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Effect of pH on fluorescence polarization of DMSO induced Friend leukemic cells
Abstract:
The effect of DMSO on Friend leukemic cell membranes was investigated in an inducible cell line (FLC) and in cell variant resistant to DMSO induction (RFLC). Fluorescence polarization (P) studies carried out at 37 degrees C with diphenyl hexatriene (DPH) have shown that P values change according to the pH, being maximum in alkaline buffer. These changes were altered when cells were grown in the presence of DMSO. Changes in P values according to the pH were abolished by glutaraldehyde and by sodium azide. Fluorescence polarization analysis of FLC cell line carried out at 4 degrees C have shown higher P values which also changed according to the pH. In DMSO induced FLC or in RFLC grown with or without DMSO, these changes were not seen. It is therefore concluded that P value changes related to pH reflect changes in the lipid-protein interactions of cell surface membrane. It is also suggested that these interactions are altered by DMSO.
Insights
Dimethyl sulfoxide (DMSO) alters lipid-protein interactions in Friend leukemic cell membranes. These changes affect how cell membranes respond to pH variations, indicating DMSO
Area of Science:
- Cell biology
- Membrane biophysics
Background:
- Dimethyl sulfoxide (DMSO) is known to induce differentiation in certain cancer cells.
- Understanding DMSO's effects on cell membranes is crucial for its therapeutic applications.
Purpose of the Study:
- To investigate the impact of DMSO on the biophysical properties of Friend leukemic cell membranes.
- To determine if DMSO affects pH-dependent changes in membrane fluidity and lipid-protein interactions.
Main Methods:
- Utilized fluorescence polarization (P) with diphenyl hexatriene (DPH) to probe membrane fluidity.
- Examined Friend leukemic cell lines (FLC) and a DMSO-resistant variant (RFLC).
- Conducted experiments at varying temperatures (37°C and 4°C) and pH levels, with and without DMSO treatment.
Main Results:
- Fluorescence polarization (P) values in FLC cells exhibited pH-dependent changes, maximal in alkaline conditions at 37°C.
- DMSO treatment abolished these pH-dependent P value changes in FLC cells.
- pH-dependent P value changes were absent in DMSO-resistant RFLC cells, regardless of DMSO exposure.
- Higher P values were observed at 4°C, also showing pH dependency in FLC, which was lost upon DMSO treatment or in RFLC.
Conclusions:
- pH-dependent changes in fluorescence polarization reflect alterations in lipid-protein interactions within the cell surface membrane.
- DMSO significantly modifies these lipid-protein interactions in Friend leukemic cells.
- DMSO's effect on membrane properties may be linked to its mechanism of action in inducing cell differentiation or resistance.