Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, Howard College Campus, University of KwaZulu-Natal , Durban, South Africa.
Epigenetics. 2021 Jan;16(1):79-91. doi: 10.1080/15592294.2020.1788324. Epub 2020 Jul 7.
Fusaric acid (FA) is a food-borne mycotoxin that mediates toxicity with limited information on its epigenetic properties. p53 is a tumour suppressor protein that regulates cell cycle arrest and apoptotic cell death. The expression of p53 is regulated transcriptionally by promoter methylation and post-transcriptionally by N-6-methyladenosine (m6A) RNA methylation. We investigated the effect of FA on p53 expression and its epigenetic regulation via promoter methylation and m6A RNA methylation in human hepatocellular carcinoma (HepG2) cells. HepG2 cells were treated with FA [0, 25, 50, 104, and 150 µg/ml; 24 h] and thereafter, DNA, RNA, and protein was isolated. Promoter methylation and expression of p53 was measured using qPCR and Western blot. RNA immuno-precipitation was used to determine m6A- levels. The expression of m6A methyltransferases ( and ), demethylases ( and ), and readers ( and ) were measured using qPCR. FA induced promoter hypermethylation ( < 0.0001) and decreased expression ( < 0.0001). FA decreased m6A- levels ( < 0.0001) by decreasing ( < 0.0001) and ( < 0.0001); and suppressed expression of ( < 0.0001), ( < 0.0001), and ( < 0.0001) that ultimately reduced p53 translation ( < 0.0001). Taken together, the data shows that FA epigenetically decreased p53 expression by altering its promoter methylation and m6A RNA methylation in HepG2 cells. This study reveals a mechanism for p53 regulation by FA and provides insight into future therapeutic interventions.
伏马菌素（FA）是一种食源性病原体毒素，其在表观遗传学特性方面的信息有限。p53 是一种肿瘤抑制蛋白，可调节细胞周期停滞和细胞凋亡。p53 的表达受启动子甲基化和 N-6-甲基腺苷（m6A）RNA 甲基化的转录后调控。我们研究了 FA 对人肝癌（HepG2）细胞中 p53 表达及其表观遗传调控的影响，包括启动子甲基化和 m6A RNA 甲基化。用 FA [0、25、50、104 和 150μg/ml；24 h]处理 HepG2 细胞，然后分离 DNA、RNA 和蛋白质。用 qPCR 和 Western blot 检测启动子甲基化和 p53 的表达。用 RNA 免疫沉淀法测定 m6A-水平。用 qPCR 检测 m6A 甲基转移酶（、和）、去甲基酶（和）和读码器（和）的表达。FA 诱导 启动子超甲基化（<0.0001）并降低 表达（<0.0001）。FA 通过降低 （<0.0001）和 （<0.0001）降低 m6A-水平（<0.0001）；并抑制 （<0.0001）、（<0.0001）和 （<0.0001）的表达，最终降低 p53 翻译（<0.0001）。总之，数据表明 FA 通过改变 HepG2 细胞中 p53 的启动子甲基化和 m6A RNA 甲基化，在表观遗传学上降低了 p53 的表达。该研究揭示了 FA 调节 p53 的机制，并为未来的治疗干预提供了思路。
