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Photofrin uptake by murine macrophages
M Korbelik1, G Krosl, D J Chaplin
1Cancer Imaging, British Columbia Cancer Research Centre, Vancouver, Canada.
Cancer Research
|May 1, 1991
Summary
Murine macrophages exhibit significantly higher Photofrin uptake than SCCVII tumor cells, suggesting phagocytosis of aggregated drug components drives this accumulation. Macrophage activity influences this process.
Area of Science:
- Photodynamic therapy
- Cellular pharmacology
- Immunology
Background:
- Photofrin is a photosensitizer used in photodynamic therapy.
- Understanding drug uptake in different cell types is crucial for optimizing therapeutic efficacy.
- Macrophages play a role in the tumor microenvironment and drug distribution.
Purpose of the Study:
- To investigate the uptake of Photofrin by murine peritoneal macrophages and SCCVII tumor cells.
- To compare the uptake capacity of macrophages versus tumor cells.
- To explore factors influencing Photofrin uptake by macrophages.
Main Methods:
- In vivo and in vitro experiments were conducted.
- Cellular Photofrin content was quantified using fluorometric assays and 14C-labeled drug.
- Murine peritoneal macrophages, tumor-associated macrophages, and SCCVII tumor cells were analyzed.
Main Results:
- Macrophages demonstrated substantially greater Photofrin uptake compared to SCCVII tumor cells.
- At 24 hours post-administration, peritoneal macrophages showed 420 ng/µg protein, tumor-associated macrophages 74 ng/µg, and SCCVII cells 15 ng/µg.
- Macrophage activity significantly influenced drug uptake, supporting a phagocytosis-driven mechanism for aggregated Photofrin.
Conclusions:
- Macrophages possess a higher capacity for Photofrin uptake than SCCVII tumor cells.
- Phagocytosis of aggregated Photofrin components is likely the primary mechanism of uptake by macrophages.
- Photofrin clearance from macrophages and tumor cells in vitro showed similar rates, with most loss occurring within the first 24 hours.