Center Kaplan

Joué-lés-Tours, France

Center Kaplan

Joué-lés-Tours, France
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Pautier P.,Institute Gustave Roussy | Joly F.,Center Francois Baclesse | Kerbrat P.,Center Eugene Marquis | Bougnoux P.,Center Kaplan | And 6 more authors.
Gynecologic Oncology | Year: 2010

Objective: This phase II investigated efficacy and tolerability of gefitinib in combination with paclitaxel (P) and carboplatin (C) for second-line treatment of patients (pts) with ovarian, tubal or peritoneal adenocarcinoma. Patients and methods: Women (> 18 years) with platinum-resistant/refractory (relapsed < 6 months), or platinum-sensitive (relapsed > 6 months) disease after first-line platinum-based and P chemotherapy. Pts received 6-8 cycles of gefitinib (500 mg/day), P (175 mg/m2 3 h infusion) and C (AUC 5) every 3 weeks, followed by gefitinib alone. The primary endpoint was objective response rate (ORR) (RECIST or Rustin criteria). Results: Sixty-eight patients (26 resistant/refractory and 42 sensitive) were enrolled (median age: 57 years). ORR and disease control rates were 19.2% and 69.2% for resistant/refractory, and 61.9% and 81.0%, for sensitive disease. Median time to progression and overall median survivals were 6.1 and 16.9 months for resistant/refractory and 9.2 and 25.7 months for sensitive disease. Grade 3/4 toxicities (in ≥ 10% patients) were neutropenia (59%), diarrhea (25%), leukopenia (22%), anemia (13%), and acne (13%). Two secondary myelodysplastic syndromes (MDS) and one secondary acute leukemia occurred during treatment, and one MDS 34 months after treatment discontinuation. Conclusion: Gefitinib, administered in combination with paclitaxel and carboplatin, provides a good clinical response but associated with an increased risk of hematologic disorders. © 2009 Elsevier Inc. All rights reserved.

Girault A.,French Institute of Health and Medical Research | Girault A.,University of Tours | Haelters J.-P.,French National Center for Scientific Research | Potier-Cartereau M.,French Institute of Health and Medical Research | And 10 more authors.
Current Medicinal Chemistry | Year: 2012

Many studies have reported changes in potassium channel expression in many cancers and the involvement of these channels in various stages of cancer progression. By contrast, data concerning SKCa channels (small conductance calcium-activated potassium channels) have only recently become available. This review aims i) to present the structure and physiology of SKCa channels, ii) to provide an overview of published data concerning the SKCa proteins produced in tumor cells, and, whenever possible, the biological function assigned to them and iii) to review previous and novel modulators of SKCa channels. SKCa channels are activated by low concentrations of intracellular calcium and consist of homo- or heteromeric assemblies of α-subunits named SK1, SK2 and SK3. SK2-3 channels are expressed in tumors and have been assigned a biological function in cancer cells: the enhancement of cell proliferation and cell migration by hijacking the functions of SK2 and SK3 channels, respectively. Two major classes of SKCa modulators have been described: toxins (apamin) and small synthetic molecules. Most SKCa blockers are pore blockers, but some modify the calcium sensitivity of SKCa channels without interacting with the apamin binding site. In this review, we present edelfosine and ohmline as atypical anticancer agents and novel SK3 inhibitors. Edelfosine and ohmline are synthetic alkyl-lipids with structures different from all previously described SKCa modulators. They should pave the way for the development of a new class of migration-targeted anticancer agents. We believe that such blockers have potential for use in the prevention or treatment of metastasis. © 2012 Bentham Science Publishers.

Chantome A.,French Institute of Health and Medical Research | Potier-Cartereau M.,French Institute of Health and Medical Research | Clarysse L.,French Institute of Health and Medical Research | Fromont G.,CHRU de Poitiers | And 16 more authors.
Cancer Research | Year: 2013

The SK3 channel, a potassium channel, was recently shown to control cancer cell migration, a critical step in metastasis outgrowth. Here, we report that expression of the SK3 channel was markedly associated with bone metastasis. The SK3 channel was shown to control constitutive Ca2+ entry and cancer cell migration through an interaction with the Ca2+ channel Orai1. We found that the SK3 channel triggers an association with the Orai1 channel within lipid rafts. This localization of an SK3-Orai1 complex seemed essential to control cancer cell migration. This suggests that the formation of this complex in lipid rafts is a gain-offunction, because we showed that none of the individual proteins were able to promote the complete phenotype. We identified the alkyl-lipid Ohmline as a disrupting agent for SK3-Orai1 lipid raft localization. Upon Ohmline treatment, the SK3-Orai1 complex moved away from lipid rafts, and SK3-dependent Ca2+ entry, migration, and bone metastases were subsequently impaired. The colocalization of SK3 and Orai1 in primary human tumors and bone metastases further emphasized the clinical relevance of our observations. Targeting SK3-Orai1 in lipid rafts may inaugurate innovative approaches to inhibit bone metastases. © 2013 American Association for Cancer Research.

Girault A.,French Institute of Health and Medical Research | Haelters J.-P.,French National Center for Scientific Research | Potier-Cartereau M.,French Institute of Health and Medical Research | Chantome A.,French Institute of Health and Medical Research | And 11 more authors.
Current Cancer Drug Targets | Year: 2011

Edelfosine is an inhibitor of SK3 channel-mediated cell migration. However, this compound bears adverse in vivo side effects. Using cell SK3 dependent cell-migration assay, patch-clamp, 125I-apamin binding, and in vivo experiments we tested the ability of 15 lipid derivatives with chemical structures inspired from edelfosine to inhibit SK3 channels. Using a structure-activity relationship approach we identified an edelfosine analog named Ohmline (1-O-hexadecyl-2-O-methyl-sn-glycero-3-lactose) with potent inhibitory effects on the SK3 channel. Its potency was greater for SK3 channels than for SK1 channels; it did not affect IKCa channels and only slightly but not significantly affected SK2 channels. This is the first SKCa channel blocker that can be used to discriminate between SK2 and SK1/SK3 channels and represents a useful tool to investigate the functional role of SK3 channels in peripheral tissues (that do not express SK1 channels). This compound, which acts with an IC 50 of 300 nM, did not displace apamin from SKCa channels and had no effect on non-specific edelfosine targets such as protein kinase C (PKC), receptors for platelet activating factor (PAF) and lysophosphatidic acid (LPA), as well as non-cancerous cells. This is promising because the pitfalls associated with the use of edelfosine-like compounds have been that their effective and high concentrations are often cytotoxic due to their detergent-like character causing normal cell lysis. Finally, Ohmline reduced metastasis development in a mice model of tumor indicating that this compound could become a lead compound for the first class of lipid-antimetastatic agent. © 2011 Bentham Science Publishers.

Jaffres P.-A.,French National Center for Scientific Research | Gajate C.,CSIC - Biological Research Center | Bouchet A.M.,University of Tours | Couthon-Gourves H.,French National Center for Scientific Research | And 7 more authors.
Pharmacology and Therapeutics | Year: 2016

Synthetic alkyl lipids, such as the ether lipids edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) and ohmline (1-O-hexadecyl-2-O-methyl-rac-glycero-3-β-lactose), are forming a class of antitumor agents that target cell membranes to induce apoptosis and to decrease cell migration/invasion, leading to the inhibition of tumor and metastasis development. In this review, we present the structure–activity relationship of edelfosine and ohmline, and we point out differences and similarities between these two amphiphilic compounds. We also discuss the mechanisms of action of these synthetic alkyl ether lipids (involving, among other structures and molecules, membrane domains, Fas/CD95 death receptor signaling, and ion channels), and highlight a key role for lipid rafts in the underlying process. The reorganization of lipid raft membrane domains induced by these alkyl lipids affects the function of death receptors and ion channels, thus leading to apoptosis and/or inhibition of cancer cell migration. The possible therapeutic use of these alkyl lipids and the clinical perspectives for these lipids in prevention or/and treatment of tumor development and metastasis are also discussed. © 2016 Elsevier Inc.

Gueguinou M.,French Institute of Health and Medical Research | Gueguinou M.,University of Tours | Gambade A.,French Institute of Health and Medical Research | Gambade A.,University of Tours | And 15 more authors.
Biochimica et Biophysica Acta - Biomembranes | Year: 2015

Membrane lipid rafts are distinct plasma membrane nanodomains that are enriched with cholesterol, sphingolipids and gangliosides, with occasional presence of saturated fatty acids and phospholipids containing saturated acyl chains. It is well known that they organize receptors (such as Epithelial Growth Factor Receptor), ion channels and their downstream acting molecules to regulate intracellular signaling pathways. Among them are Ca2 + signaling pathways, which are modified in tumor cells and inhibited upon membrane raft disruption. In addition to protein components, lipids from rafts also contribute to the organization and function of Ca2 + signaling microdomains. This article aims to focus on the lipid raft KCa/ClCa/Ca2 + channel complexes that regulate Ca2 + and EGFR signaling in cancer cells, and discusses the potential modification of these complexes by lipids as a novel therapeutic approach in tumor development. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. © 2014 Elsevier B.V.

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