Inserm U837 and Faculté de Médecine, Université de Lille II, 1 Place Verdun, 59045, Lille Cedex, France.
Apoptosis. 2010 Jul;15(7):769-81. doi: 10.1007/s10495-010-0471-2.
Lamellarin D (Lam D), a marine alkaloid, exhibits a potent cytotoxicity against many different tumors. The pro-apoptotic function of Lam D has been attributed to its direct induction of mitochondrial permeability transition (MPT). This study was undertaken to explore the mechanisms through which Lam D promotes changes in mitochondrial function and as a result apoptosis. The use of eight Lam derivatives provides useful structure-apoptosis relationships. We demonstrate that Lam D and structural analogues induce apoptosis of cancer cells by acting directly on mitochondria inducing reduction of mitochondrial membrane potential, swelling and cytochrome c release. Cyclosporin A, a well-known inhibitor of MPT, completely prevents mitochondrial signs of apoptosis. The drug decreases calcium uptake by mitochondria but not by microsomes indicating that Lam D-dependent permeability is specific to mitochondrial membranes. In addition, upon Lam D exposure, a rapid decline of mitochondrial respiration and ATP synthesis occurs in isolated mitochondria as well as in intact cells. Evaluation of the site of action of Lam D on the electron-transport chain revealed that the activity of respiratory chain complex III is reduced by a half. To determine whether Lam D could induce MPT-dependent apoptosis by inhibiting mitochondrial respiration, we generated respiration-deficient cells (rho0) derived from human melanoma cells. In comparison to parental cells, rho0 cells are totally resistant to the induction of MPT-dependent apoptosis by Lam D. Our results indicate that functional mitochondria are required for Lam D-induced apoptosis. Inhibition of mitochondrial respiration is responsible for MPT-dependent apoptosis of cancer cells induced by Lam-D.
拉米林 D（Lam D）是一种海洋生物碱，对许多不同的肿瘤具有很强的细胞毒性。Lam D 的促凋亡功能归因于其对线粒体通透性转变（MPT）的直接诱导。本研究旨在探讨 Lam D 促进线粒体功能变化并导致细胞凋亡的机制。使用八种 Lam 衍生物提供了有用的结构-凋亡关系。我们证明 Lam D 和结构类似物通过直接作用于线粒体诱导线粒体膜电位降低、肿胀和细胞色素 c 释放来诱导癌细胞凋亡。环孢菌素 A 是 MPT 的一种众所周知的抑制剂，可完全阻止线粒体凋亡的迹象。该药物减少了线粒体摄取钙，但不减少微粒体摄取钙，表明 Lam D 依赖性通透性是线粒体膜特有的。此外，在 Lam D 暴露后，分离的线粒体以及完整细胞中的线粒体呼吸和 ATP 合成迅速下降。评价 Lam D 对电子传递链作用部位的研究表明，呼吸链复合物 III 的活性降低了一半。为了确定 Lam D 是否可以通过抑制线粒体呼吸来诱导 MPT 依赖性细胞凋亡，我们生成了源自人类黑色素瘤细胞的呼吸缺陷细胞（rho0）。与亲本细胞相比，rho0 细胞对 Lam D 诱导的 MPT 依赖性细胞凋亡完全具有抗性。我们的结果表明，功能性线粒体是 Lam D 诱导细胞凋亡所必需的。线粒体呼吸的抑制是 Lam-D 诱导的癌细胞 MPT 依赖性凋亡的原因。
