Nanoparticle and targeted systems for cancer therapy

A robust platform for functional microgels via thiol-ene achemistry with reactive polyether-based nanoparticles

We herein report the development of crosslinked polyether particles as a reactive platform for the preparation of functional microgels. Thiol-ene crosslinking of poly(allyl glycidyl ether) in miniemulsion droplets - stabilized by a surface active, bio-compatible polyethylene glycol block copolymer - resulted in colloidal gels with a PEG corona and an inner polymeric network containing reactive allyl units. The stability of the allyl groups allows the microgels to be purified and stored before a second, subsequent thiol-ene functionalization step allows a wide variety of pH- and chemically-responsive groups to be introduced into the nanoparticles. The facile nature of this synthetic platform enables the preparation of microgel libraries that are responsive to different triggers but are characterized by the same size distribution, surface functionality, and crosslinking density. In addition, the utilization of a crosslinker containing cleavable ester groups renders the resulting hydrogel particles degradable at elevated pH or in the presence of esterase under physiological conditions.

Smart doxorubicin nanoparticles with high drug payload for enhanced chemotherapy against drug resistance and cancer diagnosis

Considering the obvious advantages in efficacy and price, doxorubicin (DOX) has been widely used for a range of cancers, which is usually encapsulated in various nanocarriers for drug delivery. Although effective, in most nanocarrier-based delivery systems, the drug loading capacity of DOX is rather low; this can lead to undesired systemic toxicity and excretion concern. Herein, we report for the first time the usage of pure doxorubicin nanoparticles (DOX NPs) without addition of any carriers for enhanced chemotherapy against drug-resistance. The drug payload reaches as high as 90.47%, which largely surpassed those in previous reports. These PEG stabilized DOX NPs exhibit good biocompatibility and stability, long blood circulation time, fast release in an acidic environment and high accumulation in tumors. Compared with free DOX, DOX NPs display a dramatically enhanced anticancer therapeutic efficacy in the inhibition of cell and tumor growth. Moreover, they can also be readily incorporated with other anticancer drugs for synergistic chemotherapy to overcome the drug resistance of cancers. The fluorescence properties of DOX also endow these NPs with imaging capabilities, thus making it a multifunctional system for diagnosis and treatment. This work demonstrates great potential of DOX NPs for cancer diagnosis, therapy and overcoming drug tolerance.

Reversibly cross-linked polyplexes enable cancer-targeted gene delivery via self-promoted DNA release and self-diminished toxicity

Polycations often suffer from the irreconcilable inconsistency between transfection efficiency and toxicity. Polymers with high molecular weight (MW) and cationic charge feature potent gene delivery capabilities, while in the meantime suffer from strong chemotoxicity, restricted intracellular DNA release, and low stability in vivo. To address these critical challenges, we herein developed pH-responsive, reversibly cross-linked, polyetheleneimine (PEI)-based polyplexes coated with hyaluronic acid (HA) for the effective and targeted gene delivery to cancer cells. Low-MW PEI was cross-linked with the ketal-containing linker, and the obtained high-MW analogue afforded potent gene delivery capabilities during transfection, while rapidly degraded into low-MW segments upon acid treatment in the endosomes, which promoted intracellular DNA release and reduced material toxicity. HA coating of the polyplexes shielded the surface positive charges to enhance their stability under physiological condition and simultaneously reduced the toxicity. Additionally, HA coating allowed active targeting to cancer cells to potentiate the transfection efficiencies in cancer cells in vitro and in vivo. This study therefore provides an effective approach to overcome the efficiency-toxicity inconsistence of nonviral vectors, which contributes insights into the design strategy of effective and safe vectors for cancer gene therapy.

Transport of polymeric nanoparticulate drug delivery systems in the proximity of silica and sand

The contamination of the environment with traditional therapeutics due to metabolic excretion, improper disposal, and industrial waste has been well-recognized. However, knowledge of the environmental distribution and fate of emerging classes of nanomedicine is scarce. This work investigates the effect of surface chemistry of polymeric nanoparticulate drug delivery systems (PNDDS) on their adsorption dynamics and transport in the vicinity of environmentally relevant surfaces for a concentration comparable with hospital and pharmaceutical manufacturing effluents. To this end, five different types of paclitaxel-based nanomedicine having different polymer stabilizers were employed. Their transport behavior was characterized via quartz crystal microbalance, sand column, spectrofluorometry, and dynamic light scattering techniques. PNDDS having positive zeta-potential displayed strong adsorption onto silica surfaces and no mobility in porous media of quartz sand, even in the presence of humic acid. The mobility of negatively charged PNDDS strongly depended on the amount and type of salt present in the aqueous media: Without any salt, such PNDDS demonstrated no adsorption on silica surfaces and high levels of mobility in sand columns. The presence of CaCl2 and CaSO4, even at low ionic strengths (i.e. 10 mM), induced PNDDS adsorption on silica surfaces and strongly limited the mobility of such PNDSS in sand columns.

Design strategies and applications of circulating cell-mediated drug delivery systems

Drug delivery systems, particularly nanomaterial-based drug delivery systems, possess a tremendous amount of potential to improve diagnostic and therapeutic effects of drugs. Controlled drug delivery targeted to a specific disease is designed to significantly improve the pharmaceutical effects of drugs and reduce their side effects. Unfortunately, only a few targeted drug delivery systems can achieve high targeting efficiency after intravenous injection, even with the development of numerous surface markers and targeting modalities. Thus, alternative drug and nanomedicine targeting approaches are desired. Circulating cells, such as erythrocytes, leukocytes, and stem cells, present innate disease sensing and homing properties. Hence, using living cells as drug delivery carriers has gained increasing interest in recent years. This review highlights the recent advances in the design of cell-mediated drug delivery systems and targeting mechanisms. The approaches of drug encapsulation/conjugation to cell-carriers, cell-mediated targeting mechanisms, and the methods of controlled drug release are elaborated here. Cell-based "live" targeting and delivery could be used to facilitate a more specific, robust, and smart payload distribution for the next-generation drug delivery systems.

pH-responsive iron manganese silicate nanoparticles as T1-T2* dual-modal imaging probes for tumor diagnosis

Magnetic resonance imaging (MRI) probes can be concentrated in tumors through grafting targeting agents. However, the clinical application of such targeted MRI probes is largely limited because specific agents are only used to target specific characteristics of cancer cells. The development of the MRI probes that can be used regardless of tumor types or their developmental stages is highly appreciated. The acidic tumor microenvironments and acidic organelles (endosomes/lysosomes) in cancer cells are universal phenomena of solid tumors, and nanoparticles can also accumulate in tumor tissues by enhanced permeability and retention (EPR) effect. Here, we reported the synthesis of pH-responsive T1-T2* dual-modal contrast agents based on iron manganese silicate (FeMn(SiO4)) hollow nanospheres, which can release Mn(2+) ions in acidic environments, exhibiting excellent ability as agents for magnetic resonance and red fluorescence imaging. MRI for mouse models revealed that the nanoprobes could accumulate in tumors via EPR effect and then distinguish tumors from normal tissues with the synergistic effect of T1 and T2* signal only 10 min after intravenous injection. Fluorescence imaging demonstrated that the nanoprobes could be endocytosed into cancer cells and located at their lower pH compartments. Moreover, the hollow nanospheres showed no obvious toxicity and inflammation to the major organs of mice, which made them attractive diagnostic agents for different types of cancers.

Novel patented therapeutic approaches targeting the 37/67 kDa laminin receptor for treatment of cancer and Alzheimer's disease

INTRODUCTION

The 37/67 kDa high-affinity laminin receptor (laminin receptor precursor/laminin receptor, LRP/LR) is a multi-faceted cellular receptor. It plays a vital role in the malignancy of various cancer types where it is seen to contribute to invasion, adhesion, apoptosis evasion and angiogenesis. Furthermore, it has been found to play an important role in facilitating the processes leading to neurotoxicity in Alzheimer's disease (AD). Various therapeutic options targeting this receptor have been patented with the outlook on application for the treatment/prevention of these diseases.

AREAS COVERED

The various roles that LRP/LR plays in cancer, AD and infectious diseases caused by viruses and bacteria have been examined in detail and an overview of the current patented therapeutic strategies targeting this receptor is given.

EXPERT OPINION

Molecular tools directed against LRP/LR, such as antibodies and small interfering RNA, could prove to be effective in the prevention of metastasis and angiogenesis while inducing apoptosis in cancers. Moreover, these strategies could also be applied to AD where LRP/LR is seen to facilitate the production and internalization of the neurotoxic Aβ peptide. This review provides a comprehensive overview of the mechanisms by which LRP/LR is involved in eliciting pathogenic events, while showing how the use of patented approaches targeting this receptor could be used to treat them.

Nanopotentiated combination cancer therapy: Chemotherapeutic and chemosensitizer (2C approach)

An insight into the complex cancer pathophysiology reveals that a dependable amelioration of the disease could only be envisaged with a multipronged treatment approach. It is highly evident that singular chemotherapeutic agents used in clinical practice have shown limitations like severe side effects, MDR and are often associated with poor QOL while combinations of drugs have yielded better therapeutic outcomes. The current hypothesis takes it a step forward wherein a chemotherapeutic agent is combined with a natural chemosensitizer, both loaded into a nanopotentiated particulate system, which would eventually deliver the drug cargo at the target site with certitude. The encapsulated natural bioactive would then favorably act on the tumor milieu through multiple portals and chemosensibilize the cells towards cytotoxic action of the synthetic drug moiety. This 2C (chemotherapeutic and chemosensitizer) approach along with nanosystem's attributes like high payload, prolonged action and diminished side effects would proffer a more dependable treatment modality. In conclusion, the proposed system would be a value addition to the currently available armamentarium of cancer treatment tools.

Advancements in the delivery of epigenetic drugs

INTRODUCTION

Advancements in epigenetic treatments are not only coming from new drugs, but also from modifications or encapsulation of the existing drugs into different formulations leading to greater stability and enhanced delivery to the target site. The epigenome is highly regulated and complex; therefore, it is important that off-target effects of epigenetic drugs be minimized. The step from in vitro to in vivo treatment of these drugs often requires development of a method of effective delivery for clinical translation.

AREAS COVERED

This review covers epigenetic mechanisms such as DNA methylation, chromatin remodeling and small-RNA-mediated gene regulation. There is a section in the review with examples of diseases where epigenetic alterations lead to impaired pathways, with an emphasis on cancer. Epigenetic drugs, their targets and clinical status are presented. Advantages of using a delivery method for epigenetic drugs as well as examples of current advancements and challenges are also discussed.

EXPERT OPINION

Epigenetic drugs have the potential to be very effective therapy against a number of diseases, especially cancers and neurological disorders. As with many chemotherapeutics, undesired side effects need to be minimized. Finding a suitable delivery method means reducing side effects and achieving a higher therapeutic index. Each drug may require a unique delivery method exploiting the drug's chemistry or other physical characteristic requiring interdisciplinary participation and would benefit from a better understanding of the mechanisms of action.

Controlled Drug Release from Pharmaceutical Nanocarriers

Nanocarriers providing spatiotemporal control of drug release contribute to reducing toxicity and improving therapeutic efficacy of a drug. On the other hand, nanocarriers face unique challenges in controlling drug release kinetics, due to the large surface area per volume ratio and the short diffusion distance. To develop nanocarriers with desirable release kinetics for target applications, it is important to understand the mechanisms by which a carrier retains and releases a drug, the effects of composition and morphology of the carrier on the drug release kinetics, and current techniques for preparation and modification of nanocarriers. This review provides an overview of drug release mechanisms and various nanocarriers with a specific emphasis on approaches to control the drug release kinetics.

Leukocytes as carriers for targeted cancer drug delivery

INTRODUCTION

Metastasis contributes to over 90% of cancer-related deaths. Numerous nanoparticle platforms have been developed to target and treat cancer, yet efficient delivery of these systems to the appropriate site remains challenging. Leukocytes, which share similarities to tumor cells in terms of their transport and migration through the body, are well suited to serve as carriers of drug delivery systems to target cancer sites.

AREAS COVERED

This review focuses on the use and functionalization of leukocytes for therapeutic targeting of metastatic cancer. Tumor cell and leukocyte extravasation, margination in the bloodstream, and migration into soft tissue are discussed, along with the potential to exploit these functional similarities to effectively deliver drugs. Current nanoparticle-based drug formulations for the treatment of cancer are reviewed, along with methods to functionalize delivery vehicles to leukocytes, either on the surface and/or within the cell. Recent progress in this area, both in vitro and in vivo, is also discussed, with a particular emphasis on targeting cancer cells in the bloodstream as a means to interrupt the metastatic process.

EXPERT OPINION

Leukocytes interact with cancer cells both in the bloodstream and at the site of solid tumors. These interactions can be utilized to effectively deliver drugs to targeted areas, which can reduce both the amount of drug required and various nonspecific cytotoxic effects within the body. If drug delivery vehicle functionalization does not interfere with leukocyte function, this approach may be utilized to neutralize tumor cells in the bloodstream to prevent the formation of new metastases, and also to deliver drugs to metastatic sites within tissues.

Smart Nanoparticles for Drug Delivery: Boundaries and Opportunities

Various pharmaceutical particles have been used in developing different drug delivery systems ranging from traditional tablets to state-of-the-art nanoparticle formulations. Nanoparticle formulations are unique in that the small size with huge surface area sometimes provides unique properties that larger particles and bulk materials do not have. Nanoparticle formulations have been used in improving the bioavailability of various drugs, in particular, poorly soluble drugs. Nanoparticle drug delivery systems have found their unique applications in targeted drug delivery to tumors. While nanoparticle formulations have been successful in small animal xenograft models, their translation to clinical applications has been very rare. Developing nanoparticle systems designed for targeted drug delivery, e.g., treating tumors in humans, requires clear understanding of the uniqueness of nanoparticles, as well as limitations and causes of failures in clinical applications. It also requires designing novel smart nanoparticle delivery systems that can increase the drug bioavailability and at the same time reduce the drug's side effects.

Programmable nanomedicine: synergistic and sequential drug delivery systems

Recent developments in nanomedicine for the cancer therapy have enabled programmable delivery of therapeutics by exploiting the stimuli-responsive properties of nanocarriers. These therapeutic systems were designed with the relevant chemical and physical properties that respond to different triggers for enhanced anticancer efficacy, including the reduced development of drug-resistance, lower therapeutic dose, site-specific transport, and spatiotemporally controlled release. This minireview discusses the current advances in programmable nanocarriers for cancer therapy with particular emphasis on synergistic and sequential drug delivery systems.

Modulation of the tumor microenvironment for cancer treatment: a biomaterials approach

Tumors are complex tissues that consist of stromal cells, such as fibroblasts, immune cells and mesenchymal stem cells, as well as non-cellular components, in addition to neoplastic cells. Increasingly, there is evidence to suggest that these non-neoplastic cell components support cancer initiation, progression and metastasis and that their ablation or reprogramming can inhibit tumor growth. Our understanding of the activities of different parts of the tumor stroma in advancing cancer has been improved by the use of scaffold and matrix-based 3D systems originally developed for regenerative medicine. Additionally, drug delivery systems made from synthetic and natural biomaterials deliver drugs to kill stromal cells or reprogram the microenvironment for tumor inhibition. In this article, we review the impact of 3D tumor models in increasing our understanding of tumorigenesis. We also discuss how different drug delivery systems aid in the reprogramming of tumor stroma for cancer treatment.

Rational design of cancer-targeted selenium nanoparticles to antagonize multidrug resistance in cancer cells

Multidrug resistance is one of the greatest challenges in cancer therapy. Herein we described the synthesis of folate (FA)-conjugated selenium nanoparticles (SeNPs) as cancer-targeted nano-drug delivery system for ruthenium polypyridyl (RuPOP) exhibits strong fluorescence, which allows the direct imaging of the cellular trafficking of the nanosystem. This nanosystem could effectively antagonize against multidrug resistance in liver cancer. FA surface conjugation significantly enhanced the cellular uptake of SeNPs by FA receptor-mediated endocytosis through nystain-dependent lipid raft-mediated and clathrin-mediated pathways. The nanomaterials overcame the multidrug resistance in R-HepG2 cells through inhibition of ABC family proteins expression. Internalized nanoparticles triggered ROS overproduction and induced apoptosis by activating p53 and MAPKs pathways. Moreover, FA-SeNPs exhibited low in vivo acute toxicity, which verified the safety and application potential of FA-SeNPs as nanodrugs. This study provides an effective strategy for the design of cancer-targeted nanodrugs against multidrug resistant cancers.

FROM THE CLINICAL EDITOR

In the combat against hepatocellular carcinoma, multidrug resistance remains one of the obstacles to be overcome. The authors designed and synthesized folate (FA)-conjugated selenium nanoparticles (SeNPs) with enhanced cancer-targeting capability. This system carried ruthenium polypyridyl (RuPOP), an efficient metal-based anti-cancer drug with strong fluorescence. It was shown that this combination was effective in antagonizing against multidrug resistance in vitro.

Remotely triggered release of small molecules from LaB6@SiO2-loaded polycaprolactone microneedles

We established near-infrared (NIR)-light-triggered transdermal delivery systems by encapsulating NIR absorbers, silica-coated lanthanum hexaboride (LaB6@SiO2) nanostructures and the cargo molecule to be released in biodegradable polycaprolactone (PCL) microneedles. Acting as a local heat source when exposed to an NIR laser, these nanostructures cause a phase transition of the microneedles, thereby increasing the mobility of the polymer chains and triggering drug release from the microneedles. On IR thermal images, the light-triggered melting behavior of the LaB6@SiO2-loaded microneedles was observed. By adjusting the irradiation time and the laser on/off cycles, the amount of molecules released was controlled accurately. Drug release was switched on and off for at least three cycles, and a consistent dose was delivered in each cycle with high reproducibility. The designed microneedles were remotely triggered by laser irradiation for the controlled release of a chemotherapeutic drug, doxorubicin hydrochloride, in vivo. This system would enable dosages to be adjusted accurately to achieve a desired effect, feature a low off-state drug leakage to minimize basal effects and can increase the flexibility of pharmacotherapy performed to treat various medical conditions.

Multi-modal contributions to detoxification of acute pharmacotoxicity by a triglyceride micro-emulsion

Triglyceride micro-emulsions such as Intralipid® have been used to reverse cardiac toxicity induced by a number of drugs but reservations about their broad-spectrum applicability remain because of the poorly understood mechanism of action. Herein we report an integrated mechanism of reversal of bupivacaine toxicity that includes both transient drug scavenging and a cardiotonic effect that couple to accelerate movement of the toxin away from sites of toxicity. We thus propose a multi-modal therapeutic paradigm for colloidal bio-detoxification whereby a micro-emulsion both improves cardiac output and rapidly ferries the drug away from organs subject to toxicity. In vivo and in silico models of toxicity were combined to test the contribution of individual mechanisms and reveal the multi-modal role played by the cardiotonic and scavenging actions of the triglyceride suspension. These results suggest a method to predict which drug toxicities are most amenable to treatment and inform the design of next-generation therapeutics for drug overdose.

Advances in the synthesis and application of nanoparticles for drug delivery

The continuous development of drug delivery systems (DDSs) has been extensively researched by the need to maximize therapeutic efficacy while minimizing undesirable side effects. Nanoparticle technology was recently shown to hold great promise for drug delivery applications in nanomedicine due to its beneficial properties, such as better encapsulation, bioavailability, control release, and lower toxic effect. Despite the great progress in nanomedicine, there remain many limitations for clinical application. To overcome these limitations, advanced nanoparticles for drug delivery have been developed to enable the spatially and temporally controlled release of drugs in response to specific stimuli at disease sites. Furthermore, the controlled self-assembly of organic and inorganic materials may enable their use in theranostic applications. This review presents an overview of a recent advanced nanoparticulate system that can be used as a potential drug delivery carrier and focuses on the potential applications of nanoparticles in various biomedical fields for human health care.

cRGD targeted and charge conversion-controlled release micelles for doxorubicin delivery

A biodegradable polymeric micelle with cRGD targeting and charge-conversional moiety could enhance the cellular uptake of pharmaceuticals and result in high cytotoxicity to tumor cells.

Encapsulation of doxorubicin within multifunctional gadolinium-loaded dendrimer nanocomplexes for targeted theranostics of cancer cells

Multifunctional gadolinium-loaded dendrimer nanocomplexes can be used to encapsulate doxorubicin for targeted magnetic resonance imaging and chemotherapy of cancer cells.

In situ crosslinkable hydrogels formed from modified starch and O-carboxymethyl chitosan

The degradable behavior of a hydrogel under varying pH was observed using SEM.

Preparation and study on anti-tumor effect of chitosan-coated oleanolic acid liposomes

Chitosan modified OA liposomes can achieve the desired effect of tumor-targeting drug delivery and improve the anti-tumor efficacy.

Phosphatidylcholine with cis-9,trans-11 and trans-10,cis-12 Conjugated Linoleic Acid Isomers: Synthesis and Cytotoxic Studies

Novel phosphatidylcholines and lysophosphatidylcholines with cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid (CLA) were synthesized in high yields (75–99 %). The in vitro cytotoxic activities of these compounds against three human cancer cell lines (HL-60, MCF-7, and HT-29) were evaluated. The results revealed that there are differences in the activity between phosphatidylcholine with cis-9,trans-11 and trans-10,cis-12 CLA acyl groups. 1,2-Di(9Z,11E)-octadecadienoyl-sn-glycero-3-phosphocholine was the most potent cytotoxic agent among all tested CLA derivatives and its IC50 (concentration of a compound that inhibits the proliferation of 50 % of the cancer cell population) was 29.4 µM against HL-60. Moreover, phosphatidylcholines with CLA acyls exhibited much lower cytotoxicity against non-cancer cells (Balb/3T3) than free CLA isomers.

Preparation of adenovirus-templated gold nanoshells and a study of their photothermal therapy efficacy

Adenovirus-templated gold nanoshells not only show good biocompatibility but also have excellent photothermal therapy efficacy against tumors.

A novel self-assembled targeted nanoparticle platform based on carboxymethylcellulose co-delivery of anticancer drugs

The folate–PEG–carboxymethylcellulose–betulinic acid was synthesized by introducing folate, PEG, and betulinic acid into carboxymethylcellulose, and then self-assembled into nanoparticles with HCPT being encapsulated.

Aptamer CaCO3 nanostructures: a facile, pH-responsive, specific platform for targeted anticancer theranostics

The application of cancer theranostics depends on the development of multifunctional nanostructured platforms for accurate cell targeting and controlled drug release, imaging, and therapy. Herein, a comprehensive, easily fabricated anticancer theranostic platform with a high drug-loading capacity, termed an aptamer-functionalized calcium carbonate (CaCO3 ) nanostructure (apt-CCN), is reported. Flow cytometry and confocal fluorescence microscopy studies demonstrate that apt-CCNs can specifically bind to target cancer cells, but not to control cells, and that they possess highly efficient internalization to target cancer cells. This smart nanostructure selectively reaches the lysosomes through receptor-mediated endocytosis and is responsive to the relatively low lysosome pH (4.5-5.5), which facilitates the release of doxorubicin. The apt-CCN platform offers targeted and efficient drug transport, as well as target-specific delivery of imaging agents for cancer diagnosis and therapy.

Self-assembly of glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria

Glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria.

Curcumin entrapped folic acid conjugated PLGA–PEG nanoparticles exhibit enhanced anticancer activity by site specific delivery

Herein we report curcumin entrapped nanoparticles of PLGA–PEG copolymer which were conjugated with folic acid (PPF copolymer) for site specific targeting since many cancer cells exhibit external folic acid binding receptors.

High loading of doxorubicin into styrene-terminated porous silicon nanoparticles via π-stacking for cancer treatments in vitro

Styrene-terminated PSiNPs were fabricated for high loading of doxorubicin via π-stacking, which exhibited an excellent capability for killing cancer cells.

DOX-encapsulated intelligent PAA-g-PEG/PEG–Fa polymeric micelles for intensifying antitumor therapeutic effect via active-targeted tumor accumulation

Reduction-breakable active targeting polymeric micelles as drug delivery systems could improve delivery efficiency by tumor-specific recognition.

Systemic delivery of protein nanocages bearing CTT peptides for enhanced imaging of MMP-2 expression in metastatic tumor models

Matrix metalloproteinase 2 (MMP-2) in metastatic cancer tissue, which is associated with a poor prognosis, is a potential target for tumor imaging in vivo. Here, we describe a metastatic cancer cell-targeted protein nanocage. An MMP-2-binding peptide, termed CTT peptide (CTTHWGFTLC), was conjugated to the surface of a naturally occurring heat shock protein nanocage by genetic modification. The engineered protein nanocages showed a binding affinity for MMP-2 and selective uptake in cancer cells that highly expressed MMP-2 in vitro. In near-infrared fluorescence imaging, the nanocages showed specific and significant accumulation in tumor tissue after intravenous injection in vivo. These protein nanocages conjugated with CTT peptide could be potentially applied to a noninvasive near-infrared fluorescence detection method for imaging gelatinase activity in metastatic tumors in vivo.

Development, optimization and characterization of glycyrrhetinic acid-chitosan nanoparticles of atorvastatin for liver targeting

Glycyrrhetinic acid-modified chitosan (mGA-suc-CTS) is used as liver-targeted carrier for drug delivery. In this study, nanoparticles were prepared by ionic gelation process, and glycyrrhetinic acid act as the targeting ligand. The structure of the product was confirmed by IR and NMR techniques. The main aim of this study was to deliver atorvastatin directly to the liver by using same conjugate and reduce the associated side-effects, i.e. hepatotoxicity at high dose. Characterization of the developed formulation was performed by differential scanning calorimetry, particle size measurements and cellular uptake studies. Release profile, pharmacokinetics studies and organ distribution studies showed that developed formulation shows a relative higher liver uptake. The optimized formulation showed increased plasma concentration than the CTS nanoparticles as well as plain drug and the accumulation in the liver was nearly 2.59 times more than that of obtained with the CTS nanoparticles. Pharmaceutical and pharmacological indicators suggested that the proposed strategy can be successfully utilized for liver targeting of therapeutics.

Engineered nanoparticles: thrombotic events in cancer

Engineered nanoparticles are being increasingly produced for specific applications in medicine. Broad selections of nano-sized constructs have been developed for applications in diagnosis, imaging, and drug delivery. Nanoparticles as contrast agents enable conjugation with molecular markers which are essential for designing effective diagnostic and therapeutic strategies. Such investigations can also lead to a better understanding of disease mechanisms such as cancer-associated thrombosis which remains unpredictable with serious bleeding complications and high risk of death. Here we review the recent and current applications of engineered nanoparticles in diagnosis and therapeutic strategies, noting their toxicity in relation to specific markers as a target.

Synergistic antitumor effects of doxorubicin-loaded carboxymethyl cellulose nanoparticle in combination with endostar for effective treatment of non-small-cell lung cancer

The multi-modal combination therapy is proved powerful and successful to enhance the antitumor efficacy in clinics as compared with single therapy modes. In this study, the potential of combining chemotherapy with antiangiogenic therapy for the treatment of non-small-cell lung cancer is explored. Towards this aim, OEGylated carboxymethyl cellulose-(2-(2-(2-methoxyethoxy)ethoxy)methyl)oxirane (CMC-ME2MO) is prepared by treating CMC with ME2MO in the alkaline aqueous solution, and used to efficiently carry doxorubicin (DOX) with high drug-loading content (16.64%) and encapsulation efficiency (99.78%). As compared to free DOX, the resulting nanoparticles show not only the favorable stability in vitro but also the prolonged blood circulation, improved safety and tolerability, optimized biodistribution, reduced systemic toxicity, and enhanced antitumor efficacy in vivo, indicates a potential utility in cancer chemotherapy. Furthermore, the combination of the DOX-loaded polysaccharide nanoparticles and antiangiogenic drug endostar provides synergistic effects of chemotherapy and antiangiogenic therapy, which shows the highest efficiency in tumor suppression. The combination approach of the DOX-containing nanomedicine and endostar for efficient treatment of non-small-cell lung cancer is first proposed to demonstrate the synergistic therapeutic effect. This synergistic combination proves to be a promising therapeutic regimen in cancer therapy and holds great potential for clinical application.

Potential of Nanomaterials as Movers and Packers for Drug Molecules

As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

Solid tumor-targeting theranostic polymer nanoparticle in nuclear medicinal fields

Polymer nanoparticles can be prepared by self-assembling of amphiphilic polymers, and various types of molecular assemblies have been reported. In particular, in medicinal fields, utilization of these polymer nanoparticles as carriers for drug delivery system (DDS) has been actively tried, and some nanoparticulate drugs are currently under preclinical evaluations. A radionuclide is an unstable nucleus and decays with emission of radioactive rays, which can be utilized as a tracer in the diagnostic imaging systems of PET and SPECT and also in therapeutic purposes. Since polymer nanoparticles can encapsulate most of diagnostic and therapeutic agents with a proper design of amphiphilic polymers, they should be effective DDS carriers of radionuclides in the nuclear medicinal field. Indeed, nanoparticles have been recently attracting much attention as common platform carriers for diagnostic and therapeutic drugs and contribute to the development of nanotheranostics. In this paper, recent developments of solid tumor-targeting polymer nanoparticles in nuclear medicinal fields are reviewed.

Amphiphilic polymer-mediated formation of laponite-based nanohybrids with robust stability and pH sensitivity for anticancer drug delivery

The development of pH-sensitive drug delivery nanosystems that present a low drug release at the physiological pH and are able to increase the extent of the release at a lower pH value (like those existent in the interstitial space of solid tumors (pH 6.5) and in the intracellular endolysosomal compartments (pH 5.0)) is very important for an efficient and safe cancer therapy. Laponite (LP) is a synthetic silicate nanoparticle with a nanodisk structure (25 nm in diameter and 0.92 nm in thickness) and negative-charged surface, which can be used for the encapsulation of doxorubicin (DOX, a cationic drug) through electrostatic interactions and exhibit good pH sensitivity in drug delivery. However, the colloidal instability of LP still limits its potential clinical applications. In this study, we demonstrate an elegant strategy to develop stable Laponite-based nanohybrids through the functionalization of its surface with an amphiphile PEG-PLA copolymer by a self-assembly process. The hydrophobic block of PEG-PLA acts as an anchor that binds to the surface of drug-loaded LP nanodisks, maintaining the core structure, whereas the hydrophilic PEG part serves as a protective stealth shell that improves the whole stability of the nanohybrids under physiological conditions. The resulting nanocarriers can effectively load the DOX drug (the encapsulation efficiency is 85%), and display a pH-enhanced drug release behavior in a sustained way. In vitro biological evaluation indicated that the DOX-loaded nanocarriers can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher anticancer cytotoxicity than free DOX. The merits of Laponite/PEG-PLA nanohybrids, such as good cytocompatibility, excellent physiological stability, sustained pH-responsive release properties, and improved anticancer activity, make them a promising platform for the delivery of other therapeutic agents beyond DOX.

Transferrin-conjugated nanodiamond as an intracellular transporter of chemotherapeutic drug and targeting therapy for cancer cells

AIM

PEGylated fluorescent nanodiamond (FND) conjugated with Tf (FND-PEG-Tf) was investigated for targeted drug delivery.

MATERIALS & METHODS

Human hepatoma (HepG2) and normal (L-02) cell lines were used to investigate the difference in cellular uptake of FND-PEG-Tf and its loading drug system. Nanoparticle uptake was evaluated by flow cytometry and laser scanning confocal microscopy.

RESULTS

FND-PEG-Tf showed highly specific TfR-mediated uptake by HepG2 cells, relative to negative controls (L-02 cell), which was a strong correlation among TfR density on the cell surface. The mechanism of TfR-mediated uptake was attested by free Tf with Fe³⁺ as a competitive agent. The difference in cell viability between L-02 and HepG2 cells treated with doxorubicin hydrochloride (DOX) nanoparticles (FND-PEG-Tf-DOX) can be explained by FND-PEG-Tf, which can target drug delivery to cancer cells.

CONCLUSION

FND-PEG-Tf can potentially be utilized in targeted cancer cell imaging and effective drug delivery for cancer therapy.

Synthesis, characterization and theranostic evaluation of Indium-111 labeled multifunctional superparamagnetic iron oxide nanoparticles

Indium-111 labeled, Trastuzumab-Doxorubicin Conjugated, and APTES-PEG coated magnetic nanoparticles were designed for tumor targeting, drug delivery, controlled drug release, and dual-modal tumor imaging. Superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by thermal decomposition method to obtain narrow size particles. To increase SPIONs circulation time in blood and decrease its cytotoxicity in healthy tissues, SPIONs surface was modified with 3-Aminopropyltriethoxy Silane (APTES) and then were functionalized with N-Hydroxysuccinimide (NHS) ester of Polyethylene Glycol Maleimide (NHS-PEG-Mal) to conjugate with thiolated 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9,-triacetic acid (PCTA) bifunctional chelator (BFC) and Trastuzumab antibody. In order to tumor SPECT/MR imaging, SPIONs were labeled with Indium-111 (T1/2=2.80d). NHS ester of monoethyl malonate (MEM-NHS) was used for conjugation of Doxorubicin (DOX) chemotherapeutic agent onto SPIONs surface. Mono-Ethyl Malonate allows DOX molecules to be attached to SPIONs via pH-sensitive hydrazone bonds which lead to controlled drug release in tumor region. Active and passive tumor targeting were achieved through incorporated anti-HER2 (Trastuzumab) antibody and EPR effect of solid tumors for nanoparticles respectively. In addition to in vitro assessments of modified SPIONs in SKBR3 cell lines, their theranostic effects were evaluated in HER2 + breast tumor bearing BALB/c mice via biodistribution study, dual-modal molecular imaging and tumor diameter measurements.

Mechanisms of cooperation in cancer nanomedicine: towards systems nanotechnology

Nanoparticles are designed to deliver therapeutics and diagnostics selectively to tumors. Their size, shape, charge, material, coating, and cargo determine their individual functionalities. A systems approach could help predict the behavior of trillions of nanoparticles interacting in complex tumor environments. Engineering these nanosystems may lead to biomimetic strategies where interactions between nanoparticles and their environment give rise to cooperative behaviors typically seen in natural self-organized systems. Examples include nanoparticles that communicate the location of a tumor to amplify tumor homing or self-assemble and disassemble to optimize nanoparticle transport. The challenge is to discover which nanoparticle designs lead to a desired system behavior. To this end, novel nanomaterials, deep understanding of biology, and computational tools are emerging as the next frontier.