Rho-associated serine/threonine kinases (ROCKs) are principal regulators of the actin cytoskeleton that regulate the contractility, shape, motility, and invasion of cells. We explored the relationships between structure and anti-ROCK2 activity in a group of purine derivatives substituted at the C6 atom by piperidin-1-yl or azepan-1-yl groups. Structure-activity relationship (SAR) analyses suggested that anti-ROCK activity is retained, and may be further increased, by substitution of the parent compounds at the C2 atom or by expansion of the C6 side chain. These inhibitors of ROCK can reach effective concentrations within cells, as demonstrated by a decrease in phosphorylation of the ROCK target MLC, and by inhibition of the ROCK-dependent invasion of melanoma cells in the collagen matrix. Our study may be useful for further optimization of C6-substituted purine inhibitors of ROCKs and of other sensitive kinases identified by the screening of a broad panel of protein kinases.

Department of Cell Biology Faculty of Science Charles University Prague Viničná 7 12843 Prague 2 Czech Republic

Department of Chemical Biology and Genetics Centre of the Region Haná for Biotechnological and Agricultural Research Palacký University Šlechtitelů 27 CZ 78371 Olomouc Czech Republic

Department of Clinical and Molecular Pathology Institute of Molecular and Translational Medicine Faculty of Medicine and Dentistry Palacký University Hněvotínská 3 775 15 Olomouc Czech Republic

Isotope Laboratory The Czech Academy of Sciences Institute of Experimental Botany Vídeňská 1083 142 00 Prague 4 Czech Republic

Laboratory of Growth Regulators The Czech Academy of Sciences Institute of Experimental Botany and Palacký University Šlechtitelů 27 CZ 78371 Olomouc Czech Republic

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