Department of Biochemical Sciences 'A. Rossi Fanelli', Sapienza University of Rome, I-00185 Rome, Italy.
Department of Pharmaceutical and Pharmacological Sciences, University of Padua, I-35131 Padua, Italy.
Int J Oncol. 2018 Sep;53(3):1257-1268. doi: 10.3892/ijo.2018.4452. Epub 2018 Jun 22.
Aged garlic extract (AGE) has been shown to possess therapeutic properties in cancer; however its mechanisms of action are unclear. In this study, we demonstrate by MTT assay that AGE exerts an anti-proliferative effect on a panel of both sensitive and multidrug-resistant (MDR) human cancer cell lines and enhances the effects of hyperthermia (42˚C) on M14 melanoma cells. The evaluation of the mitochondrial activity in whole cancer cells treated with AGE, performed by cytofluorimetric analysis in the presence of the lipophilic cationic fluorochrome JC-1, revealed the occurrence of dose-dependent mitochondrial membrane depolarization. Membrane potential was measured by the TPP+ selective electrode. In order to shed light on its mechanisms of action, the effects of AGE on isolated rat liver mitochondria were also examined. In this regard, AGE induced a mitochondrial membrane hyperpolarization of approximately 15 mV through a mechanism that was similar to that observed with the ionophores, nigericin or salinomycin, by activating an exchange between endogenous K+ with exogenous H+. The prolonged incubation of the mitochondria with AGE induced depolarization and matrix swelling, indicative of mitochondrial permeability transition induction that, however, occurs through a different mechanism from the well-known one. In particular, the transition pore opening induced by AGE was due to the rearrangement of the mitochondrial membranes following the increased activity of the K+/H+ exchanger. On the whole, the findings of this study indicate that AGE exerts cytotoxic effects on cancer cells by altering mitochondrial permeability. In particular, AGE in the mitochondria activates K+/H+ exchanger, causes oxidative stress and induces mitochondrial permeability transition (MPT).
大蒜素（AGE）已被证明具有治疗癌症的特性；然而，其作用机制尚不清楚。在这项研究中，我们通过 MTT 检测证实，AGE 对一系列敏感和多药耐药（MDR）人癌细胞系具有抗增殖作用，并增强了高温（42°C）对 M14 黑色素瘤细胞的作用。通过在存在脂溶性阳离子荧光染料 JC-1 的情况下，用细胞荧光计分析对用 AGE 处理的整个癌细胞的线粒体活性进行评估，发现线粒体膜去极化呈剂量依赖性。通过 TPP+选择性电极测量膜电位。为了阐明其作用机制，还研究了 AGE 对分离的大鼠肝线粒体的影响。在这方面，AGE 通过激活内源性 K+与外源性 H+之间的交换，诱导约 15 mV 的线粒体膜超极化，其机制类似于离子载体 Nigericin 或 Salinomycin 观察到的机制。线粒体与 AGE 长时间孵育会导致去极化和基质肿胀，表明诱导线粒体通透性转换，但是，这种机制与众所周知的机制不同。特别是，AGE 诱导的通透性转换孔开放是由于 K+/H+交换器活性增加导致线粒体膜重排所致。总的来说，这项研究的结果表明，AGE 通过改变线粒体通透性对癌细胞发挥细胞毒性作用。特别是，AGE 在线粒体中激活 K+/H+交换器，引起氧化应激并诱导线粒体通透性转换（MPT）。
