Objective: Prostate cancer is the most common type of cancer in males. There is currently no therapy to cure various types of cancer, and hence studies aiming to develop cancer treatment are important and ongoing. Thiosemicarbazone (TSC) and Schiff base and their metal complexes have antitumor activity and are being used as antitumor drugs. It has been revealed with quantitative-structure-activity relationship (QSAR) studies that production of new substances by structural changes in these compounds has different effects. In this study, a new TSC and its Cu, Co and Ni metal complexes synthesized in our laboratory was investigated in terms of their mechanism of action and antitumor properties by using androgen-dependent (LNCaP) and independent (PC3) human prostate cancer cell lines.

Materials and Methods: At the first stage of the study, these cell lines were treated with varying concentrations of TSC and Schiff base and their metal complexes (1,25 and 50 µM) for 24 h. Antitumor activities of these substances were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Mode of action of these antitumor substances was determined by comet assay (reveals DNA damage).

Results: TSC and its metal complexes (except Ni complex) dose-dependently reduced cell viability of LNCaP cells but they did not have any effect on viability of PC3 cells (except 25 and 50 µM). All of the substances dose-dependently increased DNA breakage in LNCaP cells, but not in PC3 cells.

Conclusion: Our results indicate that the tested agents have antitumor activity on LNCaP cell lines and these cytotoxic effects appear to be androgen reseptor dependent DNA damage.