Choi Jung-Suk, Maity Ayan, Gray Thomas, Berdis Anthony J
From the Department of Chemistry and the Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio 44115 and.
Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106.
J Biol Chem. 2015 Apr 10;290(15):9714-26. doi: 10.1074/jbc.M114.620294. Epub 2015 Feb 24.
Nucleoside transport is an essential process that helps maintain the hyperproliferative state of most cancer cells. As such, it represents an important target for developing diagnostic and therapeutic agents that can effectively detect and treat cancer, respectively. This report describes the development of a metal-containing nucleoside designated Ir(III)-PPY nucleoside that displays both therapeutic and diagnostic properties against the human epidermal carcinoma cell line KB3-1. The cytotoxic effects of Ir(III)-PPY nucleoside are both time- and dose-dependent. Flow cytometry analyses validate that the nucleoside analog causes apoptosis by blocking cell cycle progression at G2/M. Fluorescent microscopy studies show rapid accumulation in the cytoplasm within 4 h. However, more significant accumulation is observed in the nucleus and mitochondria after 24 h. This localization is consistent with the ability of the metal-containing nucleoside to influence cell cycle progression at G2/M. Mitochondrial depletion is also observed after longer incubations (Δt ∼48 h), and this effect may produce additional cytotoxic effects. siRNA knockdown experiments demonstrate that the nucleoside transporter, hENT1, plays a key role in the cellular entry of Ir(III)-PPY nucleoside. Collectively, these data provide evidence for the development of a metal-containing nucleoside that functions as a combined therapeutic and diagnostic agent against cancer.
核苷转运是一个重要过程，有助于维持大多数癌细胞的过度增殖状态。因此，它是开发分别能有效检测和治疗癌症的诊断和治疗药物的重要靶点。本报告描述了一种含金属核苷Ir(III)-PPY核苷的研发情况，该核苷对人表皮癌细胞系KB3-1具有治疗和诊断特性。Ir(III)-PPY核苷的细胞毒性作用具有时间和剂量依赖性。流式细胞术分析证实，该核苷类似物通过在G2/M期阻断细胞周期进程导致细胞凋亡。荧光显微镜研究显示，4小时内该核苷在细胞质中迅速积累。然而，24小时后在细胞核和线粒体中观察到更显著的积累。这种定位与含金属核苷影响G2/M期细胞周期进程的能力一致。长时间孵育（Δt ∼48小时）后也观察到线粒体耗竭，这种效应可能产生额外的细胞毒性作用。小干扰RNA敲低实验表明，核苷转运蛋白hENT1在Ir(III)-PPY核苷进入细胞过程中起关键作用。总体而言，这些数据为开发一种兼具治疗和诊断癌症功能的含金属核苷提供了证据。
