Radiosensitization of gliomas by intracellular generation of 5-fluorouracil potentiates prodrug activator gene therapy with a retroviral replicating vector.
Cancer Gene Ther
; 21(10): 405-410, 2014 Oct.
Article
en En
| MEDLINE
| ID: mdl-25301172
ABSTRACT
A tumor-selective non-lytic retroviral replicating vector (RRV), Toca 511, and an extended-release formulation of 5-fluorocytosine (5-FC), Toca FC, are currently being evaluated in clinical trials in patients with recurrent high-grade glioma (NCT01156584, NCT01470794 and NCT01985256). Tumor-selective propagation of this RRV enables highly efficient transduction of glioma cells with cytosine deaminase (CD), which serves as a prodrug activator for conversion of the anti-fungal prodrug 5-FC to the anti-cancer drug 5-fluorouracil (5-FU) directly within the infected cells. We investigated whether, in addition to its direct cytotoxic effects, 5-FU generated intracellularly by RRV-mediated CD/5-FC prodrug activator gene therapy could also act as a radiosensitizing agent. Efficient transduction by RRV and expression of CD were confirmed in the highly aggressive, radioresistant human glioblastoma cell line U87EGFRvIII and its parental cell line U87MG (U87). RRV-transduced cells showed significant radiosensitization even after transient exposure to 5-FC. This was confirmed both in vitro by a clonogenic colony survival assay and in vivo by bioluminescence imaging analysis. These results provide a convincing rationale for development of tumor-targeted radiosensitization strategies utilizing the tumor-selective replicative capability of RRV, and incorporation of radiation therapy into future clinical trials evaluating Toca 511 and Toca FC in brain tumor patients.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Tolerancia a Radiación
/
Retroviridae
/
Profármacos
/
Fluorouracilo
/
Vectores Genéticos
/
Glioma
Límite:
Animals
/
Female
/
Humans
Idioma:
En
Revista:
Cancer Gene Ther
Asunto de la revista:
GENETICA MEDICA
/
NEOPLASIAS
/
TERAPEUTICA
Año:
2014
Tipo del documento:
Article
País de afiliación:
Estados Unidos