Can docosahexaenoic acid inhibit metastasis by decreasing deformability of the tumor cell plasma membrane?

Murine leukemia cells were fused with small unilamellar vesicles composed of 1-stearoyl, 2-docosahexaenoylphosphatidylcholine. The docosahexaenoic acid (DHA)-modified cells were tested for deformability by forcing them through 5.0-microm Nucleopore filters. As the cellular DHA content increased, the cells passed through the filters with more difficulty. Furthermore, cells that passed through the filters had less DHA than cells that did not. Monitored by steady-state fluorescence polarization of membrane interior and surface probes, DHA reduced the membrane order in the hydrophobic interior while increasing the order at the aqueous interface. We attribute DHA's anti-metastatic properties in part to effects on membrane structure that reduce cell deformability.