INVERSE EXPRESSION OF 2 LAMININ-BINDING PROTEINS, 67LR AND GALECTIN-3, CORRELATES WITH THE INVASIVE PHENOTYPE OF TROPHOBLASTIC TISSUE

Tumor invasion of host tissues and trophoblastic penetration of the en dometrium share common biological features. Both processes involve the invasion of basement membranes, an event that is initiated by adhesio n of cancer or trophoblast cells to basement membrane components and p articularly to laminin. Adhesion to this latter glycoprotein is mediat ed through a variety of cell surface receptors. We have previously sho wn that the 67 kD Laminin Receptor (67LR) and a 31 kD Human Laminin Bi nding Protein, recently renamed galectin-3, are inversely modulated as the invasive phenotype of cancer cells progresses, with up regulation of the former, and down regulation of the latter, respectively. In th is study, we examined the expression of these two proteins in 27 human trophoblastic specimens at different gestational ages using Northern and Western blot techniques. Expression of the 67LR increased from 7 w eeks to a maximum at 12 weeks, when invasion is maximal, and then decr eased. Expression of galectin-3 was inversely modulated by the gestati onal age, with a minimum expression at 12 weeks. Our data demonstrate that invasive trophoblast displays the same pattern of laminin binding proteins expression than invasive cancer cells, and further demonstra tes that invasion of the extracellular matrix by trophoblast and cance r cells share common molecular mechanisms. (C) 1994 Academic Press, In c.