Structure‐dependent activation of gene expression by bis‐indole and quinoline‐derived activators of nuclear receptor 4A2

Abstract

Bis‐indole derivatives including 1,1‐bis(3′‐indolyl)‐1‐(4‐chlorophenyl)methane (DIM‐C‐pPhCl) and substituted quinolines such as chloroquine (CQ) and amodiaquine (AQ) are nuclear receptor 4A2 (NR4A2, Nurr1) ligands, and they exhibit anti‐inflammatory activities in mouse and rat models of Parkinson's disease, respectively. However, computational modeling demonstrates that the quinoline derivatives interact with the ligand‐binding domain, whereas the bis‐indoles preferentially interact with a C‐terminal cofactor binding site of NR4A2. In this study, the effects of DIM‐C‐pPhCl and related analogs were compared with CQ/AQ as inducers of NR4A2‐responsive genes including vasoactive intestinal peptide, osteopontin, proopiomelanocortin, and neuropilin 1 in Panc1 and Panc28 pancreatic cancer cells. The results demonstrate that, among the bis‐indole analogs, their relative potencies as inducers were structure‐gene‐ and cell context dependent. In contrast, CQ and AQ were significantly less potent than the bis‐indole derivatives and, for some of the NR4A2‐regulated genes, CQ and AQ were inactive as inducers. These results demonstrate that although bis‐indole and quinoline derivatives have been characterized as activators of NR4A2‐dependent gene expression, these two classes of compounds exhibit different activities, indicating that they are selective NR4A2 modulators.

NR4A1 Ligands as Potent Inhibitors of Breast Cancer Cell and Tumor Growth

“…The CDIM 3,5-disubstituted phenyl analogs 1,1-bis(3′-indoly)-1-(3-bromo-5-methoxyphenyl)methane (3-Br-5-OCH 3 ), 1,1-bis(3′-indolyl)-1-(3-chloro-5-trifluoromethoxyphenyl)methane (3-Cl-5-OCF 3 ), 1,1-bis(3′-indolyl)-1-(3-chloro-5-trifluoromethylphenyl)methane (3-Cl-5-CF 3 ), and 1,1-bis(3′-indolyl)-1-(3-bromo-5-trifluoromethoxyphenyl)methane (3-Br-5-OCF 3 ) were synthesized by condensation of indole (2 mol equivalents) and the corresponding aldehyde (1 mol equivalent), as described [ 29 ]. The aldehydes included 3-bromo-5-methoxybenzaldehyde (Sigma-Aldrich, St. Louis, MO, USA), 3-chloro-5-trifluoromethoxybenzaldehyde (Alfa Aesar, Ward Hill, MA, USA), 3-chloro-5-trifluoromethylbenzalldehyde (Alfa Aesar), 3-bromo-5-trifluoromethoxybenzaldehyde (Alfa Aesar), and indole was obtained from Sigma-Aldrich.…”

“…The aldehydes included 3-bromo-5-methoxybenzaldehyde (Sigma-Aldrich, St. Louis, MO, USA), 3-chloro-5-trifluoromethoxybenzaldehyde (Alfa Aesar, Ward Hill, MA, USA), 3-chloro-5-trifluoromethylbenzalldehyde (Alfa Aesar), 3-bromo-5-trifluoromethoxybenzaldehyde (Alfa Aesar), and indole was obtained from Sigma-Aldrich. The compounds were >98% pure, as determined by LC-MS [ 29 ]. Human mammary breast cancer MDA-MB-231 and SKBR3 cell lines were purchased from American Type Culture Collection (Manassas, VA, USA).…”

“…, and 1,1-bis(3 -indolyl)-1-(3-bromo-5-trifluoromethoxyphenyl)methane (3-Br-5-OCF 3 ) were synthesized by condensation of indole (2 mol equivalents) and the corresponding aldehyde (1 mol equivalent), as described [29]. The aldehydes included 3-bromo-5methoxybenzaldehyde (Sigma-Aldrich, St. Louis, MO, USA), 3-chloro-5-trifluoromethoxy-benzaldehyde (Alfa Aesar, Ward Hill, MA, USA), 3-chloro-5-trifluoromethylbenzalldehyde (Alfa Aesar), 3-bromo-5-trifluoromethoxybenzaldehyde (Alfa Aesar), and indole was obtained from Sigma-Aldrich.…”

Analogs of the Dopamine Metabolite 5,6-Dihydroxyindole Bind Directly to and Activate the Nuclear Receptor Nurr1 (NR4A2)

“…26 As well, biophysical and computational studies of the interaction of bis-indoles and other compounds targeting Nurr1 also suggest the presence of additional binding sites within the LBD. 24,44,45 Alternatively, it is possible these indoles bind to the same site, with the 5-substituted indoles inducing markedly different changes in the protein structure (and potentially interactions with co-regulatory proteins associated with transcription) than the corresponding 5,6-disubstitued indoles.…”

Nuclear Receptor 4A2 (NR4A2/NURR1) Regulates Autophagy and Chemoresistance in Pancreatic Ductal Adenocarcinoma

“…Pancreatic ductal adenocarcinoma (PDAC) is a lethal human malignancy with a five-year survival rate of 9% and it is estimated that by 2030 pancreatic cancer cis-elements in target gene promoters (9). NURR has been characterized as an important regulator in neuronal development and there is also increasing evidence of a prooncogenic role for their receptor in solid tumors (9)(10)(11) NURR regulates cell growth survival and metabolism (12)(13)(14) and studies in this laboratory identified 1,1-bis (3 -indolyl)-1-(p-chlorophenyl) methane (C-DIM12) as prototypical NURR ligand (15,16). A recent study showed that C-DIM12 inhibited glioblastoma cell and tumor growth and also blocked NURR-dependent prooncogenic pathways in glioblastoma (15).…”