Anticancer Gold(III) Porphyrins Target Mitochondrial Chaperone Hsp60

• Published in: Angewandte Chemie International Edition 2016-01, Vol.55 (4), p.1387-1391
• Main Authors: Hu, Di, Liu, Yungen, Lai, Yau-Tsz, Tong, Ka-Chung, Fung, Yi-Man, Lok, Chun-Nam, Che, Chi-Ming
• Format: Article
• Language: English
• Subjects: Affinity; Affinity labeling; Anticancer properties; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; antitumor agents; Assaying; biological targets; Biology; Cancer; Cell Line, Tumor; Chaperonin 60 - drug effects; chemical proteomics; Chemical synthesis; Chemistry; Coordination compounds; Fluorescence; Gold; Gold - chemistry; Gold - pharmacology; gold porphyrins; Heat; Heat exchange; Hsp60; Hsp60 protein; Humans; Inhibition; Labels; Ligands; Magnetic Resonance Spectroscopy; Marking; Metal complexes; Metals; Microscopy, Fluorescence; Mitochondria; Mitochondria - chemistry; Mitochondria - drug effects; Molecular structure; NMR; Nuclear magnetic resonance; Photoaffinity labeling; Physiology; Porphyrins; Porphyrins - chemistry; Porphyrins - pharmacology; Proteomics; Quenching; Reduction (metal working); Saturation; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Stability; Target recognition
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201509612

Identification of the molecular target(s) of anticancer metal complexes is a formidable challenge since most of them are unstable toward ligand exchange reaction(s) or biological reduction under physiological conditions. Gold(III) meso‐tetraphenylporphyrin (gold‐1 a) is notable for its high stability in biological milieux and potent in vitro and in vivo anticancer activities. Herein, extensive chemical biology approaches employing photo‐affinity labeling, click chemistry, chemical proteomics, cellular thermal shift, saturation‐transfer difference NMR, protein fluorescence quenching, and protein chaperone assays were used to provide compelling evidence that heat‐shock protein 60 (Hsp60), a mitochondrial chaperone and potential anticancer target, is a direct target of gold‐1 a in vitro and in cells. Structure–activity studies with a panel of non‐porphyrin gold(III) complexes and other metalloporphyrins revealed that Hsp60 inhibition is specifically dependent on both the gold(III) ion and the porphyrin ligand. Golden gun: Hsp60 is a direct molecular target of the anticancer compound gold(III) meso‐tetraphenylporphyrin (gold‐1 a) under both in vitro and cellular conditions, as revealed by chemical biology studies employing photo‐affinity labeling, click chemistry, proteomic identification, cellular thermal shift, saturation‐transfer difference NMR, protein fluorescence quenching, and protein chaperone assays.