Transcription profiling by array of human breast cancer tumors following anastrozole treatment for 2 and 16 weeks
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ABSTRACT: Analysis of breast cancer tumors following anastrozole treatment for 2 weeks and 16 weeks. The aromatase inhibitor anastrozole is an anti-estrogen drug used to treat postmenopausal women with breast cancer. Data provide insight into the molecular mechanism of action of anastrozole on hypoxia and proliferation metagenes. Core-cut tumor biopsies were collected from 81 postmenopausal women with stage I to IIIB ER+ early breast cancer before and after 2 weeks of anastrozole treatment. Further tumor biopsies were obtained from 20 of these patients after 16 weeks of anastrozole treatment prior to surgery
Project description:Tumorigenic breast cancer cells characterized by CD44 expression and low or undetectable CD24 levels (CD44+/CD24-/low) may be resistant to chemotherapy and therefore responsible for cancer relapse. Paired breast cancer core biopsies before and after neoadjuvant chemotherapy or lapatinib were obtained and as single cell suspensions stained using antibodies against CD24, CD44, and lineage markers, and then analyzed by flow cytometry. Mammosphere (MS) formation in culture was compared before and after treatment. Global gene expression differences between cancer cells bearing CD44+/CD24-/low cells and all other sorted cells, and between cancer MS and the primary bulk invasive cancers were analyzed. We report that CD44+/CD24-/low tumorigenic breast cancer cells were intrinsically chemoresistant - chemotherapy led to increased CD44+/CD24-/low cells, increased self-renewal capacity on MS assays, and enhanced tumorigeneicity in immunocompromised SCID/Beige mice. Conversely, in patients with HER2 overexpressing tumors, the EGFR/HER2 tyrosine kinase inhibitor, lapatinib decreased CD44+/CD24-/low cells, with the majority of these patients after conventional therapy achieving pathologic complete response, a validated surrogate marker for long-term survival. Gene transcription pathways that underlie chemoresistant, MS-forming CD44+/CD24-/low cells involve genes belonging to stem cell self-renewal, Wnt signaling, and early development pathways. Experiment Overall Design: Cells from human breast tumors were grown as mammospheres (MS). Experiment Overall Design: Isolated single cell suspensions from primary breast cancers were plated onto non-adherent (polyhema-coated) plastic, counted with a hematocytometer, and 20,000 cells were then seeded into a 6-well ultra-low attachment plate supplemented with 2mL MEGM, with the addition of 2 mL of freshly unfrozen MEGM every 3-4 days. Gene expression profiles were taken of both MS and primary bulk tumors and compared with each other.
Project description:Analysis of breast cancer tumors following fulvestrant treatment for 4 weeks. Fulvestrant is a highly specific ER antagonist used to treat postmenopausal women with breast cancer. Data provide insight into the molecular mechanism of action of fulvestrant on whole genome expression.
Project description:The response of tumors to PDT treatment is expected to provide information on effects of oxygen depletion, induced apoptosis, induction of an inflammatory response and induction of an ani-tumor immune response. Experiment Overall Design: NCI-H69 human SCLC xenografts were induced in SCID mice. Three pairs of xenograft tumors, PDT treated and untreated controls, were harvested four hours after PDT treatment. RNA was isolated and prepared for hybridization to human Affymetrix GeneChip arrays.
Project description:We used microarrays to identify the expression differences of FKBP5 gene between the pancreatic tumor and normal samples. On average normal samples had more FKBP5 expression compared to tumor samples .Experiment Overall Design: This experiment consists of 36 tumor samples and 16 normal samples; a total of 52 samples. 16 samples consist of both tumor and normal expression data, whereas 20 samples consist of only tumor data.
Project description:MCF-7 TET Off cells (MCF-7 wt) were used to produce stable clones expressing ER-alpha tagged with TAP-tag at the C-term (C-TAP-ER-alpha). All cells were grown in Dulbecco's modified Eagle's medium (DMEM), starved by using DMEM w/o phenol red and 5% Dextran Coated Charcoal stripped serum (DCC-FBS) for 5 days. Cells were stimulated with 17 beta Estradiol (E2), 4-idrossi-tamoxifen (Tam), raloxifene (Ral) and Fulvestrant (ICI) at the concentration of 10-8M for 12 hours or with vehicle Ethanol. Biological replicate were lysed and RNA extracted were pooled. For mRNA expression profiling, 500 ng total RNA were reverse transcribed and used for synthesis of cDNA and biotinylated cRNA. Finally cRNA were hybridized for 19 hours on Illumina HumanHT-12 v4.0 BeadChips and after scanning, data analysis was performed.
Project description:We found that trastuzumab (herceptin) treatment significantly decreased five miRNAs and increased three others in SKBr3 cells, whereas in BT474 cells it significantly decreased two miRNAs and increased nine. The only miRNA that shared the same change in both cell lines was miRNA-194 (miR-194), which was upregulated following trastuzumab treatment.
Project description:Purpose: A number of microarray studies have reported distinct molecular profiles of breast cancers (BC): basal-like, ErbB2-like and two to three luminal-like subtypes. These were associated with different clinical outcomes. However, although the basal and the ErbB2 subtypes are repeatedly recognized, identification of estrogen receptor (ER)-positive subtypes has been inconsistent. Refinement of their molecular definition is therefore needed. Materials and methods: We have previously reported a gene-expression grade index (GGI) which defines histological grade based on gene expression profiles. Using this algorithm, we assigned ER-positive BC to either high or low genomic grade subgroups and compared these to previously reported ER-positive molecular classifications. As further validation, we classified 666 ER-positive samples into subtypes and assessed their clinical outcome. Results: Two ER-positive molecular subgroups (high and low genomic grade) could be defined using the GGI. Despite tracking a single biological pathway, these were highly comparable to the previously described luminal A and B classification and significantly correlated to the risk groups produced using the 21-gene recurrence score. The two subtypes were associated with statistically distinct clinical outcome in both systemically untreated and tamoxifen-treated populations. Conclusions: The use of genomic grade can identify two clinically distinct ER-positive molecular subtypes in a simple and highly reproducible manner across multiple datasets. This study emphasizes the important role of proliferation-related genes in predicting prognosis in ER-positive BC. Experiment Overall Design: dataset of microarray experiments from primary breast tumors used to assess the reationship between GGI, molecular subtypes, and tamoxifen resistance. Experiment Overall Design: No replicate, no reference sample.
Project description:More than two thirds of breast cancers express the estrogen receptor (ER) and depend on estrogen for growth and survival. Therapies targeting ER function including aromatase inhibitors that block the production of estrogens and ER antagonists that alter ER transcriptional activity play a central role in the treatment of ER+ breast cancers of all stages. In contrast to ER- breast cancers, which frequently harbor mutations in the p53 tumor suppressor, ER+ breast cancers are predominantly wild type for p53. Despite harboring wild type p53, ER+ breast cancer cells are resistant to chemotherapy-induced apoptosis in the presence of estrogen. Using genome-wide approaches we have addressed the mechanism by which ER antagonizes the pro-apoptotic function of p53. Interestingly both ER agonists such as estradiol and selective ER modulators (SERM) such as tamoxifen promote p53 antagonism. In contrast the full ER antagonist fulvestrant blocks the ability of ER to inhibit p53-mediated cell death. This suggests an improved strategy for the treatment of ER+ breast cancer utilizing antagonists that completely block ER action together with drugs that activate p53-mediated cell death. MCF7 cells were hormone-depleted for 3 days and then treated with 10 uM doxorubicin for 12 hours