RNA editing derived epitopes function as cancer antigens to elicit immune responses

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Genomic mutations and RNA editing introduce sequence variations in proteins.
• Aberrant RNA editing is implicated in human diseases, particularly cancers.
• Human Leukocyte Antigen (HLA) molecules present peptides to T cells.

Purpose of the Study:

• To investigate if RNA-edited peptides are presented by HLA molecules.
• To determine if T cells recognize these edited peptides in cancer.
• To explore the role of RNA editing in cancer immunity.

Main Methods:

• Analysis of peptides presented by HLA molecules in cancer patients.
• Identification of T cell responses against RNA-edited peptides.
• Correlation of RNA editing levels with peptide abundance.

Main Results:

• RNA-edited peptides are naturally presented by HLA molecules.
• Effector CD8+ T cells specific for edited cyclin I peptides are found in human tumors.
• These T cells attack tumor cells presenting edited epitopes.
• Increased peptide levels and correlation with edited RNA levels observed in cancer patients.

Conclusions:

• RNA editing expands the repertoire of HLA-presented self-antigens.
• These edited antigens can be recognized by the immune system, specifically CD8+ T cells.
• This provides a mechanism for immune surveillance against cancers with deregulated RNA editing.