Lab Anim Res.  2011 Jun;27(2):99-107. 10.5625/lar.2011.27.2.99.

Gene Alterations of Ovarian Cancer Cells Expressing Estrogen Receptors by Estrogen and Bisphenol A Using Microarray Analysis

• Hwang KA
• Park SH
• Yi BR
• Choi KC

• KMID: 2053658
• DOI: http://doi.org/10.5625/lar.2011.27.2.99

Abstract

Since endocrine disrupting chemicals (EDCs) may interfere with the endocrine system(s) of our body and have an estrogenicity, we evaluated the effect(s) of bisphenol A (BPA) on the transcriptional levels of altered genes in estrogen receptor (ER)-positive BG-1 ovarian cancer cells by microarray and real-time polymerase-chain reaction. In this study, treatment with 17beta-estradiol (E2) or BPA increased mRNA levels of E2-responsive genes related to apoptosis, cancer and cell cycle, signal transduction and nucleic acid binding etc. In parallel with their microarray data, the mRNA levels of some altered genes including RAB31_MEMBER RAS ONCOGENE FAMILY (U59877), CYCLIN D1 (X59798), CYCLIN-DEPENDENT KINASE 4 (U37022), IGF-BINDING PROTEIN 4 (U20982), and ANTI-MULLERIAN HORMONE (NM_000479) were significantly induced by E2 or BPA in this cell model. These results indicate that BPA in parallel with E2 induced the transcriptional levels of E2-responsive genes in an estrogen receptor (ER)-positive BG-1 cells. In conclusion, these microarray and real-time polymerase-chain reaction results indicate that BPA, a potential weak estrogen, may have estrogenic effect by regulating E2-responsive genes in ER-positive BG-1 cells and BG-1 cells would be the best in vitro model to detect these estrogenic EDCs.

Keyword

Endocrine disrupting chemicals; estrogen; bisphenol; ovarian cancer

MeSH Terms

Anti-Mullerian Hormone
Apoptosis
Benzhydryl Compounds
Cell Cycle
Cyclin D1
Cyclin-Dependent Kinase 4
Endocrine Disruptors
Estrogens
Genes, ras
Humans
Insulin-Like Growth Factor Binding Protein 4
Microarray Analysis
Ovarian Neoplasms
Phenols
Receptors, Estrogen
RNA, Messenger
Signal Transduction
Anti-Mullerian Hormone
Benzhydryl Compounds
Cyclin D1
Cyclin-Dependent Kinase 4
Endocrine Disruptors
Estrogens
Insulin-Like Growth Factor Binding Protein 4
Phenols
RNA, Messenger
Receptors, Estrogen

Figure

• 

  Figure 1 Expression of ERα and ERβ proteins in estrogen-responsive ovarian cancer cells (BG-1). The protein was isolated and prepared as described in the Materials and Methods. The protein levels of ERα (68 kDa) and ERβ (55 kDa) were detected by immunoblot analysis by using an ERα or ERβ monoclonal antibody in BG-1 cells.

• 

  Figure 2 Hierarchical clustering analysis. A hierarchical clustering analysis was performed following treatments with 17β-estradiol (E2) and bisphenol A (BPA) at different time points (1, 8, and 24 h) in BG-1 cells. Two-dimensional hierarchical clustering was applied to the expression data from approximate 8.0 k genes, which showed significant changes in the balanced differential expression. Increased expression levels were shown in red and decreased expression levels shown in green.

• 

  Figure 3 Confirmation of gene profiles by real-time polymerase-chain reaction (PCR) analysis. Relative values of expression of the altered genes quantified by real-time PCR were shown in the graph, indicating the comparison of fold change determined by real-time PCR analysis by 17β-estradiol (E2, 10-7 M) or bisphenol A (BPA, 10-5 M) following 24 h treatment in BG-1 cells. The representative genes included RAB31_MEMBER RAS ONCOGENE FAMILY (U59877), CYCLIN D1 (X59798), CYCLIN-DEPENDENT KINASE 4 (U37022), INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN 4 (U20982), and ANTI-MULLERIAN HORMONE (NM_000479). *P<0.05 vs. vehicle.

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