The hydrophobic character of pyrazo

The hydrophobic character of pyrazolo-pyrimidines appeared to be a crucial parameter that affected compound activity. LogP values (calculated by MarvinSketch software,www.chemaxon.com) lower than 3.5 were associated to inactive compounds, while activity occurred in compounds with higher values, with the only exception SST0896 that was inactive with a logP value of 4.84. The ability of such compounds to affect GLI1 protein level and inhibit luciferase assay suggested that they might interact with GLI1 itself. To support this hypothesis, molecular docking simulations (Glide software) 26 were performed on the X-ray structure of the five-finger GLI1/DNA complex (2gli within the protein data bank). 27 Best scored poses of GlaB showed that it accommodates in the region between zinc finger 4 and 5. Moreover, Lys209, Lys219, and Arg223 (we adopt amino acid numbering of the protein data bank even if a list to convert it into the full length numbering is reported in Supporting Information Table 1) make crucial interactions with GLI1 (Supporting Information Figure 2), as previously described. The agreement between the binding pose of docked GlaB and its major interactions within the GLI1 structure with those reported in previous literature gave further support to the reliability of the computational docking protocol. The latter was then applied also to thiophene and pyrazolo-pyrimidine hit compounds in the attempt to predict their binding mode and significant interactions with GLI1.