Characterization of the cell membrane during cancer transformation.

ABSTRACT

The electric properties of the plasma membrane is an indicator of cell condition. The simple, and highly effective, normal-phase (NP) and reversed-phase (RP) high-performance liquid chromatography (HPLC) methods assess phospholipid and free unsaturated fatty acid content, respectively. Herein we focus on changes in phospholipid content [phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanoloamine (PE), phosphatidylcholine (PC)] and free unsaturated fatty acid content [arachidonic acid (AA), linoleic acid (LA), a-linolenic acid (ALA), palmitoleic acid (PA)] in the plasma membranes of non-metastatic colorectal cancer cells (pT3 stage, G2 grade). Surface charge density of normal and tumor large intestine tissue was measured by electrophoresis. The surface charge density as a function of pH, acidic (CTA) and basic (CTB-) functional group concentrations and their average association constants with hydrogen (KAH) or hydroxyl (KBOH-) ions were evaluated. Cancer transformation was accompanied by an increase in total phospholipids as well as and increase in CTA, CTB and KBOH whereas the content of free fatty acids and KAH decreased compared with unchanged tumor cells.