The probiotic Propionibacterium freudenreichii as a new adjuvant for TRAIL-based therapy in colorectal cancer

// Fabien J. Cousin Δ, 1, 2, 3, 9 , Sandrine Jouan-Lanhouet Δ, 4, 5, 10 , Nathalie Théret 4, 5, 6 , Catherine Brenner 7, 8 , Elodie Jouan 4, 5 , Gwénaëlle Le Moigne-Muller 4, 5 , Marie-Thérèse Dimanche-Boitrel ♦, 4, 5 , Gwénaël Jan ♦, 1, 2 1 INRA, UMR1253 STLO, Science et Technologie du Lait et de l’Œuf, Rennes F-35042, France 2 AGROCAMPUS OUEST, UMR1253 STLO, Rennes F-35042, France 3 CNIEL/Syndifrais, Paris 09 F-75314, France 4 INSERM, UMR1085, Institut de Recherche sur la Santé, l’Environnement et le Travail, Rennes F-35043, France 5 Biosit UMS3080, Université de Rennes 1, Rennes F-35043, France 6 INRIA, UMR6074 IRISA, Rennes F-35042, France 7 INSERM, UMRS1180, LabEx LERMIT, Châtenay-Malabry F-92290, France 8 Université de Paris Sud, Faculté de Pharmacie, Châtenay-Malabry F-92290, France 9 Current address: Research Unit Aliments Bioprocédés Toxicologie Environnements (UR ABTE) EA 4651, Université de Caen Normandie, Caen F-14032, France 10 Current address: Department for Biomedical Molecular Biology, University of Ghent, VIB Inflammation Research Center, Ghent B-9052, Belgium ♦ These authors share senior authorship Δ These authors have contributed equally to this work Correspondence to: Marie-Thérèse Dimanche-Boitrel, e-mail: marie-therese.boitrel@univ-rennes1.fr Keywords: TRAIL, RNA microarrays, colon cancer, SCFA, Propionibacterium freudenreichii Received: October 02, 2015      Accepted: January 03, 2016      Published: January 11, 2016 ABSTRACT TNF-Related Apoptosis-Inducing Ligand (TRAIL) is a well-known apoptosis inducer, which activates the extrinsic death pathway. TRAIL is pro-apoptotic on colon cancer cells, while not cytotoxic towards normal healthy cells. However, its clinical use is limited by cell resistance to cell death which occurs in approximately 50% of cancer cells. Short Chain Fatty Acids (SCFA) are also known to specifically induce apoptosis of cancer cells. In accordance, we have shown that food grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via the production and release of SCFA (propionate and acetate) acting on mitochondria. Here, we investigated possible synergistic effect between Propionibacterium freudenreichii and TRAIL. Indeed, we hypothesized that acting on both extrinsic and intrinsic death pathways may exert a synergistic pro-apoptotic effect. Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial metabolites (propionate and acetate), in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIP, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8, -9 and -3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii DMEM culture supernatants or its SCFA metabolites. These results open new perspectives for food grade P. freudenreichii -containing products in order to potentiate TRAIL-based cancer therapy in colorectal cancer.