Cell surface heparan sulfate proteoglycans are involved in the extracellular Hsp90-stimulated migration and invasion of cancer cells

Abstract

The extracellular heat shock protein 90 (Hsp90) is known to participate in cell migration and invasion. Recently, we have shown that cell surface heparan sulfate proteoglycans (HSPGs) are involved in the binding and anchoring of extracellular Hsp90 to the plasma membrane, but the biological relevance of this finding was unclear. Here, we demonstrated that the digestion of heparan sulfate (HS) moieties of HSPGs with a heparinase I/III blend and the metabolic inhibition of the sulfation of HS chains by sodium chlorate considerably impair the migration and invasion of human glioblastoma A-172 and fibrosarcoma HT1080 cells stimulated by extracellular native Hsp90. Heparin, a polysaccharide closely related to HS, also reduced the Hsp90-stimulated migration and invasion of cells. Phorbol 12-myristate 13-acetate, an intracellular inducer of cell motility bypassing the ligand activation of receptors, restored the basal migration of heparinase-and chlorate-treated cells almost to the control level, suggesting that the cell motility machinery was insignificantly affected in cells with degraded and undersulfated HS chains. On the other hand, the downstream phosphorylation of AKT in response to extracellular Hsp90 was substantially impaired in heparinase-and chloratetreated cells as compared to untreated cells. Taken together, our results demonstrated for the first time that cell surface HSPGs play an important role in the migration and invasion of cancer cells stimulated by extracellular Hsp90 and that plasma membraneassociated HSPGs are required for the efficient transmission of signal from extracellular Hsp90 into the cell.

A 2,5-Dihydroxybenzoic Acid–Gelatin Conjugate Inhibits the Basal and Hsp90-Stimulated Migration and Invasion of Tumor Cells

“…As we have shown earlier, a part of Hsp90s at the cell surface is bound to HSPGs, which represent a heparin-sensitive fraction of Hsp90 [ 29 ]. HSPG-associated Hsp90s participate in efficient motility-related signaling, and they further cell migration and invasion [ 30 ]. Since the 2,5-DHBA–gelatin conjugate exhibited heparin-like properties, we anticipated that it would disrupt the interaction of Hsp90s with cell surface HSPGs, which may lead to a decrease in cell motility.…”

“…Soluble Hsp90s of the extracellular milieu bind to cell surface receptors and induce signaling related to motility in normal and cancer cells, which enhances their migration and invasion [ 20 , 24 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Earlier we have demonstrated that cell surface HSPGs participate in the binding of Hsp90α and Hsp90β to the cell plasma membrane and that the HSPG-mediated binding of Hsp90s to cells plays a significant role in the Hsp90-stimulated motility [ 29 , 30 ]. Here, we determined how the 2,5-DHBA–gelatin polymeric conjugate affects the attachment of soluble Hsp90 to the surface of cells.…”

“…The effects of 2,5-DHBA–gelatin on the levels of cell surface Hsp90α and Hsp90β and on the basal migration/invasion of cells were similar to those of heparin, but not of dermatan sulfate and chondroitin sulfate A. Cell surface HSPGs are known to participate in the attachment of Hsp90 to the cell plasma membrane and facilitate the interaction of Hsp90s with surface receptors, which is necessary for the efficient motility-related signaling, further cell migration, and invasion [ 29 , 30 ]. Thus, the detachment of cell surface HSPG-associated Hsp90s by the 2,5-DHBA–gelatin polymeric conjugate or by heparin may lead to signaling that does not suffice for the activation of cell motility.…”

“…Earlier, we found that HSPGs associated with the cell surface participate in the binding of soluble extracellular Hsp90 and the anchoring of Hsp90 to the cell plasma membrane [ 29 ]. It was also demonstrated that cell surface-associated HSPGs facilitate the interaction of Hsp90 with surface receptors, which is required for the efficient signaling related to cell motility and further migration and invasion of cells [ 30 ]. Hence, cell-impermeable natural and artificial compounds interfering with the binding of Hsp90 to cell surface HSPGs can be considered as novel drugs targeting the invasion and migration of cancer cells; expectedly, these substances would not affect the vital functions of intracellular Hsp90.…”

Homocysteine Promotes Migration of Adventitial Fibroblasts via Angiotensin II type 1 Receptor Activation to Aggravate Atherosclerosis

“…Cells on the upper surface of the lter were removed using cotton swabs and the membranes were xed and stained with crystal violet reagent. 21,25 Invasion was quanti ed by counting 5 random elds under a light microscope (Leica, Germany) at x40 magni cation.…”