ENDOTHELIN-1 GENE-EXPRESSION AND BIOSYNTHESIS IN HUMAN ENDOMETRIAL HEC-1A CANCER-CELLS

In this study, evidence was obtained that endothelin-1 (ET-1) is produced by an established endometrial cancer (HEC-1A) cell line. PreproET-1 mRNA is present in HEC-1A cells, and immunoreactive endothelin is secreted into the medium of these cells maintained in culture. Cycloheximide treatment of these cells caused superinduction of preproET-1 mRNA. Transforming growth factor-beta acts in these cells to increase the levels of preproET-1 mRNA. This effect of transforming growth factor-beta on preproET-1 mRNA accumulation was accompanied by an increase in the amount of immunoreactive endothelin secreted into the culture medium. ET-1, added to the culture medium, did not act as a mitogen in HEC-1A cells. We speculate that ET-1 (which is known to stimulate fibroblast proliferation) produced by endometrial adenocarcinoma cells may participate in the angiogenic process that occurs during the establishment of this carcinoma in vivo.