Amylin inhibits gastric cancer progression by targeting CCN1 and affecting the PI3K/AKT signalling pathway

<b>Background: </b>After glucagon and insulin, amylin is the third most significant and active islet hormone. Amylin and insulin act synergistically to suppress postprandial blood glucose levels. Research has shown that insulin plays a vital role in the growth and progression of cancer; however, the relationship between amylin and gastric cancer (GC) is unclear. This study used a combination of <i>in vitro</i> and <i>in vivo</i> experiments to investigate the role of amylin in the progression of GC. The expression of amylin in GC and its clinical correlation were evaluated using 38 pairs of GC and healthy human clinical samples. <i>In vitro</i> studies, human GC cell lines were treated with amylin to evaluate the effects of amylin on the proliferation, apoptosis and migration of GC cells. In <i>in vivo</i> studies, xenograft mouse models were established by subcutaneous injection of GC cells into nude mice, followed by treatment with amylin to assess tumor growth. Finally, Next-Generation Sequencing Technology (RNA-seq) was used to explore the potential mechanism of amylin on GC. We found that amylin expression was reduced in GC compared to adjacent normal gastric tissues and that elevated amylin expression was negatively correlated with adverse pathological factors (<i>p</i> &lt; 0.05). Additionally, we demonstrated that amylin impeded the growth, invasion, migration, and colony formation of GC cells and suppressed the epithelial-to-mesenchymal transformation of these cells (<i>p</i> &lt; 0.05). Tumour xenograft model experiments confirmed the tumour-suppressive effect of amylin in subcutaneous tumours in nude mice (<i>p</i> &lt; 0.05). Transcriptome sequencing (RNA-seq) revealed that amylin significantly down-regulated CCN1 gene expression in GC cells (<i>p</i> &lt; 0.001). Further intervention targeting CCN1 verified its significance as a target of amylin’s anti-carcinogenic function in GC. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that amylin exerted its oncogenic effects by inhibiting the PI3K/Akt signalling pathway (<i>p</i> &lt; 0.05). Our findings demonstrate that amylin plays a crucial role in suppressing gastric cancer progression by targeting CCN1 and inhibiting the PI3K/Akt signalling pathway. These results suggest that amylin could serve as a potential therapeutic agent for GC treatment.