LASER PHOTOSENSITIZATION OF CELLS BY HYPERICIN

Administering a light dose of 90 J/cm(2) at 599 nm during incubation w ith hypericin to a highly differentiated normal epithelial cell line ( FRTL-5), derived from Fisher rat thyroid, and to a neoplastic cell lin e (MPTK-6), derived from the lung metastases of a thyroid carcinoma in duced in Fisher rats, produces cell kill at drug doses 1000 times lowe r than those necessary to cause the same mortality in the dark. The ph otocytocidal activity of this polycyclic quinone drag on neoplastic ce lls is superior to that of antitumor anthraquinone drugs, such as daun omycin and mitoxanthrone, and to the photosensitized antiviral activit y previously reported for hypericin.