Sodium hyaluronate enhances colorectal tumour cell metastatic potential invitro and in vivo

Background: Sodium hyaluronate has been used intraperitoneally to prevent p ostoperative adhesions. However, the effect of sodium hyaluronate on tumour growth and metastasis in vitro and in vivo is still unknown. Methods: Human colorectal tumour cell lines SW480, SW620 and SW707 were tre ated with sodium hyaluronate (10-500 mug/ml) and carboxymethylcellulose (0. 125-1 per cent), and tumour cell proliferation and motility were determined in vitro. For the in vivo experiments male BD IX rats were randomized to a sodium hyaluronate group (n = 11; intraperitoneal administration of 0.5 x 10(6) DHD/K12 tumour cells and 5 ml 0.4 per cent sodium hyaluronate) or a p hosphate-buffered saline group (n = 11; 0.5 x 10(6) DHD/K12 tumour cells an d 5 ml phosphate-buffered saline intraperitoneally). Four weeks later the i ntraperitoneal tumour load was visualized directly. Results: In vitro sodium hyaluronate increased tumour cell proliferation an d motility significantly. Sodium hyaluronate-induced tumour cell motility a ppeared to be CD44 receptor dependent, whereas sodium hyaluronate-induced t umour cell proliferation was CD44 receptor independent. In vivo there was a significantly higher total tumour nodule count in the peritoneal cavity of the sodium hyaluronate-treated group compared with the control (P = 0.016) . Conclusion: Sodium hyaluronate enhances tumour metastatic potential in vitr o and in vivo, which suggests that use of sodium hyaluronate to prevent adh esions in colorectal cancer surgery may also potentiate intraperitoneal tum our growth.