title: Positive cross-talk between estrogen receptor and NF-kappaB in breast cancer.
abstract: Estrogen receptors (ER) and nuclear factor-kappaB (NF-kappaB) are known to play important roles in breast cancer, but these factors are generally thought to repress each other's activity. However, we have recently found that ER and NF-kappaB can also act together in a positive manner to synergistically increase gene transcription. To examine the extent of cross-talk between ER and NF-kappaB, a microarray study was conducted in which MCF-7 breast cancer cells were treated with 17beta-estradiol (E(2)), tumor necrosis factor alpha (TNFalpha), or both. Follow-up studies with an ER antagonist and NF-kappaB inhibitors show that cross-talk between E(2) and TNFalpha is mediated by these two factors. We find that although transrepression between ER and NF-kappaB does occur, positive cross-talk is more prominent with three gene-specific patterns of regulation: (a) TNFalpha enhances E(2) action on approximately 30% of E(2)-upregulated genes; (b) E(2) enhances TNFalpha activity on approximately 15% of TNFalpha-upregulated genes; and (c) E(2) + TNFalpha causes a more than additive upregulation of approximately 60 genes. Consistent with their prosurvival roles, ER and NF-kappaB and their target gene, BIRC3, are involved in protecting breast cancer cells against apoptosis. Furthermore, genes positively regulated by E(2) + TNFalpha are clinically relevant because they are enriched in luminal B breast tumors and their expression profiles can distinguish a cohort of patients with poor outcome following endocrine treatment. Taken together, our findings suggest that positive cross-talk between ER and NF-kappaB is more extensive than anticipated and that these factors may act together to promote survival of breast cancer cells and progression to a more aggressive phenotype.
authors.affiliation: Department of Physiology, University of Illinois at Chicago, Chicago, Illinois 60612, USA. jfrasor@uic.edu
authors.forename: Jonna
authors.initials: J
authors.lastname: Frasor
authors.forename: Aisha
authors.initials: A
authors.lastname: Weaver
authors.forename: Madhumita
authors.initials: M
authors.lastname: Pradhan
authors.forename: Yang
authors.initials: Y
authors.lastname: Dai
authors.forename: Lance D
authors.initials: LD
authors.lastname: Miller
authors.forename: Chin-Yo
authors.initials: CY
authors.lastname: Lin
authors.forename: Adina
authors.initials: A
authors.lastname: Stanculescu
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004958:Estradiol / Q000494:pharmacology; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D020239:Receptor Cross-Talk; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D016328:NF-kappa B; D011960:Receptors, Estrogen; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol