PC12 cells attach to rLG1 and Ln2-P3 through syndecan-1. PC12 cells were transfected with control siRNA, syndecan-1 siRNA, syndecan-4 siRNA, or glypican-1. A, RT-PCR analysis of the expression of syndecan-1. GAPDH, glyceraldehyde-3-phosphate dehydrogenase. B, fluorescence-activated cell sorter analysis of syndecan-1 siRNA-transfected cells assessing syndecan-1 expression by using an antibody against syndecan-1 (white area) compared with IgG control (gray area). C, inhibition of cell adhesion to rLG1 and Ln2-P3 in syndecan-1 siRNA-transfected cells. siRNA-transfected cells were seeded on rLG1- or Ln2-P3-coated plates for 1 h in serum-free medium. The number of adherent cells was quantified by cell counting. Results are expressed as a percentage from the value of control siRNA-transfected cells (mean ± S.D., n = 3). *, p < 0.01. D, RT-PCR analysis of the expression of syndecan-4 and glypican-1. E, adhesion of syndecan-4 siRNA- and glypican-1 siRNA-transfected cells to rLG1 and Ln2-P3 showing no difference to the control siRNA-transfected cells. The assay conditions were the same as described in C.