Increasing Intracellular Bioavailable Copper Selectively Targets Prostate Cancer Cells

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• 作者：Michael A. Cater ; Helen B. Pearson ; Kamil Wolyniec ; Paul Klaver ; Maree Bilandzic ; Brett M. Paterson ; Ashley I. Bush ; Patrick O. Humbert ; Sharon La Fontaine ; Paul S. Donnelly ; Ygal Haupt
• 刊名：ACS Chemical Biology
• 出版年：2013
• 出版时间：July 19, 2013
• 年：2013
• 卷：8
• 期：7
• 页码：1621-1631
• 全文大小：699K
• 年卷期：v.8,no.7(July 19, 2013)
• ISSN：1554-8937

文摘

The therapeutic efficacy of two bis(thiosemicarbazonato) copper complexes, glyoxalbis[N4-methylthiosemicarbazonato]Cu^II [Cu^II(gtsm)] and diacetylbis[N4-methylthiosemicarbazonato]Cu^II [Cu^II(atsm)], for the treatment of prostate cancer was assessed in cell culture and animal models. Distinctively, copper dissociates intracellularly from Cu^II(gtsm) but is retained by Cu^II(atsm). We further demonstrated that intracellular H₂gtsm [reduced Cu^II(gtsm)] continues to redistribute copper into a bioavailable (exchangeable) pool. Both Cu^II(gtsm) and Cu^II(atsm) selectively kill transformed (hyperplastic and carcinoma) prostate cell lines but, importantly, do not affect the viability of primary prostate epithelial cells. Increasing extracellular copper concentrations enhanced the therapeutic capacity of both Cu^II(gtsm) and Cu^II(atsm), and their ligands (H₂gtsm and H₂atsm) were toxic only toward cancerous prostate cells when combined with copper. Treatment of the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model with Cu^II(gtsm) (2.5 mg/kg) significantly reduced prostate cancer burden (70%) and severity (grade), while treatment with Cu^II(atsm) (30 mg/kg) was ineffective at the given dose. However, Cu^II(gtsm) caused mild kidney toxicity in the mice, associated primarily with interstitial nephritis and luminal distention. Mechanistically, we demonstrated that Cu^II(gtsm) inhibits proteasomal chymotrypsin-like activity, a feature further established as being common to copper-ionophores that increase intracellular bioavailable copper. We have demonstrated that increasing intracellular bioavailable copper can selectively kill cancerous prostate cells in vitro and in vivo and have revealed the potential for bis(thiosemicarbazone) copper complexes to be developed as therapeutics for prostate cancer.