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Estramustine inhibits monocyte phagocytosis
L Bjermer1, E von Schoultz, B Norberg
1Department of Oncology, University of Umeå, Sweden.
Abstract:
Estramustine phosphate (EMP) influence on human monocyte phagocytosis of fluorescein isothiocyanate (FITC)-labeled yeast cells was measured in vitro. The method used, a modification of Hed's technique (FEMS Microbiol Lett 1:357, 1977), can differentiate between yeast cell engulfment and adherence to the phagocytotic cell surface. EMP is now accepted in the treatment of advanced prostatic carcinoma. In concentrations corresponding to the clinical situation (20-40 micrograms/ml), it dramatically inhibited the process of phagocytosis. The engulfment phase was inhibited, whereas cell adherence was less affected. This might be due to direct interaction with the microtubule system. The effects were totally reversible. In contrast, the metabolites estradiol and normustine did not affect engulfment of yeast cells, either as single agents or combined. The results demonstrate that the EMP complex caused an impaired phagocytosis, which could be of pathophysiological significance in the compromised cancer patients.
Insights
Estramustine phosphate (EMP) significantly impairs human monocyte phagocytosis of yeast cells in vitro. This immune cell function inhibition, observed at clinical concentrations, suggests potential pathophysiological implications for cancer patients undergoing treatment.
Area of Science:
- Immunology
- Pharmacology
- Cell Biology
Background:
- Estramustine phosphate (EMP) is utilized in advanced prostatic carcinoma treatment.
- Understanding EMP's impact on immune cell function is crucial for patient management.
- Phagocytosis is a key immune process involving engulfment and adherence.
Purpose of the Study:
- To investigate the in vitro effect of Estramustine phosphate (EMP) on human monocyte phagocytosis.
- To differentiate the impact of EMP on yeast cell engulfment versus adherence.
- To assess the role of EMP metabolites in phagocytosis.
Main Methods:
- Utilized a modified Hed's technique for in vitro phagocytosis assays.
- Employed fluorescein isothiocyanate (FITC)-labeled yeast cells for monitoring.
- Measured human monocyte interaction with yeast cells, distinguishing engulfment and adherence.
Main Results:
- Estramustine phosphate (EMP) at clinical concentrations (20-40 µg/ml) significantly inhibited yeast cell engulfment by monocytes.
- Cell adherence was less affected compared to the engulfment phase.
- EMP metabolites, estradiol and normustine, did not impact yeast cell engulfment.
Conclusions:
- Estramustine phosphate (EMP) directly impairs the phagocytic engulfment process, potentially via microtubule interaction.
- The observed inhibition of phagocytosis by EMP may have pathophysiological significance in immunocompromised cancer patients.
- Effects of EMP on phagocytosis were fully reversible.