SDA and IDA - Two aptamers to inhibit cancer cell adhesion.

Aptamers which bind to proteins involved in cell-cell interactions could have significant value to directly affect cancer cell adhesion or for directed cargo delivery. Here, I discuss two aptamers: aptamer SDA which binds to E- and P-selectin, and aptamer IDA which binds to α6β4 integrin. Both aptamers (SDA 91 nt and IDA 77 nt) bind their target proteins with dissociation constants in the 100–150 nM range and substantially inhibit special cellular adhesion, possibly a first and pivotal step in transendothelial migration during metastasis formation. The aptamers' half-lives in cell culture media are between two and six hours. IDA is internalized by integrin presenting cells within minutes thus possibly serving as vehicle for directed cargo delivery.