Analogues of the Inhoffen-Lythgoe diol with anti-proliferative activity.

The anti-proliferative activity of a series of ester- and amide-linked Inhoffen-Lythgoe side chain analogues is reported. Whereas the Inhoffen-Lythgoe diol was inactive in these studies, a number of aromatic and aliphatic ester-linked side chains demonstrated modest in vitro growth inhibition in two human cancepar cell lines, U87MG (glioblastoma) and HT-29 (colorectal adenocarcinoma). Structure-activity relationship (SAR) studies demonstrated the most active aromatic (13) and aliphatic (25 and 29) substituted analogues were approximately equipotent in U87MG and HT-29 cells. Further evaluation of 13, 25, and 29 indicated these analogues do not activate canonical vitamin D signaling nor antagonize Hedgehog (Hh) signaling. Thus, the cellular mechanism(s) that govern the anti-proliferative activity for this class of truncated vitamin D-based structures appears to be different from classical mechanisms previously identified for these scaffolds.