The Laminin-α1 Chain-Derived Peptide, AG73, Binds to Syndecans on MDA-231 Breast Cancer Cells and Alters Filopodium Formation

Figure 1

Breast cancer cell adhesion to AG73 is likely through a proteoglycan. (a) Adhesion to AG73 (A) and recombinant LG4 (rLG4) is inhibited by heparin (H, hatched; 10 mg/ml), while adhesion to LM-111 (LM) is inhibited by EDTA (E, diagonal; 5 mM) compared to PBS-treated cells (C, control, solid). The cells do not bind to the scrambled (S) peptide or rLG4 mutant (rLG4m, AG73 site mutated RKR-AAA). (b) Many different breast cancer cells (MDA-231, SUM1315, T47D, and MCF7) as well as normal breast cell lines (MCF10A) bind to AG73. (c) Heparin (H), heparan sulfate (Hs), and chondroitin sulfate B (B) significantly inhibited adhesion of MDA-231 cells to AG73 compared to PBS-treated cells (C, control). Hyaluronic acid (Ha), chondroitin sulfate A (A), and chondroitin sulfate C (CC) had no effect on adhesion to AG73 but did affect adhesion to LM-111 (LM). , , and . One-way ANOVA with Bonferroni posttest. (d) Serial dilutions of heparin, heparan sulfate, and chondroitin sulfate B inhibit adherence of cell binding. The IC₅₀ followed the order heparin (0.8 μg/ml), heparan sulfate (6.6 μg/ml), and chondroitin sulfate B (22.4 μg/ml);. (e) MDA-231 cell adhesion to LM-111 (LM), AG73, and rLG4 is inhibited by a 10-fold molar access of AG73 but not the scrambled (S) peptide. Adhesion to basement membrane extract (BME, Matrigel) was unaffected by AG73 or scrambled peptide. Cells were treated with either PBS (C, solid), 10-fold molar excess of AG73 (diagonal), or scrambled peptide (S, hatched) prior to adhesion. Bars: mean .

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