title: Membrane structural dynamics of plasma membranes of living human prostatic carcinoma cells differing in metastatic potential.
abstract: Rigidity of the outer hemileaflet of the plasma membrane of two prostatic carcinoma cell lines with different metastatic potential, 1-LN and 1-LN-EMS-10, was assessed by steady-state anisotropy, using a battery of fluorescent probes. The "bulk" membrane rigidity sensed by diphenylhexatriene, trimethylammonio-DPH, 1-palmitoyl-2-[DPH-ethylcarbonyl]-phosphatidylcholine, and 10-pyrenedecanoic acid indicated slightly higher rigidity in the membrane of the highly metastatic line (1-LN). This was accompanied by 26% greater mole fraction of cholesterol and 9% lower phospholipid, resulting in 40% greater cholesterol/phospholipid ratio. Phosphatidylethanolamine was increased 12%, but corresponding decreases in phosphatidylserine and phosphatidylinositol resulted in no significant change in molar ratio of choline/noncholine phospholipids. Whereas unsaturation index was slightly higher in 1-LN, fatty acids of 1-LN plasma membranes contained 15% more 18:1, 43% more 20:4, 26% more 22:4, and 38% less 18:2. Anisotropy gradients were determined for the two cell lines using a series of n-(9-anthroyloxy) fatty acid probes with n = 2, 3, 6, 7, 9, 12, and 16. Gradients differed only in position of anisotropy maxima, which occurred with n = 6, in 1-LN, and n = 7, in 1-LN-EMS-10. Possible relationships between observed anisotropy gradients and differences in membrane cholesterol and fatty acid composition are discussed.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Virginia Commonwealth University, Richmond 23298-0614.
authors.forename: R O
authors.initials: RO
authors.lastname: Calderon
authors.forename: W M
authors.initials: WM
authors.lastname: Grogan
authors.forename: J M
authors.initials: JM
authors.lastname: Collins
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure*; D002784:Cholesterol / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D005231:Fatty Acids, Unsaturated / Q000032:analysis; D005434:Flow Cytometry / Q000379:methods; D005456:Fluorescent Dyes; D006801:Humans; D008297:Male; D008563:Membrane Lipids / Q000032:analysis*; D009362:Neoplasm Metastasis; D010743:Phospholipids / Q000032:analysis*; D011471:Prostatic Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D005456:Fluorescent Dyes; D008563:Membrane Lipids; D010743:Phospholipids; D002784:Cholesterol