benzoporphyrin-d and Carcinoma--Squamous-Cell

A target tumor-derived whole cancer cell therapeutic vaccine was developed based on an in vitro pre-treatment by photodynamic therapy (PDT) and was investigated using a poorly immunogenic tumor model. The vaccine was produced by incubating in vitro expanded mouse squamous cell carcinoma SCCVII cells for 1 h with photosensitizer benzoporphyrin derivative (BPD), then exposing to light (690 nm, 1 J/cm2) and finally to a lethal X-ray dose. Treatment of established subcutaneous SCCVII tumors growing in syngeneic C3H/HeN mice with 2 x 10(7) PDT-vaccine cells per mouse by a peritumoral injection produced a significant therapeutic effect, including growth retardation, regression and cures. Tumor specificity of this PDT-generated vaccine was demonstrated by its ineffectiveness when prepared from a mismatched tumor cell line. Vaccine cells retrieved from the treatment site at 1 h postinjection were intermixed with dendritic cells (DC), exhibited heat shock protein 70 on their surface, and were opsonized by complement C3. Tumor-draining lymph nodes treated by the PDT-vaccine contained dramatically increased numbers of DC as well as B and T lymphocytes (with enlarged memory phenotype fraction in the latter), while high levels of surface-bound C3 were detectable on DC and to a lesser extent on B cells. The PDT-vaccine produced no therapeutic benefit against tumors growing in C3-deficient hosts. It is suggested that surface expression of heat shock proteins and complement opsonization are the two unique features of PDT-treated cells securing avid immune recognition of vaccinated tumor and the development of a strong and effective antitumor adaptive immune response.

Topics: Animals; Cancer Vaccines; Carcinoma, Lewis Lung; Carcinoma, Squamous Cell; Complement C3; Dendritic Cells; Flow Cytometry; HSP70 Heat-Shock Proteins; In Vitro Techniques; Mice; Mice, Knockout; Neoplasm Transplantation; Photochemotherapy; Photosensitizing Agents; Porphyrins

The pharmacokinetics of the photosensitizer used play a key role in the understanding of the mechanism of photodynamic therapy-induced damage. Fluorescence microscopy was used to compare time-dependent biodistribution of tetra(m-hydroxyphenyl)chlorin (mTHPC) and benzoporphyrin derivative monoacid ring A (BPD-MA) in different hamster tissues, including an early, chemically induced, squamous cell carcinoma. Following injection of 0.5 mg/kg body weight of mTHPC and 2.0 mg/kg BPD-MA, groups of three animals were sacrificed at different time points and a series of fluorescence micrographs from different excised organs were analyzed. The highest fluorescence intensities of mTHPC were observed at 96 h for squamous epithelia and skin and at 48 h for smooth muscle. There is no real peak of BPD-MA fluorescence between 30 min and 3 h in the basal epithelial layers, fibroconnective tissue, muscles or blood vessels. At 4 h after injection, the fluorescence level of BPD-MA decreased and at 24 h it had returned to background level in all observed tissues. The significantly faster clearance of BPD-MA is the principal advantage as compared to mTHPC. However, similar localization patterns in different tissues with essentially vascular affinity represent a possible disadvantage for treating early malignancies with BPD-MA as compared to mTHPC, which is mainly localized in various epithelia. For both photosensitizers no significant selectivity between early squamous cell carcinoma and healthy mucosae is seen. Pharmacokinetic studies of different photosensitizers in an appropriate animal model are essential for selecting new-generation photosensitizers with the most favorable localization for photodynamic therapy of early malignancies in hollow organs.

Topics: Animals; Carcinoma, Squamous Cell; Cricetinae; Mesocricetus; Mesoporphyrins; Microscopy, Fluorescence; Photochemotherapy; Photosensitizing Agents; Porphyrins; Tissue Distribution

The aim of this study is to modify the chick chorioallantoic membrane (CAM) model into a whole-animal tumor model for photodynamic therapy (PDT). By using intraperitoneal (i.p.) photosensitizer injection of the chick embryo, use of the CAM for PDT has been extended to include systemic delivery as well as topical application of photosensitizers. The model has been tested for its capability to mimic an animal tumor model and to serve for PDT studies by measuring drug fluorescence and PDT-induced effects. Three second-generation photosensitizers have been tested for their ability to produce photodynamic response in the chick embryo/CAM system when delivered by i.p. injection: 5-aminolevulinic acid (ALA), benzoporphyrin derivative monoacid ring A (BPD-MA), and Lutetium-texaphyrin (Lu-Tex). Exposure of the CAM vasculature to the appropriate laser light results in light-dose-dependent vascular damage with all three compounds. Localization of ALA following i.p. injections in embryos, whose CAMs have been implanted with rat ovarian cancer cells to produce nodules, is determined in real time by fluorescence of the photoactive metabolite protoporphyrin IX (PpIX). Dose-dependent fluorescence in the normal CAM vasculature and the tumor implants confirms the uptake of ALA from the peritoneum, systemic circulation of the drug, and its conversion to PpIX.

Topics: Allantois; Aminolevulinic Acid; Animals; Biological Transport; Carcinoma, Squamous Cell; Cell Division; Chick Embryo; Chorion; Female; Kinetics; Metalloporphyrins; Ovarian Neoplasms; Photosensitizing Agents; Porphyrins; Rats; Rats, Inbred F344; Tumor Cells, Cultured

Photodynamic therapy (PDT) involves laser light excitation of a tumor-localizing photosensitizer to destroy neoplasms. Benzoporphyrin derivative (BPD) is a new photosensitizer with several favorable characteristics.. Studies were designed to: 1) assess the efficacy of BPD-mediated PDT in treating in vivo squamous cell carcinomas (SCC); 2) obtain dosimetry data for BPD and laser parameters; and 3) establish clinical and histologic correlates of BPD-induced tumor regression.. Human SCC was implanted into nude mice. One group received BPD followed by laser light of 150 J/cm2 from an argon-pumped dye laser at 690 nm. Three control groups included laser energy alone, BPD alone, and no treatment.. At day 21 posttreatment only PDT-treated tumors showed a statistically significant decrease in tumor volume and complete cure rate. Clinical resolution (scar) correlated perfectly with histologic resolution (scar).. Human SCC in a nude mouse model responds to BPD-mediated PDT.

Topics: Anaplasia; Animals; Carcinoma, Squamous Cell; Cell Nucleus; Cicatrix; Humans; Laser Therapy; Male; Mice; Mice, Nude; Neoplasm Invasiveness; Photochemotherapy; Porphyrins; Radiation-Sensitizing Agents; Remission Induction; Skin Neoplasms; Tumor Cells, Cultured

Photodynamic therapy for cancer depends on the relatively selective distribution of photosensitizing agents to malignant as compared with normal tissues, rendering the malignant cells more susceptible to light-mediated damage. Photodynamic therapy has been used with only moderate success to date. The purpose of this study was to compare a new photosensitizing agent, benzoporphyrin derivative (BPD), to the standard agent presently in use, photofrin II, in a hamster cheek pouch model of squamous cell carcinoma. As well we have investigated the potential of using a tumour-specific monoclonal antibody-BPD conjugate to improve the tumour localizing properties of BPD. Treatment consisted of photodynamic therapy with either photofrin II, BPD, or a tumour-specific anti-epidermal growth factor receptor-BPD conjugate. Control groups of light alone, anti-EGFr, tumour non-specific MoAb, and tumour non-specific MoAb-BPD conjugate were included with the contralateral cheek pouch of each animal acting as a dark control. An assessment of differential delivery of BPD to tumour and to normal mucosa was undertaken using a spectrophotometric assay. Parametric statistical analysis included Student's t-tests and linear regression while non-parametric analysis was undertaken using Fisher's exact test. Animals receiving BPD alone demonstrated tumour-to-tissue levels of approximately 2:1 while animals receiving the tumour-specific anti-EGFr-BPD conjugate had significantly better tumour:tissue ratios of 26:1 (P < 0.005). Animals treated with photofrin II had a 1 month cancer-free survival of 27% while animals treated with BPD had an improved survival of 67% (P = 0.03). The group treated with the tumour-specific anti-EGFr-BPD conjugate at a twentieth the total dose of BPD had an 80% 1 month cancer-free survival which was not statistically different from the group treated with BPD alone. Benzoporphyrin appears to be a more effective photosensitizing agent than Photofrin II and its tumour selectivity can be improved using a tumour specific monoclonal antibody conjugate.

Topics: Animals; Antibodies, Monoclonal; Carcinoembryonic Antigen; Carcinoma, Squamous Cell; Cheek; Cricetinae; Dihematoporphyrin Ether; Drug Evaluation, Preclinical; ErbB Receptors; Male; Mesocricetus; Photochemotherapy; Porphyrins; Radiation-Sensitizing Agents

Biodistribution of the photosensitizer benzoporphyrin derivative monoacid ring A (BPD) was compared in DBA/2 mice bearing the syngeneic M-1 tumor and nude mice bearing the A549 human squamous cell carcinoma. These studies, using internally labeled 14C-BPD showed that in general, biodistribution between the two strains was equivalent with the exception of two tissues; lymph nodes (BPD levels were higher in nude mice) and tumor (BPD levels were lower in nude mice). Further studies were carried out in A549-tumor-bearing nude mice in which the biodistribution of BPD conjugated to a monoclonal antibody (5E8) with specificity for an antigen on A549 cells was compared to a conjugate prepared with an irrelevant monoclonal antibody (T48). These studies showed that both conjugates had biodistribution characteristics which distinguished them from free BPD in that they remained in the circulation and most tissues for significantly longer times than did free BPD. Also, with the exception of the 5E8-BPD conjugate and A549 tumor tissue, levels in all tissues were highest at the 3-h time point following injection of conjugates. In the case of A549 tumor and the 5E8-BPD conjugate the highest concentration of 14C-labeled material was observed at the 14-h time point following injection. The results reported herein show that the conjugates tested behaved differently from free BPD, indicating that the materials did not become dissociated in vivo and that the specific conjugate (5E8-BPD) demonstrated specificity for the A549 tumor in terms of the kinetics of its accumulation in tumor tissue.

Topics: Animals; Antibodies, Monoclonal; Antibody Specificity; Carcinoma, Squamous Cell; Drug Carriers; Male; Mice; Mice, Inbred DBA; Mice, Nude; Neoplasms, Experimental; Photosensitizing Agents; Porphyrins; Tissue Distribution; Tumor Cells, Cultured