Evaluation of uptake and distribution of gold nanoparticles in solid tumors

Bioactive superparamagnetic iron oxide-gold nanoparticles regulated by a dynamic magnetic field induce neuronal Ca2+ influx and differentiation

Treating neurodegenerative diseases, e.g., Alzheimer's Disease, remains a significant challenge due to the limited neuroregeneration rate in the brain. The objective of this study is to evaluate the hypothesis that external magnetic field (MF) stimulation of nerve growth factor functionalized superparamagnetic iron oxide-gold (NGF-SPIO-Au) nanoparticles (NPs) can induce Ca²⁺ influx, membrane depolarization, and enhance neuron differentiation with dynamic MF (DMF) outperforming static MF (SMF) regulation. We showed the that total intracellular Ca²⁺ influx of PC-12 cells was improved by 300% and 535% by the stimulation of DMF (1 Hz, 0.5 T, 30min) with NGF-SPIO-Au NPs compared to DMF alone and SMF with NGF-SPIO-Au NPs, respectively, which was attributed to successive membrane depolarization. Cellular uptake performed with the application of sodium azide proved that DMF enhanced cellular uptake of NGF-SPIO-Au NPs via endocytosis. In addition, DMF upregulated both the neural differentiation marker (β3-tubulin) and the cell adhesive molecule (integrin-β1) with the existence of NGF-SPIO-Au NPs, while SMF did not show these effects. The results imply that noninvasive DMF-stimulated NPs can regulate intracellular Ca²⁺ influx and enhance neuron differentiation and neuroregeneration rate.

Three-Dimensional Spheroids for Cancer Research

In vitro cell culture is one of the most widely used tools used today for increasing our understanding of various things such as protein production, mechanisms of drug action, tissue engineering, and overall cellular biology. For the past decades, however, cancer researchers have relied heavily on conventional two-dimensional (2D) monolayer culture techniques to test a variety of aspects of cancer research ranging from the cytotoxic effects of antitumor drugs to the toxicity of diagnostic dyes and contact tracers. However, many promising cancer therapies have either weak or no efficacy in real-life conditions, therefore delaying or stopping altogether their translating to the clinic. This is, in part, due to the reductionist 2D cultures used to test these materials, which lack appropriate cell-cell contacts, have altered signaling, do not represent the natural tumor microenvironment, and have different drug responses, due to their reduced malignant phenotype when compared to real in vivo tumors. With the most recent advances, cancer research has moved into 3D biological investigation. Three-dimensional (3D) cultures of cancer cells not only recapitulate the in vivo environment better than their 2D counterparts, but they have, in recent years, emerged as a relatively low-cost and scientifically accurate methodology for studying cancer. In this chapter, we highlight the importance of 3D culture, specifically 3D spheroid culture, reviewing some key methodologies for forming 3D spheroids, discussing the experimental tools that can be used in conjunction with 3D spheroids and finally their applications in cancer research.

Nanostructures as Radionuclide Carriers in Auger Electron Therapy

The concept of nanoparticle-mediated radionuclide delivery in the cancer treatment has been widely discussed in the past decade. In particular, the use of inorganic and organic nanostructures in the development of radiopharmaceuticals enables the delivery of medically important radioisotopes for radionuclide therapy. In this review, we present the development of nanostructures for cancer therapy with Auger electron radionuclides. Following that, different types of nanoconstructs that can be used as carriers for Auger electron emitters, design principles, nanoparticle materials, and target vectors that overcame the main difficulties are described. In addition, systems in which high-Z element nanoparticles are used as radionuclide carriers, causing the emission of photoelectrons from the nanoparticle surface, are presented. Finally, future research opportunities in the field are discussed as well as issues that must be addressed before nanoparticle-based Auger electron radionuclide therapy can be transferred to clinical use.

Fe3O4 magnetic nanoparticle-enhanced radiotherapy for lung adenocarcinoma via delivery of siBIRC5 and AS-ODN

Background

Radiotherapy is the mainstay treatment for lung adenocarcinoma, yet remains highly susceptible to resistance. Fe₃O₄ magnetic nanoparticles (MNPs) possess the ability to induce biological therapeutic effects. Herein, the current study set out to explore the effects of Fe₃O₄ MNPs on radiosensitivity of lung adenocarcinoma cells.

Methods

Fe₃O₄ MNPs loaded with both negatively-charged small interfering RNA against baculoviral IAP repeat containing 5 (siBIRC5) and oligodeoxynucleotide antisense (AS-ODN) to generate co-delivery NPs, followed by evaluation. Gel retardation assay was further performed to determine the binding ability of Fe₃O₄ MNPs to AS-ODN/siBIRC5. The radiosensitizing effect of NPs on lung adenocarcinoma cells was determined in the absence or the presence of NPs or radiotherapy. A549 and H460 tumor-bearing mice were established, where tumor tissues were subjected to immunohistochemistry.

Results

NPs were successfully prepared and characterized. BIRC5 expression levels were augmented in tissues of lung cancer patients. Fe₃O₄ MNPs enhanced the uptake of siBIRC5 and AS-ODN by lung adenocarcinoma cells. The presence of NPs under magnetic field reduced the BIRC5 expression and elevated the DR5 expression in lung adenocarcinoma cells. Lung adenocarcinoma cells treated with NPs exhibited inhibited tumor cell migration and increased DNA damage. After magnetic field treatment, tumors were better suppressed in the tumor-bearing mice treated with NPs, followed by radiotherapy.

Conclusion

Findings obtained in our study indicated that Fe₃O₄ MNPs-targeted delivery of siBIRC5 and AS-ODN enhances radiosensitivity, providing an innovative solution for the current clinically existing lung adenocarcinoma patients with radiotherapy resistance with a low risk of toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02971-7.

Plasmonic gap-enhanced Raman tag nanorods for imaging 3D pancreatic spheroids using surface-enhanced Raman spectroscopy and darkfield microscopy

Plasmonic gap-enhanced Raman tags (GERTs) are new emerging nanoprobes that, based on their unique surface-enhanced Raman spectroscopy (SERS) signal, can play a major role in complex imaging and detection of biological systems. GERTs are generated from a metal core nanostructure and layered with one or more metal nanosized layers, encasing a Raman active molecule. The advantages of GERTs are enhanced surface plasmon and electromagnetic resonance, as well as inherent protection of the Raman active molecule from environmental deterioration that could reduce their spectroscopic signatures over time. In this study, we used in vitro three-dimensional (3D) spheroid cultures to demonstrate these advantages. 3D spheroids mimic the in vivo tumor microenvironment better than 2D culture, with abundant extracellular matrix and hypoxia inducing variability of pH and enzymatic reactions. Here, we report the use of GERTs in large pancreatic 3D spheroids (>500 μm in apparent diameter) for complex penetration visualization. Our combined imaging technique of enhanced darkfield microscopy and SERS was able to identify the presence and distribution of the GERTs within the 3D spheroid structure. The distribution of GERTs 2 hours after the nanorods' incubation indicated accumulation, generally in the outermost layer of the spheroids but also, more randomly, in non-uniform patterns in deep layers of the 3D spheroids. These observations bring into question the mechanism of uptake and flow of the nanoparticles in function of their incubation time while demonstrating the promising potential of our approach. Additionally, the SERS signal was still detectable after 24 hours of incubation of GERTs with the 3D culture, indicating the stability of the Raman signal.

Effects of Mixtures of Engineered Nanoparticles and Metallic Pollutants on Aquatic Organisms

In aquatic environment, engineered nanoparticles (ENPs) are present as complex mixtures with other pollutants, such as trace metals, which could result in synergism, additivity or antagonism of their combined effects. Despite the fact that the toxicity and environmental risk of the ENPs have received extensive attention in the recent years, the interactions of ENPs with other pollutants and the consequent effects on aquatic organisms represent an important challenge in (nano)ecotoxicology. The present review provides an overview of the state-of-the-art and critically discusses the existing knowledge on combined effects of mixtures of ENPs and metallic pollutants on aquatic organisms. The specific emphasis is on the adsorption of metallic pollutants on metal-containing ENPs, transformation and bioavailability of ENPs and metallic pollutants in mixtures. Antagonistic, additive and synergistic effects observed in aquatic organisms co-exposed to ENPs and metallic pollutants are discussed in the case of “particle-proof” and “particle-ingestive” organisms. This knowledge is important in developing efficient strategies for sound environmental impact assessment of mixture exposure in complex environments.

Nanoparticles and organized lipid assemblies: from interaction to design of hybrid soft devices

This contribution reviews the state of art on hybrid soft matter assemblies composed of inorganic nanoparticles (NP) and lamellar or non-lamellar lipid bilayers. After a short outline of the relevant energetic contributions, we address the interaction of NPs with synthetic lamellar bilayers, meant as cell membrane mimics. We then review the design of hybrid nanostructured materials composed of lipid bilayers and some classes of inorganic NPs, with particular emphasis on the effects on the amphiphilic phase diagram and on the additional properties contributed by the NPs. Then, we present the latest developments on the use of lipid bilayers as coating agents for inorganic NPs. Finally, we remark on the main achievements of the last years and our vision for the development of the field.

Effects of Nanoparticles on Algae: Adsorption, Distribution, Ecotoxicity and Fate

With the rapid development of nanotechnology and widespread use of nanoproducts, the ecotoxicity of nanoparticles (NPs) and their potential hazards to the environment have aroused great concern. Nanoparticles have increasingly been released into aquatic environments through various means, accumulating in aquatic organisms through food chains and leading to toxic effects on aquatic organisms. Nanoparticles are mainly classified into nano-metal, nano-oxide, carbon nanomaterials and quantum dots according to their components. Different NPs may have different levels of toxicity and effects on various aquatic organisms. In this paper, algae are used as model organisms to review the adsorption and distribution of NPs to algal cells, as well as the ecotoxicity of NPs on algae and fate in a water environment, systematically. Meanwhile, the toxic effects of NPs on algae are discussed with emphasis on three aspect effects on the cell membrane, cell metabolism and the photosynthesis system. Furthermore, suggestions and prospects are provided for future studies in this area.

Tumor Chemo-Radiotherapy with Rod-Shaped and Spherical Gold Nano Probes: Shape and Active Targeting Both Matter

The morphologies of gold nanoparticles (NPs) affect their tumor accumulation through enhanced permeability and retention effect. However, detailed information and mechanisms of NPs' characteristics affecting tumor accumulation are limited. The aim of this study is to evaluate the effects of shape and active targeting ligands of theranostic NPs on tumor accumulation and therapeutic efficacy, and to elucidate the underlying mechanism.

Methods:αvβ3 integrin-targeted, cisplatin-loaded and radioisotope iodine-125 labeled spherical and rod-shaped gold nano theranostic probes (RGD-¹²⁵IPt-AuNPs and RGD-¹²⁵IPt-AuNRs) with similar sizes were fabricated and characterized. The in vivo distribution and chemo-radio therapeutic efficacy against tumors of these newly developed probes were subsequently evaluated. Moreover, a physiologically based pharmacokinetic (PBPK) model was developed to characterize the in vivo kinetics of these probes at the sub-organ level, and to reveal the mechanism of NPs' shape and active targeting ligands effects on tumor accumulation.

Result: Cisplatin and iodine-125 were loaded sequentially onto the NPs through a thin polydopamine coating layer on the NPs. Both RGD-¹²⁵IPt-AuNPs and RGD-¹²⁵IPt-AuNRs exhibited high specificity for αvβ3 in vitro, with the rod-shaped probe being more efficient. The PBPK model revealed that rod-shaped gold NPs diffused more rapidly in tumor interstitial than the spherical ones. Tumor accumulations of non-targeted and rod-shaped RAD-¹²⁵IPt-AuNRs was higher in short term (1 h post injection), but not pronounced and similar to that of non-targeted spherical RAD-¹²⁵IPt-AuNPs in 24 h after intravenous injection, revealing that the NPs' shape did not have a significant impact on tumor accumulations through enhanced permeability and retention (EPR) effect in long-term. While for actively targeted NPs, in addition to a higher distribution coefficient, RGD-¹²⁵IPt-AuNRs also had a much higher tumor maximum uptake rate constant than RGD-¹²⁵IPt-AuNPs, indicating both the shape and active targeting ligands affected the tumor uptake of rod-shaped NPs. As a result, RGD-¹²⁵IPt-AuNRs had a more effective inhibition of tumor growth than RGD-¹²⁵IPt-AuNPs by chemo-radiationtherapy.

Conclusion: Our study suggests that both the shape and active targeting ligands of gold NPs play important roles on tumor accumulation and chemo-radio therapeutic effect.

Efficacy of Surface-Modified PLGA Nanoparticles as a Function of Cervical Cancer Type

PURPOSE

Hypovascularization of cervical tumors, coupled with intrinsic and acquired drug resistance, has contributed to marginal therapeutic outcomes by hindering chemotherapeutic transport and efficacy. Recently, the heterogeneous penetration and distribution of cell penetrating peptide (CPP, here MPG) and polyethylene glycol (PEG) modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were evaluated as a function of tumor type and morphology in cervical cancer spheroids modeling hypovascularized tumor nodules. Building upon this work, this study investigates the efficacy imparted by surface-modified Doxorubicin-loaded NPs transported into hypovascularized tissue.

METHODS

NP efficacy was measured in HeLa, CaSki, and SiHa cells. NP internalization and association, and associated cell viability, were determined in monolayer and spheroid models.

RESULTS

MPG and PEG-NP co-treatment was most efficacious in HeLa cells, while PEG NPs were most efficacious in CaSki cells. NP surface-modifications were unable to improve efficacy, relative to unmodified NPs, in SiHa cells.

CONCLUSIONS

The results highlight the dependence of efficacy on tumor type and the associated microenvironment. The results further relate previous NP transport studies to efficacy, as a function of surface-modification and cell type. Longer-term, this information may help guide the design of NP-mediated strategies to maximize efficacy based on patient-specific cervical tumor origin and characteristics.

Molecular-Level "Observations" of the Behavior of Gold Nanoparticles in Aqueous Solution and Interacting with a Lipid Bilayer Membrane

We use coarse-grained molecular dynamics simulations to "observe" details of interactions between ligand-covered gold nanoparticles and a lipid bilayer model membrane. In molecular dynamics simulations, one puts the individual atoms and groups of atoms of the physical system to be "observed" into a simulation box, specifies the forms of the potential energies of interactions between them (ultimately quantum based), and lets them individually move classically according to Newton's equations of motion, based on the forces arising from the assumed potential energy forms. The atoms that are chemically bonded to each other stay chemically bonded, following known potentials (force fields) that permit internal degrees of freedom (internal rotation, torsion, vibrations), and the interactions between nonbonded atoms are simplified to Lennard-Jones forms (in our case) and coulombic (where electrical charges are present) in which the parameters are previously optimized to reproduce thermodynamic properties or are based on quantum electronic calculations. The system is started out at a reasonable set of coordinates for all atoms or groups of atoms, and then permitted to develop according to the equations of motion, one small step (usually 10 fs time step) at a time, for millions of steps until the system is at a quasi-equilibrium (usually reached after hundreds of nanoseconds). We then let the system play out its motions further for many nanoseconds to observe the behavior, periodically taking snapshots (saving all positions and energies), and post-processing the snapshots to obtain various average descriptions of the system. Alkanethiols of various lengths serve as examples of hydrophobic ligands and methyl-terminated PEG with various numbers of monomer units serve as examples of hydrophilic ligands. Spherical gold particles of various diameters as well as gold nanorods form the core to which ligands are attached. The nanoparticles are characterized at the molecular level, especially the distributions of ligand configurations and their dependence on ligand length, and surface coverage. Self-assembly of the bilayer from an isotropic solution and observation of membrane properties that correspond well to experimental values validate the simulations. The mechanism of permeation of a gold NP coated with either a hydrophobic or a hydrophilic ligand, and its dependence on surface coverage, ligand length, core diameter, and core shape, is investigated. Lipid response such as lipid flip-flops, lipid extraction, and changes in order parameter of the lipid tails are examined in detail. The mechanism of permeation of a PEGylated nanorod is shown to occur by tilting, lying down, rotating, and straightening up. The nature of the information provided by molecular dynamics simulations permits understanding of the detailed behavior of gold nanoparticles interacting with lipid membranes which in turn helps to understand why some known systems work better than others and aids the design of new particles and improvement of methods for preparing existing ones.

Analytical methodology for studying cellular uptake, processing and localization of gold nanoparticles

Interactions of gold nanoparticles (AuNPs) with live cells are known to exert a great impact on their functions, including cell signalling, genomic, proteomic, and metabolomic processes. Modern analytical techniques applied to studying nanoparticle-cell interactions are to improve our understanding of the mode of action of AuNPs, which is essential for their approval in disease therapeutics. Such methods may vary depending on what step of particle internalization is in question, i.e., cellular uptake, intracellular transport (accompanying by changes in the chemical state), translocation to different cell compartments, interaction with relevant subcellular structures and localization. This review focuses on the implementation and critical assessment of advanced analytical methodologies to investigate the cellular processing of AuNPs. Also addressed is a sought-after issue of accounting in in-vitro studies for a chemical form in which the AuNPs enter the cell in vivo.

Evaluation of Drug-Loaded Gold Nanoparticle Cytotoxicity as a Function of Tumor Vasculature-Induced Tissue Heterogeneity

The inherent heterogeneity of tumor tissue presents a major challenge to nanoparticle-mediated drug delivery. This heterogeneity spans from the molecular (genomic, proteomic, metabolomic) to the cellular (cell types, adhesion, migration) and to the tissue (vasculature, extra-cellular matrix) scales. In particular, tumor vasculature forms abnormally, inducing proliferative, hypoxic, and necrotic tumor tissue regions. As the vasculature is the main conduit for nanotherapy transport into tumors, vasculature-induced tissue heterogeneity can cause local inadequate delivery and concentration, leading to subpar response. Further, hypoxic tissue, although viable, would be immune to the effects of cell-cycle specific drugs. In order to enable a more systematic evaluation of such effects, here we employ computational modeling to study the therapeutic response as a function of vasculature-induced tumor tissue heterogeneity. Using data with three-layered gold nanoparticles loaded with cisplatin, nanotherapy is simulated interacting with different levels of tissue heterogeneity, and the treatment response is measured in terms of tumor regression. The results quantify the influence that varying levels of tumor vascular density coupled with the drug strength have on nanoparticle uptake and washout, and the associated tissue response. The drug strength affects the proportion of proliferating, hypoxic, and necrotic tissue fractions, which in turn dynamically affect and are affected by the vascular density. Higher drug strengths may be able to achieve stronger tumor regression but only if the intra-tumoral vascular density is above a certain threshold that affords sufficient transport. This study establishes an initial step towards a more systematic methodology to assess the effect of vasculature-induced tumor tissue heterogeneity on the response to nanotherapy.

Diagnosis of immunomarkers in vivo via multiplexed surface enhanced Raman spectroscopy with gold nanostars

In this work, we demonstrate the targeted diagnosis of immunomarker programmed death ligand 1 (PD-L1) and simultaneous detection of epidermal growth factor receptor (EGFR) in breast cancer tumors in vivo using gold nanostars (AuNS) with multiplexed surface enhanced Raman spectroscopy (SERS). Real-time longitudinal tracking with SERS demonstrated maximum accumulation of AuNS occurred 6 h post intravenous (IV) delivery, enabling detection of both biomarkers simultaneously. Raman signal correlating to both PD-L1 and EGFR decreased by ∼30% in control tumors where receptors were pre-blocked prior to AuNS delivery, indicating both the sensitivity and specificity of SERS in distinguishing tumors with different levels of PD-L1 and EGFR expression. Our in vivo study was combined with the first demonstration of ex vivo SERS spatial maps of whole tumor lesions that provided both a qualitative and quantitative assessment of biomarker status with near cellular-level resolution. High resolution SERS maps also provided an overview of AuNS distribution in tumors which correlated well with the vascular density. Mass spectrometry showed AuNS accumulation in tumor and liver, and clearance via spleen, and electron microscopy revealed AuNS were endocytosed in tumors, Kupffer cells in the liver, and macrophages in the spleen. This study demonstrates that SERS-based diagnosis mediated by AuNS provides an accurate measure of multiple biomarkers both in vivo and ex vivo, which will ultimately enable a clinically-translatable platform for patient-tailored immunotherapies and combination treatments.

Nanoparticle-mediated drug delivery to treat infections in the female reproductive tract: evaluation of experimental systems and the potential for mathematical modeling

A variety of drug-delivery platforms have been employed to deliver therapeutic agents across cervicovaginal mucus (CVM) and the vaginal mucosa, offering the capability to increase the longevity and retention of active agents to treat infections of the female reproductive tract (FRT). Nanoparticles (NPs) have been shown to improve retention, diffusion, and cell-specific targeting via specific surface modifications, relative to other delivery platforms. In particular, polymeric NPs represent a promising option that has shown improved distribution through the CVM. These NPs are typically fabricated from nontoxic, non-inflammatory, US Food and Drug Administration-approved polymers that improve biocompatibility. This review summarizes recent experimental studies that have evaluated NP transport in the FRT, and highlights research areas that more thoroughly and efficiently inform polymeric NP design, including mathematical modeling. An overview of the in vitro, ex vivo, and in vivo NP studies conducted to date – whereby transport parameters are determined, extrapolated, and validated – is presented first. The impact of different NP design features on transport through the FRT is summarized, and gaps that exist due to the limitations of iterative experimentation alone are identified. The potential of mathematical modeling to complement the characterization and evaluation of diffusion and transport of delivery vehicles and active agents through the CVM and mucosa is discussed. Lastly, potential advancements combining experimental and mathematical knowledge are suggested to inform next-generation NP designs, such that infections in the FRT may be more effectively treated.

Preparation and characterization of Fe3O4@Au-C225 composite targeted nanoparticles for MRI of human glioma

Objective

To study the characterization of Fe₃O₄@Au-C225 composite targeted MNPs.

Methods

Fe₃O₄@Au-C225 was prepared by the absorption method. The immunosorbent assay was used to evaluate its absorption efficiency at C225 Fc. ZETA SIZER3000 laser particle size analyzer, ultraviolet photometer and its characteristics were analyzed by VSM. the targeting effect of Fe₃O₄@Au-C225 composite targeted MNPs on U251 cells in vitro were detected by 7.0 Tesla Micro-MR; and subcutaneous transplanted human glioma in nude mice were performed the targeting effect in vivo after tail vein injection of Fe₃O₄@Au-C225 composite targeted MNPs by MRI.

Results

The self-prepared Fe₃O₄@Au composite MNPs can adsorb C225 with high efficiency of adsorption so that Fe₃O₄@Au-C225 composite targeted MNPs were prepared successfully. Fe₃O₄@Au-C225 composite targeted MNPs favorably targeted human glioma cell line U251 in vitro; Fe₃O₄@Au-C225 composite targeted MNPs have good targeting ability to xenografted glioma on nude mice in vivo, and can be traced by MRI.

Conclusion

The Fe₃O₄@Au-C225 composite targeted MNPs have the potential to be used as a tracer for glioma in vivo.

E. coli Nissle 1917-Derived Minicells for Targeted Delivery of Chemotherapeutic Drug to Hypoxic Regions for Cancer Therapy

Purpose: Systemic administration of free chemotherapeutic drugs leads to severe toxic effects, and physiological characteristics of solid tumors restrain the drugs from reaching the hypoxic regions. E. coli Nissle 1917 (EcN) has been known to penetrate the barrier and proliferate in the interface between the viable and necrotic regions of tumors. This study aimed to fabricate a nanoscale minicell via genetic engineering of EcN for targeted delivery of chemotherapeutic drugs to the hypoxic regions of tumors for cancer therapy. Methods: A large number of minicells were produced by knocking out the minCD gene and enhancing the minE expression in EcN. Then, a pH (low) insertion peptide (pHLIP) was displayed on the membrane surface through protein display technology to endow the cells with the ability to target the acidic microenvironments of tumors. The acidic-microenvironment targeting ability and therapeutic effect of the engineered minicells with chemotherapeutic drugs was thoroughly evaluated by using breast cancer cells and an orthotopic model of breast tumor. Results: The EcN-derived minicells displaying pHLIP could be directly extracted from the fermentation broth and used for delivering chemotherapeutic drugs without any further modification. Targeting of doxorubicin (DOX)-loaded minicells to cancer cells via pHLIP resulted in rapid internalization and drug release in acidic media. Importantly, the pHLIP-mosaic minicells successfully invaded the necrotic and hypoxic regions of orthotopic breast cancers where free chemotherapeutic drugs could never get to because of vascular insufficiency and high interstitial fluid pressure. This invasion resulted in significant regression of an orthotopic breast tumor in a mouse model, while no seriously pathogenic effects were observed during the animal experiments. Conclusions: This study provides a novel strategy for the fabrication of tumor-targeting carriers via genetic engineering based on biomaterials with the ability to penetrate hypoxic regions of tumors, high biocompatibility and low toxicity.

Distribution of PLGA-modified nanoparticles in 3D cell culture models of hypo-vascularized tumor tissue

BACKGROUND

Advanced stage cancer treatments are often invasive and painful-typically comprised of surgery, chemotherapy, and/or radiation treatment. Low transport efficiency during systemic chemotherapy may require high chemotherapeutic doses to effectively target cancerous tissue, resulting in systemic toxicity. Nanotherapeutic platforms have been proposed as an alternative to more safely and effectively deliver therapeutic agents directly to tumor sites. However, cellular internalization and tumor penetration are often diametrically opposed, with limited access to tumor regions distal from vasculature, due to irregular tissue morphologies. To address these transport challenges, nanoparticles (NPs) are often surface-modified with ligands to enhance transport and longevity after localized or systemic administration. Here, we evaluate stealth polyethylene-glycol (PEG), cell-penetrating (MPG), and CPP-stealth (MPG/PEG) poly(lactic-co-glycolic-acid) (PLGA) NP co-treatment strategies in 3D cell culture representing hypo-vascularized tissue.

RESULTS

Smaller, more regularly-shaped avascular tissue was generated using the hanging drop (HD) method, while more irregularly-shaped masses were formed with the liquid overlay (LO) technique. To compare NP distribution differences within the same type of tissue as a function of different cancer types, we selected HeLa, cervical epithelial adenocarcinoma cells; CaSki, cervical epidermoid carcinoma cells; and SiHa, grade II cervical squamous cell carcinoma cells. In HD tumors, enhanced distribution relative to unmodified NPs was measured for MPG and PEG NPs in HeLa, and for all modified NPs in SiHa spheroids. In LO tumors, the greatest distribution was observed for MPG and MPG/PEG NPs in HeLa, and for PEG and MPG/PEG NPs in SiHa spheroids.

CONCLUSIONS

Pre-clinical evaluation of PLGA-modified NP distribution into hypo-vascularized tumor tissue may benefit from considering tissue morphology in addition to cancer type.

Human Adipose-Derived Stem Cells Labeled with Plasmonic Gold Nanostars for Cellular Tracking and Photothermal Cancer Cell Ablation

BACKGROUND

Gold nanostars are unique nanoplatforms that can be imaged in real time and transform light energy into heat to ablate cells. Adipose-derived stem cells migrate toward tumor niches in response to chemokines. The ability of adipose-derived stem cells to migrate and integrate into tumors makes them ideal vehicles for the targeted delivery of cancer nanotherapeutics.

METHODS

To test the labeling efficiency of gold nanostars, undifferentiated adipose-derived stem cells were incubated with gold nanostars and a commercially available nanoparticle (Qtracker), then imaged using two-photon photoluminescence microscopy. The effects of gold nanostars on cell phenotype, proliferation, and viability were assessed with flow cytometry, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide metabolic assay, and trypan blue, respectively. Trilineage differentiation of gold nanostar-labeled adipose-derived stem cells was induced with the appropriate media. Photothermolysis was performed on adipose-derived stem cells cultured alone or in co-culture with SKBR3 cancer cells.

RESULTS

Efficient uptake of gold nanostars occurred in adipose-derived stem cells, with persistence of the luminescent signal over 4 days. Labeling efficiency and signal quality were greater than with Qtracker. Gold nanostars did not affect cell phenotype, viability, or proliferation, and exhibited stronger luminescence than Qtracker throughout differentiation. Zones of complete ablation surrounding the gold nanostar-labeled adipose-derived stem cells were observed following photothermolysis in both monoculture and co-culture models.

CONCLUSIONS

Gold nanostars effectively label adipose-derived stem cells without altering cell phenotype. Once labeled, photoactivation of gold nanostar-labeled adipose-derived stem cells ablates neighboring cancer cells, demonstrating the potential of adipose-derived stem cells as a vehicle for the delivery of site-specific cancer therapy.

TRAIL-NP hybrids for cancer therapy: a review

Cancer is a worldwide health problem. It is now considered as a leading cause of morbidity and mortality in developed countries. In the last few decades, considerable progress has been made in anti-cancer therapies, allowing the cure of patients suffering from this disease, or at least helping to prolong their lives. Several cancers, such as those of the lung and pancreas, are still devastating in the absence of therapeutic options. In the early 90s, TRAIL (Tumor Necrosis Factor-related apoptosis-inducing ligand), a cytokine belonging to the TNF superfamily, attracted major interest in oncology owing to its selective anti-tumor properties. Clinical trials using soluble TRAIL or antibodies targeting the two main agonist receptors (TRAIL-R1 and TRAIL-R2) have, however, failed to demonstrate their efficacy in the clinic. TRAIL is expressed on the surface of natural killer or CD8+ T activated cells and contributes to tumor surveillance. Nanoparticles functionalized with TRAIL mimic membrane-TRAIL and exhibit stronger antitumoral properties than soluble TRAIL or TRAIL receptor agonist antibodies. This review provides an update on the association and the use of nanoparticles associated with TRAIL for cancer therapy.

111In-labeled trastuzumab-modified gold nanoparticles are cytotoxic in vitro to HER2-positive breast cancer cells and arrest tumor growth in vivo in athymic mice after intratumoral injection

INTRODUCTION

Gold nanoparticles (AuNP; 30nm) were modified with polyethylene glycol (PEG) chains linked to trastuzumab for binding to HER2-positive breast cancer (BC) cells and diethylenetriaminepentaacetic acid (DTPA) for complexing the Auger electron-emitter, ¹¹¹In (trastuzumab-AuNP-¹¹¹In). Our objective was to determine the cytotoxicity of trastuzumab-AuNP-¹¹¹In on HER2-positive BC cells in vitro and evaluate its tumor growth inhibition properties and normal tissue toxicity in vivo following intratumoral (i.t.) injection in mice with s.c. HER2-overexpressing BC xenografts.

METHODS

Binding and internalization of trastuzumab-AuNP-¹¹¹In or non-targeted AuNP-¹¹¹In in SK-BR-3 (1-2×10⁶ HER2/cell) and MDA-MB-361 (5×10⁵ HER2/cell) human BC cells were studied. The surviving fraction (SF) of SK-BR-3 or MDA-MB-361 cells exposed to trastuzumab-AuNP-¹¹¹In or AuNP-¹¹¹In was determined. DNA double-strand breaks (DSBs) were assayed by probing for γ-H2AX. Tumor growth was monitored over 70days in CD1 athymic mice with s.c. MDA-MB-361 xenografts after i.t. injection of 10MBq (0.7mg; 2.6×10¹² AuNP) of trastuzumab-AuNP-¹¹¹In and normal tissue toxicity was assessed by monitoring body weight, complete blood cell (CBC) counts and serum alanine aminotransferase (ALT) and creatinine (Cr).

RESULTS

Trastuzumab-AuNP-¹¹¹In was specifically bound by SK-BR-3 and MDA-MB-361 cells. Trastuzumab-AuNP-¹¹¹In was more efficiently internalized than AuNP-¹¹¹In and localized to a peri-nuclear region. The SF fraction of SK-BR-3 cells was reduced by 1.8-fold by treatment with 3nM (7MBq/mL) of trastuzumab-AuNP-¹¹¹In. The SF of MDA-MB-361 cells was reduced by 3.7-fold at 14.4nM (33.6MBq/mL). In comparison, non-targeted AuNP-¹¹¹In at these concentrations reduced the SF of SK-BR-3 or MDA-MB-361 cells by 1.2-fold (P=0.03) and 1.7-fold (P<0.0001), respectively. DNA DSBs were greater in SK-BR-3 and MDA-MB-361 cells exposed to trastuzumab-AuNP-¹¹¹In compared to AuNP-¹¹¹In, but unlabeled trastuzumab-AuNP did not increase DNA DSBs. Local i.t. injection of trastuzumab-AuNP-¹¹¹In in CD1 athymic mice with s.c. MDA-MB-361 tumors arrested tumor growth for 70days. There was no apparent normal tissue toxicity. The radiation absorbed dose deposited in the tumor by trastuzumab-AuNP-¹¹¹In was 60.5Gy, while normal organs received <0.9Gy.

CONCLUSION

These results are promising for further development of trastuzumab-AuNP-¹¹¹In as a novel Auger electron-emitting radiation nanomedicine for local treatment of HER2-positive BC.

ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE

A local radiation treatment for HER2-positive BC based on AuNP modified with trastuzumab and labeled with the Auger electron-emitter, ¹¹¹In was developed and shown to arrest tumor growth with no normal tissue toxicity.