Objectives: Application of new cationic photosensitizers and chlorin derivatives in order to increase the efficacy of the photodynamic therapy. Materials and methods: Cationic trimetin cianine compounds have been synthesized by us and tested in melanoma, breast, colon tumors cultures, transplanted mouse tumours and xenograft. Argon dye laser equipment (Laser Marie, Finland) has been applied as a laser source. Results: The PC 218 derivative: 4l2,-(l-Etil-kinolin-4-il)etiliden] 5t 6, 7, 8-tetrahidro 2,4 difenil-1-benzopirilium prechlorate proved to be the most effective. The m-tetra-hydroxyl-fenil chlorin (mTHPC) is more effective in both tissue cultures and animals tumours than the haemotoporphyrin derivatives Photofrin 2. The efficacy of PDT is independent on the estrogen receptor content of the breast cancer cells. The breast tumor cells containing amplified copies of epidermal growth factor receptors showed moderate sensitivity to PDT. The fractionated PDT proved to be more effectiven in both transplanted mouse tumours and xenograft than the single application of PDT. Conclusions: The efficacy of the photosensitizer is improved with the increase of the absorption maximum of the compounds. The absorption maximum of the PC 218 was found to be 702 nm. The chlorin compound (Abs max 650.0 nm) induced a more favourable therapeutic response than the haemotoporphyrin derivative. The increased efficacy of the fractioned PDT could best be explained by the restoration of the oxygen level in the tumours. Our results have shown that the efficacy of the photodynamic therapy could be improved by the application of chlorin derivatives and new cationic photosensitizer and by the fractionated PDT.
|Translated title of the contribution||Application of new photosensitizer for the photodynamic therapy of cancer cells|
|Number of pages||6|
|Publication status||Published - Dec 1 1997|
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