Cholesterol content and membrane properties in metastatic melanoma compared to primary melanoma: an EPR-based study

PURPOSE: Melanoma is a malignant tumor originating from melanocytes and characterized by a rapidly increasing incidence worldwide. Its high mortality rate is primarily due to its high metastatic potential. The aim of this study was to compare the physicochemical properties of liposomes prepared from lipids extracted from primary (WM115) and metastatic (WM266.4) melanoma cells in order to better understand the lipid-related changes associated with melanoma progression. METHODS: Lipids were extracted from WM115 and WM266.4 melanoma cells using the Folch method, labeled with the 16-PC spin probe, and rehydrated to form multilamellar liposomes. Electron paramagnetic resonance (EPR) spectroscopy was performed to assess membrane fluidity and polarity, while cholesterol content and lipid droplet accumulation were also quantified. RESULTS: Liposomes prepared from lipids extracted from both cancer cell lines (metastatic WM266.4 and primary WM115 cells) exhibited high order parameters and low polarity, resembling cholesterol-enriched model membranes. However, chemiluminescence analyses revealed higher cholesterol levels and greater lipid droplet accumulation in WM266.4 cells, indicating distinct lipid organization associated with melanoma progression. CONCLUSIONS: These findings indicate clear differences in cholesterol content between primary and metastatic melanoma cells, highlighting the potential role of lipid remodeling in melanoma progression.