Co-Expression of the α2-Subunit of Laminin and the Metastatic Phenotype in Melanoma Cells

Abstract

Previous studies in this laboratory demonstrated the presence of laminin M or “M” subunit of about 300 kDa, which was shown to be absent in EHS tumor laminin or in laminin synthesized by some neoplastic cell lines (Ohno et al., 1983, 1986; Jenq et al., 1993). Because of the large number of isoforms of the laminin chains isolated in different laboratories, a new nomenclature has been proposed (Burgeson, et al., 1993). Table I shows the new names given to the “classical” laminin chains isolated from the mouse EHS tumor as well as to the new isoforms of laminin isolated from a variety of normal tissues. Thus, AB1 B2 is now designated α1ß1γ1. The “M” subunit first isolated by Ohno et al. (1983, 1986) in our laboratory has been given the new name α2. Merosin, the laminin which contains the α2-subunit has been designated α1ß1γ1. Merosin has been identified in human placenta, striated muscle, peripheral nerve and Schwannoma cells (Leivo and Engvall, 1988; Ehrig et al., 1990; Engvall et al., 1992).