DNA-dependent protein kinase regulates cytosolic double-stranded DNA secretion from irradiated macrophages to increase radiosensitivity of tumors.
Radiother Oncol
; 193: 110111, 2024 04.
Article
em En
| MEDLINE
| ID: mdl-38286241
ABSTRACT
BACKGROUND AND PURPOSE:
To investigate the molecular mechanism by which irradiated macrophages secrete cytosolic double-stranded DNA (c-dsDNA) to increase radiosensitivity of tumors. MATERIALS ANDMETHODS:
Irradiated bone marrow-derived macrophages (BMDM) were co-incubated with irradiated EO771 or MC38 cancer cells to determine clonogenic survival. c-dsDNA were measured by agarose gel or enzyme-linked immunosorbent assay. BMDM or cancer cells were analyzed with immunostaining or western blot. Subcutaneously implanted MC38 cells in myeloid-specific Prkdc knockout (KO) mice or littermate control mice were irradiated with 8 Gy to determine radiosensitivity of tumors.RESULTS:
We observed that irradiated BMDM significantly increased radiosensitivity of cancer cells. By performing immunostaining, we found that there was a dose-dependent increase in the formation of c-dsDNA and phosphorylation in DNA-dependent protein kinase (DNA-PK) in irradiated BMDM. Importantly, c-dsDNA in irradiated BMDM could be secreted to the extracellular milieu and this process required DNA-PK, which phosphorylated myosin light chain to regulate the secretion. The secreted c-dsDNA from irradiated BMDM then activated toll-like receptor-9 and subsequent nuclear factor kappa-light-chain-enhancer of activated B cells signaling in the adjacent cancer cells inhibiting radiation-induced DNA double strand break repair. Lastly, we observed that irradiated tumors in vivo had a significantly increased number of tumor-associated macrophages (TAM) with phosphorylated DNA-PK expression in the cytosol. Furthermore, tumors grown in myeloid-specific Prkdc KO mice, in which TAM lacked phosphorylated DNA-PK expression were significantly more radioresistant than those of the wild-type control mice.CONCLUSIONS:
Irradiated macrophages can increase antitumor efficacy of radiotherapy through secretion of c-dsDNA under the regulation of DNA-PK.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteína Quinase Ativada por DNA
/
Neoplasias
Limite:
Animals
Idioma:
En
Revista:
Radiother Oncol
Ano de publicação:
2024
Tipo de documento:
Article