Preclinical investigation of combined gene-mediated cytotoxic immunotherapy and immune checkpoint blockade in glioblastoma.
Neuro Oncol
; 20(2): 225-235, 2018 01 22.
Article
em En
| MEDLINE
| ID: mdl-29016938
ABSTRACT
Background:
Combined immunotherapy approaches are promising cancer treatments. We evaluated anti-programmed cell death protein 1 (PD-1) treatment combined with gene-mediated cytotoxic immunotherapy (GMCI) performed by intratumoral injection of a prodrug metabolizing nonreplicating adenovirus (AdV-tk), providing in situ chemotherapy and immune stimulation.Methods:
The effects of GMCI on PD ligand 1 (PD-L1) expression in glioblastoma were investigated in vitro and in vivo. The efficacy of the combination was investigated in 2 syngeneic mouse glioblastoma models (GL261 and CT-2A). Immune infiltrates were analyzed by flow cytometry.Results:
GMCI upregulated PD-L1 expression in vitro and in vivo. Both GMCI and anti-PD-1 increased intratumoral T-cell infiltration. A higher percentage of long-term survivors was observed in mice treated with combined GMCI/anti-PD-1 relative to single treatments. Long-term survivors were protected from tumor rechallenge, demonstrating durable memory antitumor immunity. GMCI led to elevated interferon gamma positive T cells and a lower proportion of exhausted double positive PD1+TIM+CD8+ T cells. GMCI also increased PD-L1 levels on tumor cells and infiltrating macrophages/microglia. Our data suggest that anti-PD-1 treatment improves the effectiveness of GMCI by overcoming interferon-induced PD-L1-mediated inhibitory signals, and GMCI improves anti-PD-1 efficacy by increasing tumor-infiltrating T-cell activation.Conclusions:
Our data show that the GMCI/anti-PD-1 combination is well tolerated and effective in glioblastoma mouse models. These results support evaluation of this combination in glioblastoma patients.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Encefálicas
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Terapia Combinada
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Glioblastoma
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Imunoterapia
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Anticorpos Monoclonais
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Neuro Oncol
Assunto da revista:
NEOPLASIAS
/
NEUROLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos