Discovery of quinolinediones exhibiting a heat shock response and angiogenesis inhibition.

A series of substituted quinoline-5,8-diones were synthesized and evaluated as inhibitors of the chaperone protein Hsp90 using two assays: competition for binding to C-terminal ATP-binding site and competition for binding to N-terminal ATP-binding site. In addition, the ability of the compounds to induce the heat shock response was determined using a reporter fibroblast cell line. Of all the compounds assayed, only 6-aziridinyl-2-biphenylquinoline-5,8-dione induced a heat shock response and did so without interacting at the ATP binding sites of Hsp90.

Preclinical evaluation of the pharmacodynamic properties of 2,5-diaziridinyl-3-hydroxymethyl-6-methyl-1,4-benzoquinone.

Purpose: The purpose of our study was to investigate the cellular accumulation, DNA cross-linking ability, and cellular toxicity of RH1 (2,5-diaziridinyl-3-[hydroxymethyl[-6-methyl-1,4-benzoquinone), a novel DNA alkylating agent currently in clinical trials. In addition, the in vivo efficacy of RH1 formulated in different vehicles was also compared.

Experimental Design: RH1 is activated by the two-electron reducing enzyme NQO1 [NADPH:quinone oxidoreductase] forming a potent cytotoxic agent that cross-links DNA.