title: Dual bioluminescence and near-infrared fluorescence monitoring to evaluate spherical nucleic acid nanoconjugate activity in vivo.
abstract: RNA interference (RNAi)-based gene regulation platforms have shown promise as a novel class of therapeutics for the precision treatment of cancer. Techniques in preclinical evaluation of RNAi-based nanoconjugates have yet to allow for optimization of their gene regulatory activity. We have developed spherical nucleic acids (SNAs) as a blood-brain barrier-/blood-tumor barrier-penetrating nanoconjugate to deliver small interfering (si) and micro (mi)RNAs to intracranial glioblastoma (GBM) tumor sites. To identify high-activity SNA conjugates and to determine optimal SNA treatment regimens, we developed a reporter xenograft model to evaluate SNA efficacy in vivo. Engrafted tumors stably coexpress optical reporters for luciferase and a near-infrared (NIR) fluorescent protein (iRFP670), with the latter fused to the DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT). Using noninvasive imaging of animal subjects bearing reporter-modified intracranial xenografts, we quantitatively assessed MGMT knockdown by SNAs composed of MGMT-targeting siRNA duplexes (siMGMT-SNAs). We show that systemic administration of siMGMT-SNAs via single tail vein injection is capable of robust intratumoral MGMT protein knockdown in vivo, with persistent and SNA dose-dependent MGMT silencing confirmed by Western blotting of tumor tissue ex vivo. Analyses of SNA biodistribution and pharmacokinetics revealed rapid intratumoral uptake and significant intratumoral retention that increased the antitumor activity of coadministered temozolomide (TMZ). Our study demonstrates that dual noninvasive bioluminescence and NIR fluorescence imaging of cancer xenograft models represents a powerful in vivo strategy to identify RNAi-based nanotherapeutics with potent gene silencing activity and will inform additional preclinical and clinical investigations of these constructs.
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.|Interdepartmental Biological Sciences Program, Northwestern University, Evanston, IL 60208.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Sita
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Fotini M
authors.initials: FM
authors.lastname: Kouri
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Hurley
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Merkel
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Chalastanis
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Jasmine L
authors.initials: JL
authors.lastname: May
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Serena T
authors.initials: ST
authors.lastname: Ghelfi
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Cole
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Cayton
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Stacey N
authors.initials: SN
authors.lastname: Barnaby
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Sprangers
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Nikunjkumar
authors.initials: N
authors.lastname: Savalia
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, IL 60611.
authors.forename: Charles David
authors.initials: CD
authors.lastname: James
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.|Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lee
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208; chadnano@northwestern.edu a-stegh@northwestern.edu.|Department of Chemistry, Northwestern University, Evanston, IL 60208.|Interdepartmental Biological Sciences Program, Northwestern University, Evanston, IL 60208.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin
authors.affiliation: Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611; chadnano@northwestern.edu a-stegh@northwestern.edu.|International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208.
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Stegh
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors* / Q000235:genetics; D045643:DNA Repair Enzymes / Q000037:antagonists & inhibitors* / Q000235:genetics; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005453:Fluorescence; D005909:Glioblastoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D058726:Nanoconjugates / Q000008:administration & dosage* / Q000737:chemistry; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics*; D000077204:Temozolomide; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D018906:Antineoplastic Agents, Alkylating; D058726:Nanoconjugates; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; D003606:Dacarbazine; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes; D000077204:Temozolomide
keywords: O6-methylguanine-DNA-methyltransferase; bioluminescence; glioblastoma multiforme; near-infrared fluorescence; spherical nucleic acid nanoconjugates