| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
【Purpose】Photodynamic therapy (PDT) is a treatment modality in which a systematically administered photosensitizer is activated by laser light, resulting in the generation of highly toxic singlet oxygen and subsequent destruction of targeted tissues. Talaporfin sodium (laserphyrinTM), a second generation photosensitizer, reduced cutaneous photcsensitivity as a common toxic side effect and therefore PDT with talaporfin sodium has now proved to be a clinically useful therapeutic option with reduced side effect for a subset of early lung cancer patients. Since an oral malignancy is a superficial tumor, it would appear to be a good candidate for additional application of PDT. To date, however, only a few basic clinical studies in this regard have been reported for oral cancer including tongue tumor. In the present study, we investigated anti-tumor activity of PDT with talaporfin sodium against tongue carcinoma cell lines xenografted in nude mice.
【Materials and Method】PDT was conducted using talaporfin sodium as a photosensitizer and a small-sized semiconductor laser with a wavelength of 664nm as a light source. We used two human squamous carcinoma cell, lines with different histologies. One (HSC-2) was a differentiated keratinizing cell line and the other (HSC-3) a non-keratinizing cell lines with higher grouth potential.
【Results】PDT induced apoptosis in both cell lines in a dose-dependent manner at a low range of talaporfin sodium concentration and induced necrosis at a higher concentration of the drug in vitro. However, HSC-2 was more sensitive to PDT than HSC-3 cells. PDT also exhibited a stronger anti-tumor effect on HSC-2 subcutaneous tumors (some mice were cured) than HSC-3 tumor xenografted in nude mice when laser could be illuminated internally through skin incision.
【Conclusion】These results suggest that PDT using talaporfin sodium may be a potential and efficient therapeutic approach for early tongue cancers with keratinizing histology.
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