Effect of N‐cadherin activation on Matrigel invasion and collagen I migration in melanoma cells

Melanoma progression is associated with the downregulation of E‐cadherin and the upregulation of N‐cadherin, the so‐called ‘cadherin‐switch’. The upregulation of N‐cadherin has been hypothesized to potentiate pro‐invasive and pro‐migratory signaling in other cancers. This study examined the effect of the cyclic 14‐mer peptide N‐Ac‐ CHAVDINGHAVDIC ‐NH 2 which has previously been reported to activate N‐cadherin (Skaper et al., Mol. Cell. Neurosci. 87(10):3398–3406, 2004). Two vertical growth phase melanoma cell lines, WM278 and A375, were grown in Tu2% media (4:1 mix MCDB 153 :L15 with 2% serum, 5 μg/ml insulin, 2 mM CaCl 2 ). Treated cells were mixed with SW4 (50 μg/ml) for 30 min prior to assay. Invasion (24 hr) and migration (6 hr) assays were carried out with a 48‐well modified Boyden chamber assay. Membranes were coated with 0.5 mg/ml Matrigel for invasion assay and 0.1 mg/ml rat tail collagen I for migration assay. Assays were run in Tu2% with or without SW4 (50 μg/ml) in the presence or absence of bFGF (10 ng/ml). Surprisingly, SW4 activation caused a substantial reduction in WM278 invasion (749 ± 48 to 284 ± 71 cells per 5‐high power fields, ANOVA p<0.001). SW4 also caused a lesser reduction in WM278 collagen I migration (408 ± 20 to 319 ± 11, ANOVA p<0.001). Under the study conditions, the bFGF chemotactic effect was negligible. A375 invasion was low and did not change with SW4 (32 ± 7 vs 34 ± 8). A375 migratory was also low but increased with SW4 (113 ± 12 to 154 ± 8, p<0.01). The data suggest that under some conditions N‐cadherin activation without homotypic, homophilic adhesion is capable of inhibiting melanoma invasion and migration. Supported by ATSU Graduate Program Fund