AURKB Enhances Chromosomal Remodeling of Telomeric Genes and Accelerates Tumorigenesis of Uveal Melanoma.

Abstract

Uveal melanoma (UM) is the most common intraocular malignancy in adults developing liver metastases, threatening a patient's life. Current therapeutics failed to significantly improve the survival of patients with UM. Thus, the discovery of potent drugs is imminent. Integrated bioinformatic analysis of The Cancer Genome Atlas and immunohistochemistry staining of patients' tissues revealed the oncogenic role of aurora kinase B (AURKB) in UM. Drug sensitivity assays and an orthotopic intraocular animal model were used to test the efficacy of AURKB inhibitors. RNA sequencing and immunoblotting were performed to identify the downstream effector. A chromatin immunoprecipitation assay was conducted to elucidate AURKB's transcriptional regulation on the target gene. AURKB was found overexpressed in patients with UM, resulting in a poor prognosis. Luckily, the AURKB-specific inhibitor, hesperadin, achieved prominent pharmacological efficiency in UM in vitro and in vivo. Mechanically, hesperadin compromised phosphorylation of histone H3 at serine 10 (H3S10ph) at the promoter of telomerase reverse transcriptase, accompanied by methylation of histone H3 at lysine 9. This methylated status of the promoter region forced chromatin condensation and consequently halted the transcription of telomerase reverse transcriptase. Collectively, our data demonstrated that AURKB inhibitors decelerated UM tumorigenesis by epigenetically silencing the expression of oncogenic telomerase reverse transcriptase, indicating AURKB as a potential therapeutic target in UM.