The m6A demethylases FTO and ALKBH5 aggravate the malignant progression of nasopharyngeal carcinoma by coregulating ARHGAP35

Abstract

N6-methyladenosine (m6A) is an RNA modification that can be removed by demethylases [fat mass and obesity-associated protein (FTO) and AlkB homolog 5 (ALKBH5)], which regulate gene expression and cell function. We show that m6A levels and m6A demethylase levels are altered in nasopharyngeal carcinoma (NPC) tissues vs. normal tissues. High FTO and ALKBH5 predict a poor prognosis in NPC patients. Silencing FTO and ALKBH5 inhibited the malignant behavior of patient-derived NPC cells in a short time. However, as time progressed, the inhibitory effect of FTO or ALKBH5 was weakened, and the cosilencing of FTO and ALKBH5 maintained a better inhibitory effect. Combined transcriptome and m6A-seq analysis revealed a downstream target gene that was jointly regulated by FTO and ALKBH5 in NPC, and ARHGAP35 was chosen to do further study. The synergistic silencing of FTO and ALKBH5 increased the methylation level on the mRNA CDS of a new transcription factor (ARHGAP35) and positively regulate the protein coding capacity and mRNA stability of ARHGAP35, thus leading to increased expression of ARHGAP35 and inhibition of the malignant phenotype of tumor cells. Our study revealed that the growth and metastasis of NPC can be stably inhibited through synergistic silencing of the demethylases FTO and ALKBH5, which play a positive role in the treatment of NPC by regulating the downstream transcript ARHGAP35 and increasing its m6A level.