Abstract：
N6-methyladenosine (m6A) is one of the most prevalent and conserved RNA modifications. It controls several biological processes, including the biogenesis and function of circular RNAs (circRNAs), which are a class of covalently closed-single stranded RNAs. Several studies have revealed that proteotoxic stress response induction could be a relevant anticancer therapy in Acute Myeloid Leukemia (AML). Furthermore, a strong molecular interaction between the m6A mRNA modification factors and the suppression of the proteotoxic stress response has emerged. Since the proteasome inhibition leading to the imbalance in protein homeostasis is strictly linked to the stress response induction, we investigated the role of Bortezomib (Btz) on m6A regulation and in particular its impact on the modulation of m6A-modified circRNAs expression. Here, we show that treating AML cells with Btz downregulated the expression of the m6A regulator WTAP at translational level, mainly because of increased oxidative stress. Indeed, Btz treatment promoted oxidative stress, with ROS generation and HMOX-1 activation and administration of the reducing agent N-acetylcysteine restored WTAP expression. Additionally, we identified m6A-modified circRNAs modulated by Btz treatment, including circHIPK3, which is implicated in protein folding and oxidative stress regulation. These results highlight the intricate molecular networks involved in oxidative and ER stress induction in AML cells following proteotoxic stress response, laying the groundwork for future therapeutic strategies targeting these pathways.
摘要：
N6-甲基腺苷(m6A)是最普遍和保守的RNA修饰之一。它控制着几个生物过程，包括环状RNA（circularRNAs）的生物发生和功能，它们是一类共价闭合的单链RNA。多项研究表明，蛋白毒性应激反应诱导可能是急性髓系白血病（AML）的相关抗癌疗法。此外，已经出现了m6AmRNA修饰因子与抑制蛋白毒性应激反应之间的强分子相互作用。由于蛋白酶体抑制导致蛋白质稳态失衡与应激反应诱导密切相关，我们研究了硼替佐米（Btz）对m6A调节的作用，特别是其对m6A修饰的circRNAs表达调节的影响。这里,我们发现用Btz治疗AML细胞在翻译水平下调m6A调节因子WTAP的表达，主要是因为氧化应激增加。的确,Btz处理促进氧化应激，随着ROS的产生和HMOX-1的激活以及还原剂N-乙酰半胱氨酸的施用恢复了WTAP的表达。此外,我们鉴定了由Btz处理调节的m6A修饰的circRNAs，包括circHIPK3，它与蛋白质折叠和氧化应激调节有关。这些结果强调了在蛋白毒性应激反应后AML细胞中参与氧化和ER应激诱导的复杂分子网络。为未来针对这些途径的治疗策略奠定基础。
