Experimental study of combined hyperthermic and photodynamic therapy on carcinoma in the mouse

Expression of heat shock protein 47 in the fibrous tissue adjacent to mouse tumour subjected to photodynamic therapy

The reaction of normal fibrous tissue adjacent to tumours subjected to photodynamic therapy (PDT) was investigated by assessment of the immunohistochemical expression of heat shock protein 47 (HSP47) and proliferating cell nuclear antigen (PCNA), as well as by immunoblot analysis of procollagen type I. PDT was administered to NR-S1 mouse squamous cell carcinoma or normal mouse skin. Each of four mice was investigated at several time points after receiving PDT. The levels of HSP47 expression were determined by computer-assisted image analysis. The expression of procollagen type I in the fibrous tissue adjacent to the tumours was examined by immunoblot analysis at intervals of 24 and 48h after PDT. The expression of HSP47 was first detected 6h post-PDT in the tumour-bearing mice, but no such expression was observed in the normal mice. It was also revealed that, after PDT, the fibroblast PCNA labeling indices at 24, 48, and 72h were significantly higher in both the tumour-bearing and the normal mice than in the control animals that did not receive PDT. Furthermore, procollagen type I was detected in the fibrous tissue adjacent to the tumours at 24 and 48h after PDT, but was not detected in the fibrous tissue adjacent to tumours of mice that did not receive PDT. Therefore, the present results suggest that PDT enhances the synthesis of collagen type I in the fibrous tissue adjacent to NR-S1 squamous cell carcinoma in mice, which contributes to the resultant encapsulation of such tumours.

Griseofulvin enhances the effect of aminolevulinic acid-based photodynamic therapy in vitro

OBJECTIVE

In this study, we investigated whether or not griseofulvin (GF), which is an antimycotic widely used for the oral treatment of skin fungal infections, enhanced the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) in vitro, using several tumor cell lines.

METHODS

A human squamous cell carcinoma line (KB), two human osteosarcoma cell lines from mandible (HOSM-1, HOSM-2), and the human gingiva-derived fibroblast line (HF), representing normal cells, were used. GF enhancement of ALA-PDT was evaluated by comparing the effect of ALAin combination with GF to the effect of ALAalone (GF enhancement rate of ALA-PDT). Also, the effect of GF on intracellular accumulation of protoporphyrin IX (PpIX) was evaluated by comparing the intracellular accumulation of PpIX in the ALA and GF combined treatment with that of ALA treatment alone (pGF enhancement rate of intracellular PpIX).

RESULTS

GFenhancement rate of ALA-PDT was 2.51 in KB cells, and 1.65 and 1.27 in HOSM-1 and HOSM-2 cells, respectively. GF enhancement rates of intracellular PpIX were 1.94 in KB cells, 1.53 in HOSM-1 cells, and 1.19 in HOSM-2 cells. GF enhancement rate of intracellular PpIX followed the same trends as the levels of GF enhancement rate of ALA-PDT in the different cell types. For HF, a large effect was not revealed in this study.

CONCLUSION

The present study, although preliminary, strongly suggests that concomitant treatment with ALAand GF may be very useful to enhance the effect of ALA-PDT.

Fractionated photodynamic therapy for a human oral squamous cell carcinoma xenograft

The aim of this study was to define the appropriate fractionation interval between photodynamic therapies (PDTs) for enhanced anti-tumour effects on human oral squamous cell carcinoma (HOSCC). Reoxygenation of HOSCC and the proliferative kinetics of the tumour cells following PDT exposure were evaluated in terms of immunohistochemical expression of vascular endothelial growth factor (VEGF) and the proliferating cell nuclear antigen (PCNA). The immunohistochemical expression of VEGF was quantitatively determined by computer-assisted image analysis. The VEGF expression and the PCNA labeling indices (LIs) of the tumour cells were assessed at varying time intervals after PDT. No significant differences were observed in PCNA LIs between the control group and experimental groups at 24, 48, and 72 h after PDT. The expression of VEGF after PDT exposure was demonstrated to be higher in the experimental group at 6 h than the control group, and then was comparable at 24 h between the both groups. These results indicate that the tumour cells surviving from PDT have proliferative potential, and that oxygenation in tumours subjected to PDT may be recovered after 24 h. In the next experiment, two protocols of laser irradiation in PDT were assessed on the basis of tumour volume between fractionated exposure with a 24-h interval and continuous exposure. Regrowth of the tumour was significantly suppressed by fractionated PDT. We propose here that fractionated light exposure with a 24-h interval should be utilized in PDT for an enhanced anti-tumour effect.

Enhanced Susceptibility of Mouse Squamous Cell Carcinoma to Photodynamic Therapy Combined With Low-Dose Administration of Cisplatin

PURPOSE

We have investigated the antitumor effect of photodynamic therapy (PDT), using Photofrin as the photosensitizer, combined with low-dose cisplatin (CDDP) on NR-S1 mouse squamous cell carcinoma.

MATERIALS AND METHODS

CDDP (5 mg/kg body weight) was injected intraperitoneally either 1 hour or 3 hours prior to PDT or immediately afterward. Twenty-four hours after each protocol, the antitumor effects were evaluated by percentage area of the tumor necrosis in hematoxylin-eosin stained specimens as well as terminal deoxynucleotidyl transferase-mediated d-UTP nick-end labeling indices. Furthermore, the tumor sizes were evaluated at 3, 7, and 10 days after each protocol.

RESULTS

The antitumor effect of PDT was enhanced by administration of CDDP 3 hours before PDT, whereas the administration of CDDP 1 hour before PDT or immediately after PDT did not potentiate a PDT antitumor effect.

CONCLUSION

Administration of low-dose CDDP 3 hours before PDT appears to be a useful treatment modality.

Efficacy of combined photodynamic and hyperthermic therapy with a new light source in an in vivo osteosarcoma tumor model

OBJECTIVE

In this study, we investigated the efficacy of Super Lizer (SL) as a new light source in photodynamic therapy (PDT) with hyperthermia in an in vivo osteosarcoma tumor model.

MATERIALS AND METHODS

Nude mice in three study groups (PDT only, PDT with hyperthermia in low energy, and PDT with hyperthermia in high energy) and three control groups (no treatment, photosensitizer only, and hyperthermia only) were implanted subcutaneously with human osteosarcoma cells and injected with a photosensitizing hematoporphyrin derivative (HPD) at a total dose of 10 mg/kg, in all study groups and in control group 2. At 72 h after light treatment, mice were sacrificed.

RESULTS

The tumor volume growth rates in the heat-only (1.50) and PDT-only (1.40) groups were significantly lower than the growth rate in the no-treatment group (1.82). Further, the tumor volume growth rate in the PDT with hyperthermia in high-energy group (1.19) was significantly lower than in the heat- or PDT-only groups.

CONCLUSION

Although non-laser PDT, including SL-PDT, may be beneficial only in the treatment of superficial tumors because of limited light penetration, PDT combined with hyperthermia may extend the utility of PDT in antitumor treatment. The use of SL as a new light source in PDT may significantly advance antitumor therapy due to its simplicity, ease, and cost benefit.

Anticancer effect of combined intratumor cisplatin injection and interstitial KTP laser therapy on xenografted squamous cell carcinoma

OBJECTIVE

This study was conducted to evaluate the synergistic effect of cisplatin and interstitial KTP laser therapy induced hyperthermia in vitro and in vivo (interstitial laser chemotherapy, ILCT).

METHODS

In vitro study: human hypopharyngeal squamous carcinoma cell line (SNU-1041) was incubated in 1 mL of media containing various concentrations (0, 1, 2, 5, 10, 20, 50, 100 ng/mL) of cisplatin in 37 degrees and 43 degrees C for 2 hours. The viability of the cell was evaluated by MTT assay. In vivo study: human squamous cell carcinoma tumors were grown as subcutaneous transplants in nude mice and injected into tumor with cisplatin-epigel 100 microg, followed by interstitial laser therapy (ILT) via 0.6-mm diffuser fiber tips (532 nm, 1.0J/mm(3)).

RESULTS

In vitro study: the viability of tumor cells incubated with 10 ng/mL of cisplatin was 62% and 28% in 37 degrees C and 43 degrees C, respectively (p = 0.02). In vivo study: the tumor volume in 4 weeks after treatment was 179 mm(3) in ILT group and 27 mm(3) in ILCT group. The ILCT group showed 8 (80%) complete remission of tumors at 4 weeks follow up, while tumor remission occurred in only 3 (30%) in ILT group (p < 0.05).

CONCLUSION

These results suggest ILCT may become an effective treatment for head and neck carcinoma with minimal functional deficit.

Hyperthermic photodynamic therapy combined with topical administration of OK-432 in the mouse carcinoma

This study investigated the combined effect of photodynamic therapy (PDT) using high power laser irradiation (HPL), which generates both a hyperthermic and a photodynamic effect, and OK-432 on NR-S1 mouse squamous cell carcinoma. The photosensitizer (haematoporphyrin oligomers 20 mg/kg BW) was injected to the mice intraperitoneally 48 h before laser irradiation. OK-432 was injected into the tumour 3 h prior to laser irradiation. The experimental protocols consisted of HPL-PDT with or without OK-432, low power laser PDT with or without OK-432, HPL alone and OK-432 alone, and a control group. The tumour necrotic area was determined, and tumour sizes were measured 3, 7 and 10 days after each protocol. The anti-tumour effect of HPL-PDT was enhanced by preadministration with OK-432. Treatment with OK-432 alone or hyperthermic HPL irradiation presented little anti-tumour effect. HPL-PDT in combination with OK-432 topically administered 3 h before photo-irradiation is considered to be a promising therapeutic modality.

Photodynamic parameters in the chick chorioallantoic membrane (CAM) bioassay for topically applied photosensitizers

The relative efficacy of Photofrin-based photodynamic therapy (PDT) has been compared with that of the second-generation photosensitizers 5-aminolevulinic acid (ALA), sulfonated chloro-aluminum phthalocyanine (AlPcSn), benzoporphyrin derivative monoacid ring A (BPD-MA), and lutetium texaphyrin (Lutex). PDT-induced vascular damage in the chick chorioallantoic membrane (CAM) is measured following topical application of the photosensitizers. In order to make meaningful comparisons, care is taken to keep treatment variables the same. These include light dose (5 and 10 J/cm2), power density (33 and 100 mW/cm2), and drug uptake time (30 and 90 min). The drug dose ranges from 0.1 microgram/cm2 for BPD to 5000 micrograms/cm2 for ALA. Results are also analyzed statistically according to CAM vessel type (arterioles versus venules), vessel diameter, and vessel development (embryonic age). For each photosensitizer, the order of importance for the various PDT parameters is found to be unique. The differences between the sensitizers are most likely due to variation in biophysical and biochemical characteristics, biodistribution, and uptake kinetics.

Combined intratumor cisplatinum injection and Nd:YAG laser therapy

OBJECTIVES/HYPOTHESIS

Interstitial laser therapy (ILT) has become useful for tumor palliation in patients with advanced head and neck cancer. Cisplatinum chemotherapy also is a frequent adjuvant treatment for recurrent tumors, but systemic toxicity limits application. Intratumor cisplatinum injection combined with ILT may improve therapy of these recurrent tumors with reduced toxicity.

STUDY DESIGN

Prospective. Tumor transplants were injected with cisplatinum in a gel implant before ILT to evaluate treatment response and toxicity in a preclinical study.

METHODS

UCLA-P3 human squamous cell carcinoma tumors were grown as subcutaneous transplants in nude mice and treated by intratumor injection of 2 mg/mL cisplatinum in a slow-release, collagen-based gel carrier 4 hours before interstitial implantation of Nd:YAG laser fiberoptics to induce local tumor hyperthermia. Treatment efficacy and toxicity were followed for 12 weeks after combined drug and laser therapy compared with ILT alone.

RESULTS

Combined cisplatinum gel and ILT was a significant improvement (P < .01 by chi-square test) and induced 57% complete responses without regrowth in 21 transplanted tumors compared with only 24% in 21 tumors after ILT alone during 12-week follow-up. Recurrences in both cases appeared to result from nonuniform laser energy delivery within tumors via the implanted fiberoptic tip.

CONCLUSIONS

The results of this experimental combined cisplatinum and ILT study suggest it may be possible to improve treatment of advanced head and neck cancer by intratumor injection of gel implants containing the drug followed by interstitial Nd:YAG laser hyperthermia.

Cell kinetics of mouse tumour subjected to photodynamic therapy--evaluation by proliferating cell nuclear antigen immunohistochemistry

Tumour reaction and tumour cell kinetics in mouse NR-S1 carcinoma subjected to photodynamic therapy (PDT) were evaluated by percentage of necrotic area as well as by proliferating cell nuclear antigen (PCNA) immunohistochemistry, and an effective PDT fractionation interval was proposed. PDT was carried out in mouse NR-S1 carcinomas using a photosensitizer (haematoporphyrin oligomers: 20 mg kg body weight) and pulsed Nd:YAG dye laser. The percentages of tumour necrotic area and PCNA labelling indices (LIs) in the tumours were assessed at intervals of 0, 0.5, 5, 2.5, 6, 24, 48, and 72 h after PDT. It was demonstrated that maximum damage and repopulation of the tumour cells emerge at 24 and 48 h, respectively, following PDT, suggesting that subsequent light treatment should be performed within 24 h to enhance the therapeutic effect of PDT.

The anti-tumor effect of photodynamic therapy evaluated by bromodeoxyuridine immunohistochemistry

The anti-tumor effect of photodynamic therapy (PDT) on mouse tumors was evaluated with bromodeoxyuridine (BrdU) immunohistochemistry. BrdU was injected into the mice intraperitoneally (40 mg/kg body weight). Immediately after injection of BrdU, PDT using a photosensitizing drug (hematoporphyrin oligomers: 20 mg/kg body weight) was carried out on the experimental group but not on the control group. BrdU labeling indices (LIs) of the tumor cells close to blood vessels and adjacent to the surrounding normal tissue were investigated. In the tumor cells close to blood vessels, the LIs of the experimental group were significantly lower than those of the control group. As for the tumor cells adjacent to the surrounding normal tissue, the LIs of the experimental group were similar to those of the control group. Thus, the effect of PDT was significant in the tumor cells close to the blood vessels, while the tumor cells adjacent to the surrounding normal tissue resisted PDT.

Anthrapyrazoles and interstitial laser phototherapy for experimental treatment of squamous cell carcinoma

Interstitial laser therapy (ILT) is an effective palliative treatment for advanced head and neck cancer, but recurrence often is seen at the margin. The objective of the current study was to test combined drug and laser therapy as an experimental approach for improved treatment of human squamous cell carcinoma (SCCA). Human SCCA tumor transplants were grown in nude mice and injected with the photosensitive anthrapyrazole CI-941 before ILT. Intralesional drug injections alone at levels ranging from 60 to 1200 microg/gm of tumor induced a growth delay at the higher doses, but recurrence was seen in all 35 tumors tested. SCCA tumor transplants injected with 240 microg/gm CI-941 followed after 4 hours by ILT with the KTP532 laser led to a complete response rate of 72% (21/29) compared with 45% (13/29) for ILT alone. Laser chemotherapy was a significant improvement compared with ILT when partial and complete responses were combined (P < 0.03). The results provide preclinical evidence that laser chemotherapy may become a useful minimally invasive treatment for advanced squamous cell carcinoma of the head and neck.