Deregulation and delocalization of the m6A demethylase FTO and aberrant m6A levels in ccRCC tissue samples.

Abstract

N6-methyladenosine (m⁶A) is one of the most abundant mRNA modifications established by the activity of three classes of enzymes: writers, readers, and erasers. The relevance of m⁶A in the regulation of gene expression implies its key role in normal biological processes and cancer development. Given the little knowledge about the involvement of m⁶A in clear cell Renal Carcinoma (ccRCC), our analysis should be regarded as a pilot study aimed at investigating the expression of m⁶A enzymes in tissues and urine specimens of ccRCC patients. The expression of m⁶A enzymes was validated by quantitative reverse-transcription PCR and immunohistochemistry, comparing normal and tumoral tissues. Quantification of m⁶A levels in urine specimens of healthy and cancer patients was performed by colorimetric Urine m⁶A assay. We observed the upregulation and nuclear localization of the m⁶A demethylase FTO in tumoral tissues compared with their respective normal counterparts. The nuclear expression of FTO decreases with an increase in tumor grade. Moreover, we identified a decrease in m⁶A levels in cancer samples. These findings might represent novel evidence to further investigate the issue, to reveal new diagnostic markers for tumorigenesis, leading to a potential m⁶A-targeted therapy in ccRCC.