ANTISENSE RNA OF 32-KDA LAMININ-BINDING PROTEIN INHIBITS ATTACHMENT AND INVASION OF A HUMAN COLON-CARCINOMA CELL-LINE

Tumor invasion and metastasis involves the interaction between tumor cells and basement membrane, which is mediated in part by laminin receptors/laminin-binding proteins. We have reported that a 32-kDa laminin-binding protein (LBP-32) was overexpressed in colorectal cancer at the messenger RNA (mRNA) level and correlated with clinical staging. However, the function of this protein is not yet defined. In this study, we have analyzed the role of LBP-32 in tumor cell attachment and invasion through various basement membrane components. Blockade of LBP-32 synthesis with an anti-sense RNA was utilized in this study. The partial sequence (237 bp) of LBP-32 was inserted into the EMSV33 vector in the sense or antisense direction. Clone A, a poorly differentiated human colon carcinoma cell line, was transfected with EMSV33 alone (control), or EMSV33 with the insert in sense (LBP-S) or anti-sense (LBP-AS) direction using lipofectin. The cell adhesion assays (at 37°C for 75 min) were performed using parental Clone A cells or the transfectants. Specific attachment to wells coated with laminin, fibronectin, or type IV collagen was evaluated. In vitro cell invasion assays were performed using the parental clone A cells and their transfectants to assess the passage through polycarbonate filters coated with matrigel, a reconstituted basement membrane. The results showed that (a) laminin and collagen IV (but not fibronectin) play a role in colon cancer cell attachment to substrata, and (b) anti-sense RNA of LBP-32 inhibits tumor cell attachment and invasiveness in vitro. These findings suggest a role for LBP-32 in colon cancer progression and metastasis. Modulating LBP-32 expression by anti-sense RNA or monoclonal antibodies may have clinical application in colorectal cancer therapy. © 1992.