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Gene expression of primary breast cancers from patients before and after neo-adjuvant Tamoxifen treatment

ABSTRACT: Tumor gene expression data (microarray from FFPE) was obtained from breast cancer patients enrolled in a pre-operative window trial (ClinicalTrials.gov Identifier: NCT00738777). Patients received an oral loading dose of 40 mg of tamoxifen twice daily for the first seven days, followed by a daily dose of 20 mg until surgery. A core needle biopsy of the tumor was taken prior to treatment (n=62) and post-treatment tumor material (n=40) was obtained during surgery 20.7 (±9.6) days later. Paired material was available for 27/74 patients. Differential analysis comparing gene expression before and after Tamoxifen treatment implicated activation of the NFκB pathway and an enrichment of EMT/stemness features upon Tamoxifen treatment. In line with these findings, exposure of ER+ breast cancer cell lines to tamoxifen, in vitro and in vivo, gives rise to a tamoxifen-tolerant population with similar NFκB activity and EMT/stemness characteristics as described in the corresponding publication.

ORGANISM(S): Homo sapiens

PROVIDER: GSE147271 | GEO | 2020/04/06

REPOSITORIES: GEO

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Project description:A phase-1, multi-center study in recurrent non-enhancing gliomas with IDH1 R132H mutation for patients who require surgery. The purpose of this study is to evaluate the suppression of 2-HG (2-hydroxyglutarate) by comparing the concentration of 2-HG in resected tumors from IDH1 mutant glioma subjects following AG-120 or AG-881 treatment with the 2-HG concentration in untreated, control tumors. The safety, tolerability, PK/PD, and anti tumor activity data from the study in subjects with recurrent non-enhancing Grade 2/3 LGG with an IDH1 R132H mutation for whom surgical resection is indicated will identify the recommended dose of AG-120 and AG-881 for future studies in glioma. Vorasidenib and ivosidenib inhibit mutant forms of isocitrate dehydrogenase (mIDH) and have shown preliminary clinical activity against mIDHglioma. We evaluated both agents in a perioperative phase 1 trial to explore the mechanism of action in recurrent low-grade glioma (IGG) and select a molecule for phase 3 testing. Primary end-point was concentration ofD-2-hydroxyglutarate (2-HG), the metabolic product of mIDH enzymes, measured in tumor tissue from 49 patients with mIDH1-R132H nonenhancing gliomas following randomized treatment with vorasidenib (50 mg or 10 mg once daily, q.d.), ivosidenib (500 mg q.d. or 250 mg twice daily) or no treatment before surgery. Tumor 2-HG concentrations were reduced by 92.6% (95% credible interval (CrI), 76.1–97.6) and 91.1% (95% CrI, 72.0–97.0) in patients treated with vorasidenib 50 mg q.d. and ivosidenib 500 mg q.d., respectively. Both agents were well tolerated and follow-up is ongoing. In exploratory analyses, 2-HG reduction was associated with increased DNA 5-hydroxymethylcytosine, reversal of ‘proneural’ and ‘stemness’ gene expression signatures, decreased tumor cell proliferation and immune cell activation. Vorasidenib, which showed brain penetrance and more consistent 2-HG suppression than ivosidenib, was advanced to phase 3 testing in patients with mIDHLGGs. Funded by Agios Pharmaceuticals, Inc. and Servier Pharmaceuticals LLC; ClinicalTrials.gov number NCT03343197.

Project description:Five years of tamoxifen reduces breast cancer risk by nearly 50% but is associated with significant side-effects and toxicities. A better understanding of the direct and indirect effects of tamoxifen in benign breast tissue could elucidate new mechanisms of breast carcinogenesis, suggest novel chemoprevention targets, and provide relevant early response biomarkers for Phase II prevention trials. Seventy-three women at increased risk for breast cancer were randomized to tamoxifen (20 mg daily) or placebo for three months. Blood and breast tissue samples were collected at baseline and post-treatment. Sixty-nine women completed all study activities (37 tamoxifen and 32 placebo). The selected biomarkers focused on estradiol and IGFs in the blood, DNA methylation and cytology in random periareolar fine needle aspirates, and tissue morphometry, proliferation, apoptosis, and gene expression (microarray and RT-PCR) in the tissue core samples. Tamoxifen downregulated ets-oncogene family members ETV4 and ETV5 and reduced breast epithelial cell proliferation independent of CYP2D6 genotypes or effects on estradiol, ESR1 or IGFs. Reduction in proliferation was correlated with downregulation of ETV4 and DNAJC12. Tamoxifen also modulated expression of RAB GTPases, and several genes involved in epithelial-stromal interaction, and reduced tumor suppressor gene methylation. Three months of tamoxifen did not affect breast tissue composition, cytological atypia, preneoplasia or apoptosis. Tamoxifen may durably reduce breast cancer risk through downregulation of ETV4 and ETV5 which could deplete mammary progenitor populations. This pathway has the potential to provide novel targets and early response biomarkers for phase II prevention trials. Randomized prospective double blinded placebo-controlled trial of tamoxifen (20 mg daily) versus placeo in women at increased risk for breast cancer. Gene expression was assessed in whole breast tissue cores obtained at baseline and after three months of treatment for 35 women. Core biopsies were obtained in the late luteal phase (day 28 +/- 2) for premenopausal women (N = 19). Breast lobules from the baseline and post-treatment cores were microdissected for 5 tamoxifen subjects.

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Gene expression of primary breast cancers from patients before and after neo-adjuvant Tamoxifen treatment

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