p53 Is a Mediator for Radiation-repressed Human TR2 Orphan Receptor Expression in MCF-7 Cells, a New Pathway from Tumor Suppressor to Member of the Steroid Receptor Superfamily

One of the mechanisms for epigenetic silencing of tumor suppressor genes is hypermethylation of cytosine residue at CpG islands at their promoter region that contributes to malignant progression of tumor. Therefore, activation of tumor suppressor genes that have been silenced by promoter methylation is considered to be very attractive molecular target for cancer therapy. Epigenetic silencing of glutathione S-transferase pi 1, a tumor suppressor gene, is involved in various types of cancers including breast cancer. Epigenetic silencing of tumor suppressor genes can be reversed by several molecules including natural compounds such as polyphenols that can act as a hypomethylating agent. Curcumin has been found to specifically target various tumor suppressor genes and alter their expression. To check the effect of curcumin on the methylation pattern of glutathione S-transferase pi 1 gene in MCF-7 breast cancer cell line in dose-dependent manner. To check the reversal of methylation pattern of hypermethylated glutathione S-transferase pi 1, MCF-7 breast cancer cell line was treated with different concentrations of curcumin for different time periods. DNA and proteins of treated and untreated cell lines were isolated, and methylation status of the promoter region of glutathione S-transferase pi 1 was analyzed using methylation-specific polymerase chain reaction assay, and expression of this gene was analyzed by immunoblotting using specific antibodies against glutathione S-transferase pi 1. A very low and a nontoxic concentration (10 µM) of curcumin treatment was able to reverse the hypermethylation and led to reactivation of glutathione S-transferase pi 1 protein expression in MCF-7 cells after 72 h of treatment, although the IC50 value of curcumin was found to be at 20 µM. However, curcumin less than 3 µM of curcumin could not alter the promoter methylation pattern of glutathione S-transferase pi 1. Treatment of breast cancer MCF-7 cells with curcumin causes complete reversal of glutathione S-transferase pi 1 promoter hypermethylation and leads to re-expression of glutathione S-transferase pi 1, suggesting it to be an excellent nontoxic hypomethylating agent.

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A novel role for BRCA1 in regulating breast cancer cell spreading and motility

The Journal of Cell Biology ◽

10.1083/jcb.201004136 ◽

2011 ◽

Vol 192 (3) ◽

pp. 497-512 ◽

Cited By ~ 41

Author(s):

Elisabeth D. Coene ◽

Catarina Gadelha ◽

Nicholas White ◽

Ashraf Malhas ◽

Benjamin Thomas ◽

...

Keyword(s):

Tumor Suppressor ◽

Cancer Cells ◽

Ubiquitin Ligase ◽

Fluorescent Protein ◽

Cell Spreading ◽

Dominant Negative ◽

Full Length ◽

Suppressor Activity ◽

Ubiquitin Ligase Activity ◽

Mcf 7

BRCA1 C-terminal (BRCT) domains in BRCA1 are essential for tumor suppressor function, though the underlying mechanisms remain unclear. We identified ezrin, radixin, and moesin as BRCA1 BRCT domain–interacting proteins. Ezrin–radixin–moesin (ERM) and F-actin colocalized with BRCA1 at the plasma membrane (PM) of cancer cells, especially at leading edges and focal adhesion sites. In stably expressing cancer cells, high levels of enhanced green fluorescent protein (EGFP)-BRCA11634–1863 acted as a dominant-negative factor, displacing endogenous BRCA1 from the PM. This led to delayed cell spreading, increased spontaneous motility, and irregular monolayer wound healing. MCF-7 cells (intact BRCA1) showed lower motility than HCC1937 cells (truncated BRCA1), but expression of EGFP-BRCA11634–1863 in MCF-7 increased motility. Conversely, full-length BRCA1 expression in HCC1937 decreased motility but only if the protein retained ubiquitin ligase activity. We conclude that full-length BRCA1 is important for complete tumor suppressor activity via interaction of its BRCT domains with ERM at the PM, controlling spreading and motility of cancer cells via ubiquitin ligase activity.

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Cell Cycle Phase Dependence of Estrogen and Epidermal Growth Factor (EGF) Receptor Expression in MCF-7 Cells: Implications in Antiestrogen and EGF Cell Responsiveness*

Endocrinology ◽

10.1210/endo-129-5-2719 ◽

1991 ◽

Vol 129 (5) ◽

pp. 2719-2728 ◽

Cited By ~ 15

Author(s):

XUE-FEN DONG ◽

YOLANDE BERTHOIS ◽

EVELYNE COLOMB ◽

PIERRE-MARIE MARTIN

Keyword(s):

Cell Cycle ◽

Growth Factor ◽

Epidermal Growth Factor ◽

Egf Receptor ◽

Cell Cycle Phase ◽

Receptor Expression ◽

Cycle Phase ◽

Phase Dependence ◽

Epidermal Growth ◽

Mcf 7

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Effect of a povidone-iodine intrauterine infusion on progesterone levels and endometrial steroid receptor expression in mares

Acta Veterinaria Scandinavica ◽

10.1186/1751-0147-52-66 ◽

2010 ◽

Vol 52 (1) ◽

Cited By ~ 5

Author(s):

Irene Kalpokas ◽

Fernando Perdigón ◽

Rodolfo Rivero ◽

Marilina Talmon ◽

Isabel Sartore ◽

...

Keyword(s):

Povidone Iodine ◽

Steroid Receptor ◽

Receptor Expression ◽

Steroid Receptor Expression

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Potential Metabolite Nymphayol Isolated from Water Lily (Nymphaea stellata) Flower Inhibits MCF-7 Human Breast Cancer Cell Growth via Upregulation of Cdkn2a, pRb2, p53 and Downregulation of PCNA mRNA Expressions

Metabolites ◽

10.3390/metabo10070280 ◽

2020 ◽

Vol 10 (7) ◽

pp. 280

Author(s):

Laila Naif Al-Harbi ◽

Pandurangan Subash-Babu ◽

Manal Abdulaziz Binobead ◽

Maha Hussain Alhussain ◽

Sahar Abdulaziz AlSedairy ◽

...

Keyword(s):

Breast Cancer ◽

Tumor Suppressor ◽

Cell Viability ◽

Cancer Cell ◽

Breast Cancer Cell ◽

Kinase Inhibitor ◽

B Cell Lymphoma ◽

Nuclear Antigen ◽

Mrna Levels ◽

Mcf 7

Controlled production of cyclin dependent kinases (CDK) and stabilization of tumor suppressor genes are the most important factors involved in preventing carcinogenesis. The present study aimed to explore the cyclin dependent apoptotic effect of nymphayol on breast cancer MCF-7 cells. In our previous study, we isolated the crystal from a chloroform extract of Nymphaea stellata flower petals and it was confirmed as nymphayol (17-(hexan-2-yl)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-ol) using x-ray diffraction (XRD), Fourier transform infrared (FTIR), and mass spectroscopy (MS) methods. The cytotoxic effect of nymphayol on MCF-7 cells were analyzed using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The cellular and nuclear damage was determined using propidium iodide (PI) and acridine orange/ethidium bromide (AO/ErBr) staining. Tumor suppressor and apoptosis related mRNA transcript levels were determined using real-time polymerase chain reaction (RT-PCR). Nymphayol potentially inhibits MCF-7 cell viability up to 78%, and the IC50 value was observed as 2.8 µM in 24 h and 1.4 µM in 48 h. Treatment with nymphayol significantly increased reactive oxygen species (ROS) level and the tunnel assay confirmed DNA damage. We found characteristically 76% apoptotic cells and 9% necrotic cells in PI and AO/ErBr staining after 48 h treatment with 2.8 µM of nymphayol. Gene expression analysis confirmed significantly (p ≤ 0.001) increased mRNA levels of cyclin dependent kinase inhibitor 2A (Cdkn2a), retinoblastoma protein 2 (pRb2), p53, nuclear factor erythroid 2-factor 2 (Nrf2), caspase-3, and decreased B-cell lymphoma 2 (Bcl-2), murine double minute 2 (mdm2), and proliferating cell nuclear antigen (PCNA) expression after 48 h. Nymphayol effectively inhibited breast cancer cell viability, and is associated with early expression of Cdkn2a, pRb2, and activation of p53 and caspases.

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