Alkylation of phosphorothioated thrombin binding aptamers improves the selectivity of inhibition of tumor cell proliferation upon anticoagulation

Abstract

BackgroundRecently, aptamers have been extensively researched for therapy and diagnostic applications. Thrombin-binding aptamer is a 15nt deoxyribonucleic acid screened by SELEX, it can specifically bind to thrombin and inhibit blood coagulation. Since it is also endowed with excellent antitumor activity, the intrinsic anticoagulation advantage converted to a main potential side effect for its further application in antiproliferative therapy. MethodsSite-specific alkylation was conducted through nucleophilic reaction of phosphorothioated TBAs using bromide reagents. Circular dichroism (CD) spectroscopy and surface plasmon resonance (SPR) measurements were used to evaluate anticoagulation activity, and a CCK-8 assay was used to determine cell proliferation activity. ResultsThe CD spectra of the modified TBAs were weakened, and their affinity for thrombin was dramatically reduced, as reflected by the KD values. On the other hand, their inhibition of A549 cells was retained. ConclusionsIncorporation of different alkyls apparently disrupted the binding of TBA to thrombin while maintaining the antitumor activity. General significanceA new modification strategy was established for the use of TBA as a more selective antitumor agent.