CDK13 RNA Over-Editing Mediated by ADAR1 Associates with Poor Prognosis of Hepatocellular Carcinoma Patients.

ABSTRACT

BACKGROUND/AIMS: Aberrant RNA editing, mediated by adenosine deaminases acting on RNA (ADAR), serves as a post-transcriptional event participating in tumorigenesis and prognosis. However, the RNA editing profiles during HCC progression and their clinical correlations remain unclear. METHODS: Multiple tissue samples were collected from an advanced HCC patient. RNA-seq was performed to obtain the RNA editing profiles for each sample. Two RNA editing sites from CDK13 were further validated in 60 HCC patients; and their potential regulatory mechanisms were investigated. RESULTS: In-depth analysis of the RNA-seq data revealed a significant number of editing sites (632-816) in coding regions for each tissue sample, showing branched evolution during tumorigenesis and metastasis. Two editing sites (Q103R and K96R) in CDK13 showed significant over-editing in tumor, and these phenomenon were validated in 60 HCC patients. Furthermore, the clinicopathological analysis revealed that these CDK13 over-editing sites were positively associated with TNM, PVTT and poor prognosis. In addition, the editing level of these sites were significantly correlated with the expression of ADAR1. Loss of function assays further proved that these CDK13 over-editing sites were mediated by ADAR1 in HCC cells. CONCLUSIONS: CDK13 RNA over-editing sites mediated by ADAR1 may serve as novel cancer driver events in HCC progression.