No abstract

Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods whilst concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, bio-distribution, metabolism and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed.

The current study shows the therapeutic outcome achieved in triple negative breast cancer (TNBC) by simultaneously antagonizing miR-21-induced antiapoptosis and miR-10b-induced metastasis, using antisense-miR-21-PS and antisense-miR-10b-PS delivered by polymer nanoparticles (NPs). We synthesized the antisense-miR-21 and antisense-miR-10b loaded PLGA-b-PEG polymer NPs and evaluated their cellular uptake, serum stability, release profile, and the subsequent synchronous blocking of endogenous miR-21 and miR-10b function in TNBC cells in culture, and tumor xenografts in living animals using molecular imaging. Results show that multitarget antagonization of endogenous miRNAs could be an efficient strategy for targeting metastasis and antiapoptosis in the treatment of metastatic cancer. Targeted delivery of antisense-miR-21 and antisense-miR-10b coloaded urokinase plasminogen activator receptor (uPAR) targeted polymer NPs treated mice showed substantial reduction in tumor growth at very low dose of 0.15 mg/kg, compared to the control NPs treated mice and 40% reduction in tumor growth compared to scramble peptide conjugated NPs treated mice, thus demonstrating a potential new therapeutic option for TNBC.

MicroRNAs are critical regulators of cancer initiation, progression, and dissemination. Extensive evidence suggests that the inhibition of over-expressed oncogenic miRNA function can be a robust strategy for anticancer therapy. However, in vivo targeted delivery of miRNA therapeutics to various types of cancers remains a major challenge. Inspired by their natural synthesis and cargo delivery capabilities, researchers have exploited tumor cell-derived extracellular vesicles (TEVs) for the cancer-targeted delivery of therapeutics and theranostics. Here, we investigate a TEV-based nanoplatform for multimodal miRNA delivery and phototherapy treatments as well as the magnetic resonance imaging of cancer. We demonstrated loading of anti-miR-21 that blocks the function of endogenous oncogenic miR-21 over-expressed in cancer cells into and subsequent delivery by TEVs derived from 4T1 cells. We also produced Cy5-anti-miR-21-loaded TEVs from two other cancer cell lines (HepG2 and SKBR3) and confirmed their robust homologous and heterologous transfection efficiency and intracellular Cy5-anti-miR-21 delivery. Additionally, TEV-mediated anti-miR-21 delivery attenuated doxorubicin (DOX) resistance in breast cancer cells with a 3-fold higher cell kill efficiency than in cells treated with DOX alone. We then investigated TEVs as a biomimetic source for the functionalization of gold-iron oxide nanoparticles (GIONs) and demonstrated nanotheranostic properties of TEV-GIONs in vitro. TEV-GIONs demonstrated excellent T2 contrast in in vitro magnetic resonance (MR) imaging and resulted in efficient photothermal effect in 4T1 cells. We also evaluated the biodistribution and theranostic property of anti-miR-21 loaded TEV-GIONs in vivo by labeling with indocyanine green near-infrared dye. We further validated the tumor specific accumulation of TEV-GIONs using MR imaging. Our findings demonstrate that the distribution pattern of the TEV-anti-miR-21-GIONs correlated well with the tumor-targeting capability as well as the activity and efficacy obtained in response to doxorubicin combination treatments. TEVs and TEV-GIONs are promising nanotheranostics for future applications in cancer molecular imaging and therapy.

Identifying protein-protein interactions (PPIs) is essential for understanding various disease mechanisms and developing new therapeutic approaches. Current methods for assaying cellular intermolecular interactions are mainly used for cells in culture and have limited use for the noninvasive assessment of small animal disease models. Here, we describe red light-emitting reporter systems based on bioluminescence resonance energy transfer (BRET) that allow for assaying PPIs both in cell culture and deep tissues of small animals. These BRET systems consist of the recently developed Renilla reniformis luciferase (RLuc) variants RLuc8 and RLuc8.6, used as BRET donors, combined with two red fluorescent proteins, TagRFP and TurboFP635, as BRET acceptors. In addition to the native coelenterazine luciferase substrate, we used the synthetic derivative coelenterazine-v, which further red-shifts the emission maxima of Renilla luciferases by 35 nm. We show the use of these BRET systems for ratiometric imaging of both cells in culture and deep-tissue small animal tumor models and validate their applicability for studying PPIs in mice in the context of rapamycininduced FK506 binding protein 12 (FKBP12)-FKBP12 rapamycin binding domain (FRB) association. These red light-emitting BRET systems have great potential for investigating PPIs in the context of drug screening and target validation applications.optical imaging | reporter gene P rotein-protein interactions (PPIs) are a prerequisite to most cellular processes, and their pharmacologic control offers promising avenues for therapeutic intervention in a variety of diseases (1). Developing techniques to identify and analyze these transient protein-protein associations is, therefore, of high importance. Several methods are available to investigate PPIs in vitro and in cell culture (2, 3). However, ex vivo analysis of interacting proteins neglects the intricate effects of physiologic and pathophysiologic stimuli that occur in the native microenvironment within living organisms. Similarly, in vitro drug validation ignores the pharmacokinetic properties of prospective pharmacophores. To investigate PPIs in their actual biological context, imaging technologies that enable direct translation of cell culture assays to deep tissues of living subjects are required. Current approaches for monitoring PPIs rely on the two-hybrid system (4), FRET (5), split reporter protein complementation and reconstitution (6-8), and bioluminescence resonance energy transfer (BRET) (9-11). Because most of these PPI detection schemes are optical approaches, signal attenuation by tissues constitutes the primary impediment for studying PPIs in animal models, and it results in low sensitivity for these assays, especially in the context of deep-tissue tumor models.Bioluminescence-based methods hold particular promise for imaging of PPIs in small living subjects (12, 13). Although both BRET and FRET detection schemes rely on the Förster resonance energy transfer mechanism (14), BRET systems provide enhanced sens...

Raman spectroscopy is an optical imaging modality which analyses the Raman effect in which energy is exchanged between light and matter. Although Raman spectroscopy has been widely used for chemical and molecular analysis, its use in clinical applications has been hindered by the inherently weak nature of the Raman effect. Raman-silica-gold-nanoparticles (R-Si-Au-NPs) overcome this limitation by producing high Raman signals via Surface Enhanced Raman Scattering. Targeted polyethylene glycol (PEG)-ylated R-Si-Au-NPs (e.g. PEG-R-Si-Au-NPs labeled with an affibody which binds specifically to the epidermal growth factor receptor) are currently being designed to detect colorectal cancer after administration into the bowel lumen. With this approach, PEG-R-Si-Au-NPs are not expected to enter the systemic circulation and would be removed from the body via defecation. We examined the acute toxicity and biodistribution of core PEG-R-Si-Au-NPs after different routes of administration in mice. After intravenous administration, PEG-R-Si-Au-NPs were removed from the circulation by marcophages in the liver and spleen (i.e. the reticuloendothelial system). At 24 hours, PEG-R-Si-Au-NPs elicited a mild inflammatory response and an increase in oxidative stress in the liver, which subsided by 2 weeks. No evidence of significant toxicity was observed by measuring clinical, histological, biochemical or cardiovascular parameters for 2 weeks. Notably, after administration per rectum, we observed no significant bowel or systemic toxicity and no PEG-R-Si-Au-NPs were detected systemically. Although additional studies are required to investigate the long-term effects of PEG-R-Si-Au-NPs, these initial results support the idea that they can be safely used in living subjects, especially when administered rectally.

No abstract

Networks of protein interactions mediate cellular responses to environmental stimuli and direct the execution of many different cellular functional pathways. Small molecules synthesized within cells or recruited from the external environment mediate many protein interactions. The study of small molecule-mediated interactions of proteins is important to understand abnormal signal transduction pathways in cancer and in drug development and validation. In this study, we used split synthetic renilla luciferase (hRLUC) protein fragment-assisted complementation to evaluate heterodimerization of the human proteins FRB and FKBP12 mediated by the small molecule rapamycin. The concentration of rapamycin required for efficient dimerization and that of its competitive binder ascomycin required for dimerization inhibition were studied in cell lines. The system was dually modulated in cell culture at the transcription level, by controlling nuclear factor B promoter/enhancer elements using tumor necrosis factor ␣, and at the interaction level, by controlling the concentration of the dimerizer rapamycin. The rapamycin-mediated dimerization of FRB and FKBP12 also was studied in living mice by locating, quantifying, and timing the hRLUC complementation-based bioluminescence imaging signal using a cooled charged coupled device camera. This split reporter system can be used to efficiently screen small molecule drugs that modulate protein-protein interactions and also to assess drugs in living animals. Both are essential steps in the preclinical evaluation of candidate pharmaceutical agents targeting protein-protein interactions, including signaling pathways in cancer cells.