LASER PHOTOCHEMOTHERAPY WITH ANTHRACYCLINES ON CULTURED HUMAN SQUAMOUS CARCINOMA-CELLS

A new treatment for cancer has been tested in vitro using light-sensit ive anthracyclines followed by laser photoactivation, as described by several investigators, We previously reported 10-fold enhanced laser k illing after 2 hours of incubation with daunomycin by cultured human c arcinoma cells. This short-term uptake leads to drug localization in c ytoplasmic and membrane sites prior to nuclear accumulation and topois omerase inhibition. In the present study, daunomycin was incubated for 2 or 24 hours with P3 squamous carcinoma cells to directly compare cy toplasmic vs. nuclear drug targeting before and after KTP-532 laser ac tivation, Monolayer cultures of the P3 cells sensitized with daunomyci n for 2 hours, then chilled (4 degrees C), and exposed to the KTP lase r (532 nm, 94.2 J/cm(2)) had a 2- to 10-fold increased therapeutic res ponse compared with drug or laser alone when measured by MTT tetrazoli um assays, After 24 hours of incubation with daunomycin, the chemother apeutic response of P3 tumor cells was amplified S-fold by laser expos ure, The results suggest that daunomycin and laser treatment can be co mbined for improved therapy of human cancer.