Targeting of RNA-binding protein FXR1 in HNSCC

摘要 头颈部鳞状细胞癌(HNSCC)是全球第六大常见癌症，占 超过90%的头颈部癌症，5年生存率约为50%。尽管有特定的 有效和新的治疗方法，大多数患者对目前的治疗方式仍然没有反应，并发展成 抗药性。因此，识别针对癌症途径的新分子，无论是单独的还是联合的，都是 对开发新的癌症疗法至关重要。在HNSCC中，调节失调的RNA结合蛋白(RBPs)控制 共转录和转录后事件。针对限制性商业惯例的方法并不能很好地调控基因。 在癌症中的表达。因此，控制基因表达和肿瘤生长的新治疗策略是 这是必要的。我们已发表的研究结果表明，FXR1直接与RNAG-四链(G4)区域结合 CDKN1a和一个非编码的RNA TERC(端粒酶RNA组分)，并促进生长和 HNSCC细胞增殖情况。在这里，我们的初步发现表明，甲基化的精氨酸氨基酸在 FXR1的NES(核输出信号)和RGG(富含精氨酸-甘氨酸)结构域负责G4-RNA 结合和癌细胞的生长。然而，NES/RGG结构域中特定精氨酸残基的突变 取消FXR1与CDKN1A和TERC的结合，抑制口腔癌细胞的生长和增殖。 因此，靶向FXR1RGG结构域的特异性抑制剂被认为是一个有吸引力的口服药物靶点 癌症治疗。我们计划使用基于核酸的适体，直接与精氨酸氨基酸结合。 存在于FXR1的NES/RGG结构域中，并破坏其RNA结合活性。因此，这款R21的总体目标是 建议利用结构和生化分析来筛选和鉴定FXR1的特异性适配子 Nes/RGG结构域调控其基因表达活性和口腔癌细胞生长。两个具体目标 建议对该模型进行检验。在特定的AIM 1中，我们将确定精氨酸甲基化如何影响FXR1 RNA- 用体外RNA结合试验和体内肿瘤模型研究结合功能和口腔肿瘤进展。在……里面 针对AIM2，我们将开发一种适体，直接结合并干扰甲基化的FXR1-RNA复合体 并在我们的HNSCC临床前动物模型中显示出抗肿瘤活性。我们目前的工作是一项创新的， 针对HNSCC中调控失调的RBP介导的基因表达的简单、可靠的方法。我们 将利用这些机制发现开发治疗侵袭性HNSCC肿瘤的新策略。

Abstract Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and accounts for more than 90% of head and neck cancers, with a 5-year survival rate of approximately 50%. Despite specific effective and novel therapies, most patients remain unresponsive to current treatment modalities and develop drug resistance. Therefore, identifying new molecules that target cancer pathways, alone or in combination, is critical for developing novel cancer therapies. In HNSCC, dysregulated RNA-binding proteins (RBPs) controls co- and post-transcriptional events. Approaches targeting RBPs are not well established to regulate the gene expression in cancers. Thus, new therapeutic strategies to control gene expression and tumor growth are necessary. Our published findings demonstrate that FXR1 directly binds the RNA G-quadruplex (G4) regions of mRNA CDKN1A and a non-coding RNA TERC (Telomerase RNA component) and promotes the growth and proliferation of HNSCC cells. Herein, our preliminary findings indicate that methylated arginine amino acids at the NES (nuclear export signal) and RGG (arginine-glycine rich) domain of FXR1 are responsible for G4-RNA binding and the growth of cancer cells. However, mutation of specific arginine residues in the NES/RGG domain abolished FXR1 binding with CDKN1A and TERC and reduced the growth and proliferation of oral cancer cells. Thus, targeting FXR1's RGG domain with specific inhibitors is considered an appealing drug target for oral cancer treatment. We plan to use nucleic acid-based aptamers that directly bind to the arginine amino acids present in NES/RGG domain of FXR1 and disrupt its RNA binding activities. Hence, the overall goal of this R21 proposal is to utilize structural and biochemical assays to screen and identify aptamers specific to the FXR1 NES/RGG domain to control its gene expression activities and the growth of oral cancer cells. Two specific aims are proposed to test this model. In specific aim1, we will determine how arginine methylation impacts FXR1 RNA- binding functions and oral tumor progression using in vitro RNA binding assays and in vivo tumor models. In specific aim2, we will develop an aptamer that directly binds and interfere with methylated FXR1-RNA complex and show anti-tumor activity in our preclinical animal models of HNSCC. Our present work is an innovative, straightforward, and robust approach to target the dysregulated RBP-mediated gene expression in HNSCC. We will use these mechanistic findings to develop novel strategies to treat aggressive HNSCC tumors.