Cationic long-chain ceramide LCL-30 induces cell death by mitochondrial targeting in SW403 cells

Abstract

Ceramides are sphingolipid second messengers that are involved in the mediation of cell death. There is accumulating evidence that mitochondria play a central role in ceramide-derived toxicity. We designed a novel cationic long-chain ceramide [W-pyridinium bromide D-erythro -C 16 -ceramide (LCL-30)] targeting negatively charged mitochondria. Our results show that LCL-30 is highly cytotoxic to SW403 cells (and other cancer cell lines) and preferentially accumulates in mitochondria, resulting in a decrease of the mitochondrial membrane potential, release of mitochondrial cytochrome c, and activation of caspase-3 and caspase-9. Ultrastructural analyses support the concept of mitochondrial selectivity. Interestingly, levels of endogenous mitochondrial C 16 -ceramide decreased by more than half, whereas levels of sphingosine-1-phosphate increased dramatically and selectively in mitochondria after administration of LCL-30, suggesting the presence of a mitochondrial sphingosine kinase. Of note, intracellular long-chain ceramide levels and sphingosine-1-phosphate remained unaffected in the cytosolic and extramitochondrial (nuclei/cellular membranes) cellular fractions. Furthermore, a synergistic effect of cotreatment of LCL-30 and doxorubicin was observed, which was not related to alterations in endogenous ceramide levels.Cationic long-chain pyridinium ceramides might be promising new drugs for cancer therapy through their mitochondrial preference. [Mol Cancer Ther 2006;5(6):1520 -9]

Role of human longevity assurance gene 1 and C18-ceramide in chemotherapy-induced cell death in human head and neck squamous cell carcinomas

“…Conventional short-chain ceramides, such as C 2 -and C 6 -ceramides, were shown to induce cell death in a variety of cancers. However, because of poor solubility and bioavailability of the conventional ceramides, novel pyridinium ceramides (Pyr-Cer) have been synthesized with greater water solubility and cell permeability (26,35,36). In addition, the positively charged pyridinium ring of these novel ceramides permits them to target and accumulate in negatively charged intracellular compartments, especially the mitochondria and nucleus (37).…”

Mitochondrially targeted ceramide LCL-30 inhibits colorectal cancer in mice

“…The MTT assay was performed as described previously (Dindo et al, 2006). In parallel, cells were detached using 1% trypsin (Invitrogen) and centrifuged at 800 g. Cell pellets were resuspended in PBS with trypan blue (Sigma-Aldrich) and both stained and unstained cells were counted.…”

“…Our recent work showed LCL-30, a C16-pyridinium ceramide analogue, to induce cell death in vitro by mitochondrial targeting (Dindo et al, 2006). The aim of the current study was to translate these results to an in vivo model.…”

“…Ceramides modified with a o-pyridinium moiety contain a positive charge delocalised over the p-electron system . These ceramide analogues exhibit a much higher water solubility and preferentially accumulate within the mitochondrial matrix driven by the electrochemical gradient (Novgorodov et al, 2005;Dindo et al, 2006;Senkal et al, 2006). The approach of attacking mitochondria is further supported by the fact that cancer cells' mitochondrial membrane potential tends to be more polarised than that of normal cells (Chen, 1988).…”

Nutraceutical Properties of Milk Fat Globular Membrane

“…The anticancer activity of sphingolipids is primarily associated with their metabolites, ceramide and sphingosine (Jayadev, Linardic, and Hannun 1994). Ceramide is an important second messenger implicated in various physiological functions, like apoptosis, and has recently been associated with targeting mitochondrial activity in colon cancer cells (Dahm et al 2008;Dindo et al 2006). Sphingolipid digestion is slow and occurs along the entire length of both the small intestine and the colon which results in high levels of ceramide and sphingosine in the lumen producing the potentially beneficial effects (Nilsson and Duan 2006).…”