Exposure to hypomethylating agent, 5-azacytidine, may improve iCasp9 suicide gene therapy for treating GvHD in allografts.
Gene Ther
; 23(8-9): 664-72, 2016 08.
Article
en En
| MEDLINE
| ID: mdl-27111151
ABSTRACT
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.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Azacitidina
/
Terapia Genética
/
Metilación de ADN
/
Genes Transgénicos Suicidas
/
Caspasa 9
/
Enfermedad Injerto contra Huésped
Tipo de estudio:
Etiology_studies
Límite:
Humans
Idioma:
En
Revista:
Gene Ther
Asunto de la revista:
GENETICA MEDICA
/
TERAPEUTICA
Año:
2016
Tipo del documento:
Article
País de afiliación:
Francia