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

Background: Sodium hyaluronate has been used intraperitoneally to prevent postoperative 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 treated with sodium hyaluronate (10-500μg/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 × 10⁶ DHD/ K12 tumour cells and 5ml 0.4 per cent sodium hyaluronate) or a phosphate-buffered saline group (n= 11; 0.5 × 10⁶ DHD/K12 tumour cells and 5ml phosphate-buffered saline intraperitoneally). Four weeks later the intraperitoneal tumour load was visualized directly. Results: In vitro sodium hyaluronate increased tumour cell proliferation and motility significantly. Sodium hyaluronate-induced tumour cell motility appeared to be CD44 receptor dependent, whereas sodium hyaluronate-induced tumour cell proliferation was CD44 receptor independent. In vivo there was a significantly higher total tumour nodule count in the peritoneal cavity of the sodium hyaluronatetreated group compared with the control (P = 0.016). Conclusion: Sodium hyaluronate enhances tumour metastatic potential in vitro and in vivo, which suggests that use of sodium hyaluronate to prevent adhesions in colorectal cancer surgery may also potentiate intraperitoneal tumour growth.