title: Influence of the internalization pathway on the efficacy of siRNA delivery by cationic fluorescent nanodiamonds in the Ewing sarcoma cell model.
abstract: Small interfering RNAs (siRNAs) are powerful tools commonly used for the specific inhibition of gene expression. However, vectorization is required to facilitate cell penetration and to prevent siRNA degradation by nucleases. We have shown that diamond nanocrystals coated with cationic polymer can be used to carry siRNAs into Ewing sarcoma cells, in which they remain traceable over long periods, due to their intrinsic stable fluorescence. We tested two cationic polymers, polyallylamine and polyethylenimine. The release of siRNA, accompanied by Ewing sarcoma EWS-Fli1 oncogene silencing, was observed only with polyethylenimine. We investigated cell penetration and found that the underlying mechanisms accounted for these differences in behavior. Using drugs selectively inhibiting particular pathways and a combination of fluorescence and electronic microscopy, we showed that siRNA gene silencing occurred only if the siRNA:cationic nanodiamond complex followed the macropinocytosis route. These results have potential implications for the design of efficient drug-delivery vectors.
authors.affiliation: Vectorologie et thérapeutiques anti-cancéreuses, CNRS UMR 8203, Université Paris Sud 11, Institut Gustave Roussy, Villejuif, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Alhaddad
authors.forename: Catherine
authors.initials: C
authors.lastname: Durieu
authors.forename: Géraldine
authors.initials: G
authors.lastname: Dantelle
authors.forename: Eric
authors.initials: E
authors.lastname: Le Cam
authors.forename: Claude
authors.initials: C
authors.lastname: Malvy
authors.forename: François
authors.initials: F
authors.lastname: Treussart
authors.forename: Jean-Rémi
authors.initials: JR
authors.lastname: Bertrand
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D051379:Mice; D046529:Microscopy, Electron, Transmission; D041681:NIH 3T3 Cells; D058612:Nanodiamonds / Q000008:administration & dosage* / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry / Q000648:ultrastructure; D036103:Nanotechnology; D011073:Polyamines / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry*; D012512:Sarcoma, Ewing / Q000378:metabolism*
chemical_list: D058612:Nanodiamonds; D011073:Polyamines; D034741:RNA, Small Interfering; C063994:polyallylamine; D011094:Polyethyleneimine