NEK2 regulates cellular proliferation and cabergoline sensitivity in pituitary adenomas

Objective: To identify critical roles played by NEK2 in prolactinomas and to clarify the corresponding underlying mechanisms. Methods: We performed RNA-seq on MMQ cell lines treated with the dopamine receptor agonist cabergoline (CAB) to identify genes involved in prolactinoma progression and dopamine receptor-agonist (DA) sensitivity. NEK2 was then selected for further study. The expression of NEK2 was examined using quantitative real-time PCR, western immunoblotting, and immunohistochemistry - both in pituitary adenomas (PA) and in normal pituitary tissue. We used gain-of-function and loss-of-function assays to explore the biologic roles of NEK2 in cell growth in vivo and in vitro. Co-immunoprecipitation was also used to detect the binding between NEK2 and USP7. Results: Herein, we reported that NEK2 was upregulated in prolactinomas, particularly dopamine-resistant prolactinomas. NEK2 overexpression significantly promoted pituitary tumor GH3 and MMQ cell proliferation, and it impaired cellular sensitivity to CAB. Conversely, knockdown of NEK2 inhibited GH3 and MMQ cell growth, and sensitized the cells to CAB. Mechanistically, NEK2 regulated cell proliferation via the Wnt-signaling pathway; and in addition, we demonstrated that USP7 interacted with, deubiquitylated, and stabilized NEK2. Conclusions: Collectively, our results suggest that NEK2 might be a potential therapeutic target for prolactinoma.