[Experimental studies on photoradiation therapy (PRT)--effects of PRT on cultured human cancer cell lines]

Hematoporphyrin derivative (HpD) is known to have an affinity for tumor cells. Photoradiation therapy (PRT), in which HpD is activated by an argon dye laser, is not always effective in treating all gynecological malignancies. Fundamental studies were performed to elucidate the mechanism acting on two cell lines and to evaluate efficiency when applied to them. Two cell lines established from endometrial adenocarcinoma and uterine choriocarcinoma were used in this study. There were apparent differences in 3H-thymidine incorporation on two cell lines treated by single HpD. In both cell lines, single HpD has some effects on neutral red uptake depending on the HpD concentration and length of treatment time. In PRT, a proportional increase in effects is obtained by extending the irradiation time. More than 90% effectiveness is obtained by pretreatment with HpD 40 micrograms/ml and irradiation for 3 minutes or more. On the DNA patterns of the cells, a shift in the histogram peak to diploid and a remarkable decrease in the number of high ploidy cells above tetraploidy occurred but were not so noteworthy in these two cell lines as in SKG-1 cells.