Fatty Acids of CLA-Enriched Egg Yolks Can Induce Transcriptional Activation of Peroxisome Proliferator-Activated Receptors in MCF-7 Breast Cancer Cells

Mechanisms of Anticancer Activity of a Fatty Acid Mixture Extracted from Hen Egg Yolks Enriched in Conjugated Linoleic Acid Diene (CLA) against WM793 Melanoma Cells

The conjugated linoleic acid (CLA) diene is a biologically active compound with proven health-promoting effects. In terms of anticancer properties, it has been shown that CLA reduces the proliferation of cancer cells. In this study, it has been demonstrated that a mixture of fatty acids, isolated from chicken egg yolk enriched in CLA isomers by biofortification, reduces (by 30.5%) the proliferation of human melanoma cancer cells line WM793 to a greater extent than a mixture of fatty acids not containing these isomers. At the same time, the tested fatty acid mixtures show no effect on human normal BJ fibroblast cells. For the first time, the genes with increased expression have been identified and the proteins have been activated by the fatty acid mixture of CLA-enriched egg yolk, mainly responsible for mitochondrial pathway-dependent apoptosis.

Biological Activities of Egg Yolk Lipids: A Review

As one of six dietary nutrients, lipid derived from different food matrices has been extensively studied and has an appropriate application in food, medicine, and cosmetic industry. Egg is a richly nutritive food, of which proteins and lipids possess excellent functional characteristics and biological activities. In recent years, egg yolk lipid has been successively separated and investigated, such as egg yolk oil, phospholipids, and fatty acids, which have anti-inflammatory activity, antioxidant activity, cardiovascular protection, and memory improvement, involving the regulation of cell function and physiological homeostatic balance. In this paper, the biological activities and underlying benefit of egg yolk lipids and fat-soluble components have been highlighted and summarized. Meanwhile, the quantitative data of egg yolk lipids needed to achieve any of the described biological effects and recommended concentrations relevant for dietary intake are reviewed. Finally, current challenges and crucial issues of high-efficiency utilization of egg yolk lipids are also discussed.

Identification of breast cancer risk modules via an integrated strategy

Breast cancer is one of the most common malignant cancers among females worldwide. This complex disease is not caused by a single gene, but resulted from multi-gene interactions, which could be represented by biological networks. Network modules are composed of genes with significant similarities in terms of expression, function and disease association. Therefore, the identification of disease risk modules could contribute to understanding the molecular mechanisms underlying breast cancer. In this paper, an integrated disease risk module identification strategy was proposed according to a multi-objective programming model for two similarity criteria as well as significance of permutation tests in Markov random field module score, function consistency score and Pearson correlation coefficient difference score. Three breast cancer risk modules were identified from a breast cancer-related interaction network. Genes in these risk modules were confirmed to play critical roles in breast cancer by literature review. These risk modules were enriched in breast cancer-related pathways or functions and could distinguish between breast tumor and normal samples with high accuracy for not only the microarray dataset used for breast cancer risk module identification, but also another two independent datasets. Our integrated strategy could be extended to other complex diseases to identify their risk modules and reveal their pathogenesis.

PPAR Receptors Expressed from Vectors Containing CMV Promoter Can Enhance Self-Transcription in the Presence of Fatty Acids from CLA-Enriched Egg Yolks-A Novel Method for Studies of PPAR Ligands

PPAR receptors are ligand-dependent transcription factors activated in response to various small lipophilic ligands controlling the expression of different genes involved in cellular differentiation, development, metabolism, and tumorigenesis. Unexpectedly, our previous studies have shown that single plasmid-based expression of PPARs under the control of CMV promoter/enhancer was significantly elevated in the presence of PPAR agonists. Here we show that the PPAR reporters controlled by the CMV promoter/enhancer, that was shown to contain three internal non-canonical PPRE elements, can be used as a fast screening system for more effective PPAR ligands. This model allowed us to confirm our previous results indicating that fatty acids of CLA-enriched egg yolks (EFA-CLAs) are efficient PPAR ligands that can specifically upregulate the expression of PPARα and PPARγ leading to downregulation of MCF-7 cancer cell proliferation. We also show that synthetic cis9,trans11CLA is more effective in transactivation of PPARγ, while trans10,cis12CLA of PPARα receptor indicating the selectivity of the CLA isomers. This report presents a novel, fast, and reliable strategy for simple testing of PPAR ligands using PPAR expressing plasmids containing the CMV promoter/enhancer that can trigger the positive feedback loop of PPAR self-transcription in the presence of PPAR ligands.

Pivotal Roles of Peroxisome Proliferator-Activated Receptors (PPARs) and Their Signal Cascade for Cellular and Whole-Body Energy Homeostasis

Peroxisome proliferator-activated receptors (PPARs), members of the nuclear receptor superfamily, are important in whole-body energy metabolism. PPARs are classified into three isoforms, namely, PPARα, β/δ, and γ. They are collectively involved in fatty acid oxidation, as well as glucose and lipid metabolism throughout the body. Importantly, the three isoforms of PPARs have complementary and distinct metabolic activities for energy balance at a cellular and whole-body level. PPARs also act with other co-regulators to maintain energy homeostasis. When endogenous ligands bind with these receptors, they regulate the transcription of genes involved in energy homeostasis. However, the exact molecular mechanism of PPARs in energy metabolism remains unclear. In this review, we summarize the importance of PPAR signals in multiple organs and focus on the pivotal roles of PPAR signals in cellular and whole-body energy homeostasis.

Milk fat components with potential anticancer activity-a review

During many years, the milk fat has been unfairly undervalued due to its association with higher levels of cardiovascular diseases, dyslipidaemia or obesity, among others. However, currently, this relationship is being re-evaluated because some of the dairy lipid components have been attributed potential health benefits. Due to this, and based on the increasing incidence of cancer in our society, this review work aims to discuss the state of the art concerning scientific evidence of milk lipid components and reported anticancer properties. Results from the in vitro and in vivo experiments suggest that specific fatty acids (FA) (as butyric acid and conjugated linoleic acid (CLA), among others), phospholipids and sphingolipids from milk globule membrane are potential anticarcinogenic agents. However, their mechanism of action remains still unclear due to limited and inconsistent findings in human studies.