Estrogen receptor beta (ERβ) subtype-specific ligands increase transcription, p44/p42 mitogen activated protein kinase (MAPK) activation and growth in human non-small cell lung cancer cells

In non-small cell lung cancer (NSCLC) cells, 17 beta-estradiol increases transcription, activates MAPK, and stimulates proliferation. We hypothesize that estrogen receptor beta (ER beta) mediates these responses because it, but not ER alpha, is detected in our NSCLC cell lines. To test this, we determined the effects of the ER beta-selective agonists genistein (GEN) and 2,3-bis(4-hydroxyphenyl)propionitrile (DPN) and the ER alpha-selective agonist 4,4',4 ''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) in 201T cells. The cells were transfected with either an ER alpha or an ER beta expression vector and an estrogen response element (ERE)-tk-luciferase reporter construct. PPT increased luciferase activity in cells expressing ER alpha but not ER beta. GEN and DPN selectively increased luciferase activity in ER beta-transfected cells at concentrations <= 10 nM. Fulvestrant blocked the GEN- and DPN-mediated increases, indicating that transcription was ER-dependent. GEN but not PPT mediated a significant 1.5-fold increase in reporter activity upon transfection with ERE-tk-luciferase alone, demonstrating that endogenous ER beta activates transcription. PPT and DPN increased MAPK phosphorylation (2.5-fold and 3.7-fold, respectively). However, only DPN stimulated 201T growth in vitro (p = 0.008) and in vivo (p = 0.05). We conclude that ER beta mediates genomic and non-genomic responses to estrogen in 201 T cells and that activation of both pathways may be necessary for increased proliferation of these cells. (C) 2009 Elsevier Ltd. All rights reserved.