We have discovered functionalized multiwalled carbon nanotubes with reduced protein-binding, cytotoxicity, and immune response and the associated structure-activity relationships using in silico surface molecular diversity design, combinatorial library synthesis, and multiple biological screenings. Our results demonstrated the general utility of the nanocombinatorial library approach in nanomedicine and nanotoxicity research.
IntroductionWe investigated Nestin expression in triple-negative breast cancer and examined how the modulation of Nestin expression affects cell cycle progression, survival, invasion and regulatory signaling in breast cancer stem cells (CSC) in vitro.MethodsNestin expression in 150 triple-negative breast cancer specimens were examined by immunohistochemistry. The role of Nestin expression in tumorigenesis was examined by assaying naturally occurring Nestinhigh/Nestinlow CSC from 12 breast cancer tissues, as well as CSC from 26 clinical specimens, where Nestin overexpression and silencing was achieved by genetic manipulation, for their ability to form mammospheres and induce solid tumors. Cell cycle progression, spontaneous apoptosis and invasiveness of Nestin-silenced breast CSC were investigated by flow cytometry and transwell assays. The relative levels of expression of epithelial-mesenchymal transition (EMT) and Wnt/β-catenin pathway-related molecules were determined by western blotting.ResultsNestin expression was significantly associated with poor survival in patients with triple-negative breast cancer (P = 0.01). Nestinhigh breast CSC rapidly formed typical mammospheres in vitro. Nestinhigh, but not Nestinlow CSC, efficiently formed solid tumors in vivo. Nestin silencing induced cell cycle arrest at G2/M (52.03% versus 19.99% in controls) and promoted apoptosis (36.45% versus 8.29% in controls). Nestin silencing also inhibited breast CSC invasiveness, and was associated with significantly upregulated E-cadherin, while N-cadherin, vimentin, a-smooth muscle actin (a-SMA), matrix metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF) expression was downregulated (P <0.05 for all). Nestin silencing also upregulated Axin, glycogen synthase kinase-3 beta (GSK-3β), adenomatous polyposis coli (APC), and peroxisome proliferator-activated receptor alpha (PPARa), and downregulated β-catenin, c-Myc, cyclin D and MMP-7 expression in CSC. Inhibition of the Wnt/β-catenin pathway mitigated mammosphere formation in Nestinhigh CSC, while inhibition of GSK-3β promoted the mammosphere formation in Nestinlow CSC (P <0.05 for all).ConclusionsOur data indicates that Nestin positively regulates the proliferation, survival and invasiveness of breast CSC by enhancing Wnt/β-catenin activation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-014-0408-8) contains supplementary material, which is available to authorized users.
Nanotechnology is having a tremendous impact on our society. However, societal concerns about human safety under nanoparticle exposure may derail the broad application of this promising technology. Nanoparticles may enter the human body via various routes, including respiratory pathways, the digestive tract, skin contact, intravenous injection, and implantation. After absorption, nanoparticles are carried to distal organs by the bloodstream and the lymphatic system. During this process, they interact with biological molecules and perturb physiological systems. Although some ingested or absorbed nanoparticles are eliminated, others remain in the body for a long time. The human body is composed of multiple systems that work together to maintain physiological homeostasis. The unexpected invasion of these systems by nanoparticles disturbs normal cell signaling, impairs cell and organ functions, and may even cause pathological disorders. This review examines the comprehensive health risks of exposure to nanoparticles by discussing how nanoparticles perturb various physiological systems as revealed by animal studies. The potential toxicity of nanoparticles to each physiological system and the implications of disrupting the balance among systems are emphasized.
Carbon nanotubes (CNTs) cause perturbations in immune systems and limit the application of CNTs in biomedicine. Here we demonstrate that a surface chemistry modification on multiwalled CNTs (MWCNTs) reduces their immune perturbations in mice and in macrophages. The modified MWCNTs change their preferred binding pattern from mannose receptor to scavenger receptor. This switch significantly alleviates NFκB activation and reduces immunotoxicity of MWCNTs.
Developing safe and effective nonviral gene vector is highly crucial for successful gene therapy. In the present study, we designed a series of biodegradable micelles based on hybrid polypeptide copolymers of poly(ethylene glycol)-b-poly(l-lysine)-b-poly(l-leucine) (PEG-PLL-PLLeu) for efficient gene delivery. A group of amphiphilic PEG-PLL-PLLeu hybrid polypeptide copolymers were synthesized by ring-opening polymerization of N-carboxyanhydride, and the chemical structure of each copolymer was characterized by (1)H NMR and FT-IR spectroscopy measurement. The PEG-PLL-PLLeu micelles were positively charged with tunable sizes ranging from 40 to 90 nm depending on the length of PLL and PLLeu segment. Compared with PEG-PLL copolymers, PEG-PLL-PLLeu micelles demonstrated significantly higher transfection efficiency and less cytotoxicity. Furthermore, the transfection efficiency and biocompatibility of the micelles can be simultaneously improved by tuning the length of PLL and PLLeu segments. The transfection efficiency of PEG-PLL-PLLeu micelles in vivo was two to three times higher than that of PEI(25k), which was attributable to their capability of promoting DNA condensation and cell internalization as well as successful lysosome escape. Hence well-defined PEG-PLL-PLLeu micelles would serve as highly effective nonviral vectors for in vivo gene delivery.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.