title: Tamoxifen-poly(ethylene glycol)-thiol gold nanoparticle conjugates: enhanced potency and selective delivery for breast cancer treatment.
abstract: The breast cancer treatment drug tamoxifen has been widely administered for more than three decades. This small molecule competes with 17beta-estradiol for binding to estrogen receptor, a hormone receptor upregulated in a majority of breast cancers, subsequently initiating programmed cell death. We have synthesized a thiol-PEGylated tamoxifen derivative that can be used to selectively target and deliver plasmonic gold nanoparticles to estrogen receptor positive breast cancer cells with up to 2.7-fold enhanced drug potency in vitro. Optical microscopy/spectroscopy, time-dependent dose-response data, and estrogen competition studies indicate that augmented activity is due to increased rates of intracellular tamoxifen transport by nanoparticle endocytosis, rather than by passive diffusion of the free drug. Both ligand- and receptor-dependent intracellular delivery of gold nanoparticles suggest that plasma membrane localized estrogen receptor alpha may facilitate selective uptake and retention of this and other therapeutic nanoparticle conjugates. Combined targeting selectivity and enhanced potency provides opportunities for both multimodal endocrine treatment strategies and adjunctive laser photothermal therapy.
authors.affiliation: Department of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, USA.
authors.forename: Erik C
authors.initials: EC
authors.lastname: Dreaden
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Mwakwari
authors.forename: Quaovi H
authors.initials: QH
authors.lastname: Sodji
authors.forename: Adegboyega K
authors.initials: AK
authors.lastname: Oyelere
authors.forename: Mostafa A
authors.initials: MA
authors.lastname: El-Sayed
mesh_terms: D001665:Binding Sites; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D016503:Drug Delivery Systems; D004354:Drug Screening Assays, Antitumor; D047628:Estrogen Receptor alpha / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D006801:Humans; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013629:Tamoxifen / Q000737:chemistry / Q000493:pharmacokinetics* / Q000494:pharmacology* / Q000627:therapeutic use; D014407:Tumor Cells, Cultured
chemical_list: D047628:Estrogen Receptor alpha; D008024:Ligands; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D013629:Tamoxifen; D011092:Polyethylene Glycols; D006046:Gold