title: Negatively charged AuNP modified with monoclonal antibody against novel tumor antigen FAT1 for tumor targeting.
abstract: BACKGROUND
  Herein, we demonstrated the use of a newly generated anti FAT1 antibody (clone mAB198.3) for intracellular delivery of anionic gold NPs, to form active targeting Au nanoparticles with high payload characteristics.
  
  
  METHODS
  In vitro characterizations were determined by DLS, confocal microscopy, TEM, western blot, MALDI-TOF MS/MS analysis, MTT, ICP-MS and flow cytometry analysis. In vivo targeting efficacy was investigated by in vivo bio-imaging study and ICP-MS.
  
  
  RESULTS
  The specificity of the FAT1 recognition in colon cancer was confirmed by pre-adsorbing mAb198.3, adsorption dramatically abolished the antibody reactivity on colon cancer, thus confirming the binding specificity. The DLS size distribution profile of the AuCOOH, AuCOOH(Cy5)_ mAb198.3, AuCOOH(Cy5)_isotype has showed that the modified gold nanoparticles are well dispersed in water, PBS buffer and cell culture medium with 10 % FBS. By TEM measurement, the size of Au nanoparticles with spherical morphology is about 10-20 nm. AuCOOH_198.3 NPs were stable in an acidic environment, as well as in PBS buffer, cell culture media and media with 10 % serum. MTT results revealed that Au nanoparticles have well biocompatibility. TEM results indicated that conjugation of mAb198.3 on Au nanoparticles can be an effective delivery vehicle for negatively charged gold nanoparticles and increased its intracellular transport. It was also demonstrated by confocal microscopy that AuCOOH(Cy5)_mAb198.3 could attach to the cell membrane in very short time, then gradually delivered into cells. After 4 h incubation, almost all AuCOOH(Cy5)_mAb198.3 have been uptaken into or surrounding the cytoplasm and nucleus. In vivo results showed that only about 20 % of AuCOOH accumulated in tumor site due to EPR effect, while nearly 90 % of AuCOOH_mAb198.3 was found in tumor, providing sufficient evidence for receptor-specific targeting by mAb198.3.
  
  
  CONCLUSIONS
  According to in vitro and in vivo research results, the intracellular uptake of negatively charged AuCOOH_mAB198.3 particles is enhanced to a greater extent. Thus, AuCOOH_mAb198.3 holds significant potential to improve the treatment of cancer.
authors.affiliation: Department of Pharmaceutical Chemistry and Analysis, School of Pharmacy, the Fourth Military Medical University, Xi'an, Shaanxi, 710032, China. xxfanny@fmmu.edu.cn.|Department of Immunology, the Fourth Military Medical University, Xi'an, Shaanxi, 710032, China. xxfanny@fmmu.edu.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. serena.campagnoli@externautics.com.
authors.forename: Susanna
authors.initials: S
authors.lastname: Campagnoli
authors.affiliation: Department of Pharmaceutical Chemistry and Analysis, School of Pharmacy, the Fourth Military Medical University, Xi'an, Shaanxi, 710032, China. hongwuxa@hotmail.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. alberto.grandi@externautics.com.
authors.forename: Alberto
authors.initials: A
authors.lastname: Grandi
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. matteo.parri@externautics.com.
authors.forename: Matteo
authors.initials: M
authors.lastname: Parri
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. elisa.decamilli@ieo.it.
authors.forename: Elisa
authors.initials: E
authors.lastname: De Camilli
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. guido.grandi@externautics.com.
authors.forename: Guido
authors.initials: G
authors.lastname: Grandi
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. giuseppe.viale@ieo.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Viale
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. piero.pileri@externautics.com.
authors.forename: Piero
authors.initials: P
authors.lastname: Pileri
authors.affiliation: Externautics SpA, Siena, SI, 53100, Italy. renata.grifantini@externautics.com.
authors.forename: Renata
authors.initials: R
authors.lastname: Grifantini
authors.affiliation: Department of Immunology, the Fourth Military Medical University, Xi'an, Shaanxi, 710032, China. cj6005@fmmu.edu.cn.
authors.forename: Chaojun
authors.initials: C
authors.lastname: Song
authors.affiliation: Department of Immunology, the Fourth Military Medical University, Xi'an, Shaanxi, 710032, China. immu_jin@fmmu.edu.cn.
authors.forename: Boquan
authors.initials: B
authors.lastname: Jin
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology*; D015820:Cadherins / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000008:administration & dosage* / Q000378:metabolism; D006046:Gold / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010316:Particle Size; D023041:Xenograft Model Antitumor Assays
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D015820:Cadherins; D004337:Drug Carriers; C502403:FAT1 protein, human; D006046:Gold