Synthesis and biological activity of gold and tin compounds in ovarian cancer cells

We have investigated the patterns of in vitro cytotoxicity, induced by six newly synthesized gold and tin compounds, in three human ovarian cancer cell lines (SW 626, IGROV 1 and OVCAR-3). Four gold compounds, i.e. gold(I)lupinylsulfide hydrochloride [1] (containing a naked gold atom), triethylphosphinogold(I)lupinylsulfide hydrochloride [2], triphenyl-phosphinogold(I)lupinylsulfide hydrochloride [3] and 1,2-bis(diphenylphosphino)ethane bis[gold(I)lupinylsulfide] dihydrochloride [4] (all containing a gold atom coordinated with different phosphines), were prepared. Moreover, the triethylphosphinogold(I)(2-diethylamino)ethylsulfide hydrochloride [5] in which the simple diethylaminoethylthiol replaced the bulky lupinylthiol was synthesized. The tin compound, triethyltin(IV)lupinylsulfide hydrochloride [6], was also studied. Comparative tests with cisplatin, the most widely used antitumor agent in ovarian cancer, were carried out in biological investigations. In vitro cytotoxicity, by MTT assay, showed that compound [4] and compound [6] exhibited interesting antiproliferative activity in all the three cell lines (mean IC50=1.3 and 0.7 mu M, respectively) compared to cisplatin (mean IC50=4.8 mu M). In addition, the PA-1 cell line, more sensitive to cisplatin (IC50=0.6 mu M), was included as a comparison in the study. Cell count assays confirmed the cytotoxic properties of compounds [4] and [6] against the four cell lines, reporting higher growth inhibition potency than cisplatin, with IC50 values in the sub micromolar range. [(C) 1998 Lippincott Williams & Wilkins.].