Objective: To investigate the role of the dosage-sensitive sex reversal-adrenal hypoplasia congenita region on the X chromosome 1 (DAX-1) in autophagy and proliferation of pituitary tumor cells. Methods: The differential gene group between pituitary tumors and normal pituitaries was screened by Microarray and the expression difference of DAX-1 between invasive pituitary tumor and non-invasive pituitary tumor was analyzed by Pubmed database. The expression of DAX-1 pair was knocked down by small interfering RNAs (siRNA), and the effect of DAX-1 on MMQ cells proliferation was detected by CCK-8 and colony formation assays. The expression of autophagy related genes ATG5, ATG7 and ATG12 was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Western blot and immunofluorescence experiments were performed to detect the effect of DAX-1 on the expression of LC3. Finally, xenograft experiments in nude mice was made to
observe the effect of DAX-1 knockdown on the growth and autophagy of pituitary tumor cells. Results: Compared with normal pituitary tumors, the DAX-1 gene expression was significantly down-regulated in pituitary tumors,and was lower in invasive and non-invasive pituitary tumors (P<0.05). Knockdown DAX-1 could promote MMQ cells proliferation, while overexpression of DAX-1 inhibited proliferation of MMQ cells and promoted drug sensitivity of cabergoline and bromocriptine (P<0.05). In addition, knocking-down DAX-1 could inhibit the autophagy level in MMQ cells. It was proved that knocking down DAX-1 promoted tumor growth in vivo (P<0.05). Conclusion: The DAX-1 expression is decreased in pituitary tumors, and the decreased DAX-1 promotes the development of pituitary tumors. DAX-1 may be a potential therapeutic target for pituitary tumors.