Anti-tumour activity of photodynamic therapy in combination with mitomycin C in nude mice with human colon adenocarcinoma.

The interaction of photodynamic therapy (PDT) and a chemotherapeutic drug, mitomycin C (MMC), was investigated using WiDr human colon adenocarcinoma tumours implanted on Balb/c athymic nude mice. The WiDr tumours were treated with PDT alone, MMC alone or with both. It was found that the combined treatment produced a greater retardation in the growth of the WiDr tumour than monotherapy with MMC or PDT.

Binding of etiopurpurin to human plasma proteins. Delivery in cremophor EL and dimethyl sulphoxide. III.

Binding of the photosensitizer etiopurpurin (ET2) to human plasma was assessed, using conditions that would yield a high percentage of ET2 in the form of LDL-bound monomers which may favor photosensitizer tumor localization. Two delivery systems, Cremophor EL (CRM) and dimethyl sulphoxide (DMSO), were used. The binding of ET2 to CRM-modified lipoproteins was compared to the binding of the dye to the native proteins using delivery in DMSO.

Separation of lipoproteins, albumin and gamma-globulin by single-step ultracentrifugation of human serum. Application. I: Binding of hematoporphyrin to human serum and to albumin.

Previous studies of the serum binding of the photosensitizer hematoporphyrin (Hp) have given widely different results. The serum binding of Hp is therefore further illuminated by experiment and discussion. Ultracentrifugal separation of serum is improved and applied to study the binding of Hp to human serum and HSA.

Detection of UVR-induced DNA damage in mouse epidermis in vivo using alkaline elution.

Alkaline elution has been used to detect ultraviolet radiation (UVR)-induced DNA damage in the epidermis of C3H/Tif hr/hr mice. This technique detects DNA damage in the form of single-strand breaks and alkali-labile sites (SSB) formed directly by UVA (320-400 nm) or indirectly by UVB (280-320 nm). The latter induces DNA damage such as cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4)-photoproducts, which are then converted into transient SSB by cellular endonucleases, during nucleotide excision repair (NER).

The influence of the cysteine protease inhibitor L-trans-epoxysuccinyl-leucyl amido(4-guanidio)butane (E64) on photobiological effects of tetra(4-sulfonatophenyl)porphine.

Human cervix carcinoma cells of the line NHIK 3025 were exposed to light after 18 h incubation with tetra(4-sulfonatophenyl)porphine (TPPS4) in the absence or presence of the cysteine protease inhibitor L-trans-epoxysuccinyl-leucyl amido(4-guanidino)butane (E64) followed by 1 h in sensitizer-free medium. E64 changed the photochemical properties of TPPS4 in NHIK 3025 cells, i.e.

Binding of etiopurpurin and tin-coordinated etiopurpurin to human plasma proteins. Delivery in cremophore EL and dimethyl sulfoxide (paper II).

Purpurins are potent hydrophobic photosensitizers in vivo. Cremopfore EL is an important vehicle for the administration of hydrophobic drugs. Mode-delivery-effects on the binding of etiopurpurin (ET2) to human plasma (LDL, HDL, and high density proteins, HDP) is studied for delivery in CRMaq and in DMSO by ultracentrifugation.

Lysosomes as photochemical targets.

Sulfonated tetraphenyl porphines (TPPSn) are photosensitizing dyes that localize in lysosomes of NHIK 3025 cells. In order to elucidate the mechanisms of cell inactivation by photochemical treatment with TPPSn, lysosomal enzyme inactivation and release of lysosomal contents were examined after treatment. In cells treated with TPPS4 and light, the lysosomal enzymes beta-N-acetyl-D-glucosaminidase (beta-AGA) and cathepsin(L+B) were almost completely inactivated and no enzyme activities were released from the lysosomes.

Sulfonated aluminium phthalocyanines as sensitizers for photochemotherapy. Effects of small light doses on localization, dye fluorescence and photosensitivity in V79 cells.

V79 cells incubated with di- or tetrasulfonated aluminium phthalocyanines (AlPcS2 or AlPcS4) showed a granular fluorescence pattern. Co-staining with the lysosomotropic dye acridine orange (AO) indicated that the granules that were stained by these photoactive phthalocyanines were identical to lysosomes. Small light exposures made the lysosomes permeable to the dyes without inactivating the cells.

Pressure against the tumor can reduce the efficiency of photochemotherapy.

C3D2/F1 mice with mammary carcinoma tumors growing subcutaneously on their right foot were given 10 mg/kg aluminium phthalocyanine tetrasulfonate (AlPcS4) by intraperitoneal injection. Twenty-four hours later these tumors were exposed to light at 680 nm. The size of the tumors was measured daily.

Quantitative assessment of epidermal melanogenesis in C3H/Tif hr/hr mice treated with topical furocoumarins and UVA radiation.

We report quantitative data on epidermal melanogenesis by established and new furocoumarins. The ears and dorsal skin of pigmented hairless mice were treated for 12 d with compounds in ethanol, at equi-optical concentrations, and exposed to subphototoxic doses of ultraviolet A. Increased pigmentation was observed with 6,4,4'-trimethylangelicin > psoralen > 8-methoxypsoralen > 5-methoxypsoralen > 4,4',5'-trimethylazapsoralen = bergamot oil.

Evaluation of a new photosensitizer, meso-tetra-hydroxyphenyl-chlorin, for use in photodynamic therapy: a comparison of its photobiological properties with those of two other photosensitizers.

The properties of a new photosensitizer, meso-tetra-hydroxyphenyl-chlorin (mTHPC), were studied using V79 cells (Chinese-hamster lung fibroblasts). Comparisons were made with 2 other photosensitizers: photofrin II (PII) and meso-tetra-hydroxyphenyl-porphyrin (mTHPP). A main advantage of mTHPC is that it has a strong absorption at 652 nm.

[Is UV-A a cause of malignant melanoma?].

The first action spectrum for cutaneous malignant melanoma was published recently (2). This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma.

Effects of ultraviolet radiation on intercellular communication in V79 Chinese hamster fibroblasts.

The effects of ultraviolet (UV) radiation on gap junctional intercellular communication (GJIC) in V79 Chinese hamster fibroblasts were studied by means of a dye transfer assay. Intercellular communication was shown to be altered by UVB (297/302 nm) and UVA (365 nm) radiation, the effect depending on the wavelength of exposure and time between irradiation and microinjection of the dye in the dye transfer assay. Exposure to 297/302 nm radiation induced a reduction in intercellular communication 6 min after exposure.

No correlation between DNA strand breaks and HPRT mutation induced by photochemical treatment in V79 cells.

DNA strand breaks, measured by alkaline elution, and hypoxanthine guanine phosphoribosyltransferase (HPRT) mutation were studied in V79 cells after photochemical treatment (PCT) or exposure to X-rays. Cells were incubated with the photosensitizers Photofrin II (PII) and three closely related porphyrins tetra-(3-hydroxyphenyl) porphyrin (3THPP), meso-tetra-(4-sulfonatophenyl) porphine (TPPS4) and meso-tetra-(N-methyl-4-pyridyl) porphine (TMPyPH2). These dyes are assumed to act on cellular targets mainly via singlet oxygen when excited by light.

Combination therapy: photochemotherapy; electric current; and ionizing radiation. Different combinations studied in a WiDr human colon adenocarcinoma cell line.

The interactions of pairs of the modalities Photofrin II-sensitized photochemotherapy (PCT), ionizing radiation and an electric current were investigated by the colony formation assay in WiDr cells, a human colon adenocarcinoma cell line. When the cells were treated simultaneously with PCT and an electric current, a slightly synergistic effect was observed at low exposures (surviving fraction approximately 0.1) while a seemingly antagonist effect was found at higher exposures.

Uptake and distribution of intravenously or intravesically administered photosensitizers in the rat.

Photodynamic therapy using i.v. injected porphyrin photosensitizers have been used to treat selected cases of superficial bladder cancer.

Photochemical treatment with the lysosomally localized dye tetra(4-sulfonatophenyl)porphine results in lysosomal release of the dye but not of beta-N-acetyl-D-glucosaminidase activity.

Tetra(4-sulfonatophenyl)porphine (TPPS4) sensitizes cells to photoinactivation mainly through formation of singlet oxygen. In human cervix carcinoma cells of the line NHIK 3025 TPPS4 localizes to a large extent in lysosomes as previously shown by fluorescence microscopical and spectroscopical techniques. In the present study photodamage to lysosomes was investigated.

Primary DNA damage, HPRT mutation and cell inactivation photoinduced with various sensitizers in V79 cells.

DNA strand breaks and hypoxanthine guanine phosphoribosyl transferase (HPRT) mutants were measured in parallel in photochemically treated (PCT) cells and compared at the same level of cell survival. Chinese hamster fibroblasts (V79 cells) were either incubated with the lipophilic dyes tetra(3-hydroxyphenyl)porphyrin (3THPP) and Photofrin II (PII), the anionic dye meso-tetra(4-sulfonatophenyl)porphine (TPPS4) or the cationic dye meso-tetra(N-methyl-4-pyridyl)porphine (p-TMPyPH2) before light exposure. In the cells, the lipophilic dyes were localized in membranes, including the nuclear membrane, while the hydrophilic dyes were taken up primarily into spots in the cytoplasm.

An action spectrum for UV-induced attachment of V79 Chinese hamster cells to a substratum.

When cells growing in monolayers are exposed to ultraviolet radiation (UV) their binding to the substratum is increased in strength. An action spectrum for such UV-induced binding was determined, using the time needed for trypsin-EDTA to detach the cells as a measure of the binding strength. This action spectrum was significantly different from the action spectrum for cell inactivation, which was also determined.

Biodistribution of a methylene blue derivative in tumor and normal tissues of rats.

By using a chemical extraction procedure and confocal laser scanning fluorescence microscopy we have investigated the kinetic patterns of uptake and biolocalization of a methylene blue derivative (MBD) in tumors and various normal tissues of Wistar rats bearing fibrosarcoma (Leeds ovarian tumor) after intravenous injection of MBD (10 mg kg-1 body weight). Similar kinetics of accumulation and elimination of MBD fluorescence were found in tumor tissue and surrounding normal skin and muscle tissues. However, the tumor:skin and tumor:muscle ratios of the MBD fluorescence intensity were found to be 9 and 4, respectively, 4 h after intravenous injection, indicating selective uptake of MBD by the tumor tissue.

Photobiological properties of hematoporphyrin diesters: evaluation for possible application in photochemotherapy of cancer.

The dimethyl, diethyl, dipropyl, dibutyl, diamyl, dihexyl and diheptyl esters of hematoporphyrin (Hp) were synthesized and shown to be more strongly retained on a reverse phase (C18) high performance liquid chromatography column than most components of Photofrin II (PII) - the sensitizer used for photochemical treatment of cancer in the clinic. The Hp diesters were found to be less efficient than PII in sensitizing cells to photoinactivation. This was partly due to de-esterification of the Hp diesters by esterase activity in the serum.

Binding of drugs to human plasma proteins, exemplified by Sn(IV)-etiopurpurin dichloride delivered in cremophor and DMSO.

1. The mode-delivery-effect upon the binding of Sn(IV)-etiopurpurin dichloride (SnET2) in human plasma has been studied by ultracentrifugation, combined with absorption and fluorescence spectroscopy. SnET2 was delivered to plasma either in Cremophore EL (CRM) or in dimethyl sulfoxide (DMSO).

Potentiation of photodynamic therapy by mitomycin C in cultured human colon adenocarcinoma cells.

The effects of photodynamic therapy (PDT) alone and in combination with Mitomycin C (MMC) on WiDr cells, a human colon adenocarcinoma cell line, were investigated. The addition of MMC increased the cytotoxicity of PDT. The presence of MMC resulted in a reduction or a removal of the shoulder of the PDT survival curves as well as an increase in their slopes.