SIRT1 Suppresses Pituitary Tumor Progression by Downregulating PTTG1 Expression

Abstract Pituitary tumor is among the most common types of brain tumor, and the underlying molecular mechanism of this disease is still obscure. Here we found downregulation of SIRT1 in tumor tissues of pituitary tumor patients by real-time PCR and immunohistochemistry staining. In vitro studies reveal that upregulation of SIRT1 suppresses pituitary tumor cell line growth, and vice versa. We also find that enzymatic activity of SIRT1 is required for its cellular function. Mechanism study uncovers that SIRT1 negatively regulates PTTG1 expression by deacetylation of H3K9ac at promoter region of PTTG1. Moreover, H3K9ac level at PTTG1 promoter is an essential regulatory element for PTTG1 expression. Thus SIRT1/H3K9ac/PTTG1 axis contributes to pituitary tumor formation and may provide further potential therapeutic opportunity.