ZK-119010

The recently established, estrogen receptor positive rat endometrial adenocarcinoma cell line RUCA-I was tested for estrogen responsiveness in vivo and in vitro. In vivo, 10(6) RUCA-I cells were injected subcutaneously into intact, ovariectomized, or ovariectomized, estradiol-substituted syngenic DA/Han rats. All animals developed well differentiated endometrial adenocarcinoma, that had metastasized to peripheral lymph nodes and into the lung. Ovariectomy reduced tumor and lymph node weight, as well as number of lung metastases significantly compared to controls. In another series of experiments, treatment with the pure anti-estrogen ZK 119010 basically gave the same results as seen in ovariectomized animals, whereas tamoxifen treatment had no effect on metastasis of RUCA-I cells. These findings clearly demonstrate the estrogen dependency of growth and metastasis of RUCA-I cells in vivo. In vitro, we assessed the estrogenic and anti-estrogenic potency of various anti-estrogens, thereby investigating their effects on the expression of components of the complement C3 complex as an estradiol-induced protein and on the expression of fibronectin as an estrogen-repressed protein. Evaluating the relative anti-estrogenic potency of these anti-estrogens we found that ICI 164384 and ICI 182780 behaved as complete antagonists in vitro. Tamoxifen, like estradiol, stimulated complement C3 production and repressed fibronectin expression and has to be regarded as an agonist in this particular in vitro system. ZK 119010 if given alone had no significant influence on the biosynthesis of complement C3 and of fibronectin if compared to the unstimulated control. In addition, another estrogen dependent parameter was identified. Estrogen and anti-estrogen treatment affected glycosylation of complement C3 components. After estradiol treatment predominantly the higher glycosylated epitope of complement C3 became detectable, which could be transformed into the low molecular weight epitope by treatment with hyaluronidase. Finally, we compared the anti-proliferative effects of ICI 164384 and of tamoxifen in vitro. Both anti-estrogens slightly inhibited the growth of RUCA-I rat endometrial adenocarcinoma cells. In conclusion, RUCA-I cells represent a powerful, endometrial derived experimental model to test the agonistic and antagonistic properties of anti-estrogens on growth and metastasis in vivo and on gene expression in vitro. The effects of the tested anti-estrogens on gene expression of RUCA-I cells were found to be useful in predicting their effectiveness on tumor growth in vivo.

Uterine epithelial cells have been shown by in vitro studies to be a potent source of the inflammatory cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF), and the luminal and glandular epithelium has been confirmed as the predominant site of GM-CSF expression in the intact endometrium by in situ hybridization. To examine the role of ovarian steroid hormones in GM-CSF synthesis, GM-CSF bioactivity has been measured in the supernatants of short-term primary cultures of endometrial cells prepared from mice in which steroid levels were perturbed by ovariectomy and steroid replacement or by steroid antagonists. GM-CSF production was found to fluctuate in cells harvested at different times during the estrous cycle, peaking at estrus. Endometrial cells derived from ovariectomized mice produced 25-fold less GM-CSF than did cells from estrous mice, and production was increased if ovariectomized mice were pretreated with estrogen, but not progesterone, 3 h or more before harvest. This estrogen-induced increase was inhibited by coadministration of progesterone or by induction of a decidual response and was blocked by the estrogen antagonist ZK 119,010. By contrast, pretreatment of mice with the anti-progestin RU486 significantly elevated GM-CSF output in cells from ovariectomized mice given estrogen and progesterone in combination and antagonized the inhibition of GM-CSF release seen in cells harvested from mice treated with hCG. These studies demonstrate that GM-CSF synthesis and/or release by uterine epithelial cells is stimulated by estrogen, with progesterone having a moderate inhibitory effect. Analysis of GM-CSF mRNA expression in uterine epithelial cell cultures and in intact uteri from steroid hormone-treated ovariectomized mice by quantitative reverse transcription-polymerase chain reaction indicated that the effects of estrogen and progesterone on GM-CSF release are mediated at least in part at the transcriptional level. These findings implicate GM-CSF as a local mediator of steroid-driven remodeling events in the cycling and preimplantation endometrium, possibly acting through the recruitment and behavioral regulation of granulocytes and macrophages.