Exposure to hypomethylating agent, 5-azacytidine, may improve iCasp9 suicide gene therapy for treating GvHD in allografts.
Fiche publication
Date publication
août 2016
Journal
Gene therapy
Auteurs
Membres identifiés du Cancéropôle Est :
Pr BORG Christophe, Pr DECONINCK Eric, Dr FERRAND Christophe, Dr LAROSA Fabrice, Dr DESCHAMPS Marina
Tous les auteurs :
Bôle-Richard E, Gamonet C, Certoux JM, Idirene I, Larosa F, Deconinck E, Mosseley AM, Tiberghien P, Borg C, Ferrand C, Deschamps M
Lien Pubmed
Résumé
Anti-tumor cellular immunotherapies that implement a suicide gene system can limit potential undesirable effects. In a haplo-identical bone marrow transplant clinical trial, over 90% of iCaspase-9-expressing cells were eradicated after AP1903 exposure, and signs of graft-versus-host disease disappeared. Nevertheless, low numbers of genetically modified T cells survived this treatment. We studied genetically modified cell lines (GMCL) that carried a dual iCaspase-9/ΔCD19 DNA construct (ΔCD19=truncated CD19). With AP1903 exposure, a low percentage of cells (1.47±0.67%; n=5 replications) persisted in vitro. Repeated exposures to increasing AP1903 doses generated low (GMCLLR) and high AP1903-responders (GMCLHR), which expressed different levels of surface ΔCD19 and intracellular iCaspase-9. Compared with GMCLHR, GMCLLR exhibited higher methylation of 5'-long-terminal repeat (LTR) promoters, both in the number of sequences with at least one methylated CpG (16 vs 51.5%, respectively) and in the number of CpG islands (1.2 vs 8.9%, respectively). Four days of 5-azacytidine exposure reduced methylation and increased ΔCD19 and iCaspase-9 expression. Interestingly, LTR demethylation restored GMCLLR sensitivity to AP1903 by 24.3-fold (1.8 vs 43.8%) without affecting GMCLHR. We showed that 5'-LTR-methylation inhibited transgene expression and caused AP1903 hypo-responsiveness. Treating with a hypomethylating agent restored AP1903 sensitivity. This approach can be applied in further clinical trials to improve iCaspase-9 response if low response is detected.
Mots clés
Antigens, CD19, genetics, Azacitidine, pharmacology, Bone Marrow Transplantation, adverse effects, Caspase 9, genetics, DNA Methylation, drug effects, Genes, Transgenic, Suicide, genetics, Genetic Therapy, methods, Graft vs Host Disease, etiology, Humans, Jurkat Cells, Organic Chemicals, pharmacology, Transplantation, Homologous, methods
Référence
Gene Ther.. 2016 Aug;23(8-9):664-72