Expression and ligand-binding function of the integrin alpha 4 beta 1 (VLA-4) on neural-crest-derived tumor cell lines

Abstract

Human neural-crest-derived tumor cell lines, including three neuroblastomas, an astrocytoma, a glioblastoma, a rhabdomyosarcoma and a melanoma were screened for the expression of the integrin alpha 4 beta 1 (VLA-4). The neuroblastomas IMR-32 and SK-N-SH, the astrocytoma 131-INI, the glioblastoma Fogerty and the rhabdomyosarcoma TE-671 expressed alpha 4 beta 1 as determined by cytofluorometry and immunoprecipitation. Another neuroblastoma line, LA-N-1, did not express alpha 4 beta 1. Analysis of immunoprecipitated alpha 4 beta 1 showed that the alpha 4 subunit from the various cell types differed in relative molecular weight (M(r)). The variability in the observed M(r) could be accounted for by differences in the levels of N-linked glycosylation. The observed variability in M(r) did not appear to affect function since intact cells and solubilized alpha 4 beta 1 bound to a synthetic peptide identical in sequence to the CS-1 region of the alternatively spliced IIICS domain of fibronectin, a known alpha 4 beta 1 ligand.