Estramustine phosphate is a derivative of estradiol that contains a nor-nitrogen mustard group. Estramustine phosphate destabilizes microtubules by binding to microtubule-associated proteins (MAPs) with Kd values of 10 and 15 ?M for MAP-1 and MAP-2, respectively.1 Estramustine induces cell cycle arrest in mitosis at the metaphase stage in DU145 and PC3 prostate cancer cells and induces apoptosis in U87MG human malignant glioma cells.2,3 The metabolites of estramustine phosphate have anti-androgenic effects.4 Formulations containing estramustine phosphate are used in the palliative treatment of prostate cancer.
1.Tew, K.D., and Stearns, M.E.Estramustine--a nitrogen mustard/steroid with antimicrotubule activityPharmacol. Ther.43(3)299-319(1989) 2.Hartley-Asp, B.Estramustine-induced mitotic arrest in two human prostatic carcinoma cell lines DU 145 and PC-3Prostate5(1)93-100(1984) 3.Yoshida, D., Hoshino, S., Shimura, T., et al.Drug-induced apoptosis by anti-microtubule agent, estramustine phosphate on human malignant glioma cell line, U87MG; in vitro studyJ. Neurooncol.47(2)133-140(2000) 4.Wang, L.G., Liu, X.M., Kreis, W., et al.Androgen antagonistic effect of estramustine phosphate (EMP) metabolites on wild-type and mutated androgen receptorBiochem. Pharmacol.55(9)1427-1433(1998)