Tirzepatide-induced lipid metabolic remodeling in relation to clonogenicity and migration in colorectal cancer cells: An <i>in vitro</i> and <i>in silico</i> approach.

e15561 Background: Glucagon-like peptide-1 (GLP-1)–based therapeutics have attracted increasing attention beyond metabolic disorders; however, their cellular mechanisms in colorectal cancer (CRC) remain to be explored, particularly the involvement of alternative metabolic pathways. To our knowledge, this study provides the first comparative analysis of tirzepatide-induced lipid metabolic remodeling in matched primary and metastatic CRC cell lines. Methods: The effects of tirzepatide treatment (1–500 nM) were evaluated in primary (SW480) and metastatic (SW620) CRC lines using lipid droplet (LD) staining, wound healing, and colony formation assays. In addition to the in vitro experiments, molecular docking analyses were performed to find the interactions of tirzepatide with targets involved in lipid metabolism. Molecular docking was performed using the HADDOCK 2.4 web server, with the human GLP-1 receptor (GLP-1R) included as a positive control. Publicly available data from the Human Protein Atlas were analyzed to examine the expression of GLP-1/GIP receptors and fatty acid–metabolism–associated genes ACLY and FASN. Results: LD staining indicated a decrease in lipid droplet abundance in both cell lines. Colony formation assay revealed that SW480 cells exhibited enhanced colonogenic capacity in response to tirzepatid treatment, while SW620 cells showed no significant changes. Wound-healing assay indicated that only SW620 cells exhibited enhanced migratory capacity under high-dose tirzepatid treatment at 48h. Molecular docking demonstrated that tirzepatide binds lipid metabolism–related enzymes with favorable affinity, showing strong interactions with FASN (−76.1) and ACLY (−58.2), alongside comparable binding to the GLP-1 receptor (−66.6), predominantly through hydrogen-bond–mediated interactions. The Human Protein Atlas revealed negligible expression of GLP-1 and GIP receptors in both cell lines, suggesting receptor-independent mechanisms, while FASN and ACLY showed marked expression level in both cell lines. Conclusions: Our results showed tirzepatide’s potential in the modulation of lipid metabolism, as also supported by in silico analyses. The divergent clonogenic responses, reduced LD activity, and distinct migratory behaviors observed between SW480 and SW620 cells appear to arise from differential metabolic programming rather than direct GLP-1R/GIPR–dependent signaling, highlighting a potential receptor-independent mechanism underlying tirzepatide’s cellular effects.