Deubiquitination and stabilization of programmed cell death ligand 1 by ubiquitin-specific peptidase 9, X-linked in oral squamous cell carcinoma.
Cancer Med
; 7(8): 4004-4011, 2018 08.
Article
in En
| MEDLINE
| ID: mdl-29992764
ABSTRACT
BACKGROUND:
The immune checkpoint protein programmed cell death ligand 1 (PD-L1) binds to PD1 to promote tumor cell escape from the killing effect of the immune system. However, there are few studies on the regulatory mechanisms of PD-L1 in tumors. Although PD-L1 has been reported to undergo ubiquitination in some cancers, its regulatory mechanisms in oral squamous cell carcinoma (OSCC) are unclear. Therefore, we aimed to investigate this phenomenon.METHODS:
We examined the expression and function of USP9X and PD-L1 in human oral keratinocytes (HOK) and OSCC cell lines (HN4 and HN30) as the control and relevant cancer cells using western blotting, immunoprecipitation, immunohistochemistry (IHC), T-cell-mediated tumor cell killing assay, and liquid chromatography-mass spectrometry.RESULTS:
Programmed cell death ligand 1 was highly expressed in OSCC by the regulation of the ubiquitin-proteasome pathway. Furthermore, we discovered that ubiquitin-specific peptidase 9, X-linked (USP9X) could be combined with PD-L1 to induce its deubiquitination and stabilize its protein expression in OSCC.CONCLUSION:
Our data indicate that USP9X deubiquitinates and stabilizes PD-L1. Suppressing the expression of USP9X blocks tumor cell growth. The results provide a theoretical basis for USP9X as a therapeutic target.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Mouth Neoplasms
/
Carcinoma, Squamous Cell
/
Ubiquitin Thiolesterase
/
B7-H1 Antigen
Limits:
Humans
Language:
En
Journal:
Cancer Med
Year:
2018
Document type:
Article
Affiliation country:
China