Genistein Inhibits Proliferation of BRCA1 Mutated Breast Cancer Cells: The GPR30-Akt Axis as a Potential Target

BACKGROUND: BRCA1 mutated breast cancer cells exhibit the elevated cell proliferation and the higher metastatic potential. G protein-coupled receptor 30 (GPR30) has been shown to regulate growth of hormonally responsive cancers, such as ovarian and breast cancers, and high expression of GPR30 is found in estrogen receptor (ER)-negative breast cancer cells. ER-negative breast cancer patients often have a mutation in the tumor suppressor gene, BRCA1. This study explored antiproliferative effects of genistein, a chemopreventive isoflavone present in legumes, and underlying molecular mechanisms in triple negative breast cancer cells with or without functionally active BRCA1.METHODS: Expression of BRCA1, GPR30 and Nrf2 was measured by Western blot analysis. Reactive oxygen species (ROS) accumulation was monitored by using the fluorescence-generating probe, 2’,7’-dichlorofluorescein diacetate. The effects of genistein on breast cancer cell viability and proliferation were assessed by the MTT, migration and clonogenic assays.RESULTS: The expression of GPR30 was dramatically elevated at both transcriptional and translational levels in BRCA1 mutated breast cancer cells compared to cells with wild-type BRCA1. Notably, there was diminished Akt phosporylation in GPR30 silenced cells. Treatment of BRCA1 silenced breast cancer cells with genistein resulted in the down-regulation of GPR30 expression and the inhibition of Akt phosphorylation as well as the reduced cell viability, migration and colony formation. Genistein caused cell cycle arrest at the G₂/M phase in BRCA1-mutant cells through down-regulation of cyclin B1 expression. Furthermore, BRCA1-mutant breast cancer cells exhibited higher levels of intracellular ROS than those in the wild-type cells. Genistein treatment lowered the ROS levels through up-regulation of Nrf2 expression.CONCLUSIONS: Lack of functional BRCA1 activates GPR30 signaling, thereby stimulating Akt phosphorylation and cell proliferation. Genistein induces G2/M phase arrest by down-regulating cyclin B1 expression, which is attributable to its suppression of GPR30 activation and Akt phosphorylation in BRCA1 impaired breast cancer cells.

AMP kinase/cyclooxygenase-2 pathway regulates proliferation and apoptosis of cancer cells treated with quercetin

AMPK (AMP-activated protein kinase) is highly conserved in eukaryotes, where it functions primarily as a sensor of cellular energy status. Recent studies indicate that AMPK activation strongly suppresses cell proliferation in non-malignant cells as well as in tumor cells. In this study, quercetin activated AMPK in MCF breast cancer cell lines and HT-29 colon cancer cells, and this activation of AMPK seemed to be closely related to a decrease in COX-2 expression. The application of a COX-2 inhibitor or cox-2(-/-) cells supported the idea that AMPK is an upstream signal of COX-2, and is required for the anti-proliferatory and pro-apoptotic effects of quercetin. The suppressive or growth inhibitory effects of quercetin on COX-2 were abolished by treating cancer cells with an AMPK inhibitor Compound C. These results suggest that AMPK is crucial to the anti-cancer effect of quercetin and that the AMPK-COX-2 signaling pathway is important in quercetin-mediated cancer control.

Changes in the Expression Pattern of Cyclooxygenase-2, Mapkinases and Related Apoptotic Markers by Different Levels of Estrogen Supplementation in Mature or Ovariectomized Female Rat Heart

The effects of different concentrations of estrogen supplementation to mature female rats or estrogen supplementation to ovariectomized rats on cyclooxygenase-2 (COX-2) expression, PGE2 production and mapkinases expression were investigated in experimentally induced atherogenic rats with feeding a high fat.high cholesterol diet. In the first experiment using 48-week old mature rats, the supplementation of three different levels of estrogen was compared to the basal diet. The high concentration of estrogen supplementation induced the marked up-regulation of COX-2 protein and the increase in plasma PGE2 production and this seems to be followed by the up-regulation of p38 among mapkinases. The regulation of bax showed in a reverse trend of COX-2 in heart tissues of mature female rats. In the second experimental system, female Sprague-Dawley rats were bilaterally ovariectomized; sham-operated animals were used as controls. Three weeks later, the animals were supplied with basal diet to sham-operated control group and ovariectomized control group, and estrogen supplemented diet to ovariectomized group for an eight-week experimental period. In a group supplemented with a medium dose of estrogen, COX-2 expression was up-regulated. This up-regulation was accompanied by the elevated expression of pERK1/2. Bax was increased in estrogen-fed animals indicating bax might be involved in estrogen feeding state in ovariectomized rats. Further investigations on the relationship between COX-2 and biological activities such as vasodilation by estrogen are required in in vivo system of female rats at the various physiological states.

Improve Effects of Saengshik on Patient with Fatty Liver and Hyperlipidemia in Murine

To examine the effect of Saengshik on parameters related to hepatoprotective, anthropometric, blood pressure, serum lipid and blood related indices, nonalcoholic fatty liver subjects were treated with two meal portion of Saengshik in the replacement of meals for a period of three months. Weight, Body Mass Index (BMI) and systolic blood pressure were significantly decreased after the treatment. Chronically elevated serum aspartate aminotransferase (AST), gamma-Glutamyl transferase (r-GTP) and Alkaline Phosphatase (ALP) levels showed reduction to the near normal range. Serum total triglyceride level were reduced following the treatment. Whereas, there were no changes of serum total cholesterol with Saengshik consumption. Also, additional study was conducted to investigate the effect of Saengshik supplementation to high cholesterol and fat diet on lipid metabolism in rats. Male Spraque-Dawley rats were administrated hyperlipidemiainducing diet containing 1% cholesterol and 10% lard to induce hyperlipidemia for 4 weeks and were fed on diet containing Saengshik (30%, w/w) for 7 weeks. The feeding of diet containing 30% Shaengshik significantly decreased total cholesterol (TC) contents and total triglyceride. These results demonstrate Saengshik may be beneficial for fatty liver patients in improving their lipid metabolism.