Influence of conformationally restricted nucleosides on the activity of 10-23 DNAzymes

L ROBALDO; F. IZZO; M DELLAFIORE; C. PROIETTI; P. ELIZALDE; J. MONSERRAT; A. IRIBARREN

BIOORGANIC & MEDICINAL CHEMISTRY.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2012 vol. 20 p. 2581 - 2586

0968-0896

The catalytic core of a 10–23 DNAzyme was modified introducing conformationally restricted nucleosides such as (20R)-, (20S)-20-deoxy-20-C-methyluridine, (20R)-, (20S)-20-deoxy-20-C-methylcytidine, 2,20-anhydrouridine and LNA-C, in one, two or three positions. Catalytic activities under pseudo first order conditions were compared at different Mg2+ concentrations using a short RNA substrate. At low Mg2+ concentrations, triple modified DNAzymes with similar kinetic performance to that displayed by the non-modified control were identified. In the search for a partial explanation of the obtained results, in silico studies were carried out in order to explore the conformational behavior of 20-deoxy-20-C-methylpyrimidines in the context of a loop structure, suggesting that at least partial flexibility is needed for the maintenance of activity. Finally, the modified 20-C-methyl DNAzyme activity was tested assessingthe inhibition of Stat3 expression and the decrease in cell proliferation using the human breast cancer cell line T47D.