Functional surfaces for high-resolution analysis of cancer cell interactions on exogenous hyaluronic acid

RHAMM expression tunes the response of breast cancer cell lines to hyaluronan

Hyaluronan (HA) synthesis and degradation are altered during carcinogenesis leading to an increased HA content in the tumor microenvironment, which correlates with poor prognosis and treatment outcomes. The main HA receptors, CD44 and RHAMM, are also overexpressed in tumors where they activate anti-apoptotic, proliferative, invasive, and migration signaling pathways. Herein, we used a unidirectional HA gradient to investigate in a high-throughput fashion the bi-directional communication between HA and breast cancer cell lines with different surface expression of CD44 and RHAMM. We found that the expression of CD44 and RHAMM depends on the HA density: the expression of these receptors is promoted at higher HA density and RHAMM is more sensitive to these changes when compared to CD44. Blocking either CD44 or RHAMM revealed different functions on binding and recognizing HA and a compensatory expression between these two receptors that maintains protumorigenic effectors such as cortactin. STATEMENT OF SIGNIFICANCE: We show that the expression of main hyaluronan (HA) receptors CD44 and RHAMM is enhanced in a HA concentration-dependent manner. Blocking activity experiments with either RHAMM or CD44 reveal the redundancy of these two receptors towards HA recognition and activation/recruitment of protumorigenic molecular effector, cortactin. These experiments also demonstrate that cells with overexpressed RHAMM are more sensitive to HA density than CD44 positive cells. The reported results are important for the development of therapies that target the hyaluronan signaling in the tumor microenvironment.

pH-Responsive hyaluronic acid-cloaked polycation/gold nanohybrids for tumor-targeted synergistic photothermal/gene therapy

The combination of photothermal therapy (PTT) and gene therapy (GT) has attracted intense interest in cancer treatment. However, the lack of long circulation and active tumor targeting reduces the therapeutic efficacy of complementary PTT/GT. In this work, hyaluronic acid (HA)-cloaked gold nanorods-PGED (prepared by ring-opening of polyglycidyl methacrylate (PGMA) with ethylenediamine (ED))/pDNA (AP/pDNA-HA) complexes were prepared to achieve long circulation and tumor targeting for photoacoustic imaging (PAI)-guided synergistic PTT/GT. Gold nanorods endow the complexes with photothermal effect and PAI function. Benefiting from the HA cloak, the AP/pDNA-HA complexes exhibit excellent stability, biocompatibility, long circulation behavior and active targeting. In addition, the pH-responsive characteristic of the Schiff base bonds helps the AP/pDNA-HA complexes to effectively escape from the endosome/lysosome. The antioncogene p53 was employed to investigate the gene transfection efficiency of the delivery system both in vitro and in vivo. The superiority of synergistic PTT/GT is established in a mouse 4T1 breast tumor model. The current study provides a facile strategy for constructing multifunctional gene delivery systems with long circulation and tumor targeting features, which can achieve effective imaging-guided synergistic tumor treatment.

Harnessing Focal Adhesions to Accelerate p53 Accumulation and Anoikis of A549 Cells Using Colloidal Self-Assembled Patterns (cSAPs)

Extracellular matrix (ECM) of the tumor microenvironment (TME), including topography and biological molecules, is crucial in cancer cell attachment, growth, and even the sensitivity to the chemo and cell drugs treatment. This study hypothesizes that mimic ECM structures can alter the attachment and drug sensitivity of cancer cells. A family of artificial ECM called colloidal self-assembled patterns (cSAPs) was fabricated to mimic tumor ECM structures. Cell adhesion, proliferation, and drug sensitivity of the A549 non-small cell lung cancer (NSCLC) cells were studied on 24 cSAPs, named cSAP#1-cSAP#24, where surface topography and wettability were distinct. The results showed that cell adhesion and cell spreading were generally reduced on cSAPs compared to the flat controls. In addition, the synergistic effect of cSAPs and several chemo drugs on cell survival was investigated. Interestingly, A549 cells were more sensitive to the combination of doxorubicin and cSAP#4. Under this condition, the focal adhesion kinase (FAK) signaling was downregulated while p53 signaling was upregulated, confirmed by real-time PCR and western blot analysis. It indicates that the specific surface structure could induce higher drug sensitivity and in vitro anoikis of A549 cells. A serum alternative, human platelet lysate (hPL), and different cSAPs were examined to verify our hypothesis. The result further confirmed that cell adhesion strongly affected the drug sensitivity of A549 cells. This study demonstrates that the tumor ECM is vital in cancer cell activity and drug sensitivity; therefore, it should be considered in drug discovery and therapeutic regimens.

Hyaluronan: molecular size-dependent signaling and biological functions in inflammation and cancer

Hyaluronan (HA) is a linear nonsulfated glycosaminoglycan of the extracellular matrix that plays a pivotal role in a variety of biological processes. High-molecular weight HA exhibits different biological properties than oligomers and low-molecular weight HA. Depending on their molecular size, HA fragments can influence cellular behavior in a different mode of action. This phenomenon is attributed to the different manner of interaction with the HA receptors, especially CD44 and RHAMM. Both receptors can trigger signaling cascades that regulate cell functional properties, such as proliferation migration, angiogenesis, and wound healing. HA fragments are able to enhance or attenuate the HA receptor-mediated signaling pathways, as they compete with the endogenous HA for binding to the receptors. The modulation of these pathways could be crucial for the development of pathological conditions, such as inflammation and cancer. The primary goal of this review is to critically present the importance of HA molecular size on cellular signaling, functional cell properties, and morphology in normal and pathological conditions, including inflammation and cancer. A deeper understanding of these mechanisms could contribute to the development of novel therapeutic strategies.

Combined Treatment with Hyaluronic Acid and Mesalamine Protects Rats from Inflammatory Bowel Disease Induced by Intracolonic Administration of Trinitrobenzenesulfonic Acid

Drugs such as mesalamine (5-ASA) are currently recommended for the treatment of inflammatory bowel disease (IBD). To reduce the frequency of their administration and improve their therapeutic effect, this study investigated the adhesion efficacy, wound healing promotion, and decrease in inflammation in ulcers in the colonic tissue of rats with colitis after combined treatment with hyaluronic acid (HA) and 5-ASA (IBD98-M). HA-fluoresceinamine (FL) conjugates successfully adhered to the mucosal layer and were conjugated in the vascular tissue. In addition, macroscopic and microscopic observations indicated that colonic injuries reduced significantly after treatment with IBD98-M. Compared with PBS and 5-ASA treatment alone, treatment with IBD98-M more effectively reduced bowel inflammation and promoted colonic mucosal healing in TNBS-induced colitis. IBD98-M treatment also reduced myeloperoxidase activity and the expression levels of cyclooxygenase 2 and tumor necrosis factor-αin the colitis tissue. In conclusion, IBD98-M treatment strongly promoted wound healing in colonic injuries and significantly inhibited MPO activity in the inflamed colon tissue of rats. Combined treatment with HA and 5-ASA can accelerate wound healing and reduce inflammatory reaction in rat colitis.

Effect of thiolated glycosaminoglycans on the behavior of breast cancer cells: toward the development of in vitro models of cancer

PURPOSE

The influence of extracellular matrix components like glycosaminoglycans (GAG) or adhesive proteins on the migration of cancer cells and the progression of tumorigenesis remains a challenging task. Therefore, this study aims to give insight into the interaction of cancer cells exhibiting different metastatic potential (MDA-MB-231, MDA-MB-468) with surface immobilized GAG interacting with serum proteins like fibronectin.

METHODS

Model substrata were covalently coated with different thiolated GAG (hyaluronan (HA), chondroitin sulfate (CS), heparin (Hep)) and investigated for the adsorption of fibronectin (FN) with surface plasmon resonance. Then, adhesion of breast cancer cells in the presence of and without serum proteins was studied. Further, the outgrow behavior of confluent cancer cells was examined with the help of cell migration chambers and single-cell migration with time-lapse microscopy.

RESULTS

FN adsorption revealed that the Hep-coated surfaces were able to adsorb significantly more protein than CS and HA. Generally, initial adhesion of breast cancer cells on GAG-coated substrata was inhibited for HA- and CS-coated substrata in the presence of serum proteins for both cell lines in comparison to serum-free conditions. The cell size was also significantly decreased by the influence of serum proteins. The outgrow studies clearly confirmed the different migration speed of both cancer cells while single-cell migration was particularly enhanced on HA-coated surfaces.

CONCLUSIONS

The results reveal that adsorption of serum proteins (e.g. albumin) possess an inhibiting effect on the adhesion of breast cancer cells and that single-cell migration is enhanced for both breast cancer cell lines on HA.

Carbohydrate microarrays for screening functional glycans

Carbohydrate microarrays were used for the simultaneous screening of various glycans whose binding to the cell-surface lectin elicits cellular response.

Carbohydrate microarrays have become robust and powerful tools for the rapid analysis of glycan-associated binding events. However, this microarray technology has rarely been applied in studies of glycan-mediated cellular responses. Herein we describe a carbohydrate microarray-based approach for the rapid screening of biologically active glycans that stimulate the production of reactive oxygen species (ROS) through binding to the cell-surface lectin. We employed a microarray assay and a fluorescent ROS probe to identify the functional glycans which enhance ROS production. Cells binding to glycans on the microarrays produced ROS, whose levels were decreased in the presence of a ROS scavenger or a NADPH oxidase inhibitor. The present study leads us to suggest that glycan microarrays are applicable to the simultaneous screening of various glycans whose binding to the cell-surface lectin elicits cellular response.

The motile breast cancer phenotype roles of proteoglycans/glycosaminoglycans

The consecutive stages of cancer growth and dissemination are obligatorily perpetrated through specific interactions of the tumor cells with their microenvironment. Importantly, cell-associated and tumor microenvironment glycosaminoglycans (GAGs)/proteoglycan (PG) content and distribution are markedly altered during tumor pathogenesis and progression. GAGs and PGs perform multiple functions in specific stages of the metastatic cascade due to their defined structure and ability to interact with both ligands and receptors regulating cancer pathogenesis. Thus, GAGs/PGs may modulate downstream signaling of key cellular mediators including insulin growth factor receptor (IGFR), epidermal growth factor receptor (EGFR), estrogen receptors (ERs), or Wnt members. In the present review we will focus on breast cancer motility in correlation with their GAG/PG content and critically discuss mechanisms involved. Furthermore, new approaches involving GAGs/PGs as potential prognostic/diagnostic markers or as therapeutic agents for cancer-related pathologies are being proposed.

Hyaluronic acid hydrogel stiffness and oxygen tension affect cancer cell fate and endothelial sprouting

Three-dimensional (3D) tissue culture models may recapitulate aspects of the tumorigenic microenvironment in vivo, enabling the study of cancer progression in vitro. Both hypoxia and matrix stiffness are known to regulate tumor growth. Using a modular culture system employing an acrylated hyaluronic acid (AHA) hydrogel, three hydrogel matrices with distinctive degrees of viscoelasticity - soft (78±16 Pa), medium (309± 57 Pa), and stiff (596± 73 Pa) - were generated using the same concentration of adhesion ligands. Oxygen levels within the hydrogel in atmospheric (21 %), hypoxic (5 %), and severely hypoxic (1 %) conditions were assessed with a mathematical model. HT1080 fibrosarcoma cells, encapsulated within the AHA hydrogels in high densities, generated nonuniform oxygen distributions, while lower cell densities resulted in more uniform oxygen distributions in the atmospheric and hypoxic environments. When we examined how varying viscoelasticity in atmospheric and hypoxic environments affects cell cycles and the expression of BNIP3 and BNIP3L (autophagy and apoptosis genes), and GLUT-1 (a glucose transport gene), we observed that HT1080 cells in 3D hydrogel adapted better to hypoxic conditions than those in a Petri dish, with no obvious correlation to matrix viscoelasticity, by recovering rapidly from possible autophagy/apoptotic events and alternating metabolism mechanisms. Further, we examined how HT1080 cells cultured in varying viscoelasticity and oxygen tension conditions affected endothelial sprouting and invasion. We observed that increased matrix stiffness reduced endothelial sprouting and invasion in atmospheric conditions; however, we observed increased endothelial sprouting and invasion under hypoxia at all levels of matrix stiffness with the upregulation of vascular endothelial growth factor (VEGF) and angiopoeitin-1 (ANG-1). Overall, HT1080 cells encapsulated in the AHA hydrogels under hypoxic stress recovered better from apoptosis and demonstrated greater angiogenic induction. Thus, we propose that oxygen tension more profoundly influences cell fate and the angiogenic potential of 3D cultured HT1080 fibrosarcoma cells than does matrix stiffness.

A physical sciences network characterization of non-tumorigenic and metastatic cells

To investigate the transition from non-cancerous to metastatic from a physical sciences perspective, the Physical Sciences–Oncology Centers (PS-OC) Network performed molecular and biophysical comparative studies of the non-tumorigenic MCF-10A and metastatic MDA-MB-231 breast epithelial cell lines, commonly used as models of cancer metastasis. Experiments were performed in 20 laboratories from 12 PS-OCs. Each laboratory was supplied with identical aliquots and common reagents and culture protocols. Analyses of these measurements revealed dramatic differences in their mechanics, migration, adhesion, oxygen response, and proteomic profiles. Model-based multi-omics approaches identified key differences between these cells' regulatory networks involved in morphology and survival. These results provide a multifaceted description of cellular parameters of two widely used cell lines and demonstrate the value of the PS-OC Network approach for integration of diverse experimental observations to elucidate the phenotypes associated with cancer metastasis.

Cross-talk between estradiol receptor and EGFR/IGF-IR signaling pathways in estrogen-responsive breast cancers: focus on the role and impact of proteoglycans

In hormone-dependent breast cancer, estrogen receptors are the principal signaling molecules that regulate several cell functions either by the genomic pathway acting directly as transcription factors in the nucleus or by the non-genomic pathway interacting with other receptors and their adjacent pathways like EGFR/IGFR. It is well established in literature that EGFR and IGFR signaling pathways promote cell proliferation and differentiation. Moreover, recent data indicate the cross-talk between ERs and EGFR/IGFR signaling pathways causing a transformation of cell functions as well as deregulation on normal expression pattern of matrix molecules. Specifically, proteoglycans, a major category of extracellular matrix (ECM) and cell surface macromolecules, are modified during malignancy and cause alterations in cancer cell signaling, affecting eventually functional cell properties such as proliferation, adhesion and migration. The on-going strategies to block only one of the above signaling effectors result cancer cells to overcome such inactivation using alternative signaling pathways. In this article, we therefore review the underlying mechanisms in respect to the role of ERs and the involvement of cross-talk between ERs, IGFR and EGFR in breast cancer cell properties and expression of extracellular secreted and cell bound proteoglycans involved in cancer progression. Understanding such signaling pathways may help to establish new potential pharmacological targets in terms of using ECM molecules to design novel anticancer therapies.

Glycomics approaches for the bioassay and structural analysis of heparin/heparan sulphates

The glycosaminoglycan heparan sulphate (HS) has a heterogeneous structure; evidence shows that specific structures may be responsible for specific functions in biological processes such as blood coagulation and regulation of growth factor signalling. This review summarises the different experimental tools and methods developed to provide more rapid methods for studying the structure and functions of HS. Rapid and sensitive methods for the facile purification of HS, from tissue and cell sources are reviewed. Data sets for the structural analysis are often complex and include multiple sample sets, therefore different software and tools have been developed for the analysis of different HS data sets. These can be readily applied to chromatographic data sets for the simplification of data (e.g., charge separation using strong anion exchange chromatography and from size separation using gel filtration techniques. Finally, following the sequencing of the human genome, research has rapidly advanced with the introduction of high throughput technologies to carry out simultaneous analyses of many samples. Microarrays to study macromolecular interactions (including glycan arrays) have paved the way for bioassay technologies which utilize cell arrays to study the effects of multiple macromolecules on cells. Glycan bioassay technologies are described in which immobilisation techniques for saccharides are exploited to develop a platform to probe cell responses such as signalling pathway activation. This review aims at reviewing available techniques and tools for the purification, analysis and bioassay of HS saccharides in biological systems using "glycomics" approaches.

Patterning microscale extracellular matrices to study endothelial and cancer cell interactions in vitro

The extracellular matrix (ECM) of the tumor niche provides support to residing and migrating cells and presents instructive cues that influence cellular behaviours. The ECM protein fibronectin (Fn) enables vascular network formation, while hyaluronic acid (HA) is known to facilitate breast tumor development. To recapitulate aspects of the tumor microenvironment, we developed systems of spatially defined Fn and HA for the co-culture of endothelial colony forming cells (ECFCs) and breast cancer cells (BCCs). A micropatterned system was developed using sequential microcontact printing of HA and Fn. This approach supported the preferential adhesion of ECFCs to Fn, but did not support the preferential adhesion of BCCs to HA. Thus, we developed a microstructured analog to spatially organize BCC-laden HA micromolded hydrogels adjacent to ECFCs in fibrin hydrogels. These novel, miniaturized systems allow the analysis of the spatial and temporal mechanisms regulating tumor angiogenesis, and can be applied to mimic other microenvironments of healthy and diseased tissues.

Array-based functional screening of heparin glycans

Array methodologies have become powerful tools for interrogation of glycan-protein interactions but have critically lacked the ability to generate cell response data. Here, we report the development of a slide-based array method exemplified by measurement of activation of fibroblast growth factor signaling by heparin saccharides. Heparan sulfate-deficient Swiss 3T3 cells were overlaid onto an aminosilane-coated slide surface onto which heparin saccharides had been spotted and immobilized. The cells were transiently stimulated with FGF2 and immunofluorescence measured to assess downstream ERK1/2 phosphorylation. Activation of this signaling pathway response was restricted to cells exposed to heparin saccharides competent to activate FGF2 signaling. Differential activation of the overlaid cells by different-sized heparin saccharides was demonstrated by quantitative measurement of fluorescence intensity. This "glycobioarray" platform has significant potential as a generic tool for functional glycomics screening.

Micropatterned surfaces to study hyaluronic acid interactions with cancer cells

Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix (ECM) components within the tumor microenvironment. Hyaluronic acid (HA) is one stromal ECM component that is known to facilitate tumor progression by enhancing invasion, growth, and angiogenesis(1). Interaction of HA with its cell surface receptor CD44 induces signaling events that promote tumor cell growth, survival, and migration, thereby increasing metastatic spread(2-3). HA is an anionic, nonsulfated glycosaminoglycan composed of repeating units of D-glucuronic acid and D-N-acetylglucosamine. Due to the presence of carboxyl and hydroxyl groups on repeating disaccharide units, native HA is largely hydrophilic and amenable to chemical modifications that introduce sulfate groups for photoreative immobilization (4-5). Previous studies involving the immobilizations of HA onto surfaces utilize the bioresistant behavior of HA and its sulfated derivative to control cell adhesion onto surfaces(6-7). In these studies cell adhesion preferentially occurs on non-HA patterned regions. To analyze cellular interactions with exogenous HA, we have developed patterned functionalized surfaces that enable a controllable study and high-resolution visualization of cancer cell interactions with HA. We utilized microcontact printing (uCP) to define discrete patterned regions of HA on glass surfaces. A "tethering" approach that applies carbodiimide linking chemistry to immobilize HA was used (8). Glass surfaces were microcontact printed with an aminosilane and reacted with a HA solution of optimized ratios of EDC and NHS to enable HA immobilization in patterned arrays. Incorporating carbodiimide chemistry with mCP enabled the immobilization of HA to defined regions, creating surfaces suitable for in vitro applications. Both colon cancer cells and breast cancer cells implicitly interacted with the HA micropatterned surfaces. Cancer cell adhesion occurred within 24 hours with proliferation by 48 hours. Using HA micropatterned surfaces, we demonstrated that cancer cell adhesion occurs through the HA receptor CD44. Furthermore, HA patterned surfaces were compatible with scanning electron microscopy (SEM) and allowed high resolution imaging of cancer cell adhesive protrusions and spreading on HA patterns to analyze cancer cell motility on exogenous HA.

Reconstructing the differentiation niche of embryonic stem cells using biomaterials

The biochemical cues and topographical architecture of the extracellular environment extensively influence ES cell fate. The microenvironment surrounding the developing embryo presents these instructive cues in a complex and interactive manner in order to guide cell fate decisions. Current stem cell research aims to reconstruct this multifaceted embryonic niche to recapitulate development in vitro. This review focuses on 2D and 3D differentiation niches created from natural and synthetic biomaterials to guide the differentiation of ES cells toward specific lineages. Biomaterials engineered to present specific physical constraints are also reviewed for their role in differentiation.