Joined in death: highlights of the Sixth International Meeting on Yeast Apoptosis in Leuven, Belgium, 30 April-4 May 2008

Miltefosine induces apoptosis-like cell death in yeast via Cox9p in cytochrome c oxidase

Miltefosine has antifungal properties and potential for development as a therapeutic for invasive fungal infections. However, its mode of action in fungi is poorly understood. We demonstrate that miltefosine is rapidly incorporated into yeast, where it penetrates the mitochondrial inner membrane, disrupting mitochondrial membrane potential and leading to an apoptosis-like cell death. COX9, which encodes subunit VIIa of the cytochrome c oxidase (COX) complex in the electron transport chain of the mitochondrial membrane, was identified as a potential target of miltefosine from a genomic library screen of the model yeast Saccharomyces cerevisiae. When overexpressed in S. cerevisiae, COX9, but not COX7 or COX8, led to a miltefosine-resistant phenotype. The effect of miltefosine on COX activity was assessed in cells expressing different levels of COX9. Miltefosine inhibited COX activity in a dose-dependent manner in Cox9p-positive cells. This inhibition most likely contributed to the miltefosine-induced apoptosis-like cell death.

Anti-apoptosis and cell survival: a review

Type I programmed cell death (PCD) or apoptosis is critical for cellular self-destruction for a variety of processes such as development or the prevention of oncogenic transformation. Alternative forms, including type II (autophagy) and type III (necrotic) represent the other major types of PCD that also serve to trigger cell death. PCD must be tightly controlled since disregulated cell death is involved in the development of a large number of different pathologies. To counter the multitude of processes that are capable of triggering death, cells have devised a large number of cellular processes that serve to prevent inappropriate or premature PCD. These cell survival strategies involve a myriad of coordinated and systematic physiological and genetic changes that serve to ward off death. Here we will discuss the different strategies that are used to prevent cell death and focus on illustrating that although anti-apoptosis and cellular survival serve to counteract PCD, they are nevertheless mechanistically distinct from the processes that regulate cell death.