Lipid metabolism is a critical contributor to cancer development and progression, as it influences cell signaling, membrane dynamics, and tumor aggressiveness. Extracellular vesicles (EV), mediators in intercellular communication, carry distinct lipid signatures that may serve as promising biomarkers. As breast cancer is the most frequently diagnosed malignancy in women and one of the leading causes of cancer-related deaths, elucidating the molecular mechanisms underlying its pathogenesis is essential for developing effective interventions.
Two breast cancer cell lines, MCF7 and MDA-MB 231, were used to investigate the lipid composition in non-metastatic and metastatic contexts, respectively, alongside HEK 293 as a non-cancerous control cell line. EV were isolated by size exclusion chromatography. Lipids from cells and EV were extracted by a modified Bligh and Dyer method, separated by high performance thin layer chromatography (HPTLC) and analyzed via electrospray ionization (ESI) MS. Targeted lipid identification was carried out using predefined transition lists in Skyline. Sum peak areas were calculated for each lipid species for relative quantification.
Our approach revealed that (I) the lipid composition of the cells differs among each other and that (II) EV exhibit lipid profiles distinct from their parental cells. PCA analyses showed a clear separation of the two cancer cell lines from HEK cells as well as the respective EV. Differences were detectable in the polar and the apolar lipid fractions of all cell line-derived samples compared to their respective EV. The nature and the fatty acyl composition of lipids differed significantly between HEK, MCF7 and MDA-MB 231 cells and their EV regarding chain length and the degree of saturation.
In conclusion, our lipidomics approach revealed distinct differences across non-metastatic and metastatic breast cancer cell lines and their respective EV in comparison to a healthy control model, underscoring the potential of advanced lipidomics strategies to provide novel insights into cancer biology.