Endometriosis is characterized by an impaired localization of laminin-5 and alpha3beta1 integrin receptor.

Endometriosis is an estrogen-correlated benign disease characterized by a marked ability of endometrial-like cells to invade and proliferate outside uterine cavity, resembling for some invasive aspect the cancer growth. The molecular mechanisms regulating endometrial cell invasiveness are mostly unknown, although interactions between extracellular matrix (ECM) proteins and their transmembrane receptors, integrins, are likely to play a central role. In particular, laminin (Ln)-5 could be closely involved, as it is in cancer. We have investigated the expression of Ln-1, Ln-5, and collagen IV (Coll IV) ECM proteins and their receptors, alpha3beta1 and alpha6beta4 integrins, in atrophic, proliferative, and secretive endometrium and in endometriosis. The results show that Ln-5, but not Ln-I and Coll IV, is altered in secretive endometrium as well as in endometriosis tissues. No alterations are observed in atrophic or proliferative endometrium. Consistently, the polarization of both integrin subunits alpha3 and beta1, but not alpha6 and beta4, is altered in secretive endometrium and endometriosis tissues, but not in atrophic and proliferative endometrium. These results seem to suggest that Ln-5 and alpha3beta1 could be involved in the invasive mechanism of endometriosis. The altered expression of Ln-5, by upregulating matrix metalloproteases activity, suggest an invading process similar to that of many cancer processes.

Laminin-5 with transforming growth factor-beta1 induces epithelial to mesenchymal transition in hepatocellular carcinoma.

BACKGROUND & AIMS: How hepatocellular carcinoma (HCC) cells acquire the ability to invade surrounding tissue is unknown, but epithelial mesenchymal transition (EMT) likely plays a role. We investigate how transforming growth factor (TGF)-beta1 and extracellular matrix protein Laminin-5 (Ln-5) induce EMT and cancer invasion. METHODS: Snail, Slug, E-cadherin, beta-catenin and Ln-5 were investigated on HCC tissues and on HCC cell lines. RESULTS: We show that in HCC but not in peritumoral tissue of the same HCC patients, Ln-5, Snail, and Slug are up-regulated, E-cadherin is down-regulated and beta-catenin is translocated into the nuclei. In vitro, HCC "invasive" cells, partially EMT-transformed, show low levels of E-cadherin. In presence of Ln-5, Snail, and Slug are up-regulated, E-cadherin is down-regulated, beta-catenin is translocated into the nuclei, and cells undergo a dramatic morphological change, becoming scattered and undergoing a complete EMT. This effect is reversed by anti-alpha3 but not by anti-alpha6 integrin blocking antibody. HCC "noninvasive" cells are not EMT-transformed, and have constitutively high levels of E-cadherin. In presence of Ln-5, cells undergo partial EMT, Snail, and Slug are up-regulated, E-cadherin is down-regulated but cells do not scatter. However, the presence of both Ln-5 and TGF-beta1 completes the EMT process, beta-catenin is translocated into the nuclei, cells scatter and become invasive, recalling the "invasive" cells. In this case, too, the effect is reversed by anti-alpha3 integrin blocking antibody. CONCLUSIONS: Our study shows that Ln-5 and TGF-beta1 cooperatively induce EMT in HCC, suggesting the microenvironment as a potential target for new biological therapies.