Implications of RNA pseudouridylation for cancer biology and therapeutics: a narrative review.

Background: Pseudouridine (Ψ), a C5-glycoside isomer of uridine, stands as one of the most prevalent RNA modifications in all RNA types. Distinguishing from the C-N bond linking uridine to ribose, the link between Ψ and ribose is a C-C bond, endowing Ψ modified RNA distinct properties and functions in various biological processes. The conversion of uridine to Ψ is governed by pseudouridine synthases (PUSs). RNA pseudouridylation is implicated in cancer biology and therapeutics.

Objectives: In this review, we will summarize the methods for detecting Ψ, the process of Ψ generation, the impact of Ψ modification on RNA metabolism and gene expression, the roles of dysregulated Ψ and pseudouridine synthases in cancers, and the underlying mechanism.

Methods: We conducted a comprehensive search of PubMed from its inception through February 2024. The search terms included "pseudouridine"; "pseudouridine synthase"; "PUS"; "dyskerin"; "cancer"; "tumor"; "carcinoma"; "malignancy"; "tumorigenesis"; "biomarker"; "prognosis" and "therapy". We included studies published in peer-reviewed journals that focused on Ψ detection, specific mechanisms involving Ψ and PUSs, and prognosis in cancer patients with high Ψ expression. We excluded studies lacking sufficient methodological details or appropriate controls.

Results: Ψ has been recognized as a significant biomarker in cancer diagnosis and prognosis. Abnormal Ψ modifications mediated by various PUSs result in dysregulated RNA metabolism and impaired RNA function, promoting the development of various cancers. Overexpression of PUSs is common in cancer cells and predicts poor prognosis. PUSs inhibition arrests cell proliferation and enhances apoptosis in cancer cells, suggesting PUS-targeting cancer therapy may be a potential strategy in cancer treatment.

Discussion: High Ψ levels in serum, urine, and saliva may suggest cancer, but do not specify the type, requiring additional lab markers and imaging for accurate diagnosis. Standardized detection methods are also crucial for reliable results. PUSs are linked to cancer, but more researches are needed to understand their mechanisms in different cancers. Anticancer treatments targeting PUSs are still under developed.