Octadentate Oxine-Armed Bispidine Ligand for Radiopharmaceutical Chemistry.

In this study, we present the synthesis and characterization of the octadentate bispidine ligand, H2bispox2 and its complexes with medicinally useful radiometal nuclides (111In3+ and 177Lu3+), including their X-ray diffraction single crystal structures with the stable isotopes. 111InCl3 radiolabels the ligand quantitatively at ambient conditions ([L] = 10-5 M, room temperature, pH 7 and 15 min) and the in vitro human serum stability assays demonstrated high stability of the [111In(bispox2)]+ complex over 5 days. Moreover, the ß - emitter 177Lu radiolabels the ligand at 37 °C in 30 min (pH 8). These initial investigations reveal the potential of the octadentate bispidine ligand H2bispox2 as a useful chelator for 111In and 177Lu-based radiopharmaceuticals.

Inhibition of Histone Deacetylases 1, 2, and 3 Enhances Clearance of Cholesterol Accumulation in Niemann-Pick C1 Fibroblasts.

Niemann-Pick disease type C1 (NPC1) is a rare genetic cholesterol storage disorder caused by mutations in the NPC1 gene. Mutations in this transmembrane late endosome protein lead to loss of normal cholesterol efflux from late endosomes and lysosomes. It has been shown that broad spectrum histone deacetylase inhibitors (HDACi's) such as Vorinostat correct the cholesterol accumulation phenotype in the majority of NPC1 mutants tested in cultured cells. In order to determine the optimal specificity for HDACi correction of the mutant NPC1s, we screened 76 HDACi's of varying specificity. We tested the ability of these HDACi's to correct the excess accumulation of cholesterol in patient fibroblast cells that homozygously express NPC1 I1061T , the most common mutation. We determined that inhibition of HDACs 1, 2, and 3 is important for correcting the defect, and combined inhibition of all three is needed to achieve the greatest effect, suggesting a need for multiple effects of the HDACi treatments. Identifying the specific HDACs involved in the process of regulating cholesterol trafficking in NPC1 will help to focus the search for more specific druggable targets.