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Membrane-associated proteins of adriamycin sensitive and resistant murine leukemic P388 cells
Abstract:
We have isolated an 84-fold adriamycin resistant subline, P388/R84, from mouse leukemia P388 cells by serial cultivation in methylcellulose in the presence of increasing drug concentrations. Electrophoresis of detergent soluble fractions of radiolabeled sensitive and resistant cells suggested marked alterations in the protein fractions of 160, 100, 60, 45, and 30 kd. In resistant clones labeled with 125I an increase in 160 and 100 kd proteins was accompanied by concomitant reduction in the 60, 45, and 30 kd proteins. In 35S methionine-labeled resistant cells, similar increases in the 160 and 100 kd components were observed but in contrast to 125I-labeled cells the 30 kd component was also higher. Alterations in surface proteins were confirmed in experiments where the cell extracts were adsorbed to concanavalin A polymers and extracted with 0.26 M methyl-alpha-D-mannopyranoside. Our data confirm earlier reported observations on cell-surface protein changes in cells resistant to anthracyclines and alkaloids.
Insights
Researchers developed an adriamycin-resistant cell line (P388/R84) from mouse leukemia P388 cells. This resistance is linked to significant changes in specific cell surface proteins, particularly those of 160 and 100 kd.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Adriamycin (doxorubicin) is a key chemotherapy agent.
- Drug resistance in cancer cells is a major clinical challenge.
- Understanding molecular mechanisms of drug resistance is crucial for developing new therapies.
Purpose of the Study:
- To isolate and characterize an adriamycin-resistant mouse leukemia P388 cell line.
- To investigate changes in cell surface proteins associated with adriamycin resistance.
Main Methods:
- Serial cultivation of P388 cells in increasing concentrations of adriamycin.
- Radiolabeling of sensitive and resistant cells (125I and 35S methionine).
- Electrophoresis to analyze protein fractions.
- Concanavalin A affinity chromatography to study surface proteins.
Main Results:
- An 84-fold adriamycin-resistant subline (P388/R84) was successfully established.
- Significant alterations in protein profiles were observed, including increased 160 and 100 kd proteins.
- Differential changes in 30, 45, and 60 kd proteins were noted depending on the labeling method.
- Confirmation of surface protein alterations using concanavalin A.
Conclusions:
- Adriamycin resistance in P388 cells is associated with distinct changes in cell surface protein expression.
- The identified protein alterations may contribute to the resistant phenotype.
- Findings align with previous observations of protein changes in anthracycline-resistant cells.