The heterodimeric laminin receptor α6β4 integrin plays a central role in the promotion of tumor cell growth, invasion, and organotropic metastasis. As an overproduction of the integrin is often linked to a poor prognosis, the inhibition of integrin α6β4 binding to laminin is of high therapeutical interest.
Here, we report on the combination of a cell-systematic evolution of ligands by exponential enrichment and a bead-based selection resulting in the first aptamer inhibiting the interaction between α6β4 integrin and laminin-332. This Integrin α6β4-specific DNA Aptamer (IDA) inhibits the adhesion of prostate cancer cells (PC-3) to laminin-332 with an IC50 value of 149 nmol/l. The Kd value concerning the aptamer's interaction with PC-3 cells amounts to 137 nmol/l. Further characterization showed specificity to α6 integrins and a half-life in murine blood plasma of 6 hours. Two truncated versions of the aptamer retained their binding capacity, but lost their ability to inhibit the interaction between laminin-332 and PC-3 cells. Confocal laser scanning microscope studies revealed that the aptamer was internalized into PC-3-cells. Therefore, in addition to the adhesion-blocking function of this aptamer, IDA could also be applied for the delivery of siRNA, microRNA or toxins to cancer cells presenting the integrin α6β4.
Molecular therapy. Nucleic acids. 2016 Mar 15*** epublish ***
Katharina Berg, Tobias Lange, Florian Mittelberger, Udo Schumacher, Ulrich Hahn
MIN-Faculty, Chemistry Department, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany., University Medical Center Hamburg-Eppendorf, University Cancer Center, Institute of Anatomy and Experimental Morphology, Hamburg, Germany., MIN-Faculty, Chemistry Department, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany., University Medical Center Hamburg-Eppendorf, University Cancer Center, Institute of Anatomy and Experimental Morphology, Hamburg, Germany., MIN-Faculty, Chemistry Department, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.