title: Delivery of chemo-sensitizing siRNAs to HER2+-breast cancer cells using RNA aptamers.
abstract: Human epidermal growth factor receptor 2 (HER2) expression in breast cancer is associated with an aggressive phenotype and poor prognosis, making it an appealing therapeutic target. Trastuzumab, an HER2 antibody-based inhibitor, is currently the leading targeted treatment for HER2(+)-breast cancers. Unfortunately, many patients inevitably develop resistance to the therapy, highlighting the need for alternative targeted therapeutic options. In this study, we used a novel, cell-based selection approach for isolating 'cell-type specific', 'cell-internalizing RNA ligands (aptamers)' capable of delivering therapeutic small interfering RNAs (siRNAs) to HER2-expressing breast cancer cells. RNA aptamers with the greatest specificity and internalization potential were covalently linked to siRNAs targeting the anti-apoptotic gene, Bcl-2. We demonstrate that, when applied to cells, the HER2 aptamer-Bcl-2 siRNA conjugates selectively internalize into HER2(+)-cells and silence Bcl-2 gene expression. Importantly, Bcl-2 silencing sensitizes these cells to chemotherapy (cisplatin) suggesting a potential new therapeutic approach for treating breast cancers with HER2(+)-status. In summary, we describe a novel cell-based selection methodology that enables the identification of cell-internalizing RNA aptamers for targeting therapeutic siRNAs to HER2-expressing breast cancer cells. The future refinement of this technology may promote the widespread use of RNA-based reagents for targeted therapeutic applications.
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Kristina W
authors.initials: KW
authors.lastname: Thiel
authors.forename: Luiza I
authors.initials: LI
authors.lastname: Hernandez
authors.forename: Justin P
authors.initials: JP
authors.lastname: Dassie
authors.forename: William H
authors.initials: WH
authors.lastname: Thiel
authors.forename: Xiuying
authors.initials: X
authors.lastname: Liu
authors.forename: Katie R
authors.initials: KR
authors.lastname: Stockdale
authors.forename: Alissa M
authors.initials: AM
authors.lastname: Rothman
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Hernandez
authors.forename: James O
authors.initials: JO
authors.lastname: McNamara
authors.forename: Paloma H
authors.initials: PH
authors.lastname: Giangrande
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D052157:Aptamers, Nucleotide / Q000032:analysis / Q000737:chemistry*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D052156:SELEX Aptamer Technique
chemical_list: D000970:Antineoplastic Agents; D052157:Aptamers, Nucleotide; D002945:Cisplatin; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D018719:Erb-b2 Receptor Tyrosine Kinases