The demethylase ALKBH5 mediates ZKSCAN3 expression through the m6A modification to activate VEGFA transcription and thus participates in MNNG-induced gastric cancer progression

N-Nitroso compounds (NOCs) are recognized as important factors that promote gastric cancer development, but the specific effects and potential mechanisms by which NOC exposure promotes gastric cancer are still poorly understood. In this study, we explored the effects and potential molecular mechanisms of NOCs on the promotion of gastric cancer using methylnitronitrosoguanidine (MNNG), a classical direct carcinogen of NOC. The results of in vivo and in vitro experiments showed that chronic and low-concentration MNNG exposure significantly promoted the malignant progression of tumors, including cell migration, cell invasion, vasculogenic mimicry (VM) formation, cell spheroid formation, stem cell-like marker expression, and gastric cancer growth and metastasis. Mechanistically, we revealed that demethylase ALKBH5 regulated the level of the N6‑methyladenosine (m6A) modification in the 3'UTR and CDS region of the ZKSCAN3 mRNA to promote ZKSCAN3 expression, mediated the binding of ZKSCAN3 to the VEGFA promoter region to regulate VEGFA transcription, and participated in MNNG-induced gastric cancer cell migration, invasion, VM formation, cell spheroid formation, stem cell-like marker expression and ultimately gastric cancer progression. In addition, our study revealed that ALKBH5-ZKSCAN3-VEGFA signaling was significantly activated during MNNG-induced gastric carcinogenesis, and further studies in gastric cancer patients showed that ALKBH5, ZKSCAN3, and VEGFA expression were upregulated in cancers compared with paired gastric mucosal tissues, that ALKBH5, ZKSCAN3, and VEGFA could serve as important biomarkers for determining patient prognosis, and that the molecular combination showed greater prognostic value. These findings provide a theoretical basis for developing gastric cancer interventions for NOCs and for determining gastric cancer progression. N-Nitroso compounds (NOCs) and their precursors are widely distributed in food, water, and soil and are recognized as important factors for promoting gastric cancer development, but their specific effects and potential mechanisms are still poorly understood. In this study, we found that chronic exposure to low-level MNNG (a classic carcinogenic NOCs) could significantly promote the malignant progression of gastric cancer and that the demethylase ALKBH5 mediated ZKSCAN3 expression through the m6A modification to activate VEGFA transcription and thus participated in MNNG-induced gastric cancer progression. ALKBH5, ZKSCAN3 and VEGFA showed potential value in determining the prognosis of patients with gastric cancer.