Programmed death-ligand 1 nuclear translocation: A novel perspective from membrane localization to nuclear function

Area of Science:

• Immunology
• Molecular Biology
• Oncology

Background:

• Membrane-bound programmed death-ligand 1 (PD-L1) is a known immune checkpoint molecule mediating tumor immune evasion.
• Emerging research indicates PD-L1 translocates to the nucleus (nuclear PD-L1, nPD-L1), influencing tumor progression through non-immune mechanisms.

Purpose of the Study:

• To systematically review the molecular mechanisms of PD-L1 nuclear translocation.
• To summarize the biological functions and roles of nPD-L1 in the tumor microenvironment.
• To explore the potential of nPD-L1 as a biomarker and therapeutic target.

Main Methods:

• Review of recent studies on PD-L1 nuclear translocation.
• Analysis of molecular pathways involved in nPD-L1 regulation (acetylation, endocytosis, nuclear transport, deacetylation, ubiquitination).
• Examination of nPD-L1's role in gene regulation, angiogenesis, DNA repair, and other cellular processes.

Main Results:

• PD-L1 nuclear translocation is regulated by p300, Huntingtin-interacting protein 1-related protein, Vimentin-importin α/β, and histone deacetylase 2.
• nPD-L1 influences target genes like early growth response 1, affecting angiogenesis and immune evasion.
• nPD-L1 has diverse non-immune functions, including DNA repair and pyroptosis, with both pro-tumorigenic and tumor-suppressive roles.

Conclusions:

• Nuclear translocation of PD-L1 represents a novel mechanism in cancer progression and immune evasion.
• Understanding nPD-L1's complex roles and regulatory pathways is vital for translational research and targeted therapy development.
• MIB2-mediated ubiquitination and inhibitors like BMS1166 offer potential therapeutic strategies targeting PD-L1 localization.