Effect of Hypoxia on DDR1 Expression in Pituitary Adenomas

BACKGROUND: Pituitary adenoma is a common intracranial tumor in neurosurgery. Some pituitary adenomas have the characteristics of invasive growth make them unable to be removed completely by surgery leading to easy relapse. Discoidin domain receptor l (DDR1) is a new kind of tyrosine kinase receptor on the cell surface. DDR1 can be activated by tumor microenvironment signal in tumorigenesis, increasing MMP-2/9 expression and promoting the invasive ability of tumor cells. Anoxia can promote tumor growth and metastasis. This study investigated the impact of anoxic environment DDR1 expression in pituitary adenoma. MATERIAL/METHODS: A primary hypoxia pituitary adenoma cell model was established and treated with DDR1 inhibitor nilotinib. Real-time PCR and Western blot were used to detect DDR1 mRNA and protein expression. ELISA was used to detect MMP-2/9 changes. MTT method was used to detect pituitary adenoma cell proliferation. We used a transwell chamber to determine pituitary adenoma cell invasion ability. RESULTS: DDR1 mRNA and protein were significantly overexpressed under hypoxia (P<0.05). MMP-2 and MMP-9 expression was obviously increased in supernatant (P<0.05). Pituitary adenoma cell proliferation and invasive ability improved markedly under hypoxia (P<0.05). Nilotinib could reduce DDR1 expression, decrease MMP-2 and MMP-9 expression, and inhibit pituitary adenoma cells proliferation and invasion. CONCLUSIONS: Hypoxia can increase DDR1 expression in pituitary adenoma cells, leading to improved MMP-2 and MMP-9 secretion, and promoting pituitary adenoma cell proliferation and invasion.