We have shown that synthetic and natural estrogens and related compounds inhibit the polymerization of microtubule proteins. In this study, cell growth inhibition by synthetic estrogens and their related compounds was examined by the MTT method using L1210, KB, and NIH-3T3 cells transformed with oncogenes, which are typical screening systems for carcinostatics. [(−)3R]Indenestrol B, a derivative of diethylstilbestrol (DES), which strongly inhibited the polymerization of microtubule proteins, also showed marked inhibition of the growth of KB cells and various oncogene-transformed NIH-3T3 cells. On the other hand, DES and indenestrol A markedly inhibited the growth of L1210 cells, indicating that these compounds exhibit cell-specific inhibitory effects on cell growth. Although the inhibition of cell growth by these compounds was not as strong as that by colchicine, the results clearly indicate the potential of these compounds as carcinostatics.
2001 The Pharmaceutical Society of Japan