Estrogenic and antiestrogenic regulation of MMP-2 and MMP-13 mRNA in RUCA-I endometrial tumor cells in vitro and in vivo

We investigated the influence of estrogenic and antiestrogenic treatment on proteolytic activity – especially on MMP-2 and MMP-13 – in the RUCA-I transplantable endometrial tumor model. Morphological studies demonstrate that RUCA-I cells are forming highly differentiated gland-like structures by remodelling and invading the underlying ECM. Estrogens upregulate the mRNA levels of MMP-2 and MMP-13 in the rat uterus. Treatment with the pure antiestrogen ICI 182,780 results in the downregulation of MMP-2 and MMP-13 mRNA. The same regulation for MMP-13 mRNA is found in vitro in RUCA-I cells. In contrast, in the transplantation tumor, the mRNA level of MMP-13 is repressed by estrogens and induced by ICI 182,780. MMP-2 mRNA is not regulated by hormones in the transplantation tumor and in RUCA-I cells. The divergent regulation suggests a varying influence of cell–cell-, cell–extracellular matrix interactions and soluble factors.