VIPR1 induces cuproptosis and inhibits the HIF-1α pathway in colon cancer.

Cuproptosis, a recently characterized form of programmed cell death, has been implicated in tumor progression; however, its specific role in colon cancer remains poorly understood. This study aims to elucidate the potential involvement of cuproptosis-related genes in the development and progression of colon cancer. Differentially expressed genes (DEGs) associated with cuproptosis in colon cancer were identified through bioinformatics analysis of the GSE4183 and GSE74602 datasets. Gain-of-function experiments were performed in HT29 and HCT116 colon cancer cell lines to evaluate their effects on cellular proliferation, migration, and invasion. Functional assays, including JC-1 staining, copper (Cu²⁺) quantification, and lactate/pyruvate measurements, were employed to assess mitochondrial membrane potential and metabolic reprogramming. The involvement of hypoxia-inducible factor-1 alpha (HIF-1α) was further explored through overexpression and rescue assays. To confirm the dependency of the observed effects on cuproptosis, tetrathiomolybdate (TTM) was used as a copper chelator. Additionally, vasoactive intestinal peptide receptor 1 (VIPR1) signaling was activated using its agonist, vasoactive intestinal peptide (VIP). Five downregulated cuproptosis-related hub genes (VIPR1, PYY, NPY, VIP, and SST) were identified as potential diagnostic biomarkers for colon cancer. Among them, VIPR1 overexpression significantly suppressed the proliferation, migration, and invasion of colon cancer cells, accompanied by upregulation of cuproptosis-associated proteins FDX1 and DLST. These effects were markedly attenuated by HIF1A overexpression. The application of the copper chelator TTM abolished the antitumor effects mediated by VIPR1, confirming cuproptosis dependency. Furthermore, treatment with the VIPR1 agonist VIP enhanced VIPR1 signaling, further inhibited malignant cellular behaviors, and downregulated HIF-1α activity. Dual-luciferase reporter assays showed that HIF-1α overexpression reduced the transcriptional activity of wild-type FDX1 and DLST promoters. VIPR1 acts as a tumor suppressor in colon cancer by promoting cuproptosis and disrupting cellular metabolic fitness through inhibition of HIF-1α signaling, thereby representing a promising target for therapeutic intervention.