title: A novel intracellular antibody against the E6 oncoprotein impairs growth of human papillomavirus 16-positive tumor cells in mouse models.
abstract: Single-chain variable fragments (scFvs) expressed as "intracellular antibodies" (intrabodies) can target intracellular antigens to hamper their function efficaciously and specifically. Here we use an intrabody targeting the E6 oncoprotein of Human papillomavirus 16 (HPV16) to address the issue of a non-invasive therapy for HPV cancer patients.A scFv against the HPV16 E6 was selected by Intracellular Antibody Capture Technology and expressed as I7nuc in the nucleus of HPV16-positive SiHa, HPV-negative C33A and 293T cells. Colocalization of I7nuc and recombinant E6 was observed in different cell compartments, obtaining evidence of E6 delocalization ascribable to I7nuc. In SiHa cells, I7nuc expressed by pLNCX retroviral vector was able to partially inhibit degradation of the main E6 target p53, and induced p53 accumulation in nucleus. When analyzing in vitro activity on cell proliferation and survival, I7nuc was able to decrease growth inducing late apoptosis and necrosis of SiHa cells.Finally, I7nuc antitumor activity was demonstrated in two pre-clinical models of HPV tumors. C57BL/6 mice were injected subcutaneously with HPV16-positive TC-1 or C3 tumor cells, infected with pLNCX retroviral vector expressing or non-expressing I7nuc. All the mice injected with I7nuc-expressing cells showed a clear delay in tumor onset; 60% and 40% of mice receiving TC-1 and C3 cells, respectively, remained tumor-free for 17 weeks of follow-up, whereas 100% of the controls were tumor-bearing 20 days post-inoculum. Our data support the therapeutic potential of E6-targeted I7nuc against HPV tumors.
authors.affiliation: University of Rome Tor Vergata, Department of Biology, Via della Ricerca Scientifica, Rome, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Amici
authors.affiliation: Rottapharm Biotech Srl, Biotherapeutics Discovery, Area Science Park - Basovizza, Trieste, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Visintin
authors.affiliation: University of Rome Tor Vergata, Department of Biology, Via della Ricerca Scientifica, Rome, Italy.|Istituto Superiore di Sanità, Department of Infectious, Parasitic and Immunomediated Diseases, Viale Regina Elena, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Verachi
authors.affiliation: Regina Elena National Cancer Institute, Laboratory of Virology and HPV-Unit, via delle Messi d'Oro, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Paolini
authors.affiliation: University Roma Tre, Department of Science, Viale G. Marconi, Rome, Italy.
authors.forename: Zulema
authors.initials: Z
authors.lastname: Percario
authors.affiliation: Istituto Superiore di Sanità, Department of Infectious, Parasitic and Immunomediated Diseases, Viale Regina Elena, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Di Bonito
authors.affiliation: Istituto Superiore di Sanità, Department of Infectious, Parasitic and Immunomediated Diseases, Viale Regina Elena, Rome, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Mandarino
authors.affiliation: University Roma Tre, Department of Science, Viale G. Marconi, Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Affabris
authors.affiliation: Regina Elena National Cancer Institute, Laboratory of Virology and HPV-Unit, via delle Messi d'Oro, Rome, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Venuti
authors.affiliation: Istituto Superiore di Sanità, Department of Infectious, Parasitic and Immunomediated Diseases, Viale Regina Elena, Rome, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Accardi
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D064593:Heterografts; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000821:virology*; D009856:Oncogene Proteins, Viral / Q000037:antagonists & inhibitors*; D030361:Papillomavirus Infections / Q000150:complications; D012097:Repressor Proteins / Q000037:antagonists & inhibitors*; D057127:Single-Chain Antibodies / Q000494:pharmacology*
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins; D057127:Single-Chain Antibodies
keywords: E6 oncoprotein; cancer therapy; human papillomaviruses; intracellular antibodies; scFv