Background: Osteopontin-1 is a well characterized protein in many tumour entities. Multiple roles in the processes invasion, metastasis and angiogenesis of tumours are attributed to osteopontin-1. The putative role of osteopontin-1 has not been characterized for endometrial cancer.
Material and methods: We investigated multiple endometrial cancer cell lines for osteopontin-1 mRNA- and protein-expression. Osteopontin-1 dependent effects were analysed in vitro by siRNA inhibition.
Results: All endometrial cell lines expressed osteopontin-1. Expression of osteopontin-1 was successfully inhibited by specific siRNA. Cells with reduced osteopontin-1 expression showed decreased migration in the Boyden chamber assay and invasion was reduced in the wound-healing assay. Osteopontin-1 seems to play a role in apoptotic processes of endometrial cancer cells. Inhibition of osteopontin-1 expression was associated with an increased susceptibility for radiation therapy.
Conclusion: Osteopontin-1 seems to play a role in endometrial cancer. Inhibition of osteopontin-1 expression leads to a higher susceptibility for radiation therapy. Our results suggest that a reduced expression of osteopontin-1 in endometrial cancer could inhibit the development of invasion and metastasis in these cells.