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Transcription profiling of human age-dichotomized ER+, N0 breast tumors reveals enhanced NF kappa B and AP-1 activity associated with antiestrogen resistant breast caner

ABSTRACT: Signaling pathways that converge on two different transcription factor complexes, NFκB and AP-1, have been identified in estrogen receptor (ER)-positive breast cancers resistant to the antiestrogen, tamoxifen. In this study, biomarkers co-ordinately up-regulated by NFKB and AP-1 with prognositic significance are identified in a largely TAM-treated set of ER+ node negative breast cancers. The prognostic value with respect to age is also investigated. Experiment Overall Design: 54 ER+ node negative breast tumors with known clinical outcome were analyzed. Genes co-ordinately regulated by NFKB and AP1from literature are identified from a significant gene set obtained through a minimum variation filter. Biomarker expression is used to dichotomize samples into high vs. low expressors to determine prognostic value

ORGANISM(S): Homo sapiens

SUBMITTER: Zhou Y

PROVIDER: S-ECPF-GEOD-7378 | biostudies-other | 2007

REPOSITORIES: biostudies-other

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Project description:Signaling pathways that converge on two different transcription factor complexes, NFkappaB and AP-1, have been identified in estrogen receptor (ER)-positive breast cancers resistant to the antiestrogen, tamoxifen.Two cell line models of tamoxifen-resistant ER-positive breast cancer, MCF7/HER2 and BT474, showing increased AP-1 and NFkappaB DNA-binding and transcriptional activities, were studied to compare tamoxifen effects on NFkappaB and AP-1 regulated reporter genes relative to tamoxifen-sensitive MCF7 cells. The model cell lines were treated with the IKK inhibitor parthenolide (PA) or the proteasome inhibitor bortezomib (PS341), alone and in combination with tamoxifen. Expression microarray data available from 54 UCSF node-negative ER-positive breast cancer cases with known clinical outcome were used to search for potential genes signifying upregulated NFkappaB and AP-1 transcriptional activity in association with tamoxifen resistance. The association of these genes with patient outcome was further evaluated using node-negative ER-positive breast cancer cases identified from three other published data sets (Rotterdam, n = 209; Amsterdam, n = 68; Basel, n = 108), each having different patient age and adjuvant tamoxifen treatment characteristics.Doses of parthenolide and bortezomib capable of sensitizing the two endocrine resistant breast cancer models to tamoxifen were capable of suppressing NFkappaB and AP-1 regulated gene expression in combination with tamoxifen and also increased ER recruitment of the transcriptional co-repressor, NCoR. Transcript profiles from the UCSF breast cancer cases revealed three NFkappaB and AP-1 upregulated genes--cyclin D1, uPA and VEGF--capable of dichotomizing node-negative ER-positive cases into early and late relapsing subsets despite adjuvant tamoxfien therapy and most prognostic for younger age cases. Across the four independent sets of node-negative ER-positive breast cancer cases (UCSF, Rotterdam, Amsterdam, Basel), high expression of all three NFkappaB and AP-1 upregulated genes was associated with earliest metastatic relapse.Altogether, these findings implicate increased NFkappaB and AP-1 transcriptional responses with tamoxifen resistant breast cancer and early metastatic relapse, especially in younger patients. These findings also suggest that agents capable of preventing NFkappaB and AP-1 gene activation may prove useful in restoring the endocrine responsiveness of such high-risk ER-positive breast cancers.

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Transcription profiling of human age-dichotomized ER+, N0 breast tumors reveals enhanced NF kappa B and AP-1 activity associated with antiestrogen resistant breast caner

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