Comparison of photodynamic therapy with phthalocyanine and photofrin in human colorectal carcinoma.

Photodynamic therapy (PDT) has been developed in recent years as a new modality for the treatment of various neoplastic and non-neoplastic lesions. Although the method of combining light with photosensitizers for treatment has been around for a century, further understanding has been evolved over the past decades. The method is based on the phenomenon involving the combination of photosensitizer and light. Neither drug nor light alone are effective as therapeutic agents. The antitumour effects result from direct cell damage, destruction of tumor vasculature and activation of a nonspecific immune response. The more accepted use of PDT is still restricted for ophthalmology, dermatology and treatment of some stages of esophageal, lung and urinary bladder cancer. In our experiments, the effect of phototherapy with disulfonated hydroxyaluminium phthalocyanine (Al(OH)S2Pc) and photofrin (control group) on the growth of human colorectal carcinoma on nude mice was studied. We chose colorectal carcinoma, because the Czech population has the highest incidence and it is still increasing. We try to offer a new possibility of treatment for patients with this severe disease.

Measurement of cytotoxicity of sulphonated chloroaluminium phthalocyanine on various cell systems.

Phthalocyanines (ClAlPcS) present a new generation of substances for photodynamic treatment of tumors. To find optimal therapeutic doses for i.v. or local application, it is necessary to test the maximal non-toxic concentration on model systems. As a standard testing system (cellular substrate) for definition of the in vitro cytotoxicity, human lymphocytes separated from peripheral human blood and splenocytes obtained from rabbit spleen fragments were chosen. The vitality test on human peripheral lymphocytes proved that the used concentrations in the range 0.1-1.4 mg/ml did not significantly influence vitality of the cellular substrate. The test used for determination of the migration activity did not show any influence on MI in the concentration range 0.1-0.5 mg/ml. The higher concentrations tested (range 0.6-1.4 mg/ml) lead to reduction of the migration activity presented by a decrease in the migration index MI: for c = 0.6 mg/ml, MI = 0.85; for c = 1.4 mg/ml, MI = 0.45 (normal value for MI is in the range 0.9-1.1).