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Foscan® (mTHPC) photosensitized macrophage activation: enhancement of phagocytosis, nitric oxide release and tumour necrosis factor-α-mediated cytolytic activity

By S Coutier, L Bezdetnaya, S Marchal, V Melnikova, I Belitchenko, J L Merlin and F Guillemin

Abstract

Photodynamic activation of macrophage-like cells contributes to an effective outcome of photodynamic therapy (PDT) treatment. The possibility for an enhancement of macrophage activity by photosensitization with meta-tetra(hydroxyphenyl)chlorin (mTHPC) (1 μg ml−1) was studied in U937, monocyte cell line differentiated into macrophages (U937Φ cells). Phagocytic activity of U937Φ cells was evaluated by flow-cytometry monitoring of ingestion of fluorescein-labelled Escherichia coli particles. Increase in irradiation fluence up to 3.45 mJ cm−2 (corresponding irradiation time 15 s) resulted in significant increase in fluorescence signal (145%), while at higher light fluences the signal lowered down to the untreated control values. A light energy-dependent production of tumour necrosis factor-alpha (TNF-α) by photosensitized macrophages was further demonstrated using the L929 assay. The maximum TNF-α mediated cytolysis was observed at 28 mJ cm−2 and was 1.7-fold greater than that in control. In addition, we demonstrated a fluence-dependent increase in nitric oxide (NO) production by mTHPC-photosensitized macrophages. NO release increased gradually and reached a plateau after irradiation fluence of 6.9 mJ cm−2. Cytotoxicity measurements indicated that the observed manifestations of mTHPC-photosensitized macrophage activation took place under the sublethal light doses. The relevance of the present findings to clinical mTHPC-PDT is discussed. © 1999 Cancer Research Campaig

Topics: Regular Article
Publisher: Nature Publishing Group
OAI identifier: oai:pubmedcentral.nih.gov:2374281
Provided by: PubMed Central

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Citations

  1. (1992). Activation of mouse macrophages by in vivo and in vitro treatment with a cyanine dye, lumin.
  2. (1994). Effectiveness of photofrin II in activation of macrophages and in vitro killing of retinoblastoma cells.
  3. (1998). Involvement of nitric oxide during phthalocyanine (Pc4) photodynamic therapy-mediated apoptosis.
  4. (1983). Molecular mechanisms in tumor cell killing by activated macrophages.
  5. (1993). Photodynamic therapy in oncology.
  6. (1998). Photodynamic therapy.