Antitumor therapeutic efficacy of photoactivated phthalocyanines ZnS4PC and AlS2PC in tumor-bearing mice

摘要

The photosensitizer of choice in photodynamic therapy (PDT) is the hematoporphyrin derivative (Hpd). However, Hpd has many characteristics which make it less than an ideal photosensitizer. The sulfonated phthalocyanines represent a new group of interesting compounds that have a strong absorption in the red part of the spectrum at 675 nm. In our laboratory we compare the efficacy of two phthalocyanines, the zincum tetrasulfonated (ZnS$-4$/Pc) and the aluminum disulfonated (AlS$-2$/Pc), on a murine tumor. Mice bearing MS-2 fibrosarcoma were treated with 5 or 25 mg/kg of ZnS$-4$/Pc or AlS$-2$/Pc and then the tumor mass was exposed to a laser light (100 mW for 10'). The results show that the treatment with AlS$-2$/Pc is significantly more therapeutically active in respect to the treatment with the same dose of ZnS$-4$/Pc. Moreover, resistance to rechallenge with the MS-2 tumor was evidenced by surviving animals. Studies are in progress with other murine tumors with different biological properties.