Photodynamic therapy of non melanoma skin cancer murine model by topical application of a novel mTHPC liposomal formulation

摘要

Photodynamic therapy (PDT) has been used in the treatment of various skin diseases including non melanoma skin carcinomas (NMSC). However, until now there are no publications concerning the efficacy of PDT after topical application of mTHPC. Although topical photosensitizer application presents many advantages over systemic drug administration, ALA-induced protoporphyrin IX is the only sensitizer topically used so far. In the present study photodynamic efficacy of the highly potent sensitizer meso-tetra(hydroxyphenyl)chlorin (mTHPC), supplied in a novel liposome formulation is investigated after topical application in hairless SKH-HR1 mice, bearing non melanoma skin carcinomas. The drug was applied topically for drug - light interval of 4 hours. The fluence rates were 100 and 50 mW/cm2 and two total energy doses, 10 J/cm2 and 100 J/cm2 were studied in groups of 5 animals. Three PDT sessions were performed in each animal, once every 7 days. The final evaluation of PDT effects was performed 14 days after the 3rd PDT treatment by measuring the geometrical characteristics of tumors. The groups treated with 100 mW/cm2 presented a higher complete tumor remission than the group of 50 mW/cm2 but an unusual high mortality. In the group of 50 mW/cm2 and 100 J/cm2, although the complete tumor remission percentage is poor, the tumor growth rate was decreased. No lesion, papilloma, or tumor was observed in the treated area even six months after tumor remission. Furthermore tumours up to 7 mm were achieved to be treated, indicating that this novel mTHPC formulation could be used for deeper and not only superficial carcinomas or lesions.