BACKGROUND: Clinically-approved anticancer photodynamic therapy (PDT) is now extensively studied for various cancer diagnoses. We focused on the treatment efficacy of topical administration of hydroxy-aluminum phthalocyanine (AlOH-PC) entrapped in liposomes against in vivo models of prostate carcinomas. MATERIALS AND METHODS: LNCaP and PC3 cells were subcutaneously injected into the right flank of athymic nude mice. Mice with grown tumours were used for in vivo efficacy studies. Firstly, we applied different doses of AlOH-PC to less aggressive LNCaP tumours to determine the effective dose. In later studies, we focused on more aggressive prostate tumours (PC3) using doses of liposomal-AlOH-PC gel formulation. Topical application of photosensitizers was followed by PDT irradiation (600-700 nm, 635 nm peak). Tumour growth was measured three times-a-week. RESULTS: Comparison of PDT of aggressive PC3 and less aggressive LNCaP prostate carcinomas showed that both tumour types are sensitive and treatable by liposomal formulation of AlOH-PC. For LNCaP tumours the efficient dose (100% experimental animals cured, n=8/8) was 4.5 mg/ml of AlOH-PC in the gel. Whereas, in the case of PC3 carcinomas, a dose of 4 mg/ml significantly postponed tumour growth, but no animals were cured (n=0/8); a sufficient curative dose (100% mice cured, n=8/8) was 6 mg/ml of AlOH-PC in the gel. CONCLUSION: Liposomal AlOH-PC gel has potential for effective PDT of prostate carcinomas.

Charles University Prague 3rd Faculty of Medicine Prague Czech Republic

Advances in Liposome-Encapsulated Phthalocyanines for Photodynamic Therapy