INHIBITION OF ESTROGEN-STIMULATED GROWTH OF UTERINE LEIOMYOMAS BY SELECTIVE ESTROGEN-RECEPTOR MODULATORS

Uterine leiomyoma is the most frequent gynecologic neoplasm in women. By using a panel of cell lines derived from spontaneous Eker rat leiom yomas, we examined the estrogen-responsive phenotype of these tumor ce lls. Leiomyoma-derived ELT cell lines proliferated in response to estr ogen, and estrogen-induced cell proliferation could be inhibited by th e estrogen antagonist ICI 182780 and the selective estrogen-receptor m odulators (SERMs) raloxifene and tamoxifen. In addition to inhibiting cell growth, these antagonists also inhibited estrogen-induced increas es in progesterone-receptor expression. These data indicate that SERMs such as raloxifene and tamoxifen act as estrogen antagonists in uteri ne myometrial cells and suggest that this class of compounds may be ef fective for treatment of this important gynecologic neoplasm. (C) 1996 Wiley-Liss, Inc.