m6 A-mediated regulation of PBX1-GCH1 axis promotes gastric cancer proliferation and metastasis by elevating tetrahydrobiopterin levels

  • Cancer Commun (Lond). 2022 Apr;42(4):327-344. doi: 10.1002/cac2.12281.
Yinan Liu  1  2  3 ,  Ertao Zhai  1  2 ,  Junting Chen  1  2 ,  Yan Qian  1  2 ,  Risheng Zhao  1  2 ,  Yan Ma  1  2 ,  Jianqiu Liu  1  2 ,  Zhixin Huang  1  2 ,  Shirong Cai  1  2 ,  Jianhui Chen  1  2
Affiliations
  • 1. Division of Gastrointestinal Surgery Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
  • 2. Gastric Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
  • 3. Laboratory of Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
PMID: 35261206 DOI: 10.1002/cac2.12281
Abstract

Background: Methyltransferase 3 (METTL3)-mediated N6-methyladenosine (m6 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.

Methods: 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 m6 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 (BH4 ).

Results: 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 BH4 levels in GC cells, thereby promoting tumor progression.

Conclusions: This study suggested that METTL3 Enzymes promote tumor growth and lung/lymph node metastasis via METTL3-PBX1-GCH1 axis increasing BH4 levels in GC.

Keywords
BH4; GCH1; METTL3; PBX1; gastric cancer; m6A; metabolism reprogramming; metastasis; proliferation.
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