HYAL1 overexpression is correlated with the malignant behavior of human breast cancer

Extracellular matrix (ECM) is closely correlated with tumor cell growth, proliferation, metastasis and angiogenesis, etc. Hyaluronic acid (HA) is a component of the ECM, and hyaluronidase (HAase) is a HA-degrading endoglycosidase. Levels of HAase are elevated in many cancers. Hyaluronidase-1 (HYAL1) is the major tumor-derived HAase. In this study, we detected HYAL1 expression levels in breast cancer cells and tissues, and measured the amount HAase activity in breast cancer cells. Compared with nonmalignant breast cell line HBL-100 and normal breast tissues, HYAL1 were overexpressed in breast cancer cell lines MDA-MB-231, MCF-7, invasive duct cancer tissues and metastatic lymph nodes, respectively. Accordingly, the amount HAase activity in MDA-MB-231 and MCF-7 was higher than that in HBL-100. In addition, knockdown of HYAL1 expression in MDA-MB-231 and MCF-7 cells resulted in decreased cell growth, adhesion, invasion and angiogenesis potential. Meantime, the HYAL1 knockdown markedly inhibited breast cancer cell xenograft tumor growth and microvessel density. Further studies showed that the HYAL1, HYAL2 and HA were elevated in breast cancer, and HYAL1 could downregulate HA expression. In conclusion, HYAL1 may be a potential prognostic marker and therapeutic target in breast cancer.