 1983; Alvarez et al., 2004), genotoxicity (Dopp et al., 1999; Lioi et al., 2004; Creppy et al., 2005), and mutagenicity Correspondence to: Hassen Bacha; e-mail: hassen.bacha@fmdm.rnu.tn Contract grant sponsor: Action d’Echanges Tuniso-Franc ¸aise Contract grant number: DGRST/CNRS 04/R 0803 Contract grant sponsors: Ministe `re Tunisien de l’enseignement Supe ´r- ieur, de la Recherche Scientiﬁque et de la Technologie through the Labora- toire de Recherche sur les Substances Biologiquement Compatibles: LRSBC, La Direction Ge ´ne ´rale de la Recherche Scientiﬁque et de la Re ´no- vation Technologique: DGRST et le Centre National de la Recherche Sci- entique: CNRS. Published online 12 April 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/tox.20581  C 2010 Wiley Periodicals, Inc. 579