Department of General Surgery, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China.
Department of Gastroenterology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China.
Cancer Sci. 2023 Nov;114(11):4299-4313. doi: 10.1111/cas.15953. Epub 2023 Sep 12.
N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic RNA and involved in the carcinogenesis of various malignancies. However, the functions and mechanisms of m6A in gallbladder cancer (GBC) remain unclear. In this study, we investigated the role and underlying mechanism of the RNA-binding protein YT521-B homology domain-containing family protein 2 (YTHDF2), an m6A reader, in GBC. Herein, we detected that YTHDF2 was remarkably upregulated in GBC tissues compared to normal gallbladder tissues. Functionally, YTHDF2 overexpression promoted the proliferation, tumor growth, migration, and invasion of GBC cells while inhibiting the apoptosis in vitro and in vivo. Conversely, YTHDF2 knockdown induced opposite results. Mechanistically, we further investigated the underlying mechanism by integrating RNA immunoprecipitation sequencing (RIP-seq), m6A-modified RIP-seq, and RNA sequencing, which revealed that death-associated protein kinase 3 (DAPK3) is a direct target of YTHDF2. YTHDF2 binds to the 3'-UTR of DAPK3 mRNA and facilitates its degradation in an m6A-dependent manner. DAPK3 inhibition restores the tumor-suppressive phenotype induced by YTHDF2 deficiency. Moreover, the YTHDF2/DAPK3 axis induces the resistance of GBC cells to gemcitabine. In conclusion, we reveal the oncogenic role of YTHDF2 in GBC, demonstrating that YTHDF2 increases the mRNA degradation of the tumor suppressor DAPK3 in an m6A-dependent way, which promotes GBC progression and desensitizes GBC cells to gemcitabine. Our findings provide novel insights into potential therapeutic strategies for GBC.
N6-甲基腺苷（m6A）是真核 RNA 中最丰富的内部修饰物，参与多种恶性肿瘤的发生。然而，m6A 在胆囊癌（GBC）中的功能和机制仍不清楚。在这项研究中，我们研究了 RNA 结合蛋白 YT521-B 同源结构域家族蛋白 2（YTHDF2）在 GBC 中的作用和潜在机制，YTHDF2 是一种 m6A 阅读器。在此，我们检测到 YTHDF2 在 GBC 组织中明显上调，与正常胆囊组织相比。功能上，YTHDF2 的过表达促进了 GBC 细胞的增殖、肿瘤生长、迁移和侵袭，同时抑制了体外和体内的细胞凋亡。相反，YTHDF2 的敲低诱导了相反的结果。从机制上讲，我们通过整合 RNA 免疫沉淀测序（RIP-seq）、m6A 修饰的 RIP-seq 和 RNA 测序进一步研究了潜在的机制，结果表明凋亡相关蛋白激酶 3（DAPK3）是 YTHDF2 的直接靶标。YTHDF2 与 DAPK3 mRNA 的 3'-UTR 结合，并以 m6A 依赖的方式促进其降解。DAPK3 抑制恢复了 YTHDF2 缺陷诱导的肿瘤抑制表型。此外，YTHDF2/DAPK3 轴诱导 GBC 细胞对吉西他滨的耐药性。总之，我们揭示了 YTHDF2 在 GBC 中的致癌作用，表明 YTHDF2 以 m6A 依赖的方式增加肿瘤抑制因子 DAPK3 的 mRNA 降解，从而促进 GBC 进展并使 GBC 细胞对吉西他滨脱敏。我们的研究结果为 GBC 的潜在治疗策略提供了新的见解。
