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Genomic Pathways of 17-beta-Estradiol Induced Malignant Cell Transformation in Human Breast Epithelial Cells

ABSTRACT: The estrogen-dependence of breast cancer has long been recognized, however, the role of 17β-estradiol (E2) in cancer initiation was not known until we demonstrated that it induces complete neoplastic transformation of the human breast epithelial cells MCF-10F. E2-treatment of MCF-10F cells progressively induced high colony efficiency and loss of ductulogenesis in early transformed (trMCF) cells and invasiveness in Matrigel invasion chambers. The cells that crossed the chamber membrane were collected and identified as bsMCF, and their subclones designated bcMCF, and the cells harvested from carcinoma formation in SCID mice designated caMCF. These phenotypes correlated with gene dysregulation during the progression of the transformation. The highest number of dysregulated genes was observed in caMCF, being slightly lower in bcMCF, and lowest in trMCF. This order was consistent with the extent of chromosome aberrations (caMCF > bcMCF >>> trMCF). Chromosomal amplifications were found in 1p36.12-pter, 5q21.1-qter and 13q21.31-qter. Losses of the complete chromosome 4 and 8p11.21-23.1 were found only in tumorigenic cells. In tumor-derived cell lines, additional losses were found in 3p12.1-14.1, 9p22.1-pter and 18q11.21-qter. Functional profiling of dysregulated genes revealed progressive changes in the integrin signaling pathway, inhibition of apoptosis, acquisition of tumorigenic cell surface markers and epithelial-mesenchymal transition. In tumorigenic cells, the levels of E-cadherin, EMA, and various keratins were low and CD44E/CD24 were negative, whereas SNAI2, vimentin, S100A4, FN1, HRAS, TGFβ1 and CD44H were high. The phenotypic and genomic changes triggered by estrogen exposure that lead normal cells to tumorigenesis confirm the role of this steroid hormone in cancer initiation. Keywords: Cell type comparison

ORGANISM(S): Homo sapiens

PROVIDER: GSE5116 | GEO | 2006/08/10

SECONDARY ACCESSION(S): PRJNA96609

REPOSITORIES: GEO

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Project description:The estrogen-dependence of breast cancer has long been recognized, however, the role of 17Î²-estradiol (E2) in cancer initiation was not known until we demonstrated that it induces complete neoplastic transformation of the human breast epithelial cells MCF-10F. E2-treatment of MCF-10F cells progressively induced high colony efficiency and loss of ductulogenesis in early transformed (trMCF) cells and invasiveness in Matrigel invasion chambers. The cells that; crossed the chamber membrane were collected and identified as bsMCF, and their subclones designated bcMCF, and the cells harvested from carcinoma formation in SCID mice designated caMCF. These phenotypes correlated with gene dysregulation during the progression of the ; transformation. The highest number of dysregulated genes was observed in caMCF, being slightly lower in bcMCF, and lowest in trMCF. This order was consistent with the extent of chromosome aberrations (caMCF > bcMCF >>> trMCF). Chromosomal amplifications were found in 1p36.12-pter, 5q21.1-qter and 13q21.31-qter. Losses of the complete chromosome 4 and 8p11.21-23.1 were found only in tumorigenic cells. In tumor-derived cell lines, additional losses were found in 3p12.1-14.1, 9p22.1-pter and 18q11.21-qter. Functional profiling of dysregulated genes revealed progressive changes in the integrin signaling pathway, inhibition of apoptosis, acquisition of tumorigenic cell surface markers and epithelial-mesenchymal transition. In tumorigenic cells, the levels of E-cadherin, EMA, and various keratins were low and CD44E/CD24 were negative, whereas SNAI2, vimentin, S100A4, FN1, HRAS, TGFÎ²1 and; CD44H were high. The phenotypic and genomic changes triggered by estrogen exposure that lead normal cells to tumorigenesis confirm the role of this steroid hormone in cancer initiation. Experiment Overall Design: Human MCF-10F cells were transformed by 70nM 17-beta-estradiol. The transformed cells were selected by Boyden chamber. The selected cells were injected into SCID mice and also cloned and expanded. The thus grown tumors were harvested for cell culture. Genomic DNA and total RNA were isolated from cell lines in each step for 100K SNP and gene expression microarray assay.

Project description:Estrogen is a risk factor for breast cancer, yet its mechanism in the initiation of this disease is not clear. Here we use a model of estrogen-mediated malignant transformation of MCF-10F cells to identify the temporal acquisition of changes in genome structure and gene expression that correspond to the progressive transformed phenotype culminating in tumorigenesis. Genomic DNA and total RNA were isolated from MCF10F, trMCF (MCF10F transformed by 70 nM 17-beta estradiol), bsMCF (trMCF selected by Boyden chamber, tumorigenic), bcMCF(clones of bsMCF), and caMCF (cells from tumors of bsMCF grown in SCID mice). The Affymetrix 100k SNP and HG-U133_Plus_2 chips were used for genotyping and gene expression analyses. Changes in chromosomal copy number and loss of heterozygosity were progressive. Gross changes were rarely observed in the trMCF10F cells; the earliest was a gain in chromosome 1p, 1p36.12-1p36.21. In the bsMCF and their sub-clones bcMCF, additional gains were seen in chromosomes 1p, 1p36.12-1pter, 5q, 5q21.1-5q35.3, and 13q, 13q21.32-13q34; losses were detected in chromosomes 4 and 8p, 8p11.1-8p23.1. In the caMCF, additional losses were seen in chromosomes 3p, 3p12.1-3p14.1, 9p, 9p22.1-9p24.3, and 18q, 18q11.2-18q23. Using microarray analysis we were able, in some cases, to narrow the regions of interest and their associated candidate cancer genes. The observation of progressive genomic changes, along with the tumor phenotype of a poorly differentiated adenocarcinoma, indicate an underlying mechanism common to breast cancer development in humans, and adds to the evidence indicating that estrogens are mutagenic and contribute early to the process of breast cancer. Experiment Overall Design: Human MCF-10F cells were transformed by 70nM 17-beta-estradiol. The transformed cells were selected by Boyden chamber. The selected cells were injected into SCID mice and also cloned and expanded. The thus grown tumors were harvested for cell culture. Genomic DNA and total RNA were isolated from cell lines in each step for 100K SNP and gene expression microarray assay.

Project description:Retinoids have been used as potential chemotherapeutic or chemo-preventive agents because of their differentiation, anti-proliferative, pro-apoptotic, and anti-oxidant effects. We investigated the effect of all trans- retinoic acid (ATRA) at different stages of the neoplastic transformation using an in vitro model of breast cancer progression. This model was previously developed by treating the human normal-like breast epithelial MCF-10F cells with high dose of estradiol and consist of five cell lines which shown a progressive neoplastic transformation: MCF-10F (normal stage), trMCF (premalignant stage), bsMCF (invasive stage) and caMCF (tumorigenic stage). In 3D-cultures, MCF-10F cells form tubules resembling the normal mammary gland although after treatment with high doses of estradiol, trMCF cells, formed tubules and, spherical masses which are an indication of cell transformation. By ring cloning, trMCF clone 11 which only formed spherical masses in collagen was isolated. Our results showed that the early transformed trMCF clone 11 cells shown a reduction of spherical masses and increased of tubules in collagen after being treated with 10-5M (10M-BM-5M) and 10-6M (1M-BM-5M) ATRA; the number of tubules was higher in cells treated with 10-6M ATRA (43% vs. 10% tubules). The invasive bsMCF and tumorigenic caMCF cells did not shown any changes in morphology after ATRA treatment. Analysis of expression studies in early transformed cells treated with 10-6M ATRA showed that 271 probes upregulated in trMCF clone 11 cells were downregulated after ATRA treatment and, 316 probes that were downregulated were upregulated after ATRA treatment in these cells to similar levels than the normal breast epithelial cells MCF-10F. These genes were involved in the aryl hydrocarbon receptor signaling, RAR Activation, xenobiotic metabolisms signaling, molecular mechanisms of cancer and cell morphology. Our results shown that ATRA was able to re-differentiate transformed cells at early stages of the neoplastic process suggesting that ATRA could potentially be used to inhibit the progression of premalignant lesions of the breast such as ductal carcinoma in situ (DCIS). We investigated the effect of all trans- retinoic acid (ATRA) at different stages of the neoplastic transformation using an in vitro model of breast cancer progression. This model was previously developed by treating the human normal-like breast epithelial MCF-10F cells with high dose of estradiol and consist of five cell lines which shown a progressive neoplastic transformation: MCF-10F (normal stage), trMCF (premalignant stage), bsMCF (invasive stage) and caMCF (tumorigenic stage).

Project description:Retinoids have been used as potential chemotherapeutic or chemo-preventive agents because of their differentiation, anti-proliferative, pro-apoptotic, and anti-oxidant effects. We investigated the effect of all trans- retinoic acid (ATRA) at different stages of the neoplastic transformation using an in vitro model of breast cancer progression. This model was previously developed by treating the human normal-like breast epithelial MCF-10F cells with high dose of estradiol and consist of five cell lines which shown a progressive neoplastic transformation: MCF-10F (normal stage), trMCF (premalignant stage), bsMCF (invasive stage) and caMCF (tumorigenic stage). In 3D-cultures, MCF-10F cells form tubules resembling the normal mammary gland although after treatment with high doses of estradiol, trMCF cells, formed tubules and, spherical masses which are an indication of cell transformation. By ring cloning, trMCF clone 11 which only formed spherical masses in collagen was isolated. Our results showed that the early transformed trMCF clone 11 cells shown a reduction of spherical masses and increased of tubules in collagen after being treated with 10-5M (10µM) and 10-6M (1µM) ATRA; the number of tubules was higher in cells treated with 10-6M ATRA (43% vs. 10% tubules). The invasive bsMCF and tumorigenic caMCF cells did not shown any changes in morphology after ATRA treatment. Analysis of expression studies in early transformed cells treated with 10-6M ATRA showed that 271 probes upregulated in trMCF clone 11 cells were downregulated after ATRA treatment and, 316 probes that were downregulated were upregulated after ATRA treatment in these cells to similar levels than the normal breast epithelial cells MCF-10F. These genes were involved in the aryl hydrocarbon receptor signaling, RAR Activation, xenobiotic metabolisms signaling, molecular mechanisms of cancer and cell morphology. Our results shown that ATRA was able to re-differentiate transformed cells at early stages of the neoplastic process suggesting that ATRA could potentially be used to inhibit the progression of premalignant lesions of the breast such as ductal carcinoma in situ (DCIS).

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Genomic Pathways of 17-beta-Estradiol Induced Malignant Cell Transformation in Human Breast Epithelial Cells

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