Efficacy and specificity of antisense laminin chain-specific expression vectors in blocking laminin induction by TGFβ1: Effect of laminin blockade on TGFβ1-mediated cellular responses

✍ Scribed by Sriram Rajagopal; Thomas L. Moskal; Hongmei Wang; Subhas Chakrabarty

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 213 KB
• Volume: 178
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199903)178:3<296::aid-jcp3>3.0.co;2-f

✦ Synopsis

Transforming growth factor␤1 (TGF␤1) elicits a multitude of cellular responses from the epithelial-derived human colon cancer Moser cells. TGF␤1 induces the expression of laminin and fibronectin, and previous studies show that the induction of fibronectin is functionally associated with the regulation of carcinoembryonic antigen (CEA) expression by TGF␤1 (Huang and Chakrabarty, 1994, J Biol Chem 269:28764 -28768). In this study we constructed antisense laminin chainspecific expression vectors and determined their efficacy in blocking the expression and the induction of the large multichain laminin molecule by TGF␤1. We also determined the functional role of laminin in several TGF␤1-mediated responses: growth inhibition, downmodulation of anchorage-independent growth, and cellular invasion. Expression of either antisense laminin chain A, B1, or B2 RNA resulted in a downmodulation of endogenous laminin mRNA expression and blocked the induction of laminin protein by TGF␤1 without affecting the induction of other adhesion molecules such as fibronectin or CEA. It is concluded that antisense RNA directed to only one of the laminin chains was sufficient to disrupt the induction of the complex laminin molecule in quite a specific manner. Expression of antisense laminin RNA downregulated cellular adhesion to extracellular matrix (ECM) laminin and blocked the ability of TGF␤1 to upmodulate adhesion to ECM laminin. Expression of antisense laminin RNA, however, did not alter the downregulating effect of TGF␤1 on cellular proliferation, anchorageindependent growth, or cellular invasion, suggesting that the induction of laminin did not play a significant functional role in these TGF␤1-mediated cellular responses. It is likely that other adhesion pathways may be involved in mediating the action of TGF␤1 in this cell line.