FTY720 inhibits tumor growth and angiogenesis

FTY720 administration results in a M2 associated immunoregulatory effect that positively influences the outcome of alveolar bone repair outcome in mice

The alveolar bone repair process may be influenced by multiple local and systemic factors, which include immune system cells and mediators. Macrophages allegedly play important roles in the repair process, and the transition of an initial inflammatory M1 profile into a pro-reparative M2 profile theoretically contributes to a favorable repair outcome. In this context, considering immunoregulatory molecules as potential targets for improving bone repair, this study evaluated the role of the immunoregulatory molecule FTY720, previously described to favor the development of the M2 phenotype, in the process of alveolar bone healing in C57Bl/6 (WT) mice. Experimental groups submitted to tooth extraction and maintained under control conditions or treated with FTY720 were evaluated by microtomographic (μCT), histomorphometric, immunohistochemical and molecular analysis to characterize healing and host response features at 0, 1, 3, 7 and 14 days. Our results demonstrated that the FTY720 group presented higher bone tissue density, higher bone tissue volume, greater tissue volume fraction, greater number and thickness of trabeculae and a higher number of osteoblasts and osteoclasts than the control group. Accordingly, the bone markers BMP2, BMP7, ALPL, SOST and RANK mRNA expressions increased in the FTY720 treated group. Furthermore, the levels of FIZZ, ARG2 and IL-10 mRNA increased in the FTY720 group together with the presence of CD206⁺ cells, suggesting that the boost of bone formation mediated by FTY720 involves an increased polarization and activity of M2 macrophages in healing sites. Thus, our results demonstrate that FTY720 favored the process of alveolar bone repair, probably trough a strengthened M2 response, associated with an increased expression of markers osteogenic differentiation and activity markers. Immunoregulatory strategies based in the modulation of macrophage polarization profile can comprise effective tools to improve the bone repair process.

The protective role of FTY720 in promoting survival of allograft fat in mice

Fat transplantation is widely used for soft-tissue filling and wound repair. Owing to the biological changes in adipocytes in some metabolic diseases, allograft fat can provide a better source of donor fat than autologous fat. Fingolimod (FTY720) possesses a powerful immunomodulatory function. This study aimed to investigate the protective effect of FTY720 in allogeneic fat transplantation. C57BL/6J mice that received allografts were randomly divided into two groups and treated with saline and FTY720, respectively. Fat graft samples were obtained at 1, 6, and 20 weeks posttransplantation. Graft volumes, graft structure, and immune cells were estimated using histological examination, immunohistochemistry, staining immunofluorescence (IF), and quantitative real-time polymerase chain reaction (qRT-PCR). Inflammatory cytokine mRNA expression in grafts was detected by qRT-PCR. FTY720 treatment significantly enhanced allograft retention, structural integrity, and neovascularization, thereby demonstrating the potential of FTY720 in improving graft survival. Further IF staining showed that FTY720 increased regulatory T cell infiltration and reduced macrophage infiltration to some extent. FTY720 treatment also enhanced the expression of the anti-inflammatory cytokines interleukin (IL)-4 and IL-10 and weakened the expression of the pro-inflammatory cytokines TNF-α and IL-6. Furthermore, FTY720 treatment upregulated the expression of CD31 positive cells. This study demonstrated the potential efficacy of FTY720 in improving the graft survival rate of syngeneic fat allograft models, possibly by suppressing immune rejection and promoting angiogenesis. Therefore, this study offers key insights into the potential application of a drug-assisted strategy to prolong allograft fat survival.

Molecular Pharmacology and Novel Potential Therapeutic Applications of Fingolimod

Fingolimod is a well-tolerated, highly effective disease-modifying therapy successfully utilized in the management of multiple sclerosis. The active metabolite, fingolimod-phosphate, acts on sphingosine-1-phosphate receptors (S1PRs) to bring about an array of pharmacological effects. While being initially recognized as a novel agent that can profoundly reduce T-cell numbers in circulation and the CNS, thereby suppressing inflammation and MS, there is now rapidly increasing knowledge on its previously unrecognized molecular and potential therapeutic effects in diverse pathological conditions. In addition to exerting inhibitory effects on sphingolipid pathway enzymes, fingolimod also inhibits histone deacetylases, transient receptor potential cation channel subfamily M member 7 (TRMP7), cytosolic phospholipase A2α (cPLA2α), reduces lysophosphatidic acid (LPA) plasma levels, and activates protein phosphatase 2A (PP2A). Furthermore, fingolimod induces apoptosis, autophagy, cell cycle arrest, epigenetic regulations, macrophages M1/M2 shift and enhances BDNF expression. According to recent evidence, fingolimod modulates a range of other molecular pathways deeply rooted in disease initiation or progression. Experimental reports have firmly associated the drug with potentially beneficial therapeutic effects in immunomodulatory diseases, CNS injuries, and diseases including Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and even cancer. Attractive pharmacological effects, relative safety, favorable pharmacokinetics, and positive experimental data have collectively led to its testing in clinical trials. Based on the recent reports, fingolimod may soon find its way as an adjunct therapy in various disparate pathological conditions. This review summarizes the up-to-date knowledge about molecular pharmacology and potential therapeutic uses of fingolimod.

An Insight into GPCR and G-Proteins as Cancer Drivers

G-protein-coupled receptors (GPCRs) are the largest family of cell surface signaling receptors known to play a crucial role in various physiological functions, including tumor growth and metastasis. Various molecules such as hormones, lipids, peptides, and neurotransmitters activate GPCRs that enable the coupling of these receptors to highly specialized transducer proteins, called G-proteins, and initiate multiple signaling pathways. Integration of these intricate networks of signaling cascades leads to numerous biochemical responses involved in diverse pathophysiological activities, including cancer development. While several studies indicate the role of GPCRs in controlling various aspects of cancer progression such as tumor growth, invasion, migration, survival, and metastasis through its aberrant overexpression, mutations, or increased release of agonists, the explicit mechanisms of the involvement of GPCRs in cancer progression is still puzzling. This review provides an insight into the various responses mediated by GPCRs in the development of cancers, the molecular mechanisms involved and the novel pharmacological approaches currently preferred for the treatment of cancer. Thus, these findings extend the knowledge of GPCRs in cancer cells and help in the identification of therapeutics for cancer patients.

Selenium nanoparticles coated with pH responsive silk fibroin complex for fingolimod release and enhanced targeting in thyroid cancer

Cancer-targeted drug delivery systems based on nanoparticles (NPs) have been considered promising therapies. In this study, we developed a pH-responsive smart NPs drug delivery system using silk fibroin (SF), selenium nanoparticles (Se NPs), fingolimod (FTY720), and heptapeptide (T7). The prepared FTY720@T7-SF-Se NPs were spheres with an average diameter of 120 nm, which would contribute to the enhanced permeability and retention effects in tumour regions. The encapsulation efficiency (EE) of the FTY720@T7-SF-Se NPs was 71.95 ± 3.81%. The release of FTY720 from the nanocarriers was pH-dependent, and the release of FTY720 was accelerated in an acidic environment. Both in vitro and in vivo studies showed that FTY720@T7-SF-Se NPs had an enhanced cellular uptake selectivity and antitumor activity for thyroid cancer. The bio-distribution study in vivo further demonstrated that FTY720@T7-SF-Se NPs could effectively accumulate in the tumour region, thereby enhancing the ability to kill cancer cells in vivo. In addition, studies of histology and immunohistochemistry showed that FTY720@T7-SF-Se NPs had low toxicity to the major organs of tumour-bearing mice, indicating the prepared NPs has good biocompatibility in vivo. These results suggest that the tumour-targeted NPs delivery system (FTY720@T7-SF-Se NPs) has great potential as a new tool for thyroid cancer therapy.

G Protein-Coupled Receptors at the Crossroad between Physiologic and Pathologic Angiogenesis: Old Paradigms and Emerging Concepts

G protein-coupled receptors (GPCRs) have been implicated in transmitting signals across the extra- and intra-cellular compartments, thus allowing environmental stimuli to elicit critical biological responses. As GPCRs can be activated by an extensive range of factors including hormones, neurotransmitters, phospholipids and other stimuli, their involvement in a plethora of physiological functions is not surprising. Aberrant GPCR signaling has been regarded as a major contributor to diverse pathologic conditions, such as inflammatory, cardiovascular and neoplastic diseases. In this regard, solid tumors have been demonstrated to activate an angiogenic program that relies on GPCR action to support cancer growth and metastatic dissemination. Therefore, the manipulation of aberrant GPCR signaling could represent a promising target in anticancer therapy. Here, we highlight the GPCR-mediated angiogenic function focusing on the molecular mechanisms and transduction effectors driving the patho-physiological vasculogenesis. Specifically, we describe evidence for the role of heptahelic receptors and associated G proteins in promoting angiogenic responses in pathologic conditions, especially tumor angiogenesis and progression. Likewise, we discuss opportunities to manipulate aberrant GPCR-mediated angiogenic signaling for therapeutic benefit using innovative GPCR-targeted and patient-tailored pharmacological strategies.

FTY720 inhibits mesothelioma growth in vitro and in a syngeneic mouse model

BACKGROUND

Malignant mesothelioma (MM) is a very aggressive type of cancer, with a dismal prognosis and inherent resistance to chemotherapeutics. Development and evaluation of new therapeutic approaches is highly needed. Immunosuppressant FTY720, approved for multiple sclerosis treatment, has recently raised attention for its anti-tumor activity in a variety of cancers. However, its therapeutic potential in MM has not been evaluated yet.

METHODS

Cell viability and anchorage-independent growth were evaluated in a panel of MM cell lines and human mesothelial cells (HM) upon FTY720 treatment to assess in vitro anti-tumor efficacy. The mechanism of action of FTY720 in MM was assessed by measuring the activity of phosphatase protein 2A (PP2A)-a major target of FTY720. The binding of the endogenous inhibitor SET to PP2A in presence of FTY720 was evaluated by immunoblotting and immunoprecipitation. Signaling and activation of programmed cell death were evaluated by immunoblotting and flow cytometry. A syngeneic mouse model was used to evaluate anti-tumor efficacy and toxicity profile of FTY720 in vivo.

RESULTS

We show that FTY720 significantly suppressed MM cell viability and anchorage-independent growth without affecting normal HM cells. FTY720 inhibited the phosphatase activity of PP2A by displacement of SET protein, which appeared overexpressed in MM, as compared to HM cells. FTY720 promoted AKT dephosphorylation and Bcl-2 degradation, leading to induction of programmed cell death, as demonstrated by caspase-3 and PARP activation, as well as by cytochrome c and AIF intracellular translocation. Moreover, FTY720 administration in vivo effectively reduced tumor burden in mice without apparent toxicity.

CONCLUSIONS

Our preclinical data indicate that FTY720 is a potentially promising therapeutic agent for MM treatment.

G protein-coupled receptors as promising cancer targets

G protein-coupled receptors (GPCRs) regulate an array of fundamental biological processes, such as growth, metabolism and homeostasis. Specifically, GPCRs are involved in cancer initiation and progression. However, compared with the involvement of the epidermal growth factor receptor in cancer, that of GPCRs have been largely ignored. Recent findings have implicated many GPCRs in tumorigenesis, tumor progression, invasion and metastasis. Moreover, GPCRs contribute to the establishment and maintenance of a microenvironment which is permissive for tumor formation and growth, including effects upon surrounding blood vessels, signaling molecules and the extracellular matrix. Thus, GPCRs are considered to be among the most useful drug targets against many solid cancers. Development of selective ligands targeting GPCRs may provide novel and effective treatment strategies against cancer and some anticancer compounds are now in clinical trials. Here, we focus on tumor related GPCRs, such as G protein-coupled receptor 30, the lysophosphatidic acid receptor, angiotensin receptors 1 and 2, the sphingosine 1-phosphate receptors and gastrin releasing peptide receptor. We also summarize their tissue distributions, activation and roles in tumorigenesis and discuss the potential use of GPCR agonists and antagonists in cancer therapy.

FTY720 (Fingolimod) sensitizes hepatocellular carcinoma cells to sorafenib-mediated cytotoxicity

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. The multityrosine kinase inhibitor sorafenib is used in the therapy of advanced disease. However, the effects of sorafenib are limited, and combination treatments aiming at improved survival are encouraged. The sphingosine analog FTY720 (Fingolimod), which is approved for treatment of multiple sclerosis, has shown tumor suppressive effects in cell lines and animal models of HCC. In the present study, we combined sorafenib with FTY720 in order to sensitize the HCC cell lines Huh7 and HepG2 to sorafenib treatment. Using the XTT assay we show that noncytotoxic doses of FTY720 synergistically enhanced the decrease in viability caused by treatment of both cell lines with increasing doses of sorafenib. Further studies in Huh7 revealed that combined treatment with FTY720 and sorafenib resulted in G1 arrest and enhanced cell death measured using flow cytometry analysis of cells labeled with propidium iodide (PI)/Annexin-V and PI and 4′,6-diamidino-2-phenylindole-staining of nuclei. In addition, signs of both caspase-dependent and – independent apoptosis were observed, as cotreatment with FTY720 and sorafenib caused cytochrome c release and poly-ADP ribose polymerase-cleavage as well as translocation of Apoptosis-inducing factor into the cytosol. We also detected features of autophagy blockage, as the protein levels of LC3-II and p62 were affected by combined treatment with FTY720 and sorafenib. Together, our results suggest that FTY720 sensitizes HCC cells to cytotoxic effects induced by treatment with sorafenib alone. These findings warrant further investigations of combined treatment with sorafenib and FTY720 in vivo in order to develop more effective treatment of HCC.

FTY720 reduces migration and invasion of human glioblastoma cell lines via inhibiting the PI3K/AKT/mTOR/p70S6K signaling pathway

2-Amino-2-[2-(4-octylphenyl)]-1,3-propanediol hydrochloride (FTY720), a synthetic compound from Isaria sinclairii, has been proven to possess various biological benefits including anti-cancer activity. However, the effects and related mechanisms of FTY720 on the migration and invasion of glioblastoma cells are still unclear. In the present study, we utilized U251MG and U87MG human glioblastoma cell lines to assess the effects of FTY720. We found that FTY720 significantly inhibited migration and invasion of glioblastoma cells. The anti-migration and invasion effects of FTY720 were associated with its down-regulation of matrix metalloproteinase-2 (MMP-2) and MMP-9 while up-regulation of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2. Furthermore, FTY720 modulated the expression of roundabouts 1 (ROBO1), Rho-associated kinase-1 (ROCK1), and epithelial-to-mesenchymal transition (EMT)-related factors. In addition, the phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin/p70S6 kinase (PI3K/AKT/mTOR/p70S6K) signaling pathway participated in FTY720-mediated suppression of migration and invasion. Thus, our findings demonstrated that FTY720 reduced glioblastoma cells migration and invasion via multiple signaling pathways, suggesting that FTY720 is a potential therapeutic agent against glioblastoma.

FTY720 for cancer therapy (Review)

2-Amino-2-[2-(4-octylphenyl)]-1,3-propanediol hydrochloride (FTY720) is a potent immunosuppressant which has been approved by the Food and Drug Administration (FDA) as a new treatment for multiple sclerosis. As an immunosuppressant, it displays its anti-multiple sclerosis, immunosuppressive effects by activating sphingosine-1-phosphate receptors (S1PRs). In addition to the immunosuppressive effects, FTY720 also shows preclinical antitumor efficacy in several cancer models. In most cases, phosphorylation of FTY720 is not required for its cytotoxic effect, indicating the involvement of S1PR-independent mechanisms which are starkly different from the immunosuppressive property of FTY720. In the present study, we reviewed the rapidly advancing field of FTY720 in cancer therapy as well as some molecular targets of the unphosphorylated form of FTY720.

The role of sphingosine-1-phosphate in breast cancer tumor-induced lymphangiogenesis

Sphingosine-1-phosphate (S1P) is a potent sphingolipid metabolite that regulates a number of biological processes critical for cancer. S1P produced inside cancer cells is exported and exerts its extracellular functions by binding to its specific receptors in an autocrine, paracrine, and/or endocrine manner, which is known as inside-out signaling. S1P is also known to exert its intracellular functions especially in the inflammatory process, but its relevance to cancer biology remains to be elucidated. Recently, there have been growing interests in the role of S1P in breast cancer progression, including angiogenesis and lymphangiogenesis. Our group demonstrated that activation of sphingosine kinase 1, the enzyme that catalyzes the phosphorylation of sphingosine to S1P, is a key step of this process. In this review, we will cover our current knowledge on the role of S1P signaling pathway in breast cancer progression with an emphasis on its role in tumor-induced lymphangiogenesis.

The sphingosine-1-phosphate analog FTY720 reduces muscle ceramide content and improves glucose tolerance in high fat-fed male mice

FTY720 is a sphingosine-1-phosphate analog that has been shown to inhibit ceramide synthesis in vitro. Because ceramide accumulation in muscle is associated with insulin resistance, we aimed to examine whether FTY720 would prevent muscle ceramide accumulation in high fat-fed mice and subsequently improve glucose homeostasis. Male C57Bl/6 mice were fed either a chow or high fat-diet (HFD) for 6 wk, after which they were treated with vehicle or FTY720 (5 mg/kg) daily for a further 6 wk. The ceramide content of muscle was examined and insulin action was assessed. Whereas the HFD increased muscle ceramide, this was prevented by FTY720 treatment. This was not associated with alterations in the expression of genes involved in sphingolipid metabolism. Interestingly, the effects of FTY720 on lipid metabolism were not limited to ceramide because FTY720 also prevented the HFD-induced increase in diacylglycerol and triacylglycerol in muscle. Furthermore, the increase in CD36 mRNA expression induced by fat feeding was prevented in muscle of FTY720-treated mice. This was associated with an attenuation of the HFD-induced increase in palmitate uptake and esterification. In addition, FTY720 improved glucose homeostasis as demonstrated by a reduction in plasma insulin, an improvement in whole-body glucose tolerance, an increase in insulin-stimulated glucose uptake, and Akt phosphorylation in muscle. In conclusion, FTY720 exerts beneficial effects on muscle lipid metabolism that prevent lipid accumulation and improve glucose tolerance in high fat-fed mice. Thus, FTY720 and other compounds that target sphingosine-1-phosphate signaling may have therapeutic potential in treating insulin resistance.

Sphingosine-1-phosphate antibodies as potential agents in the treatment of cancer and age-related macular degeneration

Sphingosine-1-phosphate (S1P) is a pleiotropic bioactive lipid thought to be dysregulated in a variety of disease conditions. In this review, we discuss the roles of S1P in cancer and in wet age-related macular degeneration. We also explore potential treatment strategies for these disorders, including the utility of anti-S1P antibodies acting as molecular sponges to neutralize dysregulated S1P in relevant tissues.

S1P is associated with protection in human and experimental cerebral malaria

Cerebral malaria (CM) is associated with excessive inflammatory responses and endothelial activation. Sphingosine 1-phosphate (S1P) is a signaling sphingolipid implicated in regulating vascular integrity, inflammation and T-cell migration. We hypothesized that altered S1P signaling during malaria contributes to endothelial activation and inflammation, and show that plasma S1P levels were decreased in Ugandan children with CM compared with children with uncomplicated malaria. Using the Plasmodium berghei ANKA (PbA) model of experimental CM (ECM), we demonstrate that humanized S1P lyase (hS1PL)(-/-) mice with reduced S1P lyase activity (resulting in increased bio-available S1P) had improved survival compared with wild-type littermates. Prophylactic and therapeutic treatment of infected mice with compounds that modulate the S1P pathway and are in human trials for other conditions (FTY720 or LX2931) significantly improved survival in ECM. FTY720 treatment improved vascular integrity as indicated by reduced levels of soluble intercellular adhesion molecule (sICAM), increased angiopoietin 1 (Ang1) (regulator of endothelial quiescence) levels, and decreased Evans blue dye leakage into brain parenchyma. Furthermore, treatment with FTY720 decreased IFNγ levels in plasma as well as CD4(+) and CD8(+) T-cell infiltration into the brain. Finally, when administered during infection in combination with artesunate, FTY720 treatment resulted in increased survival to ECM. These findings implicate dysregulation of the S1P pathway in the pathogenesis of human and murine CM and suggest a novel therapeutic strategy to improve clinical outcome in severe malaria.

Lung tumor development in the presence of sphingosine 1-phosphate agonist FTY720

Urethane is a chemical carcinogen which causes lung tumorigenesis in mice with similarities to human adenocarcinoma (AC). The sphingosine 1-phosphate agonist FTY720 administered to mice in doses above 5 mg/kg/day has been able to prevent hepatocellular carcinoma and bladder cancer. We used BALB/c mice in urethane-induced lung cancer model to investigate the effects of a lower dose of FTY720 (1 mg/kg/day). The benefits of FTY720 were associated with the time point of the compound administration. FTY720 30 Group presented lower incidence and smaller area of lung nodules, decreased PCNA and increased Caspase-3 expressions. The findings in FTY720 0 Group (nodule multiplicity and area, PCNA expression) were similar to Urethane Group suggesting that the administration of the compound at early time point did not affect lung tumor development. FTY720 90 Group presented the biggest nodule area which was associated with increased PCNA and decreased Caspase-3 expressions. FTY720 (30 days and 90 days) administration decreased CD4 + splenocytes and blood lymphocytes which caused opposite effects in lung tumor development - impairment and improvement respectively.In conclusion, FTY720 in low dose did not provide lung tumor inhibition in mice but its administration 30 days after the chemical carcinogen (Urethane) injection was associated with impaired tumor development.

FTY720 inhibits ceramide synthases and up-regulates dihydrosphingosine 1-phosphate formation in human lung endothelial cells

Novel immunomodulatory molecule FTY720 is a synthetic analog of myriocin, but unlike myriocin FTY720 does not inhibit serine palmitoyltransferase. Although many of the effects of FTY720 are ascribed to its phosphorylation and subsequent sphingosine 1-phosphate (S1P)-like action through S1P(1,3-5) receptors, studies on modulation of intracellular balance of signaling sphingolipids by FTY720 are limited. In this study, we used stable isotope pulse labeling of human pulmonary artery endothelial cells with l-[U-(13)C, (15)N]serine as well as in vitro enzymatic assays and liquid chromatography-tandem mass spectrometry methodology to characterize FTY720 interference with sphingolipid de novo biosynthesis. In human pulmonary artery endothelial cells, FTY720 inhibited ceramide synthases, resulting in decreased cellular levels of dihydroceramides, ceramides, sphingosine, and S1P but increased levels of dihydrosphingosine and dihydrosphingosine 1-phosphate (DHS1P). The FTY720-induced modulation of sphingolipid de novo biosynthesis was similar to that of fumonisin B1, a classical inhibitor of ceramide synthases, but differed in the efficiency to inhibit biosynthesis of short-chain versus long-chain ceramides. In vitro kinetic studies revealed that FTY720 is a competitive inhibitor of ceramide synthase 2 toward dihydrosphingosine with an apparent K(i) of 2.15 microm. FTY720-induced up-regulation of DHS1P level was mediated by sphingosine kinase (SphK) 1, but not SphK2, as confirmed by experiments using SphK1/2 silencing with small interfering RNA. Our data demonstrate for the first time the ability of FTY720 to inhibit ceramide synthases and modulate the intracellular balance of signaling sphingolipids. These findings open a novel direction for therapeutic applications of FTY720 that focuses on inhibition of ceramide biosynthesis, ceramide-dependent signaling, and the up-regulation of DHS1P generation in cells.

Sphingolipid signalling in the cardiovascular system: good, bad or both?

Sphingolipids are biologically active lipids that play important roles in various cellular processes and the sphingomyelin metabolites ceramide, sphingosine and sphingosine-1-phosphate can act as signalling molecules in most cell types. With the recent development of the immunosuppressant drug FTY720 (Fingolimod) which after phosphorylation in vivo acts as a sphingosine-1-phosphate receptor agonist, research on the role of sphingolipids in the immune and other organ systems was triggered enormously. Since it was reported that FTY720 induced a modest, but significant transient decrease in heart rate in animals and humans, the question was raised which pharmacological properties of drugs targeting sphingolipid signalling will affect cardiovascular function in vivo. The answer to this question will most likely also indicate what type of drug could be used to treat cardiovascular disease. The latter is becoming increasingly important because of the increasing population carrying characteristics of the metabolic syndrome. This syndrome is, amongst others, characterized by obesity, hypertension, atherosclerosis and diabetes. As such, individuals with this syndrome are at increased risk of heart disease. Now numerous studies have investigated sphingolipid effects in the cardiovascular system, can we speculate whether certain sphingolipids under specific conditions are good, bad or maybe both? In this review we will give a brief overview of the pathophysiological role of sphingolipids in cardiovascular disease. In addition, we will try to answer how drugs that target sphingolipid signalling will potentially influence cardiovascular function and whether these drugs would be useful to treat cardiovascular disease.

FTY720, a synthetic compound from Isaria sinclairii, inhibits proliferation and induces apoptosis in pancreatic cancer cells

FTY720, a synthetic compound produced by modification of a metabolite from Isaria sinclairii, is known as a unique immunosuppressive agent that exerts its activity by inducing apoptosis of lymphocytes [S. Suzuki, FTY720: Mechanisms of action and its effect on organ transplantation, Transplant. Proc. 31 (1999) 2779-2782]. Additionally, it has been found that FTY720 has inhibitory effects on various cancer growth and metastasis [J.D. Wang, S. Takahara, N. Nonomura, Early induction of apoptosis in androgen-independent prostate cancer cell line by FTY720 requires caspase-3 activation, Prostate 40 (1999) 50-55]. To investigate its effect on the growth and metastasis of pancreatic cancer, FTY720 was used to treat three pancreatic cancer cell lines (BxPC-3, AsPC-1, and PANC-1). The MTT assay and flow cytometry were used to evaluate the cell death after FTY720 treatment; the wound closure assay, three-dimensional (3D) Matrigel assay, and invasive assay were used to evaluate the migration, colony formation and invasion abilities after FTY720 treatment, respectively. Protein expression in BxPC-3, AsPC-1, and PANC-1 cells after FTY720 treatment was detected by Western blotting. The MTT assay indicated that the growth of pancreatic cancer cells could be inhibited by FTY720 at various concentrations between 0 and 17 microM in a dose-dependent manner, which was also confirmed by flow cytometry. The wound closure assay, 3D Matrigel assay and cell invasion assay all showed that FTY720 significantly suppressed migration, colony formation and invasion ability of cancer cells at concentrations from 5 to 17 microM. After FTY720 treatment, the phospho-Akt, Bcl-2, pro-caspase-3 expression were down-regulated while the caspase-9 protein expression was increased. In conclusion, FTY720 can inhibit the growth, migration and invasion of pancreatic cancer cells. Our study provides a preclinical support for chemotherapeutic approach with FTY720 for the treatment of pancreatic cancer.

Current perspectives on FTY720

The search for effective immunosuppressants with fewer side effects continues not only for transplantation, but also for autoimmune diseases. With a novel mechanism of action (sphingosine-1 receptor modulation), oral FTY720 (fingolimod) has the potential to address this need. FTY720 has been preclinically tested with promising results in transplantation and autoimmune disease models. Phase I studies explored the pharmacokinetics and pharmacodynamics of this novel therapeutic concept. Recently, the surprising results of two sister Phase III studies in de novo renal transplant patients, as well as a Phase II study in patients with relapsing multiple sclerosis, were published. This review discusses these findings as well as their implications for the future of sphingosine-1 receptor modulation.

The immunosuppressant FTY720 inhibits tumor angiogenesis via the sphingosine 1-phosphate receptor 1

FTY720, a sphingosine 1-phosphate (S1P) analog, acts as an immunosuppressant through trapping of T cells in secondary lymphoid tissues. FTY720 was also shown to prevent tumor growth and to inhibit vascular permeability. The MTT proliferation assay illustrated that endothelial cells are more susceptible to the anti-proliferative effect of FTY720 than Lewis lung carcinoma (LLC1) cells. In a spheroid angiogenesis model, FTY720 potently inhibited the sprouting activity of VEGF-A-stimulated endothelial cells even at concentrations that apparently had no anti-proliferative effect. Mechanistically, the anti-angiogenic effect of the general S1P receptor agonist FTY720 was mimicked by the specific S1P1 receptor agonist SEW2871. Moreover, the anti-angiogenic effect of FTY720 was abrogated in the presence of CXCR4-neutralizing antibodies. This indicates that the effect was at least in part mediated by the S1P1 receptor and involved transactivation of the CXCR4 chemokine receptor. Additionally, we could illustrate in a coculture spheroid model, employing endothelial and smooth muscle cells (SMCs), that the latter confer a strong protective effect regarding the action of FTY720 upon the endothelial cells. In a subcutaneous LLC1 tumor model, the anti-angiogenic capacity translated into a reduced tumor size in syngeneic C57BL/6 mice. Consistently, in the Matrigel plug in vivo assay, 10 mg/kg/d FTY720 resulted in a strong inhibition of angiogenesis as demonstrated by a reduced capillary density. Thus, in organ transplant patients, FTY720 may prove efficacious in preventing graft rejection as well as tumor development.

FTY720 in combination with cyclosporine--an analysis of skin allograft survival and renal function

Acute and chronic nephrotoxicity caused by CsA continuous administration impair kidney allograft survival. Several clinical and experimental protocols have shown benefits to the kidney after decreasing CsA dose, withdrawing the drug or delaying its introduction after transplantation. FTY720 is a new compound that has immunosuppressive characteristics and increase allograft survival in animal models without causing the side effects of calcineurin inhibitors (CNIs). FTY720 described mechanism of action that consists to alter the lymphocyte migration pattern without impairment of the immune system response against pathogens. In our mice model, FTY720 administered alone or in combination with CsA during 21 days increased skin allograft survival in a fully mismatched strain combination and did not cause significant changes in renal function. Moreover, renal structure was normal in all groups suggesting that at low doses (10 mg/kg/day) CsA can be associated during short-term period to other immunosuppressive drugs, i.e. FTY720 without affecting the kidney. Combination of immunosuppressive compounds with FTY720 and/or delayed introduction of low cyclosporine dose could prevent graft rejection and avoid nephrotoxicity.

Sphingolipid targets in cancer therapy

Considerable progress has been made recently in our understanding of the role of ceramide in the induction of apoptotic cell death. Ceramide is produced by cancer cells in response to exposure to radiation and most chemotherapeutics and is an intracellular second messenger that activates enzymes, leading to apoptosis. Because of its central role in apoptosis, pharmacologic manipulation of intracellular ceramide levels should result in attenuation or enhancement of drug resistance. This may be achieved through direct application of sphingolipids or by the inhibition/activation of the enzymes that either produce or use ceramide. In addition, attention should be given to the subcellular location of ceramide generation, because this has been shown to affect the biological activity of sphingolipids. This review summarizes the sphingolipid biosynthetic pathway, as it relates to the identification of important targets for drug discovery, and the development of novel agents capable of enhancing chemotherapy.