Carboxymethyl Hyaluronan-Stabilized Nanoparticles for Anticancer Drug Delivery

Pancreatic cancer: failures and hopes-a review of new promising treatment approaches

Pancreatic cancer is a challenging disease with limited treatment options and a high mortality rate. Just few therapy advances have been made in recent years. Tumor microenvironment, immunosuppressive features and mutational status represent important obstacles in the improvement of survival outcomes. Up to now, first-line therapy did achieve a median overall survival of less than 12 months and this discouraging data lead clinicians all over the world to focus their efforts on various fields of investigation: 1) sequential cycling of different systemic therapy in order to overcome mechanisms of resistance; 2) discovery of new predictive bio-markers, in order to target specific patient population; 3) combination treatment, in order to modulate the tumor microenvironment of pancreatic cancer; 4) new modalities of the delivery of drugs in order to pass the physical barrier of desmoplasia and tumor stroma. This review shows future directions of treatment strategies in advanced pancreatic cancer through a deep analysis of these recent macro areas of research.

Hyaluronic Acid-Based Drug Delivery Systems for Cancer Therapy

In recent years, hyaluronic acid (HA) has attracted increasing attention as a promising biomaterial for the development of drug delivery systems. Due to its unique properties, such as high biocompatibility, low toxicity, and modifiability, HA is becoming a basis for the creation of targeted drug delivery systems, especially in the field of oncology. Receptors for HA overexpressed in subpopulations of cancer cells, and one of them, CD44, is recognized as a molecular marker for cancer stem cells. This review examines the role of HA and its receptors in health and tumors and analyzes existing HA-based delivery systems and their use in various types of cancer. The development of new HA-based drug delivery systems will bring new opportunities and challenges to anti-cancer therapy.

Role of the Hyaluronan Receptor, Stabilin-2/HARE, in Health and Disease

Stabilin-2/HARE is the primary clearance receptor for circulating hyaluronan (HA), a polysaccharide found in the extracellular matrix (ECM) of metazoans. HA has many biological functions including joint lubrication, ocular turgor pressure, skin elasticity and hydration, cell motility, and intercellular signaling, among many others. The regulatory system for HA content in the tissues, lymphatics, and circulatory systems is due, in part, to Stabilin-2/HARE. The activity of this receptor was discovered about 40 years ago (early 1980s), cloned in the mid-1990s, and has been characterized since then. Here, we discuss the overall domain organization of this receptor and how it correlates to ligand binding, cellular signaling, and its role in known physiological disorders such as cancer.

Multivalent and multifunctional polysaccharide-based particles for controlled receptor recognition

Polysaccharides represent a versatile class of building blocks that are used in macromolecular design. By choosing the appropriate saccharide block, various physico-chemical and biological properties can be introduced both at the level of the polymer chains and the resulting self-assembled nanostructures. Here, we synthetized amphiphilic diblock copolymers combining a hydrophobic and helical poly(γ-benzyl-L-glutamate) PBLG and two polysaccharides, namely hyaluronic acid (HA) and laminarin (LAM). The copolymers could self-assemble to form particles in water by nanoprecipitation. In addition, hybrid particles containing both HA and LAM in different ratios were obtained by co-nanoprecipitation of the two copolymers. By controlling the self-assembly process, five particle samples with different morphologies and compositions were developed. The interaction between the particles and biologically relevant proteins for HA and LAM, namely CD44 and Dectin-1 respectively, was evaluated by surface plasmon resonance (SPR). We demonstrated that the particle-protein interaction could be modulated by the particle structure and composition. It is therefore suggested that this method based on nanoprecipitation is a practical and versatile way to obtain particles with controllable interactions with proteins, hence with the appropriate biological properties for biomedical applications such as drug delivery.

Gold nanoparticle-based rapid detection and isolation of cells using ligand-receptor chemistry

Identification and isolation of low-frequency cells of interest from a heterogeneous cell mixture is an important aspect of many diagnostic applications (including enumeration of circulating tumor cells) and is integral to various assays in (cancer) biology. Current techniques typically require expensive instrumentation and are not amenable to high throughput. Here, we demonstrate a simple and effective platform for cell detection and isolation using gold nanoparticles (Au NPs) conjugated with hyaluronic acid (HA) i.e. Au-PEG-HA NPs. The proposed platform exploits ligand-receptor chemistry to detect/isolate cells with high specificity and efficiency. When the Au-PEG-HA NPs come in contact with cells that express CD44 (the receptor for HA), a clear colorimetric change occurs (along with an accompanying SPR peak shift from 521 nm to 559 nm) in the solution due to NPs-cell interaction. This clearly discernible, colorimetric change can be leveraged by point-of-care devices employed in diagnostic applications. Finally, we show that we can successfully isolate viable cells from a heterogeneous cell population (including from human blood samples) with high specificity, which can be used in further downstream applications. The developed NPs-based platform can be a convenient and cost-efficient alternative for diagnostic applications and for cell isolation or sorting in research laboratories.

Tethered polymer nanoassemblies for sustained carfilzomib release and prolonged suppression of proteasome activity

AIM

Proteasome inhibitors, such as carfilzomib (CFZ), have shown potential to treat various types of cancers in preclinical models, but clinical applications are limited likely due to formulation and delivery issues. Results & methodology: Tethered polymer nanoassemblies (TNAs) were synthesized by tethering hydrophilic polymers and hydrophobic groups to charged polymer scaffolds, and then end-capping remaining amines on scaffold. Drug entrapment and drug release half-lives increased as charge was removed from scaffold. TNAs with sustained CFZ release maintained drug efficacy after preincubation and increased duration of proteasome inhibition in cancer cells compared with free CFZ.

CONCLUSION

TNAs fine-tuned CFZ release as charge was removed from polymer scaffold, which allowed for sustained proteasome inhibition in cancer cells and potentially enhanced anticancer efficacy.

Layer-by-layer nanoparticle platform for cancer active targeting

Nanoparticles as drug delivery carriers have been investigated over the last few decades, particularly for cancer treatment. The rationale in developing such nanoparticles is to maximize drug efficacy while minimizing toxic side effects. This can be most effectively achieved through target specific drug delivery. A novel biocompatible nanoparticle platform prepared using the core-shell self-assembly technique is reported. The core consists of calcium phosphate which is biocompatible and pH-sensitive, and the shell is composed of biocompatible polymers (hyaluronic acid, CD44 targeting moiety; and chitosan, physical cross-linker). Cisplatin was selected as a model drug and incorporated between the core and the shell. The nanoparticle composition was optimized for high serum stability and low protein binding. These nanoparticles demonstrated target specific delivery in human lung cancer cells (which overexpress CD44 receptors). The targeting ability of the nanoparticles was confirmed with an 8-fold increase of drug efficacy (IC₅₀) compared to cisplatin. Furthermore, the pH-sensitive core of the nanoparticle platform led to controlled drug release through destabilization in acidic conditions. This platform technology provides a simple approach for the design of targeted biocompatible nanoparticles for cancer therapy.