N6-甲基腺苷修饰的 SRPK1 通过剪接 PKM 促进肺腺癌的有氧糖酵解。
N-methyladenosine-modified SRPK1 promotes aerobic glycolysis of lung adenocarcinoma via PKM splicing.
机构信息
Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
Institute of Respiratory Diseases, Soochow University, Suzhou, 215006, China.
出版信息
Cell Mol Biol Lett. 2024 Aug 2;29(1):106. doi: 10.1186/s11658-024-00622-5.
BACKGROUND
The RNA N-methyladenosine (mA) modification has become an essential hotspot in epigenetic modulation. Serine-arginine protein kinase 1 (SRPK1) is associated with the pathogenesis of various cancers. However, the mA modification of SRPK1 and its association with the mechanism of in lung adenocarcinoma (LUAD) remains unclear.
METHODS
Western blotting and polymerase chain reaction (PCR) analyses were carried out to identify gene and protein expression. mA epitranscriptomic microarray was utilized to the assess mA profile. Loss and gain-of-function assays were carried out elucidate the impact of METTL3 and SRPK1 on LUAD glycolysis and tumorigenesis. RNA immunoprecipitation (RIP), mA RNA immunoprecipitation (MeRIP), and RNA stability tests were employed to elucidate the SRPK1's METTL3-mediated mA modification mechanism in LUAD. Metabolic quantification and co-immunoprecipitation assays were applied to investigate the molecular mechanism by which SRPK1 mediates LUAD metabolism.
RESULTS
The epitranscriptomic microarray assay revealed that SRPK1 could be hypermethylated and upregulated in LUAD. The main transmethylase METTL3 was upregulated and induced the aberrant high mA levels of SRPK1. Mechanistically, SRPK1's mA sites were directly methylated by METTL3, which also stabilized SRPK1 in an IGF2BP2-dependent manner. Methylated SRPK1 subsequently promoted LUAD progression through enhancing glycolysis. Further metabolic quantification, co-immunoprecipitation and western blot assays revealed that SRPK1 interacts with hnRNPA1, an important modulator of PKM splicing, and thus facilitates glycolysis by upregulating PKM2 in LUAD. Nevertheless, METTL3 inhibitor STM2457 can reverse the above effects in vitro and in vivo by suppressing SRPK1 and glycolysis in LUAD.
CONCLUSION
It was revealed that in LUAD, aberrantly expressed METTL3 upregulated SRPK1 levels via an mA-IGF2BP2-dependent mechanism. METTL3-induced SRPK1 fostered LUAD cell proliferation by enhancing glycolysis, and the small-molecule inhibitor STM2457 of METTL3 could be an alternative novel therapeutic strategy for individuals with LUAD.
背景
RNA N6-甲基腺苷（m6A）修饰已成为表观遗传调控的一个重要热点。丝氨酸/精氨酸蛋白激酶 1（SRPK1）与多种癌症的发病机制有关。然而，SRPK1 的 m6A 修饰及其与肺腺癌（LUAD）机制的关系尚不清楚。
方法
采用 Western blot 和聚合酶链反应（PCR）分析鉴定基因和蛋白表达。利用 m6A 转录组学微阵列评估 m6A 谱。进行缺失和功能获得实验，以阐明 METTL3 和 SRPK1 对 LUAD 糖酵解和肿瘤发生的影响。采用 RNA 免疫沉淀（RIP）、m6A RNA 免疫沉淀（MeRIP）和 RNA 稳定性试验，阐明 SRPK1 在 LUAD 中 METTL3 介导的 m6A 修饰机制。采用代谢物定量和免疫共沉淀实验，研究 SRPK1 介导 LUAD 代谢的分子机制。
结果
转录组学微阵列分析显示，SRPK1 在 LUAD 中可能发生过度甲基化和上调。主要转甲基酶 METTL3 上调并诱导 SRPK1 的异常高 m6A 水平。在机制上，METTL3 直接甲基化 SRPK1 的 m6A 位点，同时以 IGF2BP2 依赖的方式稳定 SRPK1。甲基化的 SRPK1 随后通过增强糖酵解促进 LUAD 进展。进一步的代谢物定量、免疫共沉淀和 Western blot 实验表明，SRPK1 与 hnRNPA1 相互作用，hnRNPA1 是 PKM 剪接的重要调节剂，因此在 LUAD 中通过上调 PKM2 促进糖酵解。然而，METTL3 抑制剂 STM2457 可通过抑制 LUAD 中的 SRPK1 和糖酵解来逆转上述作用。
结论
在 LUAD 中，异常表达的 METTL3 通过 m6A-IGF2BP2 依赖的机制上调 SRPK1 水平。METTL3 诱导的 SRPK1 通过增强糖酵解促进 LUAD 细胞增殖，METTL3 的小分子抑制剂 STM2457 可能是 LUAD 患者的一种替代新型治疗策略。
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