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Intracellular alkalinization induced by amphotericin B derivatives in HL-60 leukemia cells
1Service de Biophysique, Département de Biologie, Gif-sur-Yvette, France.
Abstract:
The effects on intra- and extracellular pH of two polyenic derivatives of amphotericin B, N-fructosyl amphotericin B and N-fructosyl amphotericin B methyl-ester, were tested on HL-60 promyelocytic leukemia cells. Both derivatives raised the internal pH and reduced the external pH in weakly buffered medium. These results support the idea that both derivatives induce outward proton movement from the cell to the external solution. In this respect, the non-esterified derivative proved to be more powerful that the esterified one. Under the present conditions, there was little or no regulation of pH in HL-60 cells, which exhibited an almost constant pH gradient between the external and internal pH (acid inside relative to outside). This deficiency in pH homeostasis might be due to the immature state of the HL-60 cells.
Insights
Two amphotericin B derivatives alter pH in leukemia cells, promoting proton export. The non-esterified form is more potent, suggesting impaired pH regulation in these immature cells.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Amphotericin B is an antifungal agent with known effects on cell membranes.
- Investigating amphotericin B derivatives can reveal novel biological activities.
- Understanding pH regulation in leukemia cells is crucial for therapeutic development.
Purpose of the Study:
- To evaluate the impact of two N-fructosyl amphotericin B derivatives on intra- and extracellular pH.
- To determine the mechanism of pH alteration induced by these amphotericin B derivatives.
- To assess the pH regulatory capacity of HL-60 promyelocytic leukemia cells.
Main Methods:
- Treatment of HL-60 leukemia cells with N-fructosyl amphotericin B and its methyl-ester.
- Measurement of intracellular and extracellular pH in a weakly buffered medium.
- Analysis of proton movement across the cell membrane.
Main Results:
- Both N-fructosyl amphotericin B derivatives increased intracellular pH and decreased extracellular pH.
- The derivatives were shown to induce outward proton movement from HL-60 cells.
- The non-esterified derivative exhibited a stronger effect on pH compared to the esterified form.
- HL-60 cells demonstrated limited pH regulation, maintaining a consistent pH gradient.
Conclusions:
- N-fructosyl amphotericin B and its methyl-ester promote proton efflux from HL-60 leukemia cells.
- The non-esterified derivative is more effective in altering cellular pH.
- The observed pH dysregulation in HL-60 cells may be linked to their immature cellular state.