title: Nanoparticle-Enabled Selective Destruction of Prostate Tumor Using MRI-Guided Focal Photothermal Therapy.
abstract: The Magnetic Resonance Imaging (MRI)-guided focal laser therapy has shown early promise in Phase 1 trial treating low/intermediate-risk localized prostate cancer (PCa), but the lack of tumor selectivity and low efficiency of heat generation remain as drawbacks of agent-free laser therapy. Intrinsic multifunctional porphyrin-nanoparticles (porphysomes) have been exploited to treat localized PCa by MRI-guided focal photothermal therapy (PTT) with significantly improved efficiency and tumor selectivity over prior methods of PTT, providing an effective and safe alternative to active surveillance or radical therapy.
  
  
  
  The tumor accumulation of porphysomes chelated with copper-64 was determined and compared with the clinic standard (18) F-FDG in an orthotropic PCa mouse model by positron emission tomography (PET) imaging, providing quantitative assessment for PTT dosimetry. The PTT was conducted with MRI-guided light delivery and monitored by MR thermometry, mimicking the clinical protocol. The efficacy of treatment and adverse effects to surround tissues were evaluated by histology analysis and tumor growth in survival study via MRI.
  
  
  
  Porphysomes showed superior tumor-to-prostate selectivity over (18) F-FDG (6:1 vs. 0.36:1). MR thermometry detected tumor temperature increased to ≥55°C within 2 min (671 nm at 500 mW), but minimal increase in surrounding tissues. Porphysome enabled effective PTT eradication of tumor without damaging adjacent organs in orthotropic PCa mouse model.
  
  
  
  Porphysome-enabled MRI-guided focal PTT could be an effective and safe approach to treat PCa at low risk of progression, thus addressing the significant unmet clinical needs and benefiting an ever-growing number of patients who may be over-treated and risk unnecessary side effects from radical therapies. Prostate 76:1169-1181, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
authors.forename: Cheng S
authors.initials: CS
authors.lastname: Jin
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
authors.forename: Marta
authors.initials: M
authors.lastname: Overchuk
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, Canada.|Medical Isotopes Research Center, Peking University, Beijing, China.
authors.forename: Liyang
authors.initials: L
authors.lastname: Cui
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wilson
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Bristow
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Princess Margaret Cancer Center, UHN, Toronto, Canada.|Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
mesh_terms: D000818:Animals; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage; D006358:Hot Temperature / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles / Q000008:administration & dosage*; D010789:Phototherapy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000628:therapy*; D062125:Thermometry / Q000379:methods
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: magnetic resonance imaging; porphyrin; porphysome