USP53-ALKBH5 axis inhibition boosts m6A-modified TERT RNA degradation: A potential therapeutic strategy for...

Glioblastoma (GBM) is the most common malignant glioma, with a high recurrence rate and a poor prognosis. Deubiquitinating enzyme ubiquitin-specific peptidase 53 (USP53), known to enhance the stability of downstream proteins, exhibits distinct functions in different tumors. The function of USP53 in GBM progression remains unclear. Analysis of GSE104267 and GSE4290 datasets revealed significant USP53 upregulation in GBM tissues, a finding confirmed by TCGA data comparing GBM (n = 163) with normal brain tissues (n = 207). In univariate and multivariate cox regression analysis, USP53 was identified as an independent risk factor (univariate, hazard ratio (HR) =1.5357, p = 0.0229; multivariate, HR =1.4851, p = 0.0385) for GBM progression. Patients with high expression of USP53 had worse prognosis compared to those with low expression of USP53. Functionally, USP53 knockdown potently inhibited proliferation and induced apoptosis in LN229 and A172 cells in vitro and attenuated tumorigenicity of LN229 cells in vivo. Conversely, forced expression of USP53 had a carcinogenic effect. Mechanistically, USP53 targeted ALKB homolog 5 (ALKBH5) for deubiquitination, thereby stabilizing the protein and prolonging its half-life. Restoring ALKBH5 expression rescued the proliferative deficit in USP53-silenced LN229 cells. Telomerase catalytic subunit telomerase reverse transcriptase (TERT) was identified as a downstream effector of the USP53/ALKBH5 axis, where ALKBH5 upregulated TERT RNA expression by erasing m6A modifications at position 1989 bp on TERT mRNA. Collectively, those observations demonstrate that USP53/ALKBH5 axis drives GBM progression by targeting TERT, indicating that USP53/ALKBH5 axis may serve as a potential therapeutic target for GBM.