Extracellular matrix (ECM) is closely correlated with the malignant behavior of breast cancer cells. Hyaluronan (HA) is one of the main components of ECM, and actively regulates cell adhesion, migration and proliferation by interacting with specific cell surface receptors such as CD44 and RHAMM. HA synthase 2 (HAS2) catalyzes the synthesis of HA, but its role in breast tumorigenesis remains unclear. This study assessed the roles of HAS2 in malignant behavior of human breast cancer and sought to provide mechanistic insights into the biological and pivotal roles of HAS2. We observed HAS2 was overexpressed in breast cancer cell lines and invasive duct cancer tissues, compared with the nonmalignant breast cell lines and normal breast tissues. In addition, a high level of HAS2 expression was statistically correlated with lymph node metastasis. Functional assays showed that knockdown of HAS2 expression inhibited breast tumor cell proliferation in vivo and in vitro, through the induction of apoptosis or cell cycle arrest. Further studies showed that the HA were elevated in breast cancer, and HAS2 could upregulate HA expression. In conclusion, HAS2-HA system influences the biological characteristics of human breast cancer cells, and HAS2 may be a potential prognostic marker and therapeutic target in breast cancer.
Keywords: Breast cancer; RNA interference; hyaluronan; hyaluronan synthase 2; metastasis; tumorigenesis.