Downregulation of NKD1 in human osteosarcoma and its clinical significance.

Naked cuticle homolog 1 (NKD1), a negative modulator of the canonical Wnt/β-catenin pathway, is expressed in multiple normal tissues. However, there is little information regarding NKD1 expression in osteosarcoma. The aim of the present study was to explore the expression and clinicopathological significance of NKD1 in human osteosarcoma. In the present study, NKD1 protein and mRNA expression levels were detected by western blotting and reverse transcription-quantitative polymerase chain reaction, respectively. The results revealed that NKD1 expression levels were significantly lower in osteosarcoma tissues compared with normal bone tissue, and were significantly lower in patients with lung metastasis compared with patients without lung metastasis. In addition, with increasing Enneking stage, the NKD1 expression levels decreased. These data indicated that reduction of NKD1 may be associated with carcinogenesis, lung metastasis and Enneking stage in osteosarcoma. This interpretation is consistent with the results obtained from experiments on MG63 osteosarcoma cells in vitro. In order to explore the function of NKD1 in osteosarcoma, the expression of NKD1 in the human osteosarcoma MG-63 cell line was upregulated by transfection with an adenovirus containing an NKD1 vector. The results revealed that upregulation of NKD1 expression reduced the proliferation and migration of osteosarcoma cells by inhibiting expression of β-catenin, cyclin D1 and MMP-9 protein. These data suggested that the downregulation of NKD1 may be involved in the proliferation and migration of osteosarcoma cells through the activation of the canonical Wnt signaling pathway, and it may be a potential prognostic marker and therapeutic target for patients with osteosarcoma. [ABSTRACT FROM AUTHOR]