Recent advances of molecular mechanisms of regulating PD-L1 expression in melanoma

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Melanoma is a highly invasive cancer with poor prognosis, often metastasizing early.
• Programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors represent a breakthrough in cancer therapy, including melanoma treatment.
• PD-L1 expression is a key biomarker for predicting response to immune checkpoint inhibitors and serves as an independent prognostic indicator in melanoma.

Purpose of the Study:

• To systematically review and summarize the complex regulatory mechanisms of PD-L1 expression in melanoma.
• To consolidate current knowledge on factors positively and negatively influencing PD-L1 levels.
• To provide a foundation for developing more effective and less toxic immunotherapies for melanoma.

Main Methods:

• Systematic literature review of recent advancements in PD-L1 expression regulation.
• Categorization of regulatory factors into positive and negative influences.
• Analysis of internal and external factors, signaling pathways, transcription factors, epigenetics, translation, and post-translation modifications.

Main Results:

• PD-L1 expression is positively regulated by intrinsic factors, external induction, signaling pathways, transcription factors, hypomethylation, HDAC6, and translational/post-translational modifications.
• Negative regulation of PD-L1 involves microRNAs and epigenetic modifications, specifically HDAC8.
• Interferon-gamma (IFN-γ) mediates PD-L1 regulation on exosome surfaces, showing a positive correlation.

Conclusions:

• The regulation of PD-L1 in melanoma is multifaceted, involving diverse molecular and cellular mechanisms.
• A comprehensive understanding of these regulatory pathways is essential for optimizing PD-1/PD-L1 blockade therapy.
• This review highlights the complexity of PD-L1 regulation, paving the way for novel therapeutic strategies in melanoma immunotherapy.