CHARACTERIZATION OF INTEGRIN EXPRESSION IN A WELL-DIFFERENTIATED ENDOMETRIAL ADENOCARCINOMA CELL-LINE (ISHIKAWA)

The pattern of constitutive and cycle-dependent integrins in normal en dometrium has recently been established, suggesting a role for cell ad hesion molecules in endometrial receptivity and implantation. Currentl y few, if any, models exist for the study of human endometrial integri ns and their role in establishment of the receptive endometrial phenot ype. The Ishikawa cell line maintains functional estrogen receptors an d progesterone receptors. The progesterone receptors in these cells ar e inducible by priming with estradiol and down-regulated by treatment with progesterone. In the present study, the pattern of integrin expre ssion in this well differentiated endometrial cell line is compared to that in normal endometrial epithelium using immunohistochemistry and now cytometry and is confirmed by immunoprecipitation, Western immunob lot, and FCR. Like normal endometrial epithelium, Ishikawa cells maint ain constitutive expression of alpha(2) beta(1), alpha(3) beta(1), alp ha(6) beta(1). PCR demonstrates the expected size fragments of each, a lthough evidence for alternatively spliced forms of the alpha(2)-subun it was noted. Progesterone treatment of estradiol-primed cells resulte d in increased expression of the alpha(1) beta(1) collagen-laminin rec eptor and suppression of the alpha(V) beta(3) vitronectin receptor, tw o of the cycle-dependent integrins expressed by normal endometrial epi thelium. Three data support the use of Ishikawa cells as an excellent model to study the regulation endometrial integrins and advance our un derstanding of hormonally mediated events surrounding implantation.