title: Chitosan layered gold nanorods as synergistic therapeutics for photothermal ablation and gene silencing in triple-negative breast cancer.
abstract: Small interfering RNAs (siRNAs) are extensively studied due to their promising potential as therapeutic agents for a wide variety of diseases, including cancer. However, efficient delivery of siRNAs to target cells and tissues is problematic due to a lack of suitable delivery vehicles. In this work, we developed a layer-by-layer assembled chitosan-gold nanorods (Chit-Au NRs) siRNA delivery system to overcome biological barriers upon systemic injection. This platform was able to protect siRNAs form degradation upon exposure to ribonuclease (RNase) or serum. Confocal and intravital microscopy reveals that Chit-Au NRs/siRNAs are successfully delivered into target cells and tissue, and can efficiently escape from endosomal/lysosomal structures. Furthermore, Chit-Au NRs/siRNA were found to accumulate in high levels in tumor tissue. The delivery system was able to inhibit the oncogene expression (pyruvate kinase isozymeM2, PKM2) in MDA-MB-231 triple negative breast cancer cells, resulting in suppression of cell proliferation and migration. Moreover, the anticancer efficacy was further enhanced through NR-mediated photothermal ablation. In conclusion, the synergistic therapeutic properties of Chit-Au NRs/siRNA enable effective suppression of cancer growth.
  
  
  CONCLUSIONS
  Small interfering RNA (siRNA) therapy has promising therapeutic applications, since the expression of any protein can be suppressed. However the successful implementation of siRNA has been challenging, due to rapid degradation, poor intracellular uptake and insufficient endosomal escape. Here, we have developed a gold nanorod/chitosan-based delivery vehicle for siRNA therapy. This platform successfully overcomes the afore-mentioned challenges and can simultaneously be used for photothermal therapy, due to the optical properties of gold nanorods. We show that the anticancer activity is dramatically improved by combining thermal therapy with gene silencing. Furthermore, the Au NRs carrier shows high accumulation in tumor tissue and high transfection efficiency. This manuscript has been reviewed and approved by all co-authors. The research has not been disclosed or published and is not under consideration for publication elsewhere. We would appreciate if the manuscript could be reviewed and considered for publication in Acta BIOMATERIALIA.
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
authors.forename: Zhizhou
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Thoracic Surgery, The Second Artillery General Hospital of PLA, Beijing 100088, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Liu
authors.affiliation: Research Center for Health and Nutrition, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
authors.forename: Zhaorui
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
authors.forename: Changjing
authors.initials: C
authors.lastname: Liu
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Zong-Wan
authors.initials: ZW
authors.lastname: Mao
authors.affiliation: Department of Emergency Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China. Electronic address: shn_nie@sina.com.
authors.forename: Shinan
authors.initials: S
authors.lastname: Nie
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement; D002470:Cell Survival; D048271:Chitosan / Q000737:chemistry*; D004705:Endocytosis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D018014:Gene Transfer Techniques; D006046:Gold / Q000737:chemistry*; D006801:Humans; D006979:Hyperthermia, Induced; D042541:Intracellular Space / Q000378:metabolism; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010789:Phototherapy; D014018:Tissue Distribution; D064726:Triple Negative Breast Neoplasms / Q000473:pathology / Q000628:therapy*
chemical_list: D006046:Gold; D048271:Chitosan
keywords: Breast cancer; Chitosan; Gold nanorods; Photothermal ablation; Small interfering RNA