title: Engineering Salmonella as intracellular factory for effective killing of tumour cells.
abstract: Salmonella have many desirable properties as antitumour-agent due to its ability to proliferate inside tumours and induce tumour regression. Additionally, this bacterium can be genetically engineered to deliver therapeutic proteins intratumourally. The main limitation of this approach is the efficient release of therapeutic molecules from intratumoural bacteria. Here we have developed an inducible autolysis system based in the lysis operon of the lambda phage that, in response to anhydrotetracycline, lysates Salmonella thus releasing its content. The system was combined with a salicylate cascade system that allows efficient production of therapeutic molecules in response to aspirin and with a sifA mutation that liberates bacteria from the vacuoles to a cytosolic location. The combination of these three elements makes this strain a putative powerful instrument in cancer treatment. We have used this engineered strain for the intracellular production and delivery of Cp53 peptide. The engineered strain is able to sequentially produce and release the cytotoxic peptide while proliferating inside tumour cells, thus inducing host cell death. Our results show that temporal separation of protein production from protein release is essential to efficiently kill tumour cells. The combined system is a further step in the engineering of more efficient bacteria for cancer therapy.
authors.affiliation: Centro Andaluz de Biología del Desarrollo/CSIC/Universidad Pablo de Olavide/Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain.
authors.forename: Eva María
authors.initials: EM
authors.lastname: Camacho
authors.affiliation: Centro Andaluz de Biología del Desarrollo/CSIC/Universidad Pablo de Olavide/Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Mesa-Pereira
authors.affiliation: Centro Andaluz de Biología del Desarrollo/CSIC/Universidad Pablo de Olavide/Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Medina
authors.affiliation: Centro Andaluz de Biología del Desarrollo/CSIC/Universidad Pablo de Olavide/Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain.
authors.forename: Amando
authors.initials: A
authors.lastname: Flores
authors.affiliation: Centro Andaluz de Biología del Desarrollo/CSIC/Universidad Pablo de Olavide/Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santero
mesh_terms: D017209:Apoptosis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D003600:Cytosol; D016158:Genes, p53; D005818:Genetic Engineering / Q000379:methods*; D006023:Glycoproteins / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D012459:Salicylates / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics*; D013754:Tetracyclines / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D006023:Glycoproteins; D011994:Recombinant Proteins; D012459:Salicylates; C421862:SifA protein, Salmonella; D013754:Tetracyclines; D049452:Green Fluorescent Proteins; C016229:4-epianhydrotetracycline