Transformation proceeds in a sequential manner with progressive transitions in a number of phenotypic characteristics. Similar results have been found in studies of animal and human cells treated repetitively with chemical carcinogens such as MNNG. One serious drawback to many of these studies is the lack of an identifiable and reproducible in vitro endpoint to distinguish full transformation. In our proposed studies we will use adult human endometrial cell that have been treated with MNNG in vitro and that demonstrate characteristics of human endometrial stromal cell tumors. We will also use cultured rat liver epithelial cells that have been similarly treated. We seek to test the hypothesis that a cell's ability to invade basement membrane, as monitored by a novel in vitro assay, is an in vitro phenotypic marker for full transformation. Further, we propose to examine if these fully transformed cells demonstrate concomitant alterations in expression of basement membrane proteins. We have recently shown that in a system of clonally derived cells, the invasive ability, as judged by this in vitro amnion model system, correlates and cosegregates with tumorigenicity. Work by us has also shown a significant inhibition of invasion by transformed human sarcoma cells after exposure to a novel anti-protease inhibitor. We therefore, further propose to test the hypothesis that the tumorigenic cells in this study can be chemically inhibited in vivo and that the amnion assay can serve as an in vitro measure of this ability. Our goals are: 1-To determine a quantifiable endpoint for malignant transformation in culture and 2-To use this same system as a monitor of the measure of chemical effects on fully transformed cells in vivo. If the hypothesis is supported by the weight of the experimental evidence this will give us the critical ability to accurately separate partial from full transformation. With this ability we can continue to elucidate the underlying mechanism(s) involved in tumor progression.
