Plasma Membrane Biophysical Properties Linked to the Antiproliferative Effect of Interferon-a

Abstract

The relationship of plasma membrane biophysical properties to the anti-proliferative effect of interferon-alpha (IFN-alpha) was investigated in Daudi lymphoblasts cell lines with sensitivity to growth inhibition, parallel clonal variants selected for resistance, and one revertant subclone. Lateral mobility of surface differentiation antigens (I2, CD19, CD20, and sIgM-kappa) were measured by fluorescence recovery after photobleaching (FRAP). The mean diffusion coefficients, D, values for two clones of IFN-alpha resistant Daudi cells were significantly higher (D = 8.1-11 x 10(-10) cm2/sec) than for parental sensitive cells (D = 4.9-7.4 x 10(-10) cm2/sec). Microviscosity of the plasma membranes were probed by electron spin resonance (ESR) spectrometry. These results also indicate a greater degree of molecular motional freedom in resistant cells. Treatment of sensitive lymphoblasts with IFN-alpha (100-400 U/10(6) cells) for 5-30 min consistently increased mean values of D and the degree of spin-probe motional freedom, whereas no significant differences were detected in resistant cells. The effect of IFN-alpha on the membrane potential (Em) of Daudi cells was quantitated by flow cytometry using a voltage-sensitive oxonol dye. Membrane potential of all clones was similar (-50 to -56 mV). Treatment with IFN-alpha for 8-10 min caused hyperpolarization in the sensitive cells (deltaEm up to 45 mV), but only minimal hyperpolarization in the resistant ones (deltaEm up to 7 mV). We concluded that sensitivity to IFN-alpha and treatment with IFN-alpha are related to the biophysical status of plasma membranes.

Mechanism of Free Zn(2+) Enhancing Inhibitory Effects of EGCG on the Growth of PC-3 Cells: Interactions with Mitochondria

“…In the present work, ESR study results support the premise that EGCG could interact with cell membrane of PC-3 cells that is decrease membrane fluidity. Since fluid properties of biological membranes are essential for numerous cell functions including cell growth, solute transport, signal transduction, and membrane-associated enzymatic activities [40,41], it is possible that even mild alterations in membrane fluidity could cause aberrant function and set in motion pathological processes [42]. These observations demonstrate that EGCG may have affected growth of PC-3 cells through interactions with cell membrane elicited by EGCG.…”

The Interferon-Inducible Protein Viperin Inhibits Influenza Virus Release by Perturbing Lipid Rafts

“…Previous studies have shown that IFN treatment can induce an increase in membrane fluidity and in the lateral diffusion coefficients of certain membrane proteins (Balint et al, 2005;Nathan et al, 1998). To directly monitor whether viperin expression leads to a change in membrane fluidity, we measured the membrane anisotropy using 1,6diphenyl-1,3,5-hexatriene (DPH) as a probe.…”

Epigallocatechin-3-gallate affects the growth of LNCaP cells via membrane fluidity and distribution of cellular zinc

“…Since fluid properties of biological membranes were essential for numerous cell functions including cell growth, solute transport, signal transduction, and membrane-associated enzymatic activities (Sunshine and McNamee, 1994; Salinas et al, 2005;Balint et al, 2005), it is possible that even mild alterations in membrane fluidity could cause aberrant function and set in motion pathological processes (Cooper, 1977;de Gómez Dumm et al, 2001). However, it should be noted that changes in membrane fluidity need not necessarily render them 'leaky' since transport or translocation of compounds across cell membranes is a different physiological process, which is not directly related to the horizontal fluidity of the membrane.…”