Apoptosis and cancer research have developed side by side. Both immunosurveillance by cells such as cytotoxic T cells and detection of DNA damage (for example by p53) are important in causing the disposal of unwanted cells. Both of these systems are compromised during the development of cancer. Thus, inappropriately low levels of apoptosis are now generally recognized as contributing to tumorigenesis. Likewise, several viruses have developed inhibitors of the apoptotic process to abolish immunosurveillance. The development of apoptosis agonists may therefore improve the therapeutic treatment of, amongst others, diseases such as cancer and viral infections. On the other hand, some strategies are able to increase apoptosis (such as irradiation and cytotoxic shock). A smaller but equally important body of interest has focused on the development of strategies able to reduce levels of apoptosis. This is particularly important for the treatment of diseases associated with ischemic damage (eg. stroke and myocardial infarction) and inflammatory damage (eg. endotoxic shock). Molecules able to interfere with sphingolipid pathways have recently received considerable attention with respect to their ability to modulate apoptosis.

Key Reactions
Starting point	Product	Enzyme
Ceramide Sphingomyelin Spingosine Spinogosine-1-P Sphinganine Ceramide Glucosylceramide Ceramide Sphingosine	Sphingomyelin Ceramide Spinogosine-1-P Spingosine Ceramide Glucosylceramide Ceramide Spingosine Ceramide	Sphingomyelinases synthase Sphingomyelinase Sphingosine Kinase Sphingosine-1P Phosphatatase Ceramide Synthase Cerebrosidase Glucosylceramide Synthase Ceramidase Ceramide Synthase

Identifying ways in which ceramide can induce apoptosis should facilitate the optimization of therapeutic approaches to this target. Mitochondria are believed to be the target in ceramide-mediated apoptosis. These sub-cellular organelles are also known to play a major regulatory role in apoptotic cell death (Bernardi et al, 1999; Kroemer et al, 1998; Susin et al, 1998; Green & Reed, 1998). Thus, ceramides may act on mitochondria to induce apoptosis. In most cell types, a key event in apoptosis is the release of proteins from the intermembrane space of mitochondria to the cytoplasm, including apoptosis-inducing factor, cytochrome c, procaspases, and heat shock proteins (Bernardi et al, 1999; Kroemer et al, 1998; Susin et al, 1998;Narula et al, 1999). In general, it is the release of these inter-membrane space proteins that activates the caspases and DNAses that are responsible for the execution of apoptosis. Ceramide has been shown to induce cytochrome c release when added to cell cultures (Zamzami et al, 1995; Castedo et al, 1996; Susin et al, 1997a; Susin et al, 1997b; Demaria et al, 1997; Zhang et al, 1997) and isolated mitochondria (Arora et al, 1997; Di Paolo et al, 2000; Ghafourifar et al, 1999). This may be due to the passage of cytochrome c through ceramide channels in the outer mitochondrial membrane since ceramides form large channels in planar membranes (Siskind et al, 2000; Siskind et al, 2002). Others have reported ceramide-induced increases in the permeability of liposomes (Simon & Gear, 1998; Montes et al, 2002). For example, Montes et al., 2002 showed that ceramides can induce release of vesicle contents (Montes et al, 2002). Altering the activity of local enzymes that synthesize and catabolize ceramide would cause channels to assemble or disassemble, thus regulating the permeability of the outer membrane to small proteins. Ceramides have been reported to have other effects on mitochondria, including enhanced generation of reactive oxygen species (Zamzami et al, 1995; Di Paolo et al, 2000; Quillet-Mary et al 1997; France-Lanord et al, 1997; Garcia-Ruiz et al, 1997), alteration of calcium homeostasis of mitochondria and endoplasmic recticulum (Zamzami et al, 1995; Quillet-Mary et al 1997; Garcia-Ruiz et al, 1997; Pinton et al, 2001; Muriel et al 2000), ATP depletion (Arora et al, 1997), collapse of the inner mitochondrial membrane potential (Zamzami et al, 1995; Arora et al, 1997; Di Paolo et al, 2000; Ghafourifar et al, 1999), and inhibition and/or activation of the activities of various components of the mitochondrial electron transport chain (Di Paolo et al, 2000; Gudz et al, 1997).

The identification of molecules able to stimulate ceramide-forming enzymes such as the sphingomyelinases, or those able to block enzymes responsible for the removal of ceramide, may be of therapeutic use. At least three different sphingomyelinases can be discriminated by their optimal pH: acid, neutral, and alkaline sphingomyelinases. In particular, acid sphingomyelinase has been implicated to be essential for apoptosis. This cellular glycoprotein seems to be directed either to acidic compartments to contribute to lysosomal sphingomyelin turnover, or, as recently shown by Marathe et al. (1998) and Schissel et al. (1998), into secretory vesicles, enabling sphingomyelinase secretion into the extracellular space. Secretory sphingomyelinase is derived from the same gene as acid sphingomyelinase and is secreted by macrophages and endothelial cells in response to stimulation with inflammatory cytokines such as interleukin-1 (Marathe et al, 1998).

Besides its crucial function in membrane turnover, acid sphingomyelinase has been shown to participate in receptor signaling. For example, sphingomyelin hydrolysis and ceramide generation may contribute to the response to interleukin-1, TNF, the CD95 receptor, or CD28 (Boucher et al, 1995; Cifone et al, 1994; Gulbins et al, 1995; Schutze et al, 1995; Tepper et al, 1995), although this has been brought into doubt by some (Cock et al, 1998). Furthermore, acid sphingomyelinase is activated by many forms of stress, in particular gamma and ultraviolet irradiation or cellular treatment with cytostatic drugs (Haimovitz-Friedman et al, 1997; Santana et al, 1996). Most of these stimuli seem to activate acid sphingomyelinase within minutes after receptor stimulation. Recent genetic studies employing acid sphingomyelinase-knockout mice or lymphocytes from Niemann-Pick-disease type A patients, who suffer from an inborne defect of acid sphingomyelinase, have confirmed the dominant role of acid sphingomyelinase in the cellular response to irradiation, ultraviolet light, or even after treatment with lipopolysaccharide (Haimovitz-Friedman et al, 1997; Haimovitz-Friedman et al, 1994; Santana et al, 1996). Because acid sphingomyelinase is not only activated by apoptotic stimuli, but also by the CD28 receptor (Boucher et al, 1995), which induces cell proliferation or differentiation rather than apoptosis, the function of acid sphingomyelinase may not be restricted to the induction of apoptosis.

Thus, an intriguing functional concept for the role of acid sphingomyelinase in receptor signaling activation pathways suggests that the enzyme modifies membrane fluidity by the formation of ceramide microdomains. These structural alterations of membrane morphology may then allow rapid and efficient signaling inside the cell, explaining the function of the enzyme in so many receptor systems. In this context, acid sphingomyelinase would not function as a signaling molecule per se, but rather provide the right environment for the receptor to initiate intracellular signal transduction either by interacting with other signaling molecules present in these ceramide-rich rafts or by the simple close proximity and high density of the receptor and intracellular associating proteins.

In addition to acid sphingomyelinase several groups have demonstrated an activation of neutral sphingomyelinase by the TNF or CD95 receptors. Recent studies (Liu et al, 1998) characterized the enzyme as an integral transmembrane protein. Neutral sphingomyelinases have been implicated in the regulation of cell differentiation, growth, apoptosis, and aging (Kolesnik et al, 1998). Besides its activation upon TNF (Wiegmann et al, 1994) and CD95 receptor (Cifone et al, 1995) ligation, the enzyme is also stimulated by neurotrophic factors (Dobrowsky et al, 1995), CD40 ligand (Koppenhoefer et al, 1997), L-selectin (Brenner et al, 1998), daunorubicine (Bose et al, 1995), dexamethasone (Ramachandran et al, 1990), D-cytosine arabinoside (Strum et al, 1994), and cell cycle arrest by serum deprivation or cell senescence (Itoh et al, 1991).

The complexity of these different enzymes, their distinct locations, and their different activation patterns are matched by a similar diversity of cellular effects triggered by the product of all sphingomyelinases, ceramide. In particular, ceramide has been shown to directly or indirectly interact with the kinase suppressor of Ras (KSR; identical to ceramide-activated protein kinase) (Zhang et al, 1997), a ceramide-activated protein phosphatase (Galadari et al, 1998), protein kinase C (Lozano et al, 1994; Muller et al, 1995), and Raf-1 kinase (Muller et al, 1998). The KSR protein, a membrane-associated kinase with a substrate specificity for serine or threonine in proximity to proline, has been shown to play an important role in ceramide-mediated regulation of BAD, belonging to the Bcl-2-like protein family (Basu et al, 1998). The effect of ceramide on BAD is mediated by a pathway involving KSR, Ras, c-Raf-1, and mitogen-activated protein kinase kinase-1, finally causing prolonged inactivation of Akt, which normally inhibits BAD by phosphorylation. Reduction of Akt activity prevents phosphorylation of BAD, subsequently leading to BAD-mediated cell death.

While the identification of molecules able to stimulate the formation of ceramide (eg. sphingomyelinase agonists) may offer therapeutic opportunities, inhibitors of those able to remove ceramide may also be of use. In this respect, the ceramidase family, including alkaline ceramidase, alkaline phytoceramidase, alkaline dihydroceramidase, lysosomal acid ceramidase, and neutral mitochondrial ceramidase, offers an excellent therapeutic target.

Acid ceramidase (EC 3.5.1.23): The murine acid ceramidase was the first ceramidase to be cloned (Koch et al, 1996). It is localized in the lysosome and is mainly responsible for the catabolism of ceramide. Human acid ceramidase was isolated in 1995 (Bernardo et al), and later cloned. Genetic defects and subsequent dysfunction of this enzyme lead to a fatal sphingolipidosis disease called Farber disease. Acid ceramidase is a heterodimeric glycoprotein which, under reducing conditions, is cleaved into two subunits, designated a (molecular mass ~13 kDa) and b (molecular mass ~40 kDa). Purified acid ceramidase from human urine or placenta has optimal enzyme activity at pH 4.0 and high activity toward N-lauroylsphingosine as substrate. Raisova et al (2002) have reported that inhibitors of acid ceramidase activity induce apoptosis and suppress proliferation in HaCaT keratinocytes. Similar observations have been made for melanoma cells. Likewise, overexpression of acid ceramidase protects against apoptosis (Strelow et al, 2000), an important finding given that a number of prostate cancer cell lines are know to overexpress acid ceramidase (Seelan et al, 2000). Despite these data, it should be noted that acid sphingomyelinase-deficient cell lines derived from Niemann-Pick disease patients and wild-type cell lines are equally sensitive to stress-induced apoptosis (Bezombes et al, 2001).

Neutral/alkaline ceramidase: In 2000, Mao et al (Mao et al, 2000a; 2000b) cloned and characterized two Saccharomyces cerevisiae ceramidases, YPC1p and YDC1p. Both have an alkaline pH optimum of 9.5-10 and are thus termed alkaline ceramidases. YPC1p shows a preference for phytoceramide as a substrate, whereas YDC1p shows a preference for dihydroceramide. Neither hydrolyze the unsaturated mammalian-type ceramide. In addition, YPC1p shows considerable reverse ceramidase activity, catalyzing the formation of phytoceramide and dihydroceramide from a free fatty acid and sphingoids, whereas YDC1p has very minor reverse activity. This group also demonstrated that these two ceramidases are involved in the regulation of sphingolipid metabolism in S. cerevisiae. Deletion or overexpression of these ceramidases significantly alters the turnover of many sphingolipids, including complex sphingolipids, free sphingoid bases, and their phosphates. Moreover, the critical role of these ceramidases in regulating sphingolipid metabolism is reflected by their localization to the endoplasmic reticulum. Deletion of YDC1p increases cell tolerance to heat stress, which is in agreement with the established roles of sphingolipids in heat stress responses.

Alkaline ceramidases have also been described in human cerebellum, fibroblasts, and in many rat tissues (Sugita et al, 1975; Momoi et al, 1982). Alkaline ceramidases have been best characterized in guinea pig skin epidermis, where two enzymes were purified, one to apparent homogeneity, and the other only partially (Yada et al, 1995). These two enzymes are membrane-bound, and their estimated molecular masses on SDS-PAGE are 60 and 148 kDa, respectively. In 2000, Tani et al described a 94-kDa protein isolated from mouse liver, and a 112-kDa membrane-bound ceramidase expressed by rat kidney. The heavier ceramidase has a pH optimum of 6-7 and is mainly localized at apical membranes of proximal tubules (Mitsutake et al, 2001). In contrast, the lighter protein is largely found in late endosomes/lysosomes.

Using cell homogenates of rat glomerular mesangial cells, Coroneos et al have shown that alkaline ceramidase activity is stimulated by platelet-derived growth factor and not by inflammatory cytokines such as TNF-a and interleukin-1 or the vasoconstrictor peptide endothelin-1 (Coroneos et al, 1995). In another study of primary cultures of rat hepatocytes, Nikolova-Karakashian et al observed that alkaline ceramidase activity is stimulated by low concentrations of interleukin-1 (Nikolova-Karakashian et al, 1997). The activation of ceramidase in these cells results in the formation of sphingosine, and these authors suggested that sphingosine or sphingosine 1-phosphate may mediate some of the effects of low concentrations of interleukin. In rat renal mesangial cells, both TNF-a and nitric oxide donors have been shown to stimulate sphingomyelinases, but only nitric oxide donors inhibited ceramidases and resulted in an increase in ceramide levels and the consequent biological effects (Huwiler et al, 1999). Also, in smooth muscle cells, oxidized low density lipoprotein has been shown to stimulate sphingomyelinases, ceramidases, and sphingosine kinase, leading to the production of sphingosine-1-phosphate, which these authors suggested promotes the proliferation of these cells (Auge et al, 1999). Perhaps most importantly, inhibitors of alkaline ceramidase evoke growth suppression and cell cycle arrest in HL60 cells (Bielawska et al, 1996), demonstrating the therapeutic potential of alkaline ceramidase inhibitors.

As mentioned above, some components of the ceramide pathway are proliferative and hence the indiscriminate modulation of this pathway can have unexpected and undesired effects on proliferation (Curviller et al, 1996). Hence strategies designed to target ceramide should preferably target organelles which provide the source of pro-apoptotic ceramide. This issue was addressed by Birbes et al (2001), who engineered bacterial sphingomyelinases to target various organelles. Only when this enzyme was targeted to mitochondria did the cells undergo apoptosis; its targeting to other intracellular compartments was ineffective. Apoptosis was mediated by cytochrome c release, consistent with the proposed mechanism of apoptotic activity described above. These results demonstrate that ceramide induces cell death specifically when generated in mitochondria, suggesting that the identification and targeting of mitochondrial ceramidase may confer significant therapeutic advantages over the targeting of, for example, lysosomal or plasma membrane ceramidase.

Project Profile: The possibility of targeted blockade of ceramide metabolism was first realized by El-Bawab et al (1999), who reported a novel rat brain ceramidase. An assay was developed to characterize this enzyme and used to show that its pH optimum ranged from 7 to 10. At pH 11, significant activity was still observed, whereas at pHs lower than 4.5 no activity was noted, indicating clearly that this enzyme is different from the lysosomal acid ceramidase; it was thus termed non-lysosomal ceramidase, since it was neither strictly neutral nor alkaline. The estimated molecular mass of the protein was around 95 kDa. The following year saw the cloning of the human isoform (Genebank ref NM 019893) of non-lysosomal ceramidase (El-Bawab et al, 2000). Analysis of the protein sequence revealed the presence at the N-terminus of a signal peptide, followed by a putative myristoylation site and a putative mitochondrial targeting sequence. The predicted molecular mass, isoelectric point, and pH optimum are all in agreement with values obtained for the purified rat brain enzyme. Northern blot analysis of multiple human tissues indicated that the enzyme is ubiquitously expressed, with higher levels in kidney, skeletal muscle, and heart. Using a green fluorescent protein-ceramidase fusion protein, non-lysosomal ceramidase was localized to the mitochondrion. In 2001, Usta et al further characterized this ceramidase, performing SAR studies to determine the structural requirements for its stimulation and inhibition by ceramides. Further substrate specificity data were published in 2002 (El-Bawab et al). These SAR studies have identified urea-C16-ceramide as a reversible inhibitor of the mitochondrial ceramide, and as shown in the inset, this molecule is able to dramatically increase cell death.

Patent Position: The use of inhibitors of mitochondrial ceramidase to reduce the growth of cells, such as (but not limited to) breast cancer cells, is protected by WO0155410.

Disease incidence and market values: Between 1970 and 1994, cancer claimed the lives of about 0.5 million Americans every year. According to the most recent statistics (Jemal et al, 2002), it is estimated that approximately 1.3 million new cases of cancer will be diagnosed and 555,500 people will die from cancer in the United States in the year 2002. Ceramidase inhibitors have the potential to fit into multiple sectors of the cytostatic market, although proof of concept is biased towards the apoptosis market. BCC estimated that the world-wide market for apoptosis-related products would be $11 million at the time of their report (2000). This market has been predicted to total nearly $530 million by 2005, and may reach the billion-dollar mark by the end of the decade. Although the majority of this market is related to molecules able to stimulate apoptosis, the market for blockers of apoptosis (for the treatment of cardiovascular and neurological diseases) has nevertheless been predicted to reach $160 million by 2005.

An overview of current development activity: As can be seen from the graph below (left), the level of research effort in the pharmaceutical industry regarding the development of anticancer drugs is considerable. Preclinical development is much higher than for efforts in cardiovascular disease, although the latter has a higher impact on mortality statistics. Analysis of pharmaceutical development databases suggests about 25% of all drugs in preclinical development are targeted towards cancer. In contrast, however, the number of anticancer drugs available to clinicians is relatively small - the cardiovascular arsenal is about double that available to the oncologist. Research effort is sub-divided according to pharmacological efforts in the figure below (right). With regard to anticancer drugs in general, the majority (about 50%) of all drugs (almost 2000 in total) are in preclinical development, while only a small proportion (about 200) have been launched. This again reflects the enormous preclinical research effort dedicated to oncology, and the relatively restricted number of marketed anticancer drugs. A closer look at development by pharmacological class shows that inhibitors of angiogenesis and agonists of apoptosis are emerging targets. In addition there are a large number of molecules classified as cytostatics that act independently of either of these two mechanisms, and predominantly include molecules that induce differentiation or induce cell cycle arrest. Relevant pharmacological targets include microtubulin, cyclin and cyclin-dependent kinase, DNA topoisomerase, farnesyl transferase, p53 and retinoid acid receptors. In total these classes of drug account for 778 molecules. Activity surrounding the development of cytostatics has been immense, with the number of molecules in preclinical development having doubled between 1995 and 2001. In addition, the number of therapeutic candidates entering the clinic has doubled. Remarkably, however, there has been little change in the number of marketed products.

Of note, very little activity has been reported with respect to the pharmaceutical development of molecules able to modify ceramide metabolism. As an exception, three molecules have been developed for the treatment of Gaucher's disease (all glucosylceramide synthase stimulants) and one molecule for the treatment of Niemann-Pick disease (a sphingomyelinase stimulant). None of these molecules have been developed as stimulants of apoptosis. Likewise, little patent activity is noted in this area. More generally, over 100 molecules are in development as apoptosis agonists, although approaching 70% of these remain in preclinical development. This approach remains very much experimental, and the identification and exploitation of new targets continues to attract considerable attention - indeed the number of pro-apoptotic molecules in preclinical development has risen from about 10 to over 100 since 1995.

Advantages: As a general consideration, many drugs that are used to treat cancer are susceptible to acquired resistance. One of the most common reasons for this is the development of multidrug resistance as a result of the over-expression of proteins such as p-glycoprotein, a pump that extrudes cytotoxic molecules. Of interest, the development of the multidrug resistant state has been related to perturbations in the sphingolipid pathway. For example, the accumulation of ceramide-1-phosphate has been related to drug resistance, while on the other hand ceramide has been shown to prevent multidrug resistance (Ogretmen & Hannun, 2001). Thus, in direct contrast to most anticancer treatments, ceramidase inhibitors may be able to prevent multidrug resistance. This not only confers advantages on the use of such molecules, but also raises the possibility of approaches employing combination therapy. More specifically, the efficacy of many strategies designed to increase apoptosis is often limited due to defects in the early steps of the apoptosis machinery. For example, the apoptotic activity of molecules such as Fas can be blocked through the ability of tumors to over-express endogenous inhibitors such as FLICE. Since ceramidase inhibitors act further downstream, the opportunities for drug resistance are fewer. Finally, and most specific, the possibility of developing ceramidase inhibitors has attracted considerable attention due in part to the previous two points. Targeting mitochondrial ceramidase is likely to offer significant advantages over the development of lysosomal acid ceramidase or non-mitochondrial alkaline ceramidase. This advantage is related to the ability to increase ceramide levels at the site where it evokes its apoptotic effect. In summary, therefore, targeting mitochondrial ceramidase is expected to confer greater efficacy than existing apoptosis targets.

Strategic Analysis: Apoptosis stimulators have emerged as key targets for the control of cancer. This approach has, however, remained experimental, and indeed most molecules in development remain in preclinical phases. Furthermore, as our understanding of the mechanisms of apoptosis has increased, the level of preclinical development has also increased. One particularly exciting area of apoptosis-related therapy involves the sphingolipid pathways. The sphingolipids have been shown to be involved in apoptosis and, in particular ceramide has been shown to stimulate cell death. This has led to a convincing body of evidence supporting the concept that increasing ceramide levels represents a candidate strategy for the treatment of cancer. Indeed, a large number of studies have shown that ceramide induces apoptosis, and more recently it has become apparent that this involves the release of cytochrome c from mitochondria. In particular, increases in intra-mitochondrial ceramide appear to trigger cell death. Ceramide sits at the crossroads of a number of sphingolipid pathways, which is both advantageous and disadvantageous. Advantages include a choice of different targets; however, the resulting complexity of this pathway can confer serious disadvantages. For example, sphingomyelinase agonists may be expected to induce apoptosis by increasing levels of ceramide. However, it is possible that apoptosis can be blocked by the proliferative activity of the sphingosine-1-phosphate, which forms as a result of ceramide being diverted through the ceramidase pathway, by mass action. Thus, care must be taken when targeting the sphingolipid pathway and having specificity would be of benefit. Recent findings demonstrating the existence of a mitochondrial ceramidase are therefore highly exciting. These findings suggest that the delivery of ceramidase inhibitors into mitochondria could result in an increase in ceramide levels within the mitochondria, the site of the pro-apoptotic activity of ceramide. This would minimize any anti-apoptotic activity that may arise from increasing the levels of ceramide, and more specifically its metabolites, in the cytosol. The use of mitochondrial ceramidase as a target for pro-apoptotic molecules has been patented by MUSC, and hence this enzyme holds considerable commercial opportunities. Of all the fields currently under investigation by the pharmaceutical industry, pro-apoptotic strategies are gaining particularly intense preclinical attention, and hence new approaches such as ceramidase inhibitors should be particularly attractive as commercial opportunities. To our knowledge, ceramidase inhibitors are not yet being developed within the pharmaceutical sector. Likewise, little patent activity is noted in this area. Hence companies choosing to commercialize the technology described in the present dossier are likely to become leaders in the field of ceramidase inhibitors. Exploitation of this technology is even more attractive given the availability of screens to identify novel inhibitors. This approach has been validated by the discovery of urea-C16-ceramide, which was shown to induce apoptosis in breast cancer cells, thus offering strong proof for the concept of targeting mitochondrial ceramidase. Despite the attractiveness of this target, further studies are advised. For example, it is unclear how sensitive non-cancerous cells would be to pro-apoptotic activity of ceramidase inhibitors. If there is little selectivity, an effective tumor targeting strategy would be required. In addition, cancerous cells have evolved numerous ways to avoid pharmacotherapy, and in particular they frequently display resistance to apoptotic molecules. This can result from the activity of multidrug resistant proteins, defects in proximal components of apoptosis, or insensitivity to down-stream modulators. Targeting ceramidase is unlikely to suffer from the first of these two phenomena. First, it has been shown that disturbances in sphingolipid metabolism, for example the accumulation of ceramide-1-phosphate, may be responsible for the development of drug resistance, and in fact, ceramidase inhibitors may actually prevent multidrug resistance (Ogretmen & Hannun, 2001); secondly, since ceramide is relatively distal in the apoptosis cascade, ceramidase inhibitors are likely to be unaffected by many mechanisms responsible for drug resistance. Susceptibility to downstream apoptosis resistance remains to be investigated, however. It is therefore recommended that the sensitivity to urea-C16-ceramide should be investigated across a panel of cell lines, including those with varying drug resistance phenotypes. In the event that these further studies demonstrate an acceptable therapeutic margin and sufficient efficacy, it is recommended that a screening program be rapidly initiated to identify small molecule ceramidase inhibitors.

Co-development opportunities: MUSC, who are the assignees of the patent protecting the use of mitochondrial ceramidase, are now seeking partners who would be interested in co-developing novel inhibitors of this enzyme. Optimally, MUSC would license the know-how and material necessary to screen for mitochondrial ceramidase inhibitors. For their part, it is hoped that co-development partners would have a technology platform and resources able to upscale the assay already developed by MUSC, and to screen large libraries for novel small-molecule inhibitors of mitochondrial ceramidase. As an alternative approach, co-development partners may have expertise in in silica/virtual molecular modelling.

About MUSC: Founded as a private medical college in 1824, the Medical University of South Carolina is now an academic health center with six colleges for the education of a broad range of health professionals, biomedical scientists and other health-related personnel. The 40-acre, 80-building campus in downtown Charleston, South Carolina, serves the needs of over 2300 students with a full-time faculty of over 1000. For the most recent fiscal year, MUSC was awarded over $130 million in sponsored research funding. The MUSC Foundation for Research Development is a non-profit, charitable foundation created to benefit MUSC by establishing relationships which bring ideas, technology, and expertise of the faculty, staff, and students at MUSC to industry and, ultimately, into public use. In order to accomplish this goal, the Foundation develops, administers, and otherwise facilitates selected industry-sponsored education and research projects, and manages the intellectual property, technology transfer, and other economic development-related activities of MUSC.

About the inventor: Yusuf A. Hannun is the Ralph F. Hirschmann Professor, and Chairman of the Department of Biochemistry & Molecular Biology at MUSC. Dr Hannun's laboratory is focused on studies on sphingolipid-mediated signal transduction. These studies have allowed a critical role for sphingolipids in eukaryotic stress responses to be proposed. The current goals of Dr Hannun's group are to provide a biochemical and molecular foundation for the study of ceramide-dependent pathways, and they are currently focussing on key enzymes of ceramide metabolism (such as sphingomyelinase, ceramidase and sphingomyelin synthase) that serve to regulate ceramide levels. The laboratory has a broad technology base combining chemical, biochemical, molecular, and cellular approaches which are being used to develop novel chemotherapies. With a publication track-record of almost 200 publications, Dr Hannun can be considered one of the field leaders in ceramide research.