Pharmacokinetics variability: Why nanoparticles are not just magic-bullets in oncology

The recent applications of nanotechnology in the diagnosis and treatment of common cardiovascular diseases

Almost a third of all fatalities may be attributed to cardiovascular disease (CVD), making it a primary cause of mortalities worldwide. Better diagnostic tools and secure, non-invasive imaging techniques are needed to offer accurate information on CVD progression. Several elements contribute to the success of CVD personalized therapy, and two of the most crucial are accurate diagnosis and early detection. The therapy options available for conditions with a pathogenesis that unfold over decades, such as CVD, are very condition-specific and disease-stage based. Nanotechnology is increasingly being used as a therapeutic tool in the biomedical area, where they are used in various contexts, including diagnostics, biosensing, and drug administration. This review article provides an overview of the most recent applications of nanotechnology in the detection and management of prevalent CVDs.

Cell-Derived Vesicles for Nanoparticles' Coating: Biomimetic Approaches for Enhanced Blood Circulation and Cancer Therapy

Cancer nanomedicines are designed to encapsulate different therapeutic agents, prevent their premature release, and deliver them specifically to cancer cells, due to their ability to preferentially accumulate in tumor tissue. However, after intravenous administration, nanoparticles immediately interact with biological components that facilitate their recognition by the immune system, being rapidly removed from circulation. Reports show that less than 1% of the administered nanoparticles effectively reach the tumor site. This suboptimal pharmacokinetic profile is pointed out as one of the main factors for the nanoparticles' suboptimal therapeutic effectiveness and poor translation to the clinic. Therefore, an extended blood circulation time may be crucial to increase the nanoparticles' chances of being accumulated in the tumor and promote a site-specific delivery of therapeutic agents. For that purpose, the understanding of the forces that govern the nanoparticles' interaction with biological components and the impact of the physicochemical properties on the in vivo fate will allow the development of novel and more effective nanomedicines. Therefore, in this review, the nano-bio interactions are summarized. Moreover, the application of cell-derived vesicles for extending the blood circulation time and tumor accumulation is reviewed, focusing on the advantages and shortcomings of each cell source.

Stealth nanoparticles in oncology: Facing the PEG dilemma

Nanoparticles (Nps) have revolutionized the landscape of many treatments, by modifying not only pharmacokinetic properties of the encapsulated agent, but also providing a significant protection of the drug from non-desired interactions, and reducing side-effects of the enclosed therapeutic, enabling co-encapsulation of possibly synergistic compounds or activities, allowing a controlled release of content and improving the therapeutic effect. Nevertheless, in systemic circulation, Nps suffer a rapid removal by opsonisation and the action of Mononuclear phagocyte system (MPS). To overcome this problem, different polymers, in particular Polyethyleneglycol (PEG), have been used to cover the surface of these nanocarriers forming a hydrophilic layer that allows the delay of the removal. These advantages contrast with some drawbacks such as the difficulty to interact with cell membranes and the development of immunological reactions, conforming the known, "PEG dilemma". To address and minimize this phenomenon, different strategies have been applied. Therefore, this review aims to summarize the state of the art of Pegylation strategies, comment in depth on the principal characteristics of PEG and describe the main alternatives, which are the use of cleavable PEG, addition of different polymers or even use other derivatives of cell membranes to camouflage Nps.

Metal-Polymer Nanoconjugates Application in Cancer Imaging and Therapy

Metallic-based nanoparticles present a unique set of physicochemical properties that support their application in different fields, such as electronics, medical diagnostics, and therapeutics. Particularly, in cancer therapy, the plasmonic resonance, magnetic behavior, X-ray attenuation, and radical oxygen species generation capacity displayed by metallic nanoparticles make them highly promising theragnostic solutions. Nevertheless, metallic-based nanoparticles are often associated with some toxicological issues, lack of colloidal stability, and establishment of off-target interactions. Therefore, researchers have been exploiting the combination of metallic nanoparticles with other materials, inorganic (e.g., silica) and/or organic (e.g., polymers). In terms of biological performance, metal-polymer conjugation can be advantageous for improving biocompatibility, colloidal stability, and tumor specificity. In this review, the application of metallic-polymer nanoconjugates/nanohybrids as a multifunctional all-in-one solution for cancer therapy will be summarized, focusing on the physicochemical properties that make metallic nanomaterials capable of acting as imaging and/or therapeutic agents. Then, an overview of the main advantages of metal-polymer conjugation as well as the most common structural arrangements will be provided. Moreover, the application of metallic-polymer nanoconjugates/nanohybrids made of gold, iron, copper, and other metals in cancer therapy will be discussed, in addition to an outlook of the current solution in clinical trials.

Mathematical Modeling for an MTT Assay in Fluorine-Containing Graphene Quantum Dots

The paper reports on a new mathematical model, starting with the original Hill equation which is derived to describe cell viability (V) while testing nanomaterials (NMs). Key information on the sample's morphology, such as mean size (⟨s⟩) and size dispersity (σ) is included in the new model via the lognormal distribution function. The new Hill-inspired equation is successfully used to fit MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) data from assays performed with the HepG2 cell line challenged by fluorine-containing graphene quantum dots (F:GQDs) under light (400-700 nm wavelength) and dark conditions. The extracted "biological polydispersity" (light: ⟨sMTT⟩=1.77±0.02 nm and σMTT=0.21±0.02); dark: ⟨sMTT⟩=1.87±0.02 nm and σMTT=0.22±0.01) is compared with the "morphological polydispersity" (⟨sTEM⟩=1.98±0.06 nm and σTEM=0.19±0.03), the latter obtained from TEM (transmission electron microscopy). The fitted data are then used to simulate a series of V responses. Two aspects are emphasized in the simulations: (i) fixing σ, one simulates V versus ⟨s⟩ and (ii) fixing ⟨s⟩, one simulates V versus σ. Trends observed in the simulations are supported by a phenomenological model picture describing the monotonic reduction in V as ⟨s⟩ increases (V~pa/(s)p-a; p and a are fitting parameters) and accounting for two opposite trends of V versus σ: under light (V~σ) and under dark (V~1/σ).

Pharmacokinetics and pharmacogenetics of liposomal cytarabine in AML patients treated with CPX-351

CPX-351 is a liposome encapsulating cytarabine and daunorubicin for treating Acute Myeloid Leukemia (AML) patients. To what extent differences in cytidine deaminase (CDA) activity, the enzyme that catabolizes free cytarabine in the liver, can affect the pharmacokinetics of liposomal cytarabine as well, is unknown. We have studied the pharmacokinetics (PK) of released, liposomal and total cytarabine using a population-modeling approach in 9 adult AML patients treated with liposomal CPX-351. Exposure levels and PK parameters were compared with respect to the patient's CDA status (i.e., Poor Metabolizer (PM) vs. Extensive Metabolizer (EM)). Overall response rate was 75%, and 56% of patients had non-hematological severe toxicities, including one lethal toxicity. All patients had febrile neutropenia. A large (>60%) inter-individual variability was observed on pharmacokinetics parameters and subsequent drug levels. A trend towards severe toxicities was observed in patients with higher exposure of cytarabine. Results showed that liposomal CPX-351 led to sustained exposure with reduced clearance (Cl = 0.16 L/h) and prolonged half-life (T_1/2 = 28 h). Liposomal nanoparticles were observed transiently in bone marrow with cytarabine levels 2.3-time higher than in plasma. Seven out of 9 patients were PM with a strong impact on the PK parameters, i.e., PM patients showing higher cytarabine levels as compared with EM patients (AUC: 5536 vs. 1784 ng/mL.h), sustained plasma exposure (T_1/2: 33.9 vs. 13.7 h), and reduced clearance (Cl: 0.12 vs. 0.29 L/h). This proof-of-concept study suggests that CDA status has a major impact on cytarabine PK and possibly safety in AML patients even when administered as a liposome.

Nanoparticles: A Hope for the Treatment of Inflammation in CNS

Neuroinflammation, an inflammatory response within the central nervous system (CNS), is a main hallmark of common neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), among others. The over-activated microglia release pro-inflammatory cytokines, which induces neuronal death and accelerates neurodegeneration. Therefore, inhibition of microglia over-activation and microglia-mediated neuroinflammation has been a promising strategy for the treatment of neurodegenerative diseases. Many drugs have shown promising therapeutic effects on microglia and inflammation. However, the blood–brain barrier (BBB)—a natural barrier preventing brain tissue from contact with harmful plasma components—seriously hinders drug delivery to the microglial cells in CNS. As an emerging useful therapeutic tool in CNS-related diseases, nanoparticles (NPs) have been widely applied in biomedical fields for use in diagnosis, biosensing and drug delivery. Recently, many NPs have been reported to be useful vehicles for anti-inflammatory drugs across the BBB to inhibit the over-activation of microglia and neuroinflammation. Therefore, NPs with good biodegradability and biocompatibility have the potential to be developed as an effective and minimally invasive carrier to help other drugs cross the BBB or as a therapeutic agent for the treatment of neuroinflammation-mediated neurodegenerative diseases. In this review, we summarized various nanoparticles applied in CNS, and their mechanisms and effects in the modulation of inflammation responses in neurodegenerative diseases, providing insights and suggestions for the use of NPs in the treatment of neuroinflammation-related neurodegenerative diseases.

Polymeric Lipid Hybrid Nanoparticles as a Delivery System Enhance the Antitumor Effect of Emodin in Vitro and in Vivo

This study aimed to evaluate the therapeutic efficacy of Emodin-loaded polymer lipid hybrid nanoparticles (E-PLNs) for breast cancer. The size, Zeta potential, surface morphology, encapsulation efficiency, stability, in vitro drug release of E-PLNs prepared by the nanoprecipitation method were characterized. The uptake, in-vitro cytotoxicities and apoptosis of free drug, E-PLNs were investigated against MCF-7 cells. The efficacy of E-PLNs in tumor bearing nude mice has also been studied.The average particle size of the experimentally prepared E-PLNs was (122.7±1.79) nm, and the encapsulation rate was 72.8%. Compared with free Emodin (EMO), E-PLNs showed greater toxicity to MCF-7 cells by promoting the uptake of EMO, and can promote the early apoptosis of MCF-7 cells. In addition to the morphological changes of apoptotic cells, the ratio of Bax/Bcl-2 was significantly increased, which indicated that E-PLNs can induce apoptosis in MCF-7 cells to achieve anticancer effect. Finally, E-PLNs significantly inhibited tumor growth by more than 60%, which may be related to its passive targeting effect on tumor site. Our results suggest that E-PLNs have shown good anti-breast cancer effect than free EMO. Moreover, the effect of E-PLNs on MCF-7 cells is mainly related to the induction of apoptosis.

Bortezomib-loaded lipidic-nano drug delivery systems; formulation, therapeutic efficacy, and pharmacokinetics

AIM

Nano drug delivery systems can provide the opportunity to reduce side effects and improve the therapeutic aspect of a variety of drugs. Bortezomib (BTZ) is a proteasome inhibitor approved for the treatment of multiple myeloma and mantle cell lymphoma. Severe side effects of BTZ are the major dose-limiting factor. Particulate drug delivery systems for BTZ are polymeric and lipidic drug delivery systems. This review focussed on lipidic-nano drug delivery systems (LNDDSs) for the delivery of BTZ.

RESULTS

LNDDSs including liposomes, solid lipid nanoparticles, and self-nanoemulsifying drug delivery systems showed reduce systemic side effects, improved therapeutic efficacy, and increased intestinal absorption. Besides LNDDSs were used to target-delivery of BTZ to cancer.

CONCLUSION

Overall, LNDDSs can be considered as a novel delivery system for BTZ to resolve the treatment-associated restrictions.

Engineered Nanomaterials: The Challenges and Opportunities for Nanomedicines

The emergence of nanotechnology as a key enabling technology over the past years has opened avenues for new and innovative applications in nanomedicine. From the business aspect, the nanomedicine market was estimated to worth USD 293.1 billion by 2022 with a perception of market growth to USD 350.8 billion in 2025. Despite these opportunities, the underlying challenges for the future of engineered nanomaterials (ENMs) in nanomedicine research became a significant obstacle in bringing ENMs into clinical stages. These challenges include the capability to design bias-free methods in evaluating ENMs' toxicity due to the lack of suitable detection and inconsistent characterization techniques. Therefore, in this literature review, the state-of-the-art of engineered nanomaterials in nanomedicine, their toxicology issues, the working framework in developing a toxicology benchmark and technical characterization techniques in determining the toxicity of ENMs from the reported literature are explored.

Silica-Based Nanoparticles as Drug Delivery Vehicles for Prostate Cancer Treatment

Prostate cancer (PCa) is one of the most commonly diagnosed cancers and is the fifth common cause of cancer-related mortality in men. Current methods for PCa treatment are insufficient owing to the challenges related to the non-specificity, instability and side effects caused by the drugs and therapy agents. These drawbacks can be mitigated by the design of a suitable drug delivery system that can ensure targeted delivery and minimise side effects. Silica based nanoparticles (SBNPs) have emerged as one of the most versatile materials for drug delivery due to their tunable porosities, high surface area and tremendous capacity to load various sizes and chemistry of drugs. This review gives a brief overview of the diagnosis and current treatment strategies for PCa outlining their existing challenges. It critically analyzes the design, development and application of pure, modified and hybrid SBNPs based drug delivery systems in the treatment of PCa, their advantages and limitations.

Visualization of the distribution of nanoparticle-formulated AZD2811 in mouse tumor model using matrix-assisted laser desorption ionization mass spectrometry imaging

Penetration of nanoparticles into viable tumor regions is essential for an effective response. Mass spectrometry imaging (MSI) is a novel method for evaluating the intratumoral pharmacokinetics (PK) of a drug in terms of spatial distribution. The application of MSI for analysis of nanomedicine PK remains in its infancy. In this study, we evaluated the applicability of MALDI-MSI for nanoparticle-formulated drug visualization in tumors and biopsies, with an aim toward future application in clinical nanomedicine research. We established an analytic method for the free drug (AZD2811) and then applied it to visualize nanoparticle-formulated AZD2811. MSI analysis demonstrated heterogeneous intratumoral drug distribution in three xenograft tumors. The intensity of MSI signals correlated well with total drug concentration in tumors, indicating that drug distribution can be monitored quantitatively. Analysis of tumor biopsies indicated that MSI is applicable for analyzing the distribution of nanoparticle-formulated drugs in tumor biopsies, suggesting clinical applicability.

When liposomes met antibodies: Drug delivery and beyond

Drug encapsulated liposomes and monoclonal antibodies (Mabs) are two distinctively different classes of therapeutics, but both aim to become the ultimate "magic bullet". While PEGylated liposomes rely on the enhanced permeability and retention (EPR) effect for accumulation in solid tumor tissues, Mabs are designed to bind tightly to specific surface antigens on target cells to exert effector functions. Immunoliposome (IL) refers to the structural combination of liposomes and antibodies, whereas the antibodies are usually decorated on the liposome surface. ILs can therefore take advantage of interactions between antibodies and cancer cells for more efficient endocytosis and intracellular drug delivery. The antibody structure, affinity, density, as well as the liposome surface properties and drug to lipid ratios all contribute to the IL pharmacokinetic(PK) and pharmacodynamic(PD) behaviors. The optimal formulation parameters may vary for different target cells and tissues. Furthermore, besides the delivery of cytotoxic drugs to cancer cells, new ILs are being developed to interact with multiple target receptors, multiple target cells and trigger multiple therapeutic effects. We envision that the IL format can be a great platform for the molecular engineering of multi-valent, multi-specific interactions to achieve complex biological functions for therapeutic benefits, especially in the area of cancer immunotherapy.

Ultrabright Fluorescent Polymeric Nanoparticles with a Stealth Pluronic Shell for Live Tracking in the Mouse Brain

Visualizing single organic nanoparticles (NPs) in vivo remains a challenge, which could greatly improve our understanding of the bottlenecks in the field of nanomedicine. To achieve high single-particle fluorescence brightness, we loaded polymer poly(methyl methacrylate)-sulfonate (PMMA-SO₃H) NPs with octadecyl rhodamine B together with a bulky hydrophobic counterion (perfluorinated tetraphenylborate) as a fluorophore insulator to prevent aggregation-caused quenching. To create NPs with stealth properties, we used the amphiphilic block copolymers pluronic F-127 and F-68. Fluorescence correlation spectroscopy and Förster resonance energy transfer (FRET) revealed that pluronics remained at the NP surface after dialysis (at one amphiphile per 5.5 nm²) and prevented NPs from nonspecific interactions with serum proteins and surfactants. In primary cultured neurons, pluronics stabilized the NPs, preventing their prompt aggregation and binding to neurons. By increasing dye loading to 20 wt % and optimizing particle size, we obtained 74 nm NPs showing 150-fold higher single-particle brightness with two-photon excitation than commercial Nile Red-loaded FluoSpheres of 39 nm hydrodynamic diameter. The obtained ultrabright pluronic-coated NPs enabled direct single-particle tracking in vessels of mice brains by two-photon intravital microscopy for at least 1 h, whereas noncoated NPs were rapidly eliminated from the circulation. Following brain injury or neuroinflammation, which can open the blood-brain barrier, extravasation of NPs was successfully monitored. Moreover, we demonstrated tracking of individual NPs from meningeal vessels until their uptake by meningeal macrophages. Thus, single NPs can be tracked in animals in real time in vivo in different brain compartments and their dynamics visualized with subcellular resolution.

Guidelines for the experimental design of pharmacokinetic studies with nanomaterials in preclinical animal models

A shared feature in the value proposition of every nanomaterial-based drug delivery systems is the desirable improvement in the disposition (or ADME) and pharmacokinetic profiles of the encapsulated drug being delivered. Remarkable progress has been made towards understanding the complex and multifactorial relationships between pharmacokinetic profiles and nanomaterial physicochemical properties, biological interactions, species physiology, etc. These advances have fuelled the rational design of numerous nanomaterials with long-circulation times and improved tissue accumulation (e.g., in tumours). Unfortunately, a central weakness in many of these research efforts has been the inconsistent and insufficient characterisation of the pharmacokinetic profiles of nanomaterials in scientific reporting-a problem affecting the majoirty of of contemporary nanomaterials literature and innovative nanomaterials in early stages of preclinical development especially. Given the significant role of pharmacokinetic assessments to serve as guideposts for deciding whether to continue with the preclinical development and clinical translation of drug delivery systems, the prevalence of poor pharmacokinetic characterisations in nanomaterials research is particularly alarming. A conspicuous problem in many reports is the inappropriate selection of experimental designs and methodologies for studying nanomaterial pharmacokinetics, the consequences of which are increased uncertainty over the accurate interpretation of reported pharmacokinetic data and diminished experimental reproducibility throughout the field. Thus, there is renewed interest in the establishment of consistent and comprehensive strategies for designing preclinical experiments to assess the pharmacokinetics of nanomaterials with diverse physicochemical properties. Towards this end, herein are proposed simple guidelines for the experimental design of pharmacokinetic studies with nanomaterials drawn from the best research practices, principle strategies, and important considerations used in industry for collecting pharmacokinetic data in preclinical animal models. Specifically, key experimental design factors in these studies are identified and examined in the context of nanomaterials for optimality, including blood sampling strategy and technique, sample allocation and sampling time window, test species selection, experimental sources of pharmacokinetic variability, etc. Methods for noninvasive imaging-derived pharmacokinetic assessments of theranostic nanomaterials are also explored with particular focus on emission tomography imaging modalities. Taken together, this review will provide nanomaterial researchers with practical knowledge and pragmatic recommendations for selecting the best designs and methodologies for assessing the pharmacokinetic profiles of their nanomaterials, and hopefully maximise the chances of translational success of these innovative products into humans.

Prototyping Trastuzumab Docetaxel Immunoliposomes with a New FCM-Based Method to Quantify Optimal Antibody Density on Nanoparticles

Developing targeted nanoparticles is a rising strategy to improve drug delivery in oncology. Antibodies are the most commonly used targeting agents. However, determination of their optimal number at the surface remains a challenging issue, mainly due to the difficulties in measuring precisely surface coating levels when prototyping nanoparticles. We developed an original quantitative assay to measure the exact number of coated antibodies per nanoparticle. Using flow cytometry optimized for submicron particle analysis and beads covered with known amounts of human IgG-kappa mimicking various amounts of antibodies, this new method was tested as part of the prototyping of docetaxel liposomes coated with trastuzumab against Her2+ breast cancer. This quantification method allowed to discriminate various batches of immunoliposomes depending on their trastuzumab density on nanoparticle surface (i.e., 330 (Immunoliposome-1), 480 (Immunoliposome-2) and 690 (Immunoliposome-3), p = 0.004, One-way ANOVA). Here we showed that optimal number of grafted antibodies on nanoparticles should be finely tuned and highest density of targeting agent is not necessarily associated with highest efficacy. Overall, this new method should help to better prototype third generation nanoparticles.

Perspectives on the Future of Nanomedicine to Impact Patients: An Analysis of US Federal Funding and Interventional Clinical Trials

The US and governments around the world, and companies, have made a considerable investment in nanomedicine, and there have been important discoveries. Nevertheless, there has been considerable debate as to whether the investment, both in money and in time, has been worth it. That question is not yet definitively answerable. However, investigators (and investors) might also wonder if the efforts in nanomedicine are likely to continue at the same pace as over the past decade. For this paper, an analysis was done by searching Medline, RePORT, the DOD (CDMRP), the NSF, and ClinicalTrials.gov. The major findings from the analysis are as follows: (1) The number of journal articles on the subject of nanomedicine continues to steadily rise and the areas "Drug Carriers" and "Drug Delivery Systems" are experiencing particularly rapid growth. (2) The level of funding from the Department of Health and Human Services (NIH and others) for indications other than cancer has been greater than that for cancer. (3) Funding for applications in HIV/AIDS has been strong. (4) Most of the cancers are being impacted. (5) The number of clinical trials are more highly focused in breast, skin, metastatic, and ovarian cancers, though the noncancer indications of pain and infections are also highly represented. The trials are primarily in Phases I and II, suggesting a long horizon before translating to a high impact on patients. (6) The vast majority of the clinical trials are for the evaluation of established nanomedicine formulations (liposomes and nab-paclitaxel/Abraxane) in combination with other therapies. Nevertheless, the number of clinical trials with other nanomedicine formulations has been increasing since 2009. Relatively few of the trials are for micelles or dendrimers. Taken as a whole, the analysis provides a picture that nanomedicine continues to be highly funded and highly studied but with few recent breakthroughs. Nanomedicine has yet to provide the "silver bullet" for therapy in cancer or other diseases, and it remains unclear whether it ever will.

Incorporation of doxorubicin in different polymer nanoparticles and their anticancer activity

Background: Nanoparticles are under investigation as carrier systems for anticancer drugs. The expression of efflux transporters such as the ATP-binding cassette (ABC) transporter ABCB1 is an important resistance mechanism in therapy-refractory cancer cells. Drug encapsulation into nanoparticles has been shown to bypass efflux-mediated drug resistance, but there are also conflicting results. To investigate whether easy-to-prepare nanoparticles made of well-tolerated polymers may circumvent transporter-mediated drug efflux, we prepared poly(lactic-co-glycolic acid) (PLGA), polylactic acid (PLA), and PEGylated PLGA (PLGA-PEG) nanoparticles loaded with the ABCB1 substrate doxorubicin by solvent displacement and emulsion diffusion approaches and assessed their anticancer efficiency in neuroblastoma cells, including ABCB1-expressing cell lines, in comparison to doxorubicin solution. Results: The resulting nanoparticles covered a size range between 73 and 246 nm. PLGA-PEG nanoparticle preparation by solvent displacement led to the smallest nanoparticles. In PLGA nanoparticles, the drug load could be optimised using solvent displacement at pH 7 reaching 53 µg doxorubicin/mg nanoparticle. These PLGA nanoparticles displayed sustained doxorubicin release kinetics compared to the more burst-like kinetics of the other preparations. In neuroblastoma cells, doxorubicin-loaded PLGA-PEG nanoparticles (presumably due to their small size) and PLGA nanoparticles prepared by solvent displacement at pH 7 (presumably due to their high drug load and superior drug release kinetics) exerted the strongest anticancer effects. However, nanoparticle-encapsulated doxorubicin did not display increased efficacy in ABCB1-expressing cells relative to doxorubicin solution. Conclusion: Doxorubicin-loaded nanoparticles made by different methods from different materials displayed substantial discrepancies in their anticancer activity at the cellular level. Optimised preparation methods resulted in PLGA nanoparticles characterised by increased drug load, controlled drug release, and high anticancer efficacy. The design of drug-loaded nanoparticles with optimised anticancer activity at the cellular level is an important step in the development of improved nanoparticle preparations for anticancer therapy. Further research is required to understand under which circumstances nanoparticles can be used to overcome efflux-mediated resistance in cancer cells.

Improvement of the anti-proliferative activity of the peptide ERα17p in MCF-7 breast cancer cells using nanodiamonds

Nanodiamonds (NDs) are emerging delivery systems with biomedical applications and interesting perspectives in oncology. Their use has been proposed to assist the internalization of anticancer drugs and to decrease administered drug doses. The pro-apoptotic peptide ERα17p, which is issued from the hinge/N-terminus parts of the AF2 region of the human estrogen receptor α (ERα), is active at a concentration of 10μM on breast cancer cells and particularly on those cancer cells that are ERα-positive. We have synthesized ND@ERα17p conjugates by physisorption of the cationic peptide ERα17p on the surface of anionic NDs. Resulting ND@ERα17p suspensions were characterized by far-UV electronic circular dichroism (ECD), dynamic light scattering (DLS) and zetametry. We then tested the anti-proliferative action of ND@ERα17p on ERα-positive MCF-7 breast carcinoma cells. ND@ERα17p allowed a decrease of the active concentration to 0.1nM (ND@ERα17p), revealing unambiguously that NDs could be used to improve the anti-proliferative action of this peptide. This preliminary study proposes a novel approach for enhancing the apoptotic action displayed by ERα17p, in the context of breast cancer.

Graphene quantum dots unraveling: Green synthesis, characterization, radiolabeling with 99mTc, in vivo behavior and mutagenicity

Graphene is one of the crystalline forms of carbon, along with diamond, graphite, carbon nanotubes, and fullerenes, and is considered as a revolutionary and innovating product. The use of a graphene-based nanolabels is one of the latest and most prominent application of graphene, especially in the field of diagnosis and, recently, in loco radiotherapy when coupled with radioisotopes. However, its biological behavior and mutagenicity in different cell or animal models, as well as the in vivo functional activities, are still unrevealed. In this study we have developed by a green route of synthesizing graphene quantum dots (GQDs) and characterized them. We have also developed a methodology for direct radiolabeling of GQDs with radioisotopes.Finally; we have evaluated in vivo biological behavior of GQDs using two different mice models and tested in vitro mutagenicity of GQDs. The results have shown that GQDs were formed with a size range of 160-280 nm, which was confirmed by DRX and Raman spectroscopy analysis, corroborating that the green synthesis is an alternative, environmentally friendly way to produce graphene. The radiolabeling test has shown that stable radiolabeled GQDs can be produced with a high yield (>90%). The in vivo test has demonstrated a ubiquitous behavior when administered to healthy animals, with a high uptake by liver (>26%) and small intestine (>25%). Otherwise, in an inflammation/VEGF hyperexpression animal model (endometriosis), a very peculiar behavior of GQDs was observed, with a high uptake by kidneys (over 85%). The mutagenicity test has demonstrated A:T to G:C substitutions suggesting that GQDs exhibits mutagenic activity.

Turning cold tumors into hot tumors: harnessing the potential of tumor immunity using nanoparticles

INTRODUCTION

Immune checkpoint inhibitors have considerably changed the landscape of oncology. However apart from world-acclaimed success stories limited to melanoma and lung cancer, many solid tumors failed to respond to immune checkpoint inhibitors due to limited immunogenicity, unfavorable tumor micro-environments (TME), lack of infiltrating T lymphocytes or increases in Tregs. Areas covered: Combinatorial strategies are foreseen as the future of immunotherapy and using cytotoxics or modulating agents is expected to boost the efficacy of immune checkpoint inhibitors. In this respect, nanoparticles displaying unique pharmacokinetic features such as tumor targeting properties, optimal payload delivery and long-lasting interferences with TME, are promising candidates for such combinations. This review covers the basis, expectancies, limits and pitfalls of future combination between nanoparticles and immune check point inhibitors. Expert opinion: Nanoparticles allow optimal delivery of variety of payloads in tumors while sparing healthy tissue, thus triggering immunogenic cell death. Depleting tumor stroma could further help immune cells and monoclonal antibodies to better circulate in the TME, plus immune-modulating properties of the charged cytotoxics. Finally, nanoparticles themselves present immunogenicity and antigenicity likely to boost immune response at the tumor level.

From 3D spheroids to tumor bearing mice: efficacy and distribution studies of trastuzumab-docetaxel immunoliposome in breast cancer

Purpose

Nanoparticles are of rising interest in cancer research, but in vitro canonical cell monolayer models are not suitable to evaluate their efficacy when prototyping candidates. Here, we developed three-dimensional (3D) spheroid models to test the efficacy of trastuzumab-docetaxel immunoliposomes in breast cancer prior to further testing them in vivo.

Materials and methods

Immunoliposomes were synthesized using the standard thin film method and maleimide linker. Two human breast cancer cell lines varying in Her2 expression were tested: Her2+ cells derived from metastatic site: mammary breast MDA-MB-453 and triple-negative MDA-MB-231 cells. 3D spheroids were developed and tested with fluorescence detection to evaluate viability. In vivo efficacy and biodistribution studies were performed on xenograft bearing nude mice using fluorescent and bioluminescent imaging.

Results

In vitro, antiproliferative efficacy was dependent upon cell type, size of the spheroids, and treatment scheduling, resulting in subsequent changes between tested conditions and in vivo results. Immunoliposomes performed better than free docetaxel + free trastuzumab and ado-trastuzumab emtansine (T-DM1). On MDA-MB-453 and MDA-MB-231 cell growth was reduced by 76% and 25%, when compared to free docetaxel + free trastuzumab and by 85% and 70% when compared to T-DM1, respectively. In vivo studies showed tumor accumulation ranging from 3% up to 15% of the total administered dose in MDA-MB-453 and MDA-MB-231 bearing mice. When compared to free docetaxel + free trastuzumab, tumor growth was reduced by 89% (MDA-MB-453) and 25% (MDA-MB-231) and reduced by 66% (MDA-MB-453) and 29% (MDA-MB-231) when compared to T-DM1, an observation in line with data collected from 3D spheroids experiments.

Conclusion

We demonstrated the predictivity of 3D in vitro models when developing and testing nanoparticles in experimental oncology. In vitro and in vivo data showed efficient drug delivery with higher efficacy and prolonged survival with immunoliposomes when compared to current anti-Her2 breast cancer strategies.