Olivier Cuvillier

Downregulating sphingosine kinase-1 for cancer therapy

Background: The sphingolipids ceramide and sphingosine 1-phosphate (S1P) are key regulators of cell death and proliferation. The subtle balance between their intracellular levels is governed mainly by sphingosine kinase-1, which produces the pro-survival S1P. Sphingosine kinase-1 is an oncogene; is overexpressed in many tumors; protects cancer cells from apoptosis in vitro and in vivo; and its activity is decreased by anticancer therapies. Hence, sphingosine kinase-1 appears to be a target of interest for therapeutic manipulation. Objective: This review considers recent developments regarding the involvement of sphingosine kinase-1 as a therapeutic target for cancer, and describes the pharmacological tools currently available. Results/conclusion: The studies described provide strong evidence that strategies to kill cancer cells via sphingosine kinase-1 inhibition are valid and could have a favorable therapeutic index.

The sphingosine kinase-1 survival pathway is a molecular target for the tumor-suppressive tea and wine polyphenols in prostate cancer

The sphingosine kinase‐1/sphingosine 1‐phosphate (SphK1/S1P) pathway has been associated with cancer promotion and progression and resistance to treatments in a number of cancers, including prostate adenocarcinoma. Here we provide the first evidence that dietary agents, namely, epigallocatechin gallate (EGCg, IC50≈75 µM), resveratrol (IC50≈40 µM), or a mixture of polyphenols from green tea [polyphenon E (PPE), IC50≈70 µM] or grapevine extract (vineatrol, IC50≈30 µM), impede prostate cancer cell growth in vitro and in vivo by inhibiting the SphK1/S1P pathway. We establish that SphK1 is a downstream effector of the ERK/phospholipase D (PLD) pathway, which is inhibited by green tea and wine polyphenols. Enforced expression of SphK1 impaired the ability of green tea and wine polyphenols, as well as pharmacological inhibitors of PLD and ERK activities, to induce apoptosis in PC‐3 and C4‐2B cells. The therapeutic efficacy of these polyphenols on tumor growth and the SphK1/S1P pathway were confirmed in animals using a heterotopic PC‐3 tumor in place model. PC‐3/SphK1 cells implanted in animals developed larger tumors and resistance to treatment with polyphenols. Furthermore, using an orthotopic PC‐3/ GFP model, the chemopreventive effect of an EGCg or PPE diet was associated with SphK1 inhibition, a decrease in primary tumor volume, and occurrence and number of metastases. These results provide the first demonstration that the prosurvival, antiapoptotic SphK1/S1P pathway represents a target of dietary green tea and wine polyphenols in cancer.—Brizuela, L., Dayon, A., Doumerc, N., Ader, I., Golzio, M., Izard, J.‐C., Hara, Y., Malavaud, B., Cuvillier, O. The sphingosine kinase‐1 survival pathway is a molecular target for the tumor‐suppressive tea and wine polyphenols in prostate cancer. FASEB J. 24, 3882–3894 (2010). www.fasebj.org

Sphingosine kinase 1 inhibition sensitizes hormone-resistant prostate cancer to docetaxel.

It has recently been shown that docetaxel chemotherapy is effective in prolonging life in patients with prostate cancer (PCa). We have investigated potential ways of increasing the effectiveness of chemotherapy in this disease. We have previously reported that sphingosine kinase 1 (SphK1) inhibition is a key step in docetaxel‐induced apoptosis in the PC‐3 PCa cell line and that pharmacologicalSphK1 inhibition is chemosensitizing in the docetaxel‐resistant PCa LNCaP cell line. In this study we have addressed the mechanism of docetaxel‐induced apoptosis of PC‐3 cells and identified SphK1‐dependent and ‐independent components. We have shown that SphK1 inhibition by docetaxel is a two‐step process involving an initial loss of enzyme activity followed by a decrease in SphK1 gene expression. Using hormoneresistant PC‐3 and DU145 PCa cells we have demonstrated that both pharmacological and siRNA‐mediated SphK1 inhibition leads to a four‐fold decrease in the docetaxel IC50 dose. This work points out to potential ways of increasing the effectiveness of chemotherapy for PCa by SphK1 inhibition.

1H and 13C-NMR assignments for sialylated oligosaccharide-alditols related to mucins. Study of thirteen components from hen ovomucin and swallow nest mucin

Four hundred MHz 1H-NMR and 100 MHz 13C-NMR spectra of thirteen sialylated oligosaccharide-alditols isolated from hen ovomucin and swallow nests (Collocalia mucin) were studied. The resonance assignments were determined by combining multiple-relayed coherence-transfer chemical-shift-correlated spectroscopy (multiple-Relay-Cosy) and 1H/13C chemical-shift-correlated 2-D experiments.

Sphingosine 1-phosphate signaling through its receptor S1P5 promotes chromosome segregation and mitotic progression

Targeting the signaling lipid S1P might suppress tumor growth by slowing mitosis. Sphingolipids stimulate mitosis Drugs that attempt to halt the increased rate of cell division or mitosis in tumors are usually toxic to healthy cells as well. Thus, identifying a more cancer-specific target that promotes cell division may be more effective and may have fewer side effects. Andrieu et al. found that the kinase SphK1 and its lysophospholipid product (S1P) stimulated mitosis through a pathway that is associated with cell proliferation. Both SphK1 and S1P are increased in abundance in many cancer types, and drugs that target the downstream pathway are in clinical trials. The findings reveal an unexpected potential therapeutic target to limit tumor cell proliferation. Sphingosine kinase 1 (SphK1) promotes cell proliferation and survival, and its abundance is often increased in tumors. SphK1 produces the signaling lipid sphingosine 1-phosphate (S1P), which activates signaling cascades downstream five G protein–coupled receptors (S1P1–5) to modulate vascular and immune system function and promote proliferation. We identified a new function of the SphK1-S1P pathway specifically in the control of mitosis. SphK1 depletion in HeLa cells caused prometaphase arrest, whereas its overexpression or activation accelerated mitosis. Increasing the abundance of S1P promoted mitotic progression, overrode the spindle assembly checkpoint (SAC), and led to chromosome segregation defects. S1P was secreted through the transporter SPNS2 and stimulated mitosis by binding to and activating S1P5 on the extracellular side, which then activated the intracellular phosphatidylinositol 3-kinase (PI3K)–AKT pathway. Knockdown of S1P5 prevented the S1P-induced spindle defect phenotype. RNA interference assays revealed that the mitotic kinase Polo-like kinase 1 (PLK1) was an important effector of S1P-S1P5 signaling-induced mitosis in HeLa cells. Our findings identify an extracellular signal and the downstream pathway that promotes mitotic progression and may indicate potential therapeutic targets to inhibit the proliferation of cancer cells.

Abstract A38: IMODI initiative: a novel holistic and integrative approach with patient-derived tumor models

Many reports support that xenografts from patient-derived xenografts in mice or rat recapitulate well the molecular diversity, cellular heterogeneity, and histology seen in patient tumors. However, several lacks such as the limited clinical diversity of the PDXs, the absence of influence of human microbiome, the absence of human drug metabolism and the reduced immune system are limiting the predictive values of these PDX models. To set-up a holistic integration of these criticisms, we have associated efforts from public hospitals, academic groups, biotechs and private pharmaceutical companies with the financial support of the French Ministry of Industry. First, to improve the clinical diversity of the PDX collections, surgical specimens or biopsies from patients with 8 different types of cancers (lung, breast, ovary, pancreas, liver, prostate, AML, myeloma) are collected since 2013 to establish large collections of PDXs in mice. In addition, primary cultures of cells from these samples are established leading to a collection of cell lines from the stroma and the tumoral compartment. The established models are being evaluated for ex vivo and in vivo sensitivities to relevant anticancer drugs, histological and molecular characteristics. All model characteristics are being compiled in a web-based database for efficient features search and interconnection. Second, to improve our knowledge on the role of the human microbiote, feces and feeding habits are collected from patients with cancer and from mice with PDXs before and after treatment allowing a comparison of the microbiote profiles. In order to mimic the human drug metabolism, we are generating mice with humanized liver showing distinct drug pharmacokinetic profiles from the ones observed in parental mice. Finally, humanization of the immune system in mice is developed by several approaches including the use of induced pluripotent stem cells from cancer patients. We will present the first models characterized and will discuss their usefulness and chance to bring benefit to patients via this holistic strategy developed within IMODI initiative. Citation Format: Francoise LE VACON, Laurent Arnould, Alain Bruno, Loreley Calvet, Marc Colombel, Jill Corre, Olivier Cuvillier, Benedicte Eckel, Nico Forraz, Alexandra Gonzalez-Jouhanneaud, Dominique Guenot, Juan Iovanna, Mariana Kuras, Christophe Lautrette, Bernard Malavaud, Philippe Merle, Florence Meyer-Losic, Francoise Praz, Olivier Rosmorduc, Jean-Emmanuel Sarry, Severine Tabone, Philippe Vaglio, Loic Ysebaert, Olivier Duchamp. IMODI initiative: a novel holistic and integrative approach with patient-derived tumor models. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A38.

Abstract 4826: A therapeutic sphingosine 1-phosphate antibody improves intratumoral oxygenation and sensitizes to chemotherapy in prostate cancer animal model

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Hypoxia promotes neovascularization, metastasis, and resistance to treatments. The activation of the transcription factor HIF-1α has been identified as the master mechanism of adaptation to hypoxia. We recently identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α activity under hypoxia in multiple cancer cell models including prostate cancer (Ader et al, Cancer Res, 2008). S1P elicits proliferation, survival, or angiogenesis, and is believed to exert most of its actions as a ligand for a family of specific GPCRs to elicit paracrine or autocrine signaling. We have suggested that inhibiting SphK1/S1P signaling, which is upregulated under hypoxia, may normalize the microenvironment and increase sensitivity to chemotherapy, in the broader concept of “normalization of tumor vessels” as tumor oxygenation is known to enhance response to chemotherapy (Ader et al., Cancer Res, 2009). Methods: Quantification of intratumoral hypoxia and angiogenesis, and treatment efficacy (primary tumor, metatasis dissemination) using an orthotopic (o.t) xenograft model of fluorescent hormone refractory prostate cancer cells. Results: We first provide in vitro evidence that inhibition of the S1P exogenous signaling, through pharmacological inhibition of its receptors or by taking advantage of a monoclonal antibody neutralizing S1P, blocks HIF-1α accumulation and its activity in prostate cancer cells under to hypoxia. Second, using an o.t model of prostate cancer, we show that an anti-S1P antibody inhibits intratumoral hypoxia and modifies vessel architecture and improves tumor perfusion within 5 days of treatment. Third, we show for the first time that an anti-S1P strategy sensitizes to docetaxel, the ‘gold standard’ treatment for hormone-refractory prostate cancer. A 5-day anti-S1P antibody pretreatment markedly sensitizes to docetaxel in an o.t. PC-3/GFP model established in nude mice. The combination anti-S1P antibody together with docetaxel was not only accompanied by a smaller primary tumor volume compared to docetaxel treatment, but also significantly reduced the occurrence and number of metastases. Conclusion: These preclinical data establish the proof-of-concept that blocking the exogenous action of S1P induces vascular normalization, improves intratumoral oxygenation and sensitizes to chemotherapy in prostate cancer animal model. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4826. doi:1538-7445.AM2012-4826