A putative new proteinous factor negative for stromal growth. Purification and identification from endometrial carcinoma extract.

Abstract

Uterine endometrial carcinoma has been reported to synthesize and secrete some putative mitogens that elicit either a positive or negative proliferation response in endometrial fibroblasts. The purposes of this study were to isolate and to identify the negative growth factor(s) from endometrial carcinoma extract. The factor was isolated by a sequence of molecular size exclusion filtration, anion exchange chromatography, gel filtration and Affi-Gel Blue chromatography, followed by NH2-terminal amino acid sequencing. Mitogenicity was determined by [3H]thymidine incorporation into the endometrial fibroblasts. The purification procedure yielded a single active protein band (68 kDa). The protein, purified approximately 20,000-fold, evoked 90% inhibition of [3H]-thymidine incorporation into endometrial fibroblasts in the nanomolar range. This potent growth inhibitor is a previously unidentified protein molecule as revealed by amino acid sequences. Endometrial carcinoma could produce a new protein that may act as a paracrine factor to suppress the growth of its stroma endometrial fibroblasts.