Synthesis and evaluation of Hsp90 inhibitors that contain the 1,4-naphthoquinone scaffold

Synthesis and evaluation of arylquinones as BACE1 inhibitors, β-amyloid peptide aggregation inhibitors, and destabilizers of preformed β-amyloid fibrils

BACE1 activity, inhibition of Aβ aggregation, and disaggregation of preformed Aβ fibrils constitute the three major targets in the development of small-molecule lipophilic new drugs for the treatment of Alzheimer's disease (AD). Quinones are widely distributed among natural products and possess relevant and varied biological activities including antitumor and antibiotic, inhibition of HIV-1 reverse transcriptase, antidiabetic, or COX-inhibition, among others. We report herein the interaction of several arylquinones and their derivatives with the amyloidogenic pathway of the amyloid precursor protein processing. Our studies put forward that these compounds are promising candidates in the development of new drugs which are effective simultaneously towards the three major targets of AD.

Synthesis and cytotoxic activities of some 2-arylnaphtho[2,3-d]oxazole-4,9-dione derivatives on androgen-dependent (LNCaP) and androgen-independent (PC3) human prostate cancer cell lines

The synthesis of five 2-arylnaphtho[2,3-d]oxazole-4,9-dione derivatives was accomplished by refluxing 2-amino-3-bromo-1,4-naphthoquinone with appropriate benzoyl chloride analogs at elevated temperatures. In vitro anticancer evaluation of these compounds was performed on androgen-dependent, LNCaP, and androgen-independent, PC3, human prostate cancer cell lines. In general, these compounds displayed slightly stronger cytotoxicity on the androgen-dependent LNCaP than on the androgen-independent PC3 prostate cancer cell lines. The meta-substituted 2-(3-Chloro-phenyl)-naphtho[2,3-d]oxazole-4,9-dione (10) appear to display the best cytotoxicity on both cell lines with an IC(50) of 0.03 μM on LNCaP and 0.08 μM on PC3 after 5 days of exposure.

Synthesis and evaluation of radamide analogues, a chimera of radicicol and geldanamycin

Previously, we reported the Hsp90 inhibitory activity of radamide, an open chain amide chimera of geldanamycin and radicicol. Attempts to further expand upon structure-activity relationships for this class of Hsp90 inhibitors led to the preparation of a series of radamide analogues focused on differing tether lengths and quinone mimics. In addition, the cup-shaped conformation adopted by the two natural products when bound to the Hsp90 N-terminal ATP binding pocket suggests that conformationally biased compounds may demonstrate improved binding and inhibition. The preparation and evaluation of radamide analogues with cis/trans alpha,beta-unsaturated amides yielded compounds that exhibit improved antiproliferative activity. In addition, several analogues demonstrated the ability to induce degradation of Hsp90-dependent oncogenic signaling proteins in vitro, a hallmark of Hsp90 N-terminal inhibition.