A cell surface chondroitin sulfate proteoglycan, immunologically related to CD44, is involved in type I collagen-mediated melanoma cell motility and invasion.

Abstract

The metastatic spread of tumor cells occurs through a complex series of events, one of which involves the adhesion of tumor cells to extracellular matrix (ECM) components. Multiple interactions between cell surface receptors of an adherent tumor cell and the surrounding ECM contribute to cell motility and invasion. The current studies evaluate the role of a cell surface chondroitin sulfate proteoglycan (CSPG) in the adhesion, motility, and invasive behavior of a highly metastatic mouse melanoma cell line (K1735 M4) on type I collagen matrices. By blocking mouse melanoma cell production of CSPG with p-nitrophenyl beta-D-xylopyranoside (beta-D-xyloside), a compound that uncouples chondroitin sulfate from CSPG core protein synthesis, we observed a corresponding decrease in melanoma cell motility on type I collagen and invasive behavior into type I collagen gels. Melanoma cell motility on type I collagen could also be inhibited by removing cell surface chondroitin sulfate with chondroitinase. In contrast, type I collagen-mediated melanoma cell adhesion and spreading were not affected by either beta-D-xyloside or chondroitinase treatments. These results suggest that mouse melanoma CSPG is not a primary cell adhesion receptor, but may play a role in melanoma cell motility and invasion at the level of cellular translocation. Furthermore, purified mouse melanoma cell surface CSPG was shown, by affinity chromatography and in solid phase binding assays, to bind to type I collagen and this interaction was shown to be mediated, at least in part, by chondroitin sulfate. Additionally we have determined that mouse melanoma CSPG is composed of a 110-kD core protein that is recognized by anti-CD44 antibodies on Western blots. Collectively, our data suggests that interactions between a cell surface CD44-related CSPG and type I collagen in the ECM may play an important role in mouse melanoma cell motility and invasion, and that the chondroitin sulfate portion of the proteoglycan seems to be a critical component in mediating this effect.

CD44-related chondroitin sulfate proteoglycan, a cell surface receptor implicated with tumor cell invasion, mediates endothelial cell migration on fibrinogen and invasion into a fibrin matrix.

“…For chondroitinase ABC treatment, cells were pretreated with varying concentrations of chondroitinase ABC (15 min, 37 Њ C; Sigma Chemical Co.) before adhesion and migration assays as previously described (13). Chondroitinase ABC was also included in the cell medium during the adhesion and migration assays.…”

“…The cellular extracts were centrifuged (1,500 rpm, 5 min) to remove insoluble material. The extracts were dialyzed (mol wt cut off 3,500) against successive changes of acetate buffer (0.5 M C 2 H 3 O 2 Na, pH 6.8, 0.1 Na 2 SO 4 , 10 mM EDTA, 0.1 mM PMSF, 10 mM 6-aminohexanoic acid) until the amount of radioactivity in the dialysate buffer was at background levels (13).…”

“…Microspikes are a specific cell surface microdomain believed to facilitate the initial contact of the cell with the ECM. Melanoma cell surface CSPG, which contains a core protein recognized by CD44 antibodies, plays an important role in mediating melanoma cell motility and invasion into type I collagen gels (13). Although the mechanism by which cell surface CD44-related CSPG mediates tumor cell migration and invasion remains to be elucidated, CD44 has been implicated in mediating cell-cell and cell-ECM interactions and is associated with the cell cytoskeleton (14,15) and plays a role in cell migration (16).…”

Antibodies to CD44 enhance adhesion of normal CD34+ cells and acute myeloblastic but not lymphoblastic leukaemia cells to bone marrow stroma

“…The larger isoform fails to bind hyaluronic acid but does adhere to the extracellular matrix proteins fibronectin, laminin and collagen (Wayner & Carter, 1987). Removal of the chondroitin sulphate side chains eliminates this binding (Faassen et al, 1992;. CD44 is also known to bind chondroitin sulphate containing ligands such as serglycin (Naujokas et al, 1993;Toyama-Sorimachi et al, 1995).…”

A6 Peptide Activates CD44 Adhesive Activity, Induces FAK and MEK Phosphorylation, and Inhibits the Migration and Metastasis of CD44-Expressing Cells

“…In addition to HA, CD44 can bind several other extracellular matrix ligands including osteopontin (10,11), fibronectin (12), and collagen (13), and it interacts with other membrane proteins, including HER2 (14). Three discrete regions of CD44 interact with HA (15)(16)(17)(18).…”