β1C Integrin Expression in Human Endometrial Proliferative Diseases

Integrins are ubiquitous cell adhesion molecules that are involved in maintaining normal tissue morphology and have been implicated in the aggressive behavior of several malignancies. β1C integrin is an alternatively spliced variant of the β1A integrin subunit that, at variance with β1A, inhibits epithelial cell proliferation. β1C integrin is expressed in non-proliferative, benign prostatic epithelium and is down-regulated in prostatic adenocarcinoma. In the current study, we examined β1C expression at mRNA and protein levels in 18 endometrial adenocarcinoma and in 20 endometrial hyperplastic tissues, using Northern and Western blotting analysis and immunohistochemistry. The pattern of integrin expression was compared to that of the endometrium of 14 normal cycling women. The results of this study document inhibited β1C integrin expression in endometrial adenocarcinoma, both at the mRNA and protein levels, at variance with significantly up-regulated β1C mRNA expression in endometrial hyperplasia, in comparison with normal proliferative endometria. Our data suggest a key role of the regulation of β1C integrin expression in the pathogenesis of endometrial proliferative diseases: β1C integrin may act as growth modulator in cancer cells, playing a role in downstream intracellular signaling.