Carnosine regulation of intracellular pH homeostasis promotes lysosome-dependent tumor immunoevasion.
Nat Immunol
; 25(3): 483-495, 2024 Mar.
Article
em En
| MEDLINE
| ID: mdl-38177283
ABSTRACT
Tumor cells and surrounding immune cells undergo metabolic reprogramming, leading to an acidic tumor microenvironment. However, it is unclear how tumor cells adapt to this acidic stress during tumor progression. Here we show that carnosine, a mobile buffering metabolite that accumulates under hypoxia in tumor cells, regulates intracellular pH homeostasis and drives lysosome-dependent tumor immune evasion. A previously unrecognized isoform of carnosine synthase, CARNS2, promotes carnosine synthesis under hypoxia. Carnosine maintains intracellular pH (pHi) homeostasis by functioning as a mobile proton carrier to accelerate cytosolic H+ mobility and release, which in turn controls lysosomal subcellular distribution, acidification and activity. Furthermore, by maintaining lysosomal activity, carnosine facilitates nuclear transcription factor X-box binding 1 (NFX1) degradation, triggering galectin-9 and T-cell-mediated immune escape and tumorigenesis. These findings indicate an unconventional mechanism for pHi regulation in cancer cells and demonstrate how lysosome contributes to immune evasion, thus providing a basis for development of combined therapeutic strategies against hepatocellular carcinoma that exploit disrupted pHi homeostasis with immune checkpoint blockade.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Carnosina
/
Carcinoma Hepatocelular
/
Neoplasias Hepáticas
Limite:
Humans
Idioma:
En
Revista:
Nat Immunol
Assunto da revista:
ALERGIA E IMUNOLOGIA
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China