aluminum-tetrasulfophthalocyanine and Fibrosarcoma

Levels of disulfonated and tetrasulfonated aluminum phthalocyanines (AlPcS2,4) were measured in cells derived from FsaR tumors (murine fibrosarcoma) using a fluorescence-activated cell sorter (FACS). The tumors were excised from animals injected with the sensitizer 24 h earlier and enzymatically dissociated. Before flow cytometry, the cells were stained with fluorescein isothiocyanate-conjugated anti-mouse monoclonal antibodies to specific immune cell membrane markers (Mac1, Fc receptor (FcR) or CD45). Staining to FcR and CD45 was combined with a DNA stain Hoechst 33342. This enabled concomitant discrimination to be made by the FACS between different populations of tumor-infiltrating host cells and malignant cells. The results showed on average 1.49 times higher AlPcS2 levels and 1.16 times higher AlPcS4 levels in Mac1-positive (Mac1+) compared with Mac1-negative (Mac1-) tumor cell populations. The same type of experiments performed with SCCVII tumor (squamous cell carcinoma) gave average Mac1+/Mac1- ratios of 1.75 and 1.45 for AlPcS2 and AlPcS4 respectively. The data using other antibodies and DNA staining are consistent with the conclusion that, based on average per cell content, elevated levels of AlPcS2, and to a lesser extent AlPcS4, are retained in tumor-associated macrophages (TAM). The levels of these photosensitizers in other leukocytes and in non-immune host cells were not substantially different from those in malignant tumor cells. It is also shown that elevated levels of AlPcS2 and AlPcS4 are not localized in all TAM, but rather in a fraction of this cell population characterized by extremely high photosensitizer content.

Topics: Animals; Benzimidazoles; Biomarkers; Female; Fibrosarcoma; Flow Cytometry; Fluorescein-5-isothiocyanate; Indoles; Macrophage-1 Antigen; Mice; Mice, Inbred C3H; Organometallic Compounds; Radiation-Sensitizing Agents; Sarcoma, Experimental; Staining and Labeling; Tissue Distribution

The purpose of this study was to examine the effects of photodynamic therapy utilizing aluminum phthalocyanine tetrasulfonate in vitro on several human malignant and normal cell types, with or without hyperthermia. Cells examined included normal skin fibroblasts, HT-1080 fibrosarcoma cells, SCC-25 (squamous cell carcinoma) and malignant melanoma cells. An argon-pumped continuous wave tunable dye laser at 675 nm was used as the light source, hyperthermia groups were heated to 42.5 degrees C, and radioisotope incorporation was used to measure DNA and protein synthesis as toxicity assays. Results showed an energy-dose, and A1PcS-concentration dependent toxicity in all cell lines examined, with moderate selectivity toward malignant cells. Hyperthermia alone was slightly toxic in melanomas and HT-1080 cell lines but had no effect in normal fibroblasts or SCC-25 cells. Hyperthermia synergistically potentiated the effects of PDT in all cell lines, and the combined modality was significantly more toxic in all malignant cell lines compared with normal cells. Thus, addition of hyperthermia to PDT protocols may enhance the efficacy of this treatment modality in vitro.

Topics: Carcinoma, Squamous Cell; Cell Line; Cell Survival; DNA Replication; DNA, Neoplasm; Fibroblasts; Fibrosarcoma; Humans; Hyperthermia, Induced; Indoles; Laser Therapy; Melanoma; Neoplasm Proteins; Organometallic Compounds; Photochemotherapy; Radiation-Sensitizing Agents; Skin; Skin Neoplasms; Tumor Cells, Cultured

Photodynamic therapy (PDT) involves the use of laser or noncoherent light energy with photosensitizing dyes to induce a cytotoxic reaction in the target cells, resulting in cell injury and/or death. In this study, we have examined laser-induced phototoxicity in normal human skin fibroblasts and HT-1080 fibrosarcoma cells incubated with aluminum phthalocyanine tetrasulfonate (AlPcS) in vitro. The culture, laser, and photosensitizer parameters were varied in attempts to establish the conditions for differential cytotoxicity between normal and malignant human fibroblasts. Biochemical assays, as a measure of cytotoxicity, included [3H]thymidine incorporation (an index of DNA replication), [35S]methionine incorporation (a measure of protein synthetic activity), and the MTT assay (an indirect index of mitochondrial activity). In the absence of laser irradiation, AlPcS was non-toxic to both cell lines in concentrations up to 25 micrograms/ml. Laser light alone at 675 nm (the absorption maximum of AlPcS) had no effect on the cells at energy densities up to 16 J/cm2. In the presence of 3 or 10 micrograms/ml of AlPcS, both cell lines demonstrated marked energy-dependent toxicity. If an 8-h or a 24-h "efflux" period in AlPcS-free medium was allowed to take place prior to laser irradiation, normal fibroblasts were much less sensitive to PDT, whereas fibrosarcoma cells still exhibited a marked degree of toxicity. The results indicate that, under appropriate treatment conditions, AlPcS is capable of preferentially sensitizing a malignant mesenchymal cell line, while sparing its non-malignant normal cell counterpart.

Topics: Fibroblasts; Fibrosarcoma; Humans; Indoles; Lasers; Organometallic Compounds; Photochemotherapy; Radiation-Sensitizing Agents; Skin; Tumor Cells, Cultured