The quinone methide aurin is a heat shock response inducer that causes proteotoxic stress and Noxa-dependent apoptosis in malignant melanoma cells.

Abstract

Pharmacological induction of proteotoxic stress is rapidly emerging as a promising strategy for cancer cell-directed chemotherapeutic intervention. Here, we describe the identification of a novel drug-like heat shock response inducer for the therapeutic induction of proteotoxic stress targeting malignant human melanoma cells. Screening a focused library of compounds containing redox-directed electrophilic pharmacophores employing the Stress & Toxicity PathwayFinder(TM) PCR Array technology as a discovery tool, a drug-like triphenylmethane-derivative (aurin; 4-[bis(p-hydroxyphenyl)methylene]-2,5-cyclohexadien-1-one) was identified as an experimental cell stress modulator that causes (i) heat shock factor transcriptional activation, (ii) up-regulation of heat shock response gene expression (HSPA6, HSPA1A, DNAJB4, HMOX1), (iii) early unfolded protein response signaling (phospho-PERK, phospho-eIF2α, CHOP (CCAAT/enhancer-binding protein homologous protein)), (iv) proteasome impairment with increased protein-ubiquitination, and (v) oxidative stress with glutathione depletion. Fluorescence polarization-based experiments revealed that aurin displays activity as a geldanamycin-competitive Hsp90α-antagonist, a finding further substantiated by molecular docking and ATPase inhibition analysis. Aurin exposure caused caspase-dependent cell death in a panel of human malignant melanoma cells (A375, G361, LOX-IMVI) but not in non-malignant human skin cells (Hs27 fibroblasts, HaCaT keratinocytes, primary melanocytes) undergoing the aurin-induced heat shock response without impairment of viability. Aurin-induced melanoma cell apoptosis depends on Noxa up-regulation as confirmed by siRNA rescue experiments demonstrating that siPMAIP1-based target down-regulation suppresses aurin-induced cell death. Taken together, our data suggest feasibility of apoptotic elimination of malignant melanoma cells using the quinone methide-derived heat shock response inducer aurin.

• Authors: Angela L Davis, Shuxi Qiao, Jessica L Lesson, Montserrat Rojo de la Vega, Sophia L Park, Carol M Seanez, Vijay Gokhale, Christopher M Cabello, Georg T Wondrak
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 290 Issue 3 Pg. 1623-38 (Jan 16 2015) ISSN: 1083-351X [Electronic] United States
• PMID: 25477506 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Chemical References

• Adaptor Proteins, Signal Transducing
• Adaptor Proteins, Vesicular Transport
• Heat-Shock Proteins
• Indolequinones
• NOXA1 protein, human
• RNA, Small Interfering
• quinone methide
• Aurintricarboxylic Acid
• aurin
• Glutathione

Topics

• Adaptor Proteins, Signal Transducing
• Adaptor Proteins, Vesicular Transport (metabolism)
• Apoptosis
• Aurintricarboxylic Acid (analogs & derivatives, chemistry)
• Cell Line, Tumor
• Cell Survival
• Drug Screening Assays, Antitumor
• Flow Cytometry
• Glutathione (metabolism)
• Heat-Shock Proteins (metabolism)
• Heat-Shock Response (genetics)
• Humans
• Indolequinones (chemistry)
• Inhibitory Concentration 50
• Keratinocytes (drug effects)
• Melanocytes (drug effects)
• Melanoma (drug therapy)
• Membrane Potential, Mitochondrial
• Models, Molecular
• Oxidative Stress
• Polymerase Chain Reaction
• RNA, Small Interfering (metabolism)
• Skin Neoplasms (drug therapy)
• Up-Regulation