Self-organized nanoparticles based on chitosan-folic acid and dextran succinate-doxorubicin conjugates for drug targeting

Optimized lipopolymers with curcumin to enhance AZD5582 and GDC0152 activity and downregulate inhibitors of apoptosis proteins in glioblastoma multiforme

Inhibition to glioblastoma multiforme (GBM) propagation is a critical challenge in clinical practice because binding of inhibitors of apoptosis proteins (IAPs) to caspase prevents cancer cells from death. In this study, folic acid (FA), lactoferrin (Lf) and rabies virus glycoprotein (RVG) were grafted on lipopolymers (LPs) composed of poly(ε-caprolactone) and Compritol 888 ATO to encapsulate AZD5582 (AZD), GDC0152 (GDC) and curcumin (CURC). The standard deviations of initial particle diameter and particle diameter after storage for 30 days were involved in LP composition optimization. The functionalized LPs were used to permeate the blood-brain barrier (BBB) and constrain IAP quantity in GBM cells. Experimental results revealed that an increase in Span 20 (emulsifier) concentration enlarged the size of LPs, and enhanced the entrapment and releasing efficiency of AZD, DGC and CURC. 1H nuclear magnetic resonance spectra showed that the hydrogen bonds between the LPs and drugs supported the sustained release of AZD, DGC and CURC from the LPs. The LPs modified with the three targeting biomolecules facilitated the penetration of AZD, GDC and CURC across the BBB, and could recognize U87MG cells and human brain cancer stem cells. Immunofluorescence staining, flow cytometry and western blot demonstrated that CURC-incorporated LPs enhanced AZD and GDC activity in suppressing cellular IAP 1 (cIAP1) and X-linked IAP (XIAP) levels, and raising caspase-3 level in GBM. Surface FA, Lf and RVG also promoted the ability of the drug-loaded LPs to avoid carcinoma growth. The current FA-, Lf- and RVG-crosslinked LPs carrying AZD, DGC and CURC can be promising in hindering IAP expressions for GBM management.

Folic Acid-Chitosan Oligosaccharide Conjugates Decorated Nanodiamond as Potential Carriers for the Oral Delivery of Doxorubicin

Oral administration of doxorubicin (DOX) is preferred but challenged owing to poor permeability in the gastrointestinal tract (GIT), efflux of P-glycoprotein, short residence time in the intestine, and rapid hydrolysis. Herein, folic acid-chitosan oligosaccharide conjugate (FA-COS)-modified hydroxylated nanodiamond (ND-OH) was designed to enhance the oral bioavailability of DOX. The carboxyl surface of ND was modified into hydroxyl terminal group to increase the colloidal stability of the system under different pH conditions in GIT. FA-COS modification could prolong retention time, endow the drug with sustained release properties, and actively target intestinal FA receptors. In contrast to DOX/ND-OH, the particle size of DOX/ND-OH/FA-COS increased from 189.5 ± 2.8 to 224.5 ± 1.4 nm, and the zeta potential reversed from - 9.1 ± 0.2 to 14.8 ± 0.4 mV. At 48 h, DOX/ND-OH and DOX/ND-OH/FA-COS released 69.07 ± 5.70% and 35.87 ± 5.64%, respectively. FA-COS modification effectively enhanced the cytotoxicity and intracellular uptake of ND-OH/DOX by Caco-2 cells and prolonged intestinal retention in rats. The internalization of DOX/ND-OH and DOX/ND-OH/FA-COS was mainly mediated by energy-dependent clathrin- and caveolae-mediated endocytosis pathways. Pharmacokinetic study demonstrated that the AUC_0-t of DOX/ND-OH and DOX/ND-OH/FA-COS was enhanced by 3.94- and 6.08-fold compared to DOX solution, respectively. These results illustrated that DOX/ND-OH/FA-COS could be an effective strategy to enhance the oral bioavailability of DOX.

Surface engineered nanocarriers for the management of breast cancer

Breast cancer is commonly known life-threatening malignancy in women after lung cancer. The standard of care (SOC) treatment for breast cancer primarily includes surgery, radiotherapy, hormonal therapy, and chemotherapy. However, the effectiveness of conventional chemotherapy is restricted by several limitations such as poor targeting, drug resistance, poor drug delivery, and high toxicity. Nanoparticulate drug delivery systems have gained a lot of interest in the scientific community because of its unique features and promising potential in breast cancer diagnosis and treatment. The unique physicochemical and biological properties of the nanoparticulate drug delivery systems promotes the drug accumulation, Pharmacokinetic profile towards the tumor site and thereby, reduces the cytotoxicity towards healthy cells. In addition, to improve tumor-specific drug delivery, researchers have focused on surface engineered nanocarrier system with targeting molecules/ligands that are specific to overexpressed receptors present on cancer cells. In this review, we have summarized the different biological ligands and surface-engineered nanoparticles, enlightening the physicochemical characteristics, toxic effects, and regulatory considerations of nanoparticles involved in treatment of breast cancer.

Nanomaterial-based blood-brain-barrier (BBB) crossing strategies

Increasing attention has been paid to the diseases of central nervous system (CNS). The penetration efficiency of most CNS drugs into the brain parenchyma is rather limited due to the existence of blood-brain barrier (BBB). Thus, BBB crossing for drug delivery to CNS remains a significant challenge in the development of neurological therapeutics. Because of the advantageous properties (e.g., relatively high drug loading content, controllable drug release, excellent passive and active targeting, good stability, biodegradability, biocompatibility, and low toxicity), nanomaterials with BBB-crossability have been widely developed for the treatment of CNS diseases. This review summarizes the current understanding of the physiological structure of BBB, and provides various nanomaterial-based BBB-crossing strategies for brain delivery of theranostic agents, including intranasal delivery, temporary disruption of BBB, local delivery, cell penetrating peptide (CPP) mediated BBB-crossing, receptor mediated BBB-crossing, shuttle peptide mediated BBB-crossing, and cells mediated BBB-crossing. Clinicians, biologists, material scientists and chemists are expected to be interested in this review.

Ligand decorated chitosan as an advanced nanocarrier for targeted delivery: a critical review

Nontargeted delivery systems present nonspecific delivery, low transfection efficiency and high toxicity. Ligand-conjugated chitosan (CS) nanocarriers have emerged as an outstanding option for achieving active delivery specifically and preferentially to the target sites by exploiting receptors mediated endocytosis. Mannosylated CS nanocarriers have brought tremendous breakthrough in gene therapy and have proven to be an excellent choice for treatment of infectious and inflammatory diseases. Similarly, folate and antibodies-conjugated CS play a significant role in diagnosis and treatment of various cancers. Current evidences obviously propose ligand-decorated CS as an attractive option for diagnosis and treatment of dreadful conditions. In order to bring huge revolution in the field of targeted delivery, challenges associated with these nanocarriers needs to be addressed.

Advances in Receptor-Mediated, Tumor-Targeted Drug Delivery

Receptor-mediated drug delivery presents an opportunity to enhance therapeutic efficiency by accumulating drug within the tissue of interest and reducing undesired, off-target effects. In cancer, receptor overexpression is a platform for binding and inhibiting pathways that shape biodistribution, toxicity, cell binding and uptake, and therapeutic function. This review will identify tumor-targeted drug delivery vehicles and receptors that show promise for clinical translation based on quantitative in vitro and in vivo data. The authors describe the rationale to engineer a targeted drug delivery vehicle based on the ligand, chemical conjugation method, and type of drug delivery vehicle. Recent advances in multivalent targeting and ligand organization on tumor accumulation are discussed. Revolutionizing receptor-mediated drug delivery may be leveraged in the therapeutic delivery of chemotherapy, gene editing tools, and epigenetic drugs.

Synthesis of folate‑chitosan nanoparticles loaded with ligustrazine to target folate receptor positive cancer cells

In addition to its vasodilatory effect, ligustrazine (LZ) improves the sensitivity of multidrug resistant cancer cells to chemotherapeutic agents. To enhance the specificity of LZ delivery to tumor cells/tissues, folate-chitosan nanoparticles (FA-CS-NPs) were synthesized by combination of folate ester with the amine group on chitosan to serve as a delivery vehicle for LZ (FA-CS-LZ-NPs). The structure of folate-chitosan and characteristics of FA-CS-LZ-NPs, including its size, encapsulation efficiency, loading capacity and release rates were analyzed. MCF-7 (folate receptor-positive) and A549 (folate receptor-negative) cells cultured with or without folate were treated with FA-CS-LZ-NPs, CS-LZ-NPs or LZ to determine cancer-targeting specificity of FA-CS-LZ-NPs. Fluorescence intensity of intracellular LZ was observed by laser scanning confocal microscopy, and concentration of intracellular LZ was detected by HPLC. The average size of FA-CS-LZ-NPs was 182.7±0.56 nm, and the encapsulation efficiency and loading capacity was 59.6±0.23 and 15.3±0.16% respectively. The cumulative release rate was about 95% at pH 5.0, which was higher than that at pH 7.4. There was higher intracellular LZ accumulation in MCF-7 than that in A549 cells and intracellular LZ concentration was not high when MCF-7 cells were cultured with folate. These results indicated that the targeting specificity of FA-CS-LZ-NPs was mediated by folate receptor. Therefore, the FA-CS-LZ-NPs may be a potential folate receptor-positive tumor cell targeting drug delivery system that could possibly overcome multidrug resistance during cancer therapy.

Quercetin-Loaded Solid Lipid Nanoparticle Dispersion with Improved Physicochemical Properties and Cellular Uptake

The objective of this study was to formulate and characterize properties of solid lipid nanoparticle (SLN) dispersion containing quercetin. SLN was prepared by ultrasonication method using tripalmitin and lecithin as lipid core and then the surface was coated with chitosan. Entrapment efficiency was greater than 99%, and mean particle size of SLN was 110.7 ± 1.97 nm with significant increase in the coated SLN (c-SLN). Zeta potential was proportionally increased and reached plateau at 5% of chitosan coating with respect to tripalmitin. Differential scanning calorimetry showed disappearance of endothermic peak of quercetin in SLNs, indicating conversion of crystalline state to amorphous state. FTIR study of SLNs showed no change in the spectrum of quercetin, which indicates that the lipid and chitosan were not incompatible with quercetin. When coating amount was greater than 2.5% of tripalmitin, particle size and zeta potential were very stable even at 40°C up to 90 days. All SLN dispersions showed significantly faster release profile compared to pure quercetin powder. At pH 7.0, the release rate was increased in proportion to the coating amount. Interestingly, at pH 3.0, chitosan coating of 5.0% or greater decreased the rate. Cellular uptake of quercetin was performed using Caco-2 cells and showed that all SLN dispersions were significantly better than quercetin dispersed in distilled water. However, cellular uptake of quercetin from c-SLN was significantly lower than that from uncoated SLN.

Folate-mediated chemotherapy and diagnostics: An updated review and outlook

Folate receptor (FR) is highly expressed in many types of human cancers, and it has been actively studied for developing targeted chemotherapy and diagnostic agents. Tremendous efforts have been made in developing FR-targeted nanomedicines and nanoprobes and translating them into clinical applications. This article provides a concise review on the latest development of folate-mediated nanomedicines and nanoprobes for chemotherapy and diagnostics with an emphasis on in vivo applications. The cellular uptake mechanisms, pharmacokinetics (PK), administration routes and major challenges in FR-targeted nanoparticles are discussed.

Development and characterization of folic acid-conjugated chitosan nanoparticles for targeted and controlled delivery of gemcitabinein lung cancer therapeutics

The present study was designed to investigate the tumor-targeting potential of gemcitabine (GEM)-loaded surface-tailored chitosan (CS)/poly (ethylene glycol) nanoparticles (FA-PEG-GEM-NPs). The nanoparticles encapsulated with GEM were prepared, characterized, and tethered with folic acid. The developed formulations were characterized with respect to particle size/poly-dispersity index, shape, and zeta potential analysis. The in vitro study shows the sustained drug-release kinetics during 48 h. The present result shows remarkable cytotoxicity rendered by GEM when delivered through FA-PEG-GEM-NPs formulation. The microscopic assessment is suggestive of significant uptake of FA-PEG-GEM-NPs in comparison with the unmodified PEG-GEM-NPs and free drug. Finally, our results advocate for the sizeable compatibility, comparatively less organ toxicity, and higher anti-tumor activity of ligand-anchored and PEGylated CS nanoparticles in vitro and corroborated by in vivo investigations. In conclusion, it is interpreted that surface-tailored nanoparticles are capable to ferry bioactives selectively and specifically to tumor sites with the interception of minimal side effects, thereby suggesting their potential application in cancer therapeutics.

Molecular beacon-decorated polymethylmethacrylate core-shell fluorescent nanoparticles for the detection of survivin mRNA in human cancer cells

One of the main goals of nanomedicine in cancer is the development of effective drug delivery systems, primarily nanoparticles. Survivin, an overexpressed anti-apoptotic protein in cancer, represents a pharmacological target for therapy and a Molecular Beacon (MB) specific for survivin mRNA is available. In this study, the ability of polymethylmethacrylate nanoparticles (PMMA-NPs) to promote survivin MB uptake in human A549 cells was investigated. Fluorescent and positively charged core PMMA-NPs of nearly 60nm, obtained through an emulsion co-polymerization reaction, and the MB alone were evaluated in solution, for their analytical characterization; then, the MB specificity and functionality were verified after adsorption onto the PMMA-NPs. The carrier ability of PMMA-NPs in A549 was examined by confocal microscopy. With the optimized protocol, a hardly detectable fluorescent signal was obtained after incubation of the cells with the MB alone (fluorescent spots per cell of 1.90±0.40 with a mean area of 1.04±0.20µm²), while bright fluorescent spots inside the cells were evident by using the MB loaded onto the PMMA-NPs. (27.50±2.30 fluorescent spots per cell with a mean area of 2.35±0.16µm²). These results demonstrate the ability of the PMMA-NPs to promote the survivin-MB internalization, suggesting that this complex might represent a promising strategy for intracellular sensing and for the reduction of cancer cell proliferation.

In vitro and in vivo evaluation of xanthan gum-succinic anhydride hydrogels for the ionic strength-sensitive release of antibacterial agents

In this work, we report a new approach to prepare high gel performance hydrogels which are used as ionic strength-sensitive drug release systems. Succinic anhydride (SA)-modified xanthan (XG-SA) derivatives were prepared and confirmed by Fourier transform-infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. Rheological measurements showed that the storage moduli (G') and loss moduli (G'') of XG-SA were much higher than native XG suggesting a higher stability of the hydrogels. XG-SA could form stable hydrogels when the content of a dry gel was 1.4 wt%. Drug release studies showed the ionic strength-sensitive and sustained release of gentamicin (GS) for 9 days under aqueous physiological conditions. Biofilm inhibition assay revealed that the XG-SA/GS hydrogels were sufficient to inhibit biofilm formation. The Kirby-Bauer method showed that there was a zone of inhibition at around 8.2 mm indicating the excellent bactericidal function of the hydrogels. Cytocompatibility assessment against human lens epithelial cells revealed that the hydrogels supported cell adhesion, proliferation and migration when the loading dosage of GS was 1 mg g-1. XG-SA/GS hydrogels were compared to native XG-SA in the rabbit subcutaneous S. aureus infection model. XG-SA/GS hydrogels yielded a significantly lower degree of infection than XG-SA hydrogels at day 7. In this way, XG-SA hydrogels are promising drug delivery materials for antibacterial applications.

Receptor-Mediated Drug Delivery Systems Targeting to Glioma

Glioma has been considered to be the most frequent primary tumor within the central nervous system (CNS). The complexity of glioma, especially the existence of the blood-brain barrier (BBB), makes the survival and prognosis of glioma remain poor even after a standard treatment based on surgery, radiotherapy, and chemotherapy. This provides a rationale for the development of some novel therapeutic strategies. Among them, receptor-mediated drug delivery is a specific pattern taking advantage of differential expression of receptors between tumors and normal tissues. The strategy can actively transport drugs, such as small molecular drugs, gene medicines, and therapeutic proteins to glioma while minimizing adverse reactions. This review will summarize recent progress on receptor-mediated drug delivery systems targeting to glioma, and conclude the challenges and prospects of receptor-mediated glioma-targeted therapy for future applications.

Polymer-Based Prodrugs: Improving Tumor Targeting and the Solubility of Small Molecule Drugs in Cancer Therapy

The majority of anticancer drugs have poor aqueous solubility, produce adverse effects in healthy tissue, and thus impose major limitations on both clinical efficacy and therapeutic safety of cancer chemotherapy. To help circumvent problems associated with solubility, most cancer drugs are now formulated with co-solubilizers. However, these agents often also introduce severe side effects, thereby restricting effective treatment and patient quality of life. A promising approach to addressing problems in anticancer drug solubility and selectivity is their conjugation with polymeric carriers to form polymer-based prodrugs. These polymer-based prodrugs are macromolecular carriers, designed to increase the aqueous solubility of antitumor drugs, can enhance bioavailability. Additionally, polymer-based prodrugs approach exploits unique features of tumor physiology to passively facilitate intratumoral accumulation, and so improve chemodrug pharmacokinetics and pharmacological properties. This review introduces basic concepts of polymer-based prodrugs, provides an overview of currently emerging synthetic, natural, and genetically engineered polymers that now deliver anticancer drugs in preclinical or clinical trials, and highlights their major anticipated applications in anticancer therapies.

Design of liposomal formulations for cell targeting

Liposomes have gained extensive attention as carriers for a wide range of drugs due to being both nontoxic and biodegradable as they are composed of substances naturally occurring in biological membranes. Active targeting for cells has explored specific modification of the liposome surface by functionalizing it with specific targeting ligands in order to increase accumulation and intracellular uptake into target cells. None of the Food and Drug Administration-licensed liposomes or lipid nanoparticles are coated with ligands or target moieties to delivery for homing drugs to target tissues, cells or subcellular organelles. Targeted therapies (with or without controlled drug release) are an emerging and relevant research area. Despite of the numerous liposomes reviews published in the last decades, this area is in constant development. Updates urgently needed to integrate new advances in targeted liposomes research. This review highlights the evolution of liposomes from passive to active targeting and challenges in the development of targeted liposomes for specific therapies.

Folate-conjugated nanoparticles as a potent therapeutic approach in targeted cancer therapy

The selective and efficient drug delivery to tumor cells can remarkably improve different cancer therapeutic approaches. There are several nanoparticles (NPs) which can act as a potent drug carrier for cancer therapy. However, the specific drug delivery to cancer cells is an important issue which should be considered before designing new NPs for in vivo application. It has been shown that cancer cells over-express folate receptor (FR) in order to improve their growth. As normal cells express a significantly lower levels of FR compared to tumor cells, it seems that folate molecules can be used as potent targeting moieties in different nanocarrier-based therapeutic approaches. Moreover, there is evidence which implies folate-conjugated NPs can selectively deliver anti-tumor drugs into cancer cells both in vitro and in vivo. In this review, we will discuss about the efficiency of different folate-conjugated NPs in cancer therapy.