Collagens, stromal cell-derived factor-1alpha and basic fibroblast growth factor increase cancer cell invasiveness in a hyaluronan hydrogel

HYDRHA: Hydrogels of hyaluronic acid. New biomedical approaches in cancer, neurodegenerative diseases, and tissue engineering

In the last decade, hyaluronic acid (HA) has attracted an ever-growing interest in the biomedical engineering field as a biocompatible, biodegradable, and chemically versatile molecule. In fact, HA is a major component of the extracellular matrix (ECM) and is essential for the maintenance of cellular homeostasis and crosstalk. Innovative experimental strategies in vitro and in vivo using three-dimensional (3D) HA systems have been increasingly reported in studies of diseases, replacement of tissue and organ damage, repairing wounds, and encapsulating stem cells for tissue regeneration. The present work aims to give an overview and comparison of recent work carried out on HA systems showing advantages, limitations, and their complementarity, for a comprehensive characterization of their use. A special attention is paid to the use of HA in three important areas: cancer, diseases of the central nervous system (CNS), and tissue regeneration, discussing the most innovative experimental strategies. Finally, perspectives within and beyond these research fields are discussed.

Cancer cell migration on straight, wavy, loop and grid microfibre patterns

Cell migration plays an important role in physiological and pathological processes where the fibrillar morphology of extracellular matrices (ECM) could regulate the migration dynamics. To mimic the morphological characteristics of fibrillar matrix structures, low-voltage continuous electrospinning was adapted to construct straight, wavy, looped and gridded fibre patterns made of polystyrene (of fibre diameter ca. 3 μm). Cells were free to explore their different shapes in response to the directly-adhered fibre, as well as to the neighbouring patterns. For all the patterns studied, analysing cellular migration dynamics of MDA-MB-231 (a highly migratory breast cancer cell line) demonstrated two interesting findings: first, although cells dynamically adjust their shapes and migration trajectories in response to different fibrillar environments, their average step speed is minimally affected by the fibre global pattern; secondly, a switch in behaviour was observed when the pattern features approach the upper limit of the cell body's minor axis, reflecting that cells' ability to divert from an existing fibre track is limited by the size along the cell body's minor axis. It is therefore concluded that the upper limit of cell body's minor axis might act as a guide for the design of microfibre patterns for different purposes of cell migration.

Hyaluronic acid-based hydrogels to study cancer cell behaviors

Hyaluronic acid (HA) is a natural polysaccharide and a key component of the extracellular matrix (ECM) in many tissues. Therefore, HA-based biomaterials are extensively utilized to create three dimensional ECM mimics to study cell behaviors in vitro. Specifically, derivatives of HA have been commonly used to fabricate hydrogels with controllable properties. In this review, we discuss the various chemistries employed to fabricate HA-based hydrogels as a tunable matrix to mimic the cancer microenvironment and subsequently study cancer cell behaviors in vitro. These include Michael-addition reactions, photo-crosslinking, carbodiimide chemistry, and Diels-Alder chemistry. The utility of these HA-based hydrogels to examine cancer cell behaviors such as proliferation, migration, and invasion in vitro in various types of cancer are highlighted. Overall, such hydrogels provide a biomimetic material-based platform to probe cell-matrix interactions in cancer cells in vitro and study the mechanisms associated with cancer progression.

Sustained release of stem cell factor in a double network hydrogel for ex vivo culture of cord blood-derived CD34+ cells

OBJECTIVES

Stem cell factor (SCF) is considered as a commonly indispensable cytokine for proliferation of haematopoietic stem cells (HSCs), which is used in large dosages during ex vivo culture. The work presented here aimed to reduce the consumption of SCF by sustained release but still support cells proliferation and maintain the multipotency of HSCs.

MATERIALS AND METHODS

Stem cell factor was physically encapsulated within a hyaluronic acid/gelatin double network (HGDN) hydrogel to achieve a slow release rate. CD34+ cells were cultured within the SCF-loaded HGDN hydrogel for 14 days. The cell number, phenotype and functional capacity were investigated after culture.

RESULTS

The HGDN hydrogels had desirable properties and encapsulated SCF kept being released for more than 6 days. SCF remained the native bioactivity, and the proliferation of HSCs within the SCF-loaded HGDN hydrogel was not affected, although the consumption of SCF was only a quarter in comparison with the conventional culture. Moreover, CD34+ cells harvested from the SCF-loaded HGDN hydrogels generated more multipotent colony-forming units (CFU-GEMM).

CONCLUSION

The data suggested that the SCF-loaded HGDN hydrogel could support ex vivo culture of HSCs, thus providing a cost-effective culture protocol for HSCs.

Down-regulation of KLF5 in cancer-associated fibroblasts inhibit gastric cancer cells progression by CCL5/CCR5 axis

It was well known that cancer-associated fibroblasts (CAFs) were an essential factor in tumor progression. However, the actual mechanism of stromal fibroblasts activation and tumor promoting effects remain unclear. Here, we showed that KLF5 expression was more frequently observed in gastric cancer-associated fibroblasts compared with normal mucosal fibroblasts. Moreover, KLF5 expression in tumor stroma was closely associated with clinicopathological features such as tumor size, invasion depth, cell grade and lymph node metastasis, as well as poor prognosis in patients with gastric cancer. In addition, we further demonstrated that KLF5-regulating CAFs affect gastric cancer cells progression by CCL5 secretion and activation of CCR5. Taken together, we concluded that KLF5 expression in gastric cancer-associated fibroblasts contribute to poor survival and promote cancer cells progression by activation of CCL5/CCR5 axis, which suggesting that KLF5 in CAFs might be considered as a promising target for the treatment of gastric cancer.

Engineered Hydrogels in Cancer Therapy and Diagnosis

Over the last decade, numerous investigations have attempted to clarify the intricacies of tumor development to propose effective approaches for cancer treatment. Thanks to the unique properties of hydrogels, researchers have made significant progress in tumor model reconstruction, tumor diagnosis, and associated therapies. Notably, hydrogel-based systems can be adjusted to respond to cancer-specific hallmarks and/or external stimuli. These well-known drug reservoirs can be used as smart carriers for multiple cargos, including both naked and nanoparticle-encapsulated chemotherapeutics, genes, and radioisotopes. Recent works have attempted to specialize hydrogels for cancer research; we comprehensively review this topic for the first time, synthesizing past results and defining paths for future work.

An update on applications of nanostructured drug delivery systems in cancer therapy: a review

Cancer is a main public health problem that is known as a malignant tumor and out-of-control cell growth, with the potential to assault or spread to other parts of the body. Recently, remarkable efforts have been devoted to develop nanotechnology to improve the delivery of anticancer drug to tumor tissue as minimizing its distribution and toxicity in healthy tissue. Nanotechnology has been extensively used in the advance of new strategies for drug delivery and cancer therapy. Compared to customary drug delivery systems, nano-based drug delivery method has greater potential in different areas, like multiple targeting functionalization, in vivo imaging, extended circulation time, systemic control release, and combined drug delivery. Nanofibers are used for different medical applications such as drug delivery systems.

Toward 3D biomimetic models to understand the behavior of glioblastoma multiforme cells

Glioblastoma multiforme (GBM) tumors are one of the most deadly forms of human cancer and despite improved treatments, median survival time for the majority of patients is a dismal 12-15 months. A hallmark of these aggressive tumors is their unique ability to diffusively infiltrate normal brain tissue. To understand this behavior and successfully target the mechanisms underlying tumor progression, it is crucial to develop robust experimental ex vivo disease models. This review discusses current two-dimensional (2D) experimental models, as well as animal-based models used to examine GBM cell migration, including their advantages and disadvantages. Recent attempts to develop three-dimensional (3D) tissue engineering-inspired models and their utility in unraveling the role of microenvironment on tumor cell behaviors are also highlighted. Further, the use of 3D models to bridge the gap between 2D and animal models is explored. Finally, the broad utility of such models in the context of brain cancer research is examined.

Glioblastoma behaviors in three-dimensional collagen-hyaluronan composite hydrogels

Glioblastoma multiforme (GBM) tumors, which arise from glia in the central nervous system (CNS), are one of the most deadly forms of human cancer with a median survival time of ∼1 year. Their high infiltrative capacity makes them extremely difficult to treat, and even with aggressive multimodal clinical therapies, outcomes are dismal. To improve understanding of cell migration in these tumors, three-dimensional (3D) multicomponent composite hydrogels consisting of collagen and hyaluronic acid, or hyaluronan (HA), were developed. Collagen is a component of blood vessels known to be associated with GBM migration; whereas, HA is one of the major components of the native brain extracellular matrix (ECM). We characterized hydrogel microstructural features and utilized these materials to investigate patient tumor-derived, single cell morphology, spreading, and migration in 3D culture. GBM morphology was influenced by collagen type with cells adopting a rounded morphology in collagen-IV versus a spindle-shaped morphology in collagen-I/III. GBM spreading and migration were inversely dependent on HA concentration; with higher concentrations promoting little or no migration. Further, noncancerous astrocytes primarily displayed rounded morphologies at lower concentrations of HA; in contrast to the spindle-shaped (spread) morphologies of GBMs. These results suggest that GBM behaviors are sensitive to ECM mimetic materials in 3D and that these composite hydrogels could be used to develop 3D brain mimetic models for studying migration processes.

Mimicking white matter tract topography using core-shell electrospun nanofibers to examine migration of malignant brain tumors

Glioblastoma multiforme (GBM), one of the deadliest forms of human cancer, is characterized by its high infiltration capacity, partially regulated by the neural extracellular matrix (ECM). A major limitation in developing effective treatments is the lack of in vitro models that mimic features of GBM migration highways. Ideally, these models would permit tunable control of mechanics and chemistry to allow the unique role of each of these components to be examined. To address this need, we developed aligned nanofiber biomaterials via core-shell electrospinning that permit systematic study of mechanical and chemical influences on cell adhesion and migration. These models mimic the topography of white matter tracts, a major GBM migration 'highway'. To independently investigate the influence of chemistry and mechanics on GBM behaviors, nanofiber mechanics were modulated by using different polymers (i.e., gelatin, poly(ethersulfone), poly(dimethylsiloxane)) in the 'core' while employing a common poly(ε-caprolactone) (PCL) 'shell' to conserve surface chemistry. These materials revealed GBM sensitivity to nanofiber mechanics, with single cell morphology (Feret diameter), migration speed, focal adhesion kinase (FAK) and myosin light chain 2 (MLC2) expression all showing a strong dependence on nanofiber modulus. Similarly, modulating nanofiber chemistry using extracellular matrix molecules (i.e., hyaluronic acid (HA), collagen, and Matrigel) in the 'shell' material with a common PCL 'core' to conserve mechanical properties revealed GBM sensitivity to HA; specifically, a negative effect on migration. This system, which mimics the topographical features of white matter tracts, should allow further examination of the complex interplay of mechanics, chemistry, and topography in regulating brain tumor behaviors.

Survival of cord blood haematopoietic stem cells in a hyaluronan hydrogel for ex vivo biomimicry

Haematopoietic stem cells (HSCs) and haematopoietic progenitor cells (HPCs) grow in a specified niche in close association with the microenvironment, the so-called 'haematopoietic niche'. Scaffolds have been introduced to overcome the liquid culture limitations, mimicking the presence of the extracellular matrix (ECM). In the present study the hyaluronic acid scaffold, already developed in the laboratory, has been used for the first time to maintain long-term cultures of CD34⁺ haematopoietic cells obtained from human cord blood. One parameter investigated was the impact on ex vivo survival of CD34⁺ cord blood cells (CBCs) on the hyaluronic acid surface, immobilized with peptides containing the RGD motif. This peptide was conjugated by coating the hyaluronan hydrogel and cultured in serum-free liquid phase complemented with stem cell factor (SCF), a commonly indispensable cytokine for haematopoiesis. Our work demonstrated that these hyaluronan hydrogels were superior to traditional liquid cultures by maintaining and expanding the HPCs without the need for additional cytokines, and a colonization of 280-fold increment in the hydrogel compared with liquid culture after 28 days of ex vivo expansion.

Elastin-derived peptides: matrikines critical for glioblastoma cell aggressiveness in a 3-D system

In the most common primary brain tumors, malignant glioma cells invade the extracellular matrix (ECM) and proliferate rapidly in the cerebral tissue, which is mainly composed of hyaluronan (HA) along with the elastin present in the basement membrane of blood vessels. To determine the role of ECM components in the invasive capacity of glioma cell lines, we developed a 3-D cell-culture system, based on a hydrogel in which HA can be coreticulated with kappa-elastin (HA-kappaE). Using this system, the invasiveness of cells from four glioma cell lines was dramatically increased by the presence of kappaE and a related, specific peptide (VGVAPG)(3). In addition, MMP-2 secretion increased and MMP-12 synthesis occurred. Extracellular injections of kappaE or (VGVAPG)(3) provoked a pronounced and dose-dependent increase in [Ca(2+)](i). kappaE significantly enhanced the expression of the genes encoding elastin-receptor and tropoelastin. We propose the existence of a positive feedback loop in which degradation of elastin generates fragments that stimulate synthesis of tropoelastin followed by further degradation as well as migration and proliferation of the very cells responsible for degradation. All steps in this ECM-based loop could be blocked by the addition of either of the EBP antagonists, lactose, and V-14 peptide, suggesting that the loop itself should be considered as a new therapeutic target.