Direct antiproliferative effect of nonsteroidal 17β-hydroxysteroid dehydrogenase type 1 inhibitors in vitro.

Inhibition of the local formation of estrogens seems to be an attractive strategy for pharmacological intervention in hormone-dependent disorders. The direct antiproliferative properties of ten nonsteroidal 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) inhibitors were investigated on human cancer cell lines of gynecological origin. The mechanism of the antiproliferative action was approximated by cell cycle analysis, fluorescent microscopy, BrdU assay, determination of caspase-3 activity and quantification of the expression of cell cycle regulators at mRNA level. Treatment of HeLa cells with some of the compounds resulted in a concentration-dependent inhibition of the G1-S transition and an increase in the apoptotic population. The most effective agents increased the expression of tumor suppressors p21 and p53, while CDK2 and Rb were down-regulated. The reported anticancer actions of the tested compounds are independent of the 17β-HSD1-inhibiting capacity. These results indicate that it is possible to combine direct antiproliferative activity and 17β-HSD1 inhibition resulting in novel agents with dual mode of action.