title: Evaluation of cytotoxic properties of a cyclopamine glucuronide prodrug in rat glioblastoma cells and tumors.
abstract: Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor. Activation of the developmental hedgehog (Hh) pathway is observed in GBM, particularly in the so-called glioma stem cells (GSCs). An inhibitor of this pathway is the steroidal alkaloid cyclopamine, an antagonist of the Hh coreceptor Smoothened (SMO). To limit the toxicity of cyclopamine toward Hh-dependent non-tumor cells, our group previously reported the synthesis of a prodrug (called 1b), designed to deliver cyclopamine in the presence of β-glucuronidase, an enzyme found in the necrotic area of GBM. Here, we aimed to analyze the in vitro, ex vivo, and in vivo cytotoxic properties of this prodrug in the C6 rat GBM cells. In the presence of β-glucuronidase, the activated prodrug 1b was toxic and downregulated expression of Gli1, a Hh target gene, in C6 cells and C6-GSCs, but not in normal rat astrocytes in which the Hh pathway is weakly activated. In the absence of β-glucuronidase, prodrug 1b displayed no obvious toxicity toward rat brain tissue explants while cyclopamine clearly affected brain tissue viability. When administered to rats bearing fluorescent C6-derived GBM, the prodrug 1b reduced the tumor density more efficiently than cyclopamine. Prodrug 1b thus appears as a promising concept to optimize confinement of cyclopamine cytotoxicity within the tumors, with more limited effects in the surrounding normal brain tissue.
authors.affiliation: "Récepteurs, Régulations et Cellules Tumorales" (2RCT) Group, Université de Poitiers, 1 Rue Georges Bonnet, 86022, Poitiers, France.|CNRS FRE 3511, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Souheyla
authors.initials: S
authors.lastname: Bensalma
authors.affiliation: "Récepteurs, Régulations et Cellules Tumorales" (2RCT) Group, Université de Poitiers, 1 Rue Georges Bonnet, 86022, Poitiers, France.|CNRS FRE 3511, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Chadeneau
authors.affiliation: Institut de Chimie des Milieux et des Matériaux (IC2MP), Université de Poitiers, UMR-CNRS 7285, 4 Rue Michel Brunet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Legigan
authors.affiliation: Institut de Chimie des Milieux et des Matériaux (IC2MP), Université de Poitiers, UMR-CNRS 7285, 4 Rue Michel Brunet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Renoux
authors.affiliation: Laboratoire des Neurosciences Expérimentales et Cliniques (LNEC), Université de Poitiers, INSERM U 1084, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Gaillard
authors.affiliation: "Récepteurs, Régulations et Cellules Tumorales" (2RCT) Group, Université de Poitiers, 1 Rue Georges Bonnet, 86022, Poitiers, France.|CNRS FRE 3511, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Madryssa
authors.initials: M
authors.lastname: de Boisvilliers
authors.affiliation: CNRS FRE 3511, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Pinet-Charvet
authors.affiliation: Institut de Chimie des Milieux et des Matériaux (IC2MP), Université de Poitiers, UMR-CNRS 7285, 4 Rue Michel Brunet, TSA 51106, 86073, Poitiers Cedex 9, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Papot
authors.affiliation: "Récepteurs, Régulations et Cellules Tumorales" (2RCT) Group, Université de Poitiers, 1 Rue Georges Bonnet, 86022, Poitiers, France. jean.marc.muller@univ-poitiers.fr.|CNRS FRE 3511, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France. jean.marc.muller@univ-poitiers.fr.
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Muller
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use / Q000633:toxicity; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D005966:Glucuronidase / Q000378:metabolism; D053823:Hedgehog Proteins / Q000378:metabolism; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000378:metabolism; D000072086:Smoothened Receptor; D014704:Veratrum Alkaloids / Q000494:pharmacology* / Q000627:therapeutic use / Q000633:toxicity; D000071676:Zinc Finger Protein GLI1
chemical_list: D000970:Antineoplastic Agents; C498521:Gli1 protein, rat; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D043562:Receptors, G-Protein-Coupled; C498555:Smo protein, rat; D000072086:Smoothened Receptor; D014704:Veratrum Alkaloids; D000071676:Zinc Finger Protein GLI1; D005966:Glucuronidase; C000541:cyclopamine