Photodynamic action of meta-tetrahydroxyphenylchlorin (mTHPC) on an ovarian cancer cell line

Meta-tetrahydroxyphenylchlorin (mTHPC) exhibits significant cytotoxicity ag ainst a variety of human cells in culture in combination with light, but al so in dark reaction. The ovarian cancer cell line SK-OV3 was incubated with various concentrations of mTHPC and in comparison with Taxol and Cisplatin ; then the effect on cell growth was determined. mTHPC exhibited an IC50 of 0.9 mu M after 24 hours incubation (IC50 of 1.25 after 2 hours), whereas C isplatin and Taxol, which, have been used as first line agents for the trea tment of ovarian carcinomas, inhibited cell proliferation with an IC50 conc entration of 4.6 mu M and 78 nM after 24 hours incubation, respectively. In cubation of SK-OV3 cells with mTHPC for 5 days resulted in cytostatic cytot oxicity ata concentration of 0.5 mu M. The photodynamic effect of mTHPC dep ends/among other parameters/on the concentration of the dye present. In com bination with light (approximate to 15 J/cm(2)) a linear relationship betwe en the dose of mTHPC and the amount of necrotic cells was observable. Highe r concentrations of mTHPC caused necrosis of the ovarian tumor cells. The i ntracellular concentration of mTHPC showed a linear increase up to 28.6 nM (incubation concentration). In summary, these studies demonstrated that mTH PC exhibits potent antiproliferative activity by inducing necrosis after ap plication of Eight. MTHPC might be a promising agent with cytostatic and ph otodynamic properties for the treatment of metastising ovarian carcinomas. A sensitive PCR method was not able to show the induction of apoptosis in t he SK-OV3 ovarian cell line. Using propidium staining, it could be proved t hat the cell death was caused by necrosis and not through apoptosis after i rradiation with light.