<p>Supplementary Figures S1-S6. Supplementary Fig S1. Histological and immunohistological analysis of a pituitary adenoma from a MENX and 3D organotypic cultures obtained from a rat; Supplementary Fig S2. (A) Expression of phosphorylated (p) AKT and P-S6 proteins in pituitary tumors of MENX mutant rats. (B)Principle component analysis (PCA) of MALDI Imaging proteomics data; Supplementary Fig S3. Hematoxylin and eosin (H&E) staining of MENX-associated pituitary tumors; Supplementary Fig S4. Scatter plot images of gene expression profiling done on NVPBEZ235-treated (Group 1) 3D rat primary NFPA cultures versus DMSO-treated cultures (Control Group); Supplementary Fig S5. Co-IF of BD-1 (green) and LH (red) in human normal pituitary; Supplementary Fig S6. Knock-down of Defb1 in BON1 and QGHP1 cells.</p>
ARTICLE ABSTRACT
Purpose: Novel therapeutic approaches are needed to improve the postoperative management of residual nonfunctioning pituitary adenomas (NFPA), given their high relapse rate. Here, we evaluated the antitumor efficacy of the dual PI3K/mTOR inhibitor NVP-BEZ235 in the only available model of spontaneous NFPAs (MENX rats).Experimental Design: Organotypic cultures of rat primary NFPAs were incubated with NVP-BEZ235 and assessed for cell viability, proliferation, apoptosis, and PI3K/mTOR inhibition. NVP-BEZ235, or placebo, was administered to MENX rats and tumor response was monitored noninvasively by diffusion weighted-magnetic resonance imaging (DW-MRI). Following treatment, tumor tissues were investigated for cell proliferation, apoptosis, and PI3K/mTOR inhibition. Genes mediating the cytotoxic activity of NVP-BEZ235 were identified by gene-expression profiling. Among them, Defb1, encoding beta-defensin 1, was further studied for its role in pituitary cells and in human pancreatic neuroendocrine tumor (NET) cells.Results: NVP-BEZ235 showed antiproliferative and pro-cell death activities against NFPAs both in vitro and in vivo, and the response to the drug correlated with inhibition of the PI3K pathway. DW-MRI identified early functional changes (decreased cellularity) in the adenomas before their size was affected and emerged as a useful modality to assess therapy response. The cytotoxic effect of PI3K/mTOR blockade in NFPA was mediated by several genes, including Defb1. NVP-BEZ235 treatment induced Defb1 expression in NFPAs in vitro and in vivo, and in pancreatic NET cells. High Defb1 levels sensitized NET cells to PI3K/mTOR inhibition.Conclusions: Our findings provide rationale for clinical investigation of PI3K/mTOR inhibition in NFPAs and identify novel effectors of PI3K-mediated neuroendocrine cell survival. Clin Cancer Res; 21(14); 3204–15. ©2015 AACR.
