Abstract
Parathyroid hormone (PTH) strongly stimulates hyaluronan (HA) synthesis and secretion of both normal and carcinogenic cells of the osteoblastic lineage and improves skeletal microarchitecture. HA, a glycosaminoglycan component of the extracellular matrix (ECM), is capable of transmitting ECM‐derived signals to regulate cellular function. In this study, we investigated whether the changes of HA metabolism induced by PTH (1–34) and PTH (7–84) peptides in moderately MG‐63 and well‐differentiated Saos 2 osteosarcoma cell lines, are correlated to their migration capabilities. Our results demonstrate that intermittent PTH (1–34) treatment significantly (P ≤ 0.01) supported the migration of MG‐63 cells, increased their HA‐synthase‐2 (HAS2) expression (P ≤ 0.001), and enhanced their high‐molecular size HA deposition in the pericellular matrix. Both increased endogenous HA production (P ≤ 0.01) and treatment with exogenous high‐molecular weight HA (P ≤ 0.05) correlated to a significant increase of MG‐63 cell migration capacity. Transfection with siHAS2 showed that PTH (1–34), mainly through HAS2, enhanced HA and regulated MG‐63 cell motility. Interestingly, continuous PTH (1–34) treatment stimulated both Saos 2 cell HAS2 (P ≤ 0.001) and HAS1 (P ≤ 0.001) isoform expression inhibited their HYAL2 expression (P ≤ 0.001) and modestly (P ≤ 0.05) enhanced their migration. Therefore, the PTH (1–34) administration mode appears to distinctly modulate the migratory responses of the MG‐63 moderately and Saos 2 well‐differentiated osteosarcoma cell lines. Conclusively, the obtained data suggest that there is a regulatory effect of PTH (1–34), in an administration mode‐dependent manner, on HA metabolism that is essential for osteosarcoma cell migration. © 2010 IUBMB IUBMB Life, 62(5): 377–386, 2010