Unknown,Transcriptomics,Genomics,Proteomics

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Endocrine response in invasive lobular carcinoma is characterized by unique estrogen-mediated gene expression and de novo tamoxifen resistance

ABSTRACT: This SuperSeries is composed of the SubSeries listed below. Refer to individual Series

ORGANISM(S): Homo sapiens

SUBMITTER: Uma Chandran

PROVIDER: E-GEOD-50695 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Invasive lobular carcinoma cell lines are characterized by unique estrogen-mediated gene expression patterns and altered tamoxifen response.

Sikora Matthew J MJ Cooper Kristine L KL Bahreini Amir A Luthra Soumya S Wang Guoying G Chandran Uma R UR Davidson Nancy E NE Dabbs David J DJ Welm Alana L AL Oesterreich Steffi S

Cancer research 20140114 5

Invasive lobular carcinoma (ILC) is a histologic subtype of breast cancer that is frequently associated with favorable outcomes, as approximately 90% of ILC express the estrogen receptor (ER). However, recent retrospective analyses suggest that patients with ILC receiving adjuvant endocrine therapy may not benefit as much as patients with invasive ductal carcinoma. On the basis of these observations, we characterized ER function and endocrine response in ILC models. The ER-positive ILC cell line ...[more]

PMID: 24425047

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Project description:Invasive lobular carcinoma (ILC) is a histological subtype of breast cancer that is frequently associated with favorable outcomes, as ~90% of ILC express the estrogen receptor (ER). However, recent retrospective analyses suggest that ILC patients receiving adjuvant endocrine therapy may not benefit from improved outcomes versus other breast cancer patients. Based on these observations, we characterized ER function and endocrine response in ILC models. The ER-positive ILC cell lines MDA MB 134VI (MM134) and SUM44PE were used to examine the ER-regulated transcriptome in vitro via gene expression microarray analyses and ER ChIP-Seq. In parallel, estrogen response was assessed in vivo in the patient-derived ILC xenograft HCI-013. Response to endocrine therapy was also examined in ILC cell lines. We identified 915 genes that were uniquely E2-regulated in ILC cell lines versus other breast cancer cell lines, and a subset of these genes were also regulated in vivo in HCI-013. We observed that MM134 were de novo tamoxifen resistant, and were induced to grow by 4-hydroxytamoxifen, as well as other anti-estrogens, as partial agonists. Growth was accompanied by agonist activity of tamoxifen on ER-mediated gene expression. Though tamoxifen induced cell growth, MM134 cells required FGFR1 signaling to maintain viability and were sensitive to combined endocrine therapy and FGFR1 inhibition. Our observation that ER drives a unique program of gene expression in ILC cells correlates with the ability of tamoxifen to induce growth in these cells. Targeting growth factors using FGFR1 inhibitors may block survival pathways required by ILC and reverse tamoxifen resistance. Cells were hormone deprived by replacing growth medium with IMEM+2% charcoal stripped serum for 3 days. Following deprivation, cells were treated for 3 or 24 hours with 1nM E2 or vehicle (0.01% EtOH) in biological quadruplicate. Following treatment, cells were lysed and RNA was harvested using the Illustra RNAspin Mini kit (GE Health). cRNA synthesis and labeling was performed using the Ambion MessageAmp Premier Kit (Life Technologies), and cRNA was hybridized to U133A 2.0 arrays (Affymetrix, Santa Clara, CA). cRNA synthesis and labeling, hybridization, and scanning were performed by the University of Pittsburgh Cancer Biomarkers Facility.

Project description:Invasive lobular carcinoma (ILC) is a histological subtype of breast cancer that is frequently associated with favorable outcomes, as ~90% of ILC express the estrogen receptor (ER). However, recent retrospective analyses suggest that ILC patients receiving adjuvant endocrine therapy may not benefit from improved outcomes versus other breast cancer patients. Based on these observations, we characterized ER function and endocrine response in ILC models. The ER-positive ILC cell lines MDA MB 134VI (MM134) and SUM44PE were used to examine the ER-regulated transcriptome in vitro via gene expression microarray analyses and ER ChIP-Seq. In parallel, estrogen response was assessed in vivo in the patient-derived ILC xenograft HCI-013. Response to endocrine therapy was also examined in ILC cell lines. We identified 915 genes that were uniquely E2-regulated in ILC cell lines versus other breast cancer cell lines, and a subset of these genes were also regulated in vivo in HCI-013. We observed that MM134 were de novo tamoxifen resistant, and were induced to grow by 4-hydroxytamoxifen, as well as other anti-estrogens, as partial agonists. Growth was accompanied by agonist activity of tamoxifen on ER-mediated gene expression. Though tamoxifen induced cell growth, MM134 cells required FGFR1 signaling to maintain viability and were sensitive to combined endocrine therapy and FGFR1 inhibition. Our observation that ER drives a unique program of gene expression in ILC cells correlates with the ability of tamoxifen to induce growth in these cells. Targeting growth factors using FGFR1 inhibitors may block survival pathways required by ILC and reverse tamoxifen resistance. Cells were hormone deprived by replacing growth medium with IMEM+10% charcoal stripped serum for 3 days. Following deprivation, cells were treated for 3 or 24 hours with 1nM E2 or vehicle (0.01% EtOH) in biological quadruplicate. Following treatment, cells were lysed and RNA was harvested using the Illustra RNAspin Mini kit (GE Health). cRNA synthesis and labeling was performed using the Ambion MessageAmp Premier Kit (Life Technologies), and cRNA was hybridized to U133A 2.0 arrays (Affymetrix, Santa Clara, CA). cRNA synthesis and labeling, hybridization, and scanning were performed by the University of Pittsburgh Cancer Biomarkers Facility.

Project description:Introduction: Although changes in microRNA (miRNA) expression correlate with breast cancer diagnostic markers, comparatively little is known about miRNA regulation by selective estrogen receptor modulators (SERMs), e.g., tamoxifen (TAM), or their role in endocrine-resistance. Methods: A microarray approach was used to identify miRNAs differentially expressed and regulated by 4-hydroxyTAM (4-OHT) in MCF-7/TAM-sensitive versus LY2 TAM/endocrine-resistant human breast cancer cells after 6 h treatment. The expression of specific miRNAs was validated by quantitative, real-time PCR. Control miRNAs and time-course studies showed important gene-, time-, and cell- specific differences in miRNA expression. Results: 97 miRNAs were differentially expressed in MCF-7 versus LY2 cells. Bioinformatic analyses to impute the biological significance of these miRNAs by identifying 36 predicted gene targets of these miRNAs from amongst those reported to be regulated by MCF-7 cells was performed and agreement was found in direction of anticipated regulation for 12 of those putative targets. Among the miRNAs differentially expressed in MCF-7 versus LY2 cells, and that putatively target mRNAs regulated by 4-OHT in MCF-7 cells, are: miRs- 10a, 21, 22, 29a, 93, 125b, 181, 200a, 200b, 200c; 205, 221, and 222. Q-PCR assessment showed agreement with microarray data: miR- 10a, 22, 125b, 181, and 222 are higher in LY2 whereas miR-21 and miR-200a are lower in LY2 than MCF-7. 4-OHT increased miR-10a, miR-21, miR-22, miR-125b, miR-181a, miR-200a, and miR-222 in MCF-7 cells and reduced miR-10a in LY2 cells. E2 reduced the miR-21expression in MCF-7 cells. Treatment with ICI 182,780 revealed that ER suppresses miR-10a, miR-21, miR-22, miR-200a, miR-221, and miR-222 expression in MCF-7 cells. Time-dependent changes in select miRNA expression were observed in control, E2, and 4-OHT-treated MCF-7 cells. ESR1/ER? was significantly lower in LY2 than MCF-7, commensurate with higher let-7 family member, miR-221, and miR-222 expression in LY2. Reflecting inverse association with miR-200 family expression, the expression of ZEB1 was higher in LY2 than MCF-7 cells and concomitantly, E-cadherin expression was absent in LY2 cells indicating that LY2 have undergone epithelial to mesenchymal transition. Conclusions: Our studies identifying miRNAs with opposite expression between the two cell lines, indicate the involvement of these miRNAs in endocrine resistance. The purpose of this experiment is: 1. To identify miRNAs that are regulated (up or down) by 4-OHT in MCF-7 and LY2 cell lines (comparison of values from EtOH versus 4-OHT treated cells). 2. To identify miRNAs that are differentially regulated under basal (EtOH) conditions between MCF-7 and LY2 cell lines. 3. To identify miRNAs that are differentially regulated by 4-OHT in MCF-7 versus LY2 cells.

Dataset Information

Endocrine response in invasive lobular carcinoma is characterized by unique estrogen-mediated gene expression and de novo tamoxifen resistance

Publications

Invasive lobular carcinoma cell lines are characterized by unique estrogen-mediated gene expression patterns and altered tamoxifen response.

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