Humans ; Parathyroid Neoplasms/genetics* ; Molecular Biology ; Parathyroid Glands

BACKGROUNDBone morphogenetic protein-6 (BMP-6) is closely correlated with tumor differentiation and skeletal metastasis. Estrogen is considered as a stimulant for the initiation and promotion of breast cancer. Previous studies demonstrated that 17beta-estadiol (E2) can selectively increase the expression of BMP-6. This experiment is designed to detect the molecular mechanism of estrogen activating BMP-6 gene transcription in human estrogen receptor positive (ER+) breast cancer cell line MCF-7.

METHODSAfter the treatment of MCF-7 cells with E2 at different concentrations (10(-11) mol/L, 10(-9) mol/L, 10(-7) mol/L), the BMP-6 expression level was examined through real-time polymerase chain reaction. Through restriction enzyme digestion, human BMP-6 1.2 kb long promoter, BMP-6 0.7 kb long promoter was cloned into pGL-3 basic vector; after the treatment with 10(-7) mol/L E2, luciferase activities of the two promoters were detected. Site-directed mutagenesis was performed to obtain the mutant forms of estrogen response element half-site (1/2 ERE) element and Sp1 sites in the BMP-6 promoter, the activities of these mutant form promoters were detected following the methods mentioned above. Chromatin immunoprecipitation (ChIP) assay was also used to confirm the binding of estrogen receptor alpha (ERalpha) on BMP-6 promoter in the presence of E2.

RESULTSE2 dose dependently increased BMP-6 mRNA expression in human ER+ breast cancer cell line MCF-7. At a dose of 10(-7) mol/L E2, human BMP-6 1.2 kb promoter activity was increased by 90% compared with the control group treated with ethanol (P < 0.05). Both the 1/2 ERE response element mutant form and the Sp1 site mutant form of the BMP-6 promoter abolished the activation of the BMP-6 promoter's response to E2. Through ChIP assay, the binding of ERalpha on 1/2 ERE response element in BMP-6 promoter was further validated.

CONCLUSIONEstrogen induces BMP-6 expression in human ER+ breast cancer cell line MCF-7 through its receptor ERalpha binding on 1/2 ERE element in the BMP-6 promoter.

Bone Morphogenetic Protein 6 ; Bone Morphogenetic Proteins ; genetics ; Breast Neoplasms ; genetics ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Estradiol ; pharmacology ; Estrogen Receptor alpha ; physiology ; Female ; Humans ; Parathyroid Hormone-Related Protein ; secretion ; Promoter Regions, Genetic ; Transcriptional Activation ; drug effects

Adenocarcinoma, Follicular ; radiotherapy ; secondary ; Adolescent ; Adult ; Aged ; Bone Neoplasms ; secondary ; Carcinoma, Papillary ; radiotherapy ; secondary ; Child ; Chromosome Aberrations ; radiation effects ; Dose-Response Relationship, Radiation ; Humans ; Hypoparathyroidism ; etiology ; Iodine Radioisotopes ; administration & dosage ; Lung ; physiopathology ; Lung Neoplasms ; secondary ; Lymphatic Metastasis ; Middle Aged ; Parathyroid Glands ; physiopathology ; Salivary Glands ; physiopathology ; Thyroid Neoplasms ; genetics ; pathology ; radiotherapy

Multiple endocrine neoplasia type 1 (MEN1) syndrome includes varying combinations of endocrine and non-endocrine tumors. There are also a considerable number of atypical MEN1 syndrome. In this case, a 68-yr-old woman was referred to the Department of Endocrinology for hypercalcemia. Five years ago, she had diagnosed as primary hyperaldosteronism and now newly diagnosed as parathyroid hyperplasia with laboratory and pathologic findings. Hurthle-cell thyroid cancer was also resected during the parathyroid exploration and small meningioma was found on brain MRI. Her general condition has markedly improved and her adrenal mass and meningioma are being closely observed now. We could find the loss of heterozygosity of the MEN1 locus in parathyroid glands, suggesting a MEN1-related tumor, but not a germline mutation. Considering a variety of phenotypic expression and a limitation of current molecular analysis, periodic follow up will be needed in patients with a MEN1-like phenotype.
Aged ; Base Sequence ; Brain/radionuclide imaging ; Female ; Humans ; Hyperaldosteronism/complications/*diagnosis ; Hyperparathyroidism, Primary/*diagnosis/etiology/pathology ; Loss of Heterozygosity ; Magnetic Resonance Imaging ; Meningeal Neoplasms/complications/*diagnosis/radionuclide imaging ; Meningioma/complications/*diagnosis/radionuclide imaging ; Mutation ; Parathyroid Glands/pathology ; Proto-Oncogene Proteins/genetics/metabolism ; Sequence Analysis, DNA ; Thyroid Neoplasms/complications/*diagnosis/pathology ; Tomography, X-Ray Computed