1-1-bis(3--indolyl)-1-(4-hydroxyphenyl)methane and Pancreatic-Neoplasms

Topics: Cell Adhesion; Cell Line, Tumor; Cell Movement; Colonic Neoplasms; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Indoles; Integrin beta1; Nuclear Receptor Subfamily 4, Group A, Member 1; Pancreatic Neoplasms; Phenols; Phenylacetates

NR4A1 (Nur77, TR3) is an orphan nuclear receptor that is overexpressed in pancreatic cancer and exhibits pro-oncogenic activity. RNA interference of NR4A1 expression in Panc-1 cells induced apoptosis and subsequent proteomic analysis revealed the induction of several markers of endoplasmic reticulum stress, including glucose-related protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), and activating transcription factor-4 (ATF-4). Treatment of pancreatic cancer cells with the NR4A1 antagonist 1,1-bis(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) gave similar results. Moreover, both NR4A1 knockdown and DIM-C-pPhOH induced reactive oxygen species (ROS), and induction of ROS and endoplasmic reticulum stress by these agents was attenuated after cotreatment with antioxidants. Manipulation of NR4A1 expression coupled with gene expression profiling identified a number of ROS metabolism transcripts regulated by NR4A1. Knockdown of one of these transcripts, thioredoxin domain containing 5 (TXNDC5), recapitulated the elevated ROS and endoplasmic reticulum stress; thus, demonstrating that NR4A1 regulates levels of endoplasmic reticulum stress and ROS in pancreatic cancer cells to facilitate cell proliferation and survival. Finally, inactivation of NR4A1 by knockdown or DIM-C-pPhOH decreased TXNDC5, resulting in activation of the ROS/endoplasmic reticulum stress and proapoptotic pathways.. The NR4A1 receptor is pro-oncogenic, regulates the ROS/endoplasmic reticulum stress pathways, and inactivation of the receptor represents a novel pathway for inducing cell death in pancreatic cancer.

Topics: Apoptosis; Cell Growth Processes; Cell Line, Tumor; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Indoles; Microscopy, Electron, Transmission; Nuclear Receptor Subfamily 4, Group A, Member 1; Oxidative Stress; Pancreatic Neoplasms; Phenols; Protein Disulfide-Isomerases; Reactive Oxygen Species; Tissue Array Analysis; Transfection

Activation of the orphan nuclear receptor TR3/Nur77 (NR4A1) promotes apoptosis and inhibits pancreatic tumor growth, but its endogenous function and the effects of its inactivation have yet to be determined. TR3 was overexpressed in human pancreatic tumors compared with nontumor tissue. Small interfering RNA-mediated knockdown of TR3 or cell treatment with the TR3 antagonist 1,1-bis(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) decreased proliferation, induced apoptosis, and decreased expression of antiapoptotic genes including Bcl-2 and survivin in pancreatic cancer cells. Survivin suppression was mediated by formation of a TR3-Sp1-p300 DNA binding complex on the proximal GC-rich region of the survivin promoter. When administered in vivo, DIM-C-pPhOH induced apoptosis and inhibited tumor growth in an orthotopic model of pancreatic cancer, associated with inhibition of the same antiapoptotic markers observed in vitro. Our results offer preclinical validation of TR3 as a drug target for pancreatic cancer chemotherapy, based on the ability of TR3 inhibitors to block the growth of pancreatic tumors.

Topics: Animals; Anisoles; Apoptosis; Cell Growth Processes; Cell Line, Tumor; E1A-Associated p300 Protein; Gene Knockdown Techniques; Humans; Indoles; Inhibitor of Apoptosis Proteins; Male; Mice; Mice, Nude; Microtubule-Associated Proteins; Nuclear Receptor Subfamily 4, Group A, Member 1; Pancreatic Neoplasms; Phenols; RNA, Small Interfering; Sp1 Transcription Factor; Survivin; Transcriptional Activation; Transfection; Xenograft Model Antitumor Assays