title: Modified-chitosan/siRNA nanoparticles downregulate cellular CDX2 expression and cross the gastric mucus barrier.
abstract: Development of effective non-viral vectors is of crucial importance in the implementation of RNA interference in clinical routine. The localized delivery of siRNAs to the gastrointestinal mucosa is highly desired but faces specific problems such as the stability in gastric acidity conditions and the presence of the mucus barrier. CDX2 is a transcription factor critical for intestinal differentiation being involved in the initiation and maintenance of gastrointestinal diseases. Specifically, it is the trigger of gastric intestinal metaplasia which is a precursor lesion of gastric cancer. Its expression is also altered in colorectal cancer, where it may constitute a lineage-survival oncogene. Our main objective was to develop a nanoparticle-delivery system of siRNA targeting CDX2 using modified chitosan as a vector. CDX2 expression was assessed in gastric carcinoma cell lines and nanoparticles behaviour in gastrointestinal mucus was tested in mouse explants. We show that imidazole-modified chitosan and trimethylchitosan/siRNA nanoparticles are able to downregulate CDX2 expression and overpass the gastric mucus layer but not colonic mucus. This system might constitute a potential therapeutic approach to treat CDX2-dependent gastric lesions.
authors.affiliation: IPATIMUP- Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal; INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal; Gastroenterology Department, Unidade Local Saúde da Guarda, Guarda, Portugal; Gulbenkian Programme for Advanced Medical Education, Lisboa, Portugal; Faculdade de Medicina da Universidade do Porto, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Sadio
authors.affiliation: Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Jenny K
authors.initials: JK
authors.lastname: Gustafsson
authors.affiliation: IPATIMUP- Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal; Faculdade de Engenharia da Universidade do Porto, Porto, Portugal.
authors.forename: Carla Pereira
authors.initials: CP
authors.lastname: Gomes
authors.affiliation: Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Gunnar C
authors.initials: GC
authors.lastname: Hansson
authors.affiliation: IPATIMUP- Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal; Faculdade de Medicina da Universidade do Porto, Porto, Portugal.
authors.forename: Leonor
authors.initials: L
authors.lastname: David
authors.affiliation: INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal; Faculdade de Engenharia da Universidade do Porto, Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Pêgo
authors.affiliation: IPATIMUP- Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal; Faculdade de Medicina da Universidade do Porto, Porto, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Almeida
mesh_terms: D000818:Animals; D000071616:CDX2 Transcription Factor; D045744:Cell Line, Tumor; D048271:Chitosan / Q000737:chemistry*; D003106:Colon / Q000378:metabolism; D015536:Down-Regulation; D005753:Gastric Mucosa / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000737:chemistry; D051379:Mice; D009093:Mucus / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D034741:RNA, Small Interfering / Q000378:metabolism*; D014162:Transfection
chemical_list: D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D018398:Homeodomain Proteins; D007093:Imidazoles; D034741:RNA, Small Interfering; C029899:imidazole; D048271:Chitosan