Cisplatin-loaded Au–Au2S nanoparticles for potential cancer therapy: Cytotoxicity,in vitro carcinogenicity, and cellular uptake

A Novel Cu(II) Loaded Polypeptide SO2 Prodrug Nanoformulation Combining Chemodynamic and Gas Anticancer Therapies

Sulfur dioxide (SO2)-based gas therapy and chemodynamic therapyare both reactive oxygen species (ROS)-mediated anticancer strategies, but there are few reports of their combined application. To this end, a novel graft-type copolymeric SO2 prodrug, PLG-g-mPEG-DNs, is designed and synthesized in this work. The amphiphilic polypeptides can self-assemble into nanoparticles (NPs) and encapsulated Cu(II) ions by metal-carboxyl coordination. In vitro release results showed that the obtained NPs-Cu can respond to the acidic pH and high glutathione levels typical of a tumor microenvironment to release Cu(II) and SO2 simultaneously. Both a Cu(II)-triggered Fenton-like reaction and the SO2 gas would promote ROS production and upregulate the oxidative stress in tumor cells, leading to an enhanced killing effect towards 4T1 cancer cells compared to either Cu(II) or the NPs alone. Furthermore, the in vitro hemolysis of NPs-Cu is less than 1.0% at a high concentration of 8 mg/mL, indicating good blood compatibility and the potential for in vivo tumor inhibition application.

Cisplatin uptake and release in pH sensitive zeolitic imidazole frameworks

Cancer remains hard to treat, partially due to the non-specificity of chemotherapeutics. Metal-organic frameworks (MOFs) are promising carriers for targeted chemotherapy, yet, to date, there have been few detailed studies to systematically enhance drug loading while maintaining controlled release. In this work, we investigate which molecular simulation methods best capture the experimental uptake and release of cisplatin from UiO-66 and UiO-66(NH₂). We then screen a series of biocompatible, pH-sensitive zeolitic imidazolate frameworks (ZIFs) for their ability to retain cisplatin in healthy parts of the patient and release it in the vicinity of a tumor. Pure-component GCMC simulations show that the maximum cisplatin loading depends on the pore volume. To achieve this maximum loading in the presence of water, either the pore size needs to be large enough to occupy both cisplatin and its solvation shell or the MOF-cisplatin interaction must be more favorable than the cisplatin-shell interaction. Both solvated and non-solvated simulations show that cisplatin release rates can be controlled by either decreasing the pore limiting diameters or by manipulating framework-cisplatin interaction energies to create strong, dispersed adsorption sites. The latter method is preferable if cisplatin loading is performed from solution into a pre-synthesized framework as weak interaction energies and small pore window diameters will hinder cisplatin uptake. Here, ZIF-82 is most promising. If it is possible to load cisplatin during crystallization, ZIF-11 would outcompete the other MOFs screened as cisplatin cannot pass through its pore windows; therefore, release rates would be purely driven by the pH triggered framework degradation.

Methodology for characterization of platinum-based drug's targeted delivery nanosystems

Conventional anticancer therapies exploiting platinum-based drugs rely principally on the intravascular injection of the therapeutic agent. The anticancer drug is distributed throughout the body by the systemic blood circulation undergoing cellular uptake, rapid clearance and excretion. Consequently, only a small portion of the platinum-based drug reaches the tumor site, which is associated with severe side effects. For this reason, targeted delivery systems are of great need since they offer enhanced and selective delivery of a drug to cancerous cells making the therapy safe and more effective. Up to date, a variety of the Pt-based drug targeted delivery systems (Pt-based DTDSs) utilizing nanomaterials have been developed and tested using a range of analytical techniques that provided essential information on their synthesis, stability, biodistribution and cytotoxicity. Here we summarize those experimental techniques indicating their applicability at different stages of the research, as well as pointing out their strengths, advantages, drawbacks and limitations. Also, the existing strategies and approaches are critically reviewed with the objective to reveal and give rise to the development of the analytical methodology suitable for reliable Pt-based DTDSs characterization which would eventually result in novel therapies and better patients' outcomes.

pH responsible and fluorescent Cy5.5-PEG-g-A-HA/CDDP complex nanoparticles: synthesis, characterization, and application for targeted drug delivery

Clinical application of cisplatin (CDDP) against various solid tumors is often limited due to its poor selectivity and severe side effect. Considering this, in our study, CDDP was incorporated in fluorescent PEG amine grafted aldehyde hyaluronic acid by imine bond and metal ion coordination bond linking and formed a complex, the complex was then self-assembled into nanoparticles in water simply. FT-IR, XRD, DLS and SEM analysis demonstrated that the nanoparticles were prepared successfully and exhibited a spherical structure with size ranged from 216.4 to 372.3 nm in diameter. CDDP releasing from the nanoparticles was in a controlled manner, and had faster release rate at lower pH, indicating the nanoparticles were responsive to tumor micro-acid environment. Since fluorescent Cy5.5 and targeting hyaluronic acid existed on the surface of the nanoparticles, CLSM images clearly showed that the nanoparticles could target and internalize into HeLa cells, and then inhibited the growth of HeLa cells. In addition, MTT, AO-EB staining, and hemolysis assay showed that the nanoparticles had good cyto-/hemo-compatibility. Hence, the nanoparticles had the potential to be used for cancer therapy and diagnosis. The further in vivo experiment will be shown in the next work. pH responsible and fluorescent Cy5.5-PEG-g-A-HA/CDDP complex nanoparticles were facilely fabricated for controlled and targeted delivery of CDDP.

Nanoparticle formulations of cisplatin for cancer therapy

The genotoxic agent cisplatin, used alone or in combination with radiation and/or other chemotherapeutic agents, is an important first-line chemotherapy for a broad range of cancers. The clinical utility of cisplatin is limited both by intrinsic and acquired resistance and dose-limiting normal tissue toxicity. That cisplatin shows little selectivity for tumor versus normal tissue may be a critical factor limiting its value. To overcome the low therapeutic ratio of the free drug, macromolecular, liposomal, and nanoparticle drug delivery systems have been explored toward leveraging the enhanced permeability and retention effect and promoting delivery of cisplatin to tumors. Here, we survey recent advances in nanoparticle formulations of cisplatin, focusing on agents that show promise in preclinical or clinical settings. WIREs Nanomed Nanobiotechnol 2016, 8:776-791. doi: 10.1002/wnan.1390 For further resources related to this article, please visit the WIREs website.

Release kinetics of paclitaxel and cisplatin from two and three layered gold nanoparticles

Gold nanoparticles functionalized with biologically compatible layers may achieve stable drug release while avoiding adverse effects in cancer treatment. We study cisplatin and paclitaxel release from gold cores functionalized with hexadecanethiol (TL) and phosphatidylcholine (PC) to form two-layer nanoparticles, or TL, PC, and high density lipoprotein (HDL) to form three-layer nanoparticles. Drug release was monitored for 14 days to assess long term effects of the core surface modifications on release kinetics. Release profiles were fitted to previously developed kinetic models to differentiate possible release mechanisms. The hydrophilic drug (cisplatin) showed an initial (5-h) burst, followed by a steady release over 14 days. The hydrophobic drug (paclitaxel) showed a steady release over the same time period. Two layer nanoparticles released 64.0±2.5% of cisplatin and 22.3±1.5% of paclitaxel, while three layer nanoparticles released the entire encapsulated drug. The Korsmeyer-Peppas model best described each release scenario, while the simplified Higuchi model also adequately described paclitaxel release from the two layer formulation. We conclude that functionalization of gold nanoparticles with a combination of TL and PC may help to modulate both hydrophilic and hydrophobic drug release kinetics, while the addition of HDL may enhance long term release of hydrophobic drug.

Cisplatin-loaded polymeric nanoparticles: characterization and potential exploitation for the treatment of non-small cell lung carcinoma

Cisplatin-loaded poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) nanoparticles (CDDP-NPs) were characterized and exploited for the treatment of non-small cell lung carcinoma (NSCLC). In vitro metabolism experiments showed that a glutamic acid 5-mPEG ester [CH3O(CH2CH2O)nGlu] was generated when the poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) (PLG-g-mPEG5K) was incubated with HeLa cells. This suggests that the poly(glutamic acid) backbone of the PLG-g-mPEG5K is biodegradable. Furthermore, the size of the CDDP-NPs in an aqueous solution was affected by varying the pH (5.0-8.0) and their degradation rate was dependent on temperature. The CDDP-NPs could also bind to the model nucleotide 2'-deoxyguanosine 5'-monophosphate, indicating a biological activity similar to cisplatin. The CDDP-NPs showed a significantly lower peak renal platinum concentration after a single systemic administration when compared to free cisplatin. In vivo experiments with a Lewis lung carcinoma (LLC) model showed that the CDDP-NPs suppressed the growth of tumors. In addition, LLC tumor-bearing mice treated with the CDDP-NPs (5mg/kg cisplatin eq.) showed much longer survival rates (median survival time: 51days) as compared with mice treated with free cisplatin (median survival time: 18days), due to the acceptable antitumor efficacy and low systemic toxicity of CDDP-NPs. These results suggest that the CDDP-NPs may be successfully applied to the treatment of NSCLC.

Controllable conversion of plasmonic Cu2-xS nanoparticles to Au2S by cation exchange and electron beam induced transformation of Cu2-xS-Au2S core/shell nanostructures

Self-doped Cu2-xS nanocrystals (NCs) were converted into monodisperse Cu2-xS-Au2S NCs of tunable composition, including pure Au2S, by cation exchange. The near-infrared (NIR) localized surface plasmon resonance (LSPR) was dampened and red-shifted with increasing Au content. Cation exchange was accompanied by elimination of cation vacancies and a change in crystal structure. Partially exchanged Cu2-xS-Au2S core/shell structures evolved to dumbbell-like structures under electron irradiation in the transmission electron microscope (TEM).

Rare Earth Nanoprobes for Functional Biomolecular Imaging and Theranostics

Contrast agents designed to visualize the molecular mechanisms underlying cancer pathogenesis and progression have deepened our understanding of disease complexity and accelerated the development of enhanced drug strategies targeted to specific biochemical pathways. For the next generation probes and imaging systems to be viable, they must exhibit enhanced sensitivity and robust quantitation of morphologic and contrast features, while offering the ability to resolve the disease-specific molecular signatures that may be critical to reconstitute a more comprehensive portrait of pathobiology. This feature article provides an overview on the design and advancements of emerging biomedical optical probes in general and evaluates the promise of rare earth nanoprobes, in particular, for molecular imaging and theranostics. Combined with new breakthroughs in nanoscale probe configurations, and improved dopant compositions, and multimodal infrared optical imaging, rare-earth nanoprobes can be used to address a wide variety of biomedical challenges, including deep tissue imaging, real-time drug delivery tracking and multispectral molecular profiling.

Detoxifying antitumoral drugs via nanoconjugation: the case of gold nanoparticles and cisplatin

Nanoparticles (NPs) have emerged as a potential tool to improve cancer treatment. Among the proposed uses in imaging and therapy, their use as a drug delivery scaffold has been extensively highlighted. However, there are still some controversial points which need a deeper understanding before clinical application can occur. Here the use of gold nanoparticles (AuNPs) to detoxify the antitumoral agent cisplatin, linked to a nanoparticle via a pH-sensitive coordination bond for endosomal release, is presented. The NP conjugate design has important effects on pharmacokinetics, conjugate evolution and biodistribution and results in an absence of observed toxicity. Besides, AuNPs present unique opportunities as drug delivery scaffolds due to their size and surface tunability. Here we show that cisplatin-induced toxicity is clearly reduced without affecting the therapeutic benefits in mice models. The NPs not only act as carriers, but also protect the drug from deactivation by plasma proteins until conjugates are internalized in cells and cisplatin is released. Additionally, the possibility to track the drug (Pt) and vehicle (Au) separately as a function of organ and time enables a better understanding of how nanocarriers are processed by the organism.

Antibody-conjugated gold-gold sulfide nanoparticles as multifunctional agents for imaging and therapy of breast cancer

The goal of this study was to develop near-infrared (NIR) resonant gold-gold sulfide nanoparticles (GGS-NPs) as dual contrast and therapeutic agents for cancer management via multiphoton microscopy followed by higher intensity photoablation. We demonstrate that GGS-NPs exposed to a pulsed, NIR laser exhibit two-photon induced photoluminescence that can be utilized to visualize cancerous cells in vitro. When conjugated with anti-HER2 antibodies, these nanoparticles specifically bind SK-BR-3 breast carcinoma cells that over-express the HER2 receptor, enabling the cells to be imaged via multiphoton microscopy with an incident laser power of 1 mW. Higher excitation power (50 mW) could be employed to induce thermal damage to the cancerous cells, producing extensive membrane blebbing within seconds leading to cell death. GGS-NPs are ideal multifunctional agents for cancer management because they offer the ability to pinpoint precise treatment sites and perform subsequent thermal ablation in a single setting.

Interfacial properties and in vitro cytotoxic effects of surface-modified near infrared absorbing Au-Au(2)S nanoparticles

Near infrared (NIR) absorbing Au-Au(2)S nanoparticles were modified with surfactants of different hydrocarbon chain lengths to allow loading of anticancer drug, cisplatin. The interfacial interactions and surfactant chain length effects on drug loading, optical properties and cytotoxicity were discussed in this work. Short-chain surfactants were oriented closer to the surface normal and were adsorbed at higher densities. Surface modification also changed the optical properties of the particles. Notably, particles modified with short-chain surfactants exhibited a red shift, whereas particles modified with long-chain surfactants showed a blue shift. The in vitro cytotoxicity of drug-loaded surface-modified particles was dependent on the surfactants' chain length. Significant cytotoxicity was observed for 1 mg/ml of drug-loaded particles using surfactants with the shortest chain length. After NIR triggered drug release, the released Pt compounds were observed to be cytotoxic, while remaining nanoparticles did not exhibit any cytotoxicity. Also, the released Pt compounds upon NIR irradiation of drug-loaded particles were observed to be more toxic and had a different molecular structure from cisplatin.

Novel gelatin-siloxane nanoparticles decorated by Tat peptide as vectors for gene therapy

In principle, the technique of gene delivery involves taking complete or parts of genes that can code specific messages and delivering them to selected cells in the body. Such a transfer of plasmid DNA into mammalian cells has posed major challenges for gene therapy. A series of gelatin-siloxane nanoparticles (GS NPs) with controlled size and surface charge were synthesized through a two-step sol-gel process. In order to increase the efficiency of cellular uptake, HIV-derived Tat peptide was further grafted to GS NPs. In vitro co-location and endocytosis inhibition experiments suggested that the as-synthesized TG NPs may enter HeLa cells via a combined pathway of lipid-raft- and receptor-dependent endocytosis, and only cause little cell damage. Moreover, this study shows the encapsulation of a plasmid DNA in TG NPs to be obtained as a non-viral gene vector. This kind of encapsulation provides complete protection to the plasmid DNA from the external DNase and serum environment, and generates the hope that the resulting formulation can be developed into a potential vector for effective gene delivery. In order to check this potential, the reporter gene pSVβ-gal was encapsulated, and in vitro transfection efficiency of this system was found to be nearly 130% compared to the commercially available transfection reagent Lipofectamine™.