A NEW APPROACH TO CANCER-THERAPY DUE TO APPROPRIATE UPTAKE AND RETENTION KINETICS OF META-TETRAHYDROXY-PHENYLCHLORIN IN A HUMAN FIBROBLAST CELL-LINE

Studies have shown that meta-tetrahydroxy-phenylchlorin is an efficien t tumor targeting agent for laser photodynamic therapy. The effectiven ess of this approach for cancer treatment depends on drug concentratio n, incubation time and extracellular protein. We studied uptake and re tention kinetics of mTHPC in a human fibroblast cell line. Our results clearly demonstrate a difference in the amount of extracellular mTHPC at an incubation temperature of 37 degrees C compared to 20 degrees C and 4 degrees C. pH-values were always constant and not responsible f or the increase. Furthermore, both absorption and fluorescence of mTHP C increase when incubated at normal human body temperature. Incubation of human fibroblast cells with mTHPC (10 micg/mL) showed that intrace llular mTHPC increases in a linear manner reaching saturation after 24 hours and declining until 48 hours with concommitant increase of supe rnatant mTHPC. Therefore, we believe that tumor cells can be treated o ptimally with PDT following a delay >24 hours after drug administratio n with a minimum of damage to surrounding normal tissues.