Abstract
Biological response modifier antitumor effects are enhanced by the activation of the host defense mechanisms. We have investigated the antitumor effect of photodynamic therapy (PDT) and/or local administration of a biological response modifier, the streptococcal preparation OK-432, on transplanted NR-S1 mouse squamous cell carcinoma. Hematoporphyrin oligomers (20 mg/kg body weight) were used to photosensitize PDT. A pulsed Nd:YAG dye laser, tuned at 630 nm, was used as the light source. The laser power was 15 mJ cm−2 pulse−1, and the irradiation time was 40 min. The photosensitizer was injected intraperitoneally 48 h before laser irradiation. Where used, OK-432 was injected into the tumor either 3 h prior to PDT or immediately afterwards. The antitumor effects were evaluated 48 h after each protocol by (a) estimating the area of tumor necrosis (%) in hematoxylin/eosin-stained specimens, and (b) bromodeoxyuridine immunohistochemistry. Furthermore, the tumor sizes were evaluated 3, 7 and 10 days after each protocol, and the survival time after each protocol was evaluated as well. The anti-tumor effect of PDT was enhanced by administration of OK-432 3 h before PDT, whereas the administration of OK-432 immediately after PDT did not potentiate a PDT antitumor effect. Treatment with OK-432 alone had little effect on tumors. Photodynamic therapy in combination with local administration of OK-432 3 h before PDT is considered to be a useful treatment modality.
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Received: 23 July 1999 / Accepted: 31 May 2000
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Uehara, M., Sano, K., Wang, ZL. et al. Enhancement of the photodynamic antitumor effect by streptococcal preparation OK-432 in the mouse carcinoma. Cancer Immunol Immunother 49, 401–409 (2000). https://doi.org/10.1007/s002620000134
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DOI: https://doi.org/10.1007/s002620000134