Division of Gastrointestinal Surgery Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
Gastric Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
Cancer Commun (Lond). 2022 Apr;42(4):327-344. doi: 10.1002/cac2.12281. Epub 2022 Mar 9.
Methyltransferase 3 (METTL3)-mediated N6-methyladenosine (m A) RNA modification has been demonstrated to be a potential factor in promoting gastric cancer (GC). METTL3 regulates a series of signaling pathways by modifying various mRNAs. This study aimed to identify novel METTL3-mediated signaling pathways and explored possible targets for use in the clinical setting of gastric cancer.
To investigate the proliferation and metastatic capacity of GC cell lines with METTL3 knockdown, a xenograft, lung metastasis, and popliteal lymph node metastasis model was used. The m A-modified RNA immunoprecipitation (Me-RIP) sequence was utilized to explore the target mRNAs of METTL3. Cell counting kit 8 and transwell assays were performed to investigate the promoting function of pre-B cell leukemia homeobox 1 (PBX1) and GTP cyclohydrolase 1 (GCH1). Western blotting and chromatin immunoprecipitation were employed to confirm the involvement of the METTL3-PBX1-GCH1 axis. ELISA and liquid chromatography-mass spectrometry were used to explore the biological function of tetrahydrobiopterin (BH ).
Knockdown of METTL3 suppressed xenograft tumor growth and lung/lymph node metastasis in vivo. Mechanistically, we found that METTL3 combined with and stabilized PBX1 mRNAs. Chromatin immunoprecipitation (ChIP) and further experiments suggested that PBX1 acted as a transcription factor inducing GCH1 expression. Moreover, the METTL3-PBX1-GCH1 axis increased BH levels in GC cells, thereby promoting tumor progression.
This study suggested that METTL3 enzymes promote tumor growth and lung/lymph node metastasis via METTL3-PBX1-GCH1 axis increasing BH4 levels in GC.
甲基转移酶 3（METTL3）介导的 N6-甲基腺苷（m A）RNA 修饰已被证明是促进胃癌（GC）的潜在因素。METTL3 通过修饰各种 mRNA 来调节一系列信号通路。本研究旨在鉴定新的 METTL3 介导的信号通路，并探索可能用于胃癌临床治疗的潜在靶点。
为了研究 METTL3 敲低对 GC 细胞系增殖和转移能力的影响，我们构建了异种移植瘤、肺转移和腘窝淋巴结转移模型。采用 m A 修饰 RNA 免疫沉淀（Me-RIP）序列来探索 METTL3 的靶 mRNA。采用细胞计数试剂盒 8 和 Transwell 实验来研究前 B 细胞白血病 homeobox 1（PBX1）和 GTP 环化水解酶 1（GCH1）对细胞增殖和迁移的促进作用。采用 Western blot 和染色质免疫沉淀实验来验证 METTL3-PBX1-GCH1 轴的作用。采用酶联免疫吸附试验（ELISA）和液相色谱-质谱联用技术（LC-MS）来探索四氢生物蝶呤（BH4）的生物学功能。
METTL3 敲低抑制了体内异种移植瘤的生长和肺/淋巴结转移。机制上，我们发现 METTL3 与 PBX1 mRNA 结合并使其稳定。染色质免疫沉淀（ChIP）实验和进一步的实验表明，PBX1 作为一种转录因子诱导 GCH1 表达。此外，METTL3-PBX1-GCH1 轴增加了 GC 细胞中的 BH4 水平，从而促进了肿瘤的进展。
本研究表明，METTL3 酶通过 METTL3-PBX1-GCH1 轴增加 GC 中 BH4 水平来促进肿瘤生长和肺/淋巴结转移。
