title: Formulated siRNAs targeting Rankl prevent osteolysis and enhance chemotherapeutic response in osteosarcoma models.
abstract: The development of osteosarcoma, the most common malignant primary bone tumor is characterized by a vicious cycle established between tumor proliferation and paratumor osteolysis. This osteolysis is mainly regulated by the receptor activator of nuclear factor κB ligand (RANKL). Preclinical studies have demonstrated that Rankl blockade by soluble receptors is an effective strategy to prevent osteolytic lesions leading to osteosarcoma inhibition. A new therapeutic option could be to directly inhibit Rankl expression by small interfering RNAs (Rkl-siRNAs) and combine these molecules with chemotherapy to counteract the osteosarcoma development more efficiently. An efficient siRNA sequence directed against both mouse and rat mRNAs coding Rankl was first validated in vitro and tested in two models of osteosarcoma: a syngenic osteolytic POS-1 model induced in immunocompetent mice and a xenograft osteocondensant model of rat OSRGA in athymic mice. Intratumor injections of Rankl-directed siRNAs in combination with the cationic liposome RPR209120/DOPE reduced the local and systemic Rankl production and protected bone from paratumor osteolysis. Although Rkl-siRNAs alone had no effect on tumor development in both osteosarcoma models, it significantly blocked tumor progression when combined with ifosfamide compared with chemotherapy alone. Our results indicate that siRNAs could be delivered using cationic liposomes and thereby could inhibit Rankl production in a specific manner in osteosarcoma models. Moreover, the Rankl inhibition mediated by RNA interference strategy improves the therapeutic response of primary osteosarcoma to chemotherapy.
authors.affiliation: INSERM, U957, Nantes, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Rousseau
authors.forename: Virginie
authors.initials: V
authors.lastname: Escriou
authors.forename: François
authors.initials: F
authors.lastname: Lamoureux
authors.forename: Régis
authors.initials: R
authors.lastname: Brion
authors.forename: Julie
authors.initials: J
authors.lastname: Chesneau
authors.forename: Séverine
authors.initials: S
authors.lastname: Battaglia
authors.forename: Jérome
authors.initials: J
authors.lastname: Amiaud
authors.forename: Daniel
authors.initials: D
authors.lastname: Scherman
authors.forename: Dominique
authors.initials: D
authors.lastname: Heymann
authors.forename: Françoise
authors.initials: F
authors.lastname: Rédini
authors.forename: Valérie
authors.initials: V
authors.lastname: Trichet
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001483:Base Sequence; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007150:Immunohistochemistry; D051379:Mice; D008819:Mice, Nude; D010014:Osteolysis / Q000235:genetics*; D012516:Osteosarcoma / Q000188:drug therapy*; D053245:RANK Ligand / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics*; D051381:Rats
chemical_list: D000970:Antineoplastic Agents; D053245:RANK Ligand; D034741:RNA, Small Interfering