Photodynamic Treatment of Transplantable Bladder Tumors in Rodents After Pretreatment with Chloroaluminum Tetrasulfophthalocyanine

Abstract

Chloroaluminum tetrasulfophthalocyanine (AIPCS) was used as a photosensitizer for the photodynamic treatment of transplantable N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) induced urothelial tumors. Two groups of six rats each were injected with AIPCS (three .mu.g./gm. body weight) and 24 hours after injection underwent photodynamic treatment with red light (> 590 nm., 360 joules/cm.2). Tumors examined four hours (Group I) and 24 hours (Group II) after the completion of phototreatment showed extensive hemorrhagic necrosis. Tumors treated with AIPCS alone showed no changes. In two other groups of six rats each, blood flow to tumors treated with AIPCS alone (Group III) and AIPCS plus light (Group IV) was measured using the radioactive microsphere technique. AIPCS plus light resulted in a significant decrease (p < .05) in tumor blood flow within 10 minutes of completion of phototreatment while AIPCS alone had not effect on tumor blood flow. These findings are similar to those observed when higher doses (10 .mu.g./gm. to 20 .mu.g./gm. body weight) of hematoporphyrin derivative (HpD) and light were used for phototreatment of FANFT induced tumors. AIPCS is a stable sulfonated derivative of tetraazotetrabenzoporphyrin which absorbs maximally in the red portion of the visible spectrum, a region with good tissue penetration properties. These studies suggest the AIPCS may be a useful new agent for photodynamic therapy of cancer.