CD44-Mediated Adhesion to Hyaluronic Acid Contributes to Mechanosensing and Invasive Motility

Abstract

The high molecular weight glycosaminoglycan, hyaluronic acid (HA), makes up a significant portion of the brain extracellular matrix (ECM). Glioblastoma multiforme (GBM), a highly invasive brain tumor, is associated with aberrant HA secretion, tissue stiffening, and overexpression of the HA receptor CD44. Here, transcriptomic analysis, engineered materials, and measurements of adhesion, migration, and invasion were used to investigate how HA/CD44 ligation contributes to the mechanosensing and invasive motility of GBM tumor cells, both intrinsically and in the context of RGD/integrin adhesion. Analysis of transcriptomic data from The Cancer Genome Atlas (TCGA) reveals up-regulation of transcripts associated with HA/CD44 adhesion. CD44 suppression in culture reduces cell adhesion to HA on short time scales (0.5h post-incubation) even if RGD is present, whereas maximal adhesion on longer time scales (3h) requires both CD44 and integrins. Moreover, time-lapse imaging demonstrates that cell adhesive structures formed during migration on bare HA matrices are more short-lived than cellular protrusions formed on surfaces containing RGD. Interestingly, adhesion and migration speed were dependent on HA hydrogel stiffness, implying that CD44-based signaling is intrinsically mechanosensitive. Finally, CD44 expression paired with an HA-rich microenvironment maximized three-dimensional invasion, whereas CD44 suppression or abundant integrin-based adhesion limited it. These findings demonstrate that CD44 transduces HA-based stiffness cues, temporally precedes integrin-based adhesion maturation, and facilitates invasion.

Anti-tumor and anti-invasion effects of a combination of 4-methylumbelliferone and ionizing radiation in human fibrosarcoma cells

“…A highly potent invasive tumor exhibits aberrant secretion of HA and overexpression of cluster of differentiation 44 antigen, which acts as the HA receptor (16). HA is produced from injured tissue stroma and is rapidly deposited in the extracellular matrix, where it regulates repair processes through cross-talk with various inflammatory conditions, including carcinogenesis (17).…”

Tissue mechanics regulate brain development, homeostasis and disease

“…This hyaluronic-acid-lectican-TNC complex (a corrupted version of the PNN structure described above and shown in Fig. 3A) stiffens the tumor tissue relative to normal brain by limiting the flexibility of the ECM Day et al, 2004;Kim and Kumar, 2014). Because increased amounts of hyaluronic acid are produced in GBMs (Fig.…”

Biomimetic Strategies for the Glioblastoma Microenvironment

“…Irrelevant components of the brain ECM, such as chitosan-alginate hydrogels (Kievit et al, 2010) and collagen-agarose hydrogels (Ulrich et al, 2010), were chosen because they have a biologically inert to investigate biophysical effects of the matrices solely, resulting in a mechanosensitive Umesh et al, 2014), have been performed to examine the role of mechanobiological regulation in GBM invasion. For investigating mechanosensing characteristics of GBM cells, the modified forms of HA gels, such as HA-methacrylate (Me-HA) or RGDfunctionalized Me-HA (Ananthanarayanan et al, 2011;Kim and Kumar, 2014), were used to control the matrix stiffness, observing the stiffness-dependent GBM features via CD44-mediated mechanosensing.…”

“…Therefore, to investigate the role of HA in GBM invasion, the HA is chemically modified so that it is cross-linked. Chemically modified forms of HA hydrogels include thiolated HA (Rao et al, 2013a), methacrylated HA (Ananthanarayanan et al, 2011;Kim and Kumar, 2014), and mixtures with GelMA . GBM cells are strongly influenced by the HA concentration and show increased invasion via CD44-mediated HA adhesion (Kim and Kumar, 2014).…”

“…Chemically modified forms of HA hydrogels include thiolated HA (Rao et al, 2013a), methacrylated HA (Ananthanarayanan et al, 2011;Kim and Kumar, 2014), and mixtures with GelMA . GBM cells are strongly influenced by the HA concentration and show increased invasion via CD44-mediated HA adhesion (Kim and Kumar, 2014). Physical blending with other cross-linkable hydrogels, such as collagen, is another means of incorporating HA components into ECM-mimetic model system.…”