ABSTRACT
@#【Objective】To investigate the effects of zinc on the formation of atherosclerotic macrophage foaming and plaque formation and its mechanism.【Methods】The macrophage foaming model was established by stimulating THP-1cells with oxLDL. The degree of foaming in different zinc concentrations of 0，30 and 60 μmol/Lwas detected by oil red Ostaining and the intake of lipid by foam cells was measured by DiI-oxLDL fluorescence. The relevant scavenger protein ex⁃pression of CD36，SR-A was detected by immunoblotting. The relative expression level of zinc ion transporters was detect⁃ed by real-time fluorescent quantitative PCR. ApoE-/- mice were randomly divided into 4 groups，the normal feed group（Chow group），the high-fat zinc-deficient group（HFD-ZnD），and the high-fat normal zinc group（HFD），high-fatand zinc-supplement group（HFD-ZnS），blood lipids and the protein of the mice aorta were detected in the 13 week.【Results】Compared with the normal zinc group，the oil red O density increased（P < 0.05），and add zinc ion decreased the intake of the DiI-oxLDL by foam cells（P < 0.01）. In the 0 μmol/L zinc group，the SR-A and CD36 protein expressionin the foam cells increased（P < 0.05）and 15μmol/L Zn2+ treatment before stimulating with oxLDL reduced the contentsof SR-A and CD36 proteins（P < 0.05）. Compared the oxLDL-treated group with the control group，the mRNA expres⁃sion levels of ZIP10，ZIP12 and ZIP14 increased，and the mRNA expression levels of ZIP4，ZIP7 and ZIP8 decreased（P < 0.05）；while the mRNA expression of ZnT4 was up-regulated（P < 0.01），and the mRNA expression of ZnT1 was down-regulated（P < 0.05）. Compared with Chow group，low density lipoprotein cholesterol（LDL-C），total cholesterol（TC）and triglyceride（TG）were increased in HFD group and HFD-ZnD group，respectively（P < 0.05）；HFD-ZnD group High-density lipoprotein cholesterol（HDL-C）was significantly elevated. Moreover，the LDL-C of the HFD-ZnS group was significantly lower than that of the HFD-ZnD group（P < 0.05）. The SR-A protein of the mice aorta of the HFD and HFD-ZnD group increased compared to the Chow group（P < 0.01），HFD-ZnS could restrain the increase（P < 0.05）. Compared with the Chow group，the ratio of plaque area in the aorta to the total arterial lumen area was significantly in⁃creased in the HFD-ZnD group（P < 0.01），and HFD-ZnS significantly inhibited this increase（P < 0.01）.【Conclusions】 Extracellular zinc deficiency aggravates lipid deposition in macrophages，and the mechanism may be regulated by up-reg⁃ulating the scavenger receptor CD36 and SR-A. Zinc ion transporters are involved in macrophage foaming and formation ofarterial plaques. Zinc deficiency can increase LDL-C and promote the increase of arterial plaque induced by high-fat diet.
ABSTRACT
PURPOSE: Chloride channel-3 (ClC-3) is a member of the chloride channel family and plays a critical role in a variety of cellular activities. The aim of the present study is to explore the molecular mechanisms underlying the antitumor effect of silencing ClC-3 in breast cancer. METHODS: Human breast cancer cell lines MDA-MB-231 and MCF-7 were used in the experiments. Messenger RNA and protein expression were examined by quantitative real-time polymerase chain reaction and western blot analysis. Cell proliferation was measured by the bromodeoxyuridine method, and the cell cycle was evaluated using fluorescence-activated cell sorting. Protein interaction in cells was analyzed by co-immunoprecipitation. Tumor tissues were stained with hematoxylin-eosin and tumor burden was measured using the Metamorph software. RESULTS: Breast cancer tissues collected from patients showed an increase in ClC-3 expression. Knockdown of ClC-3 inhibited the secretion of insulin-like growth factor (IGF)-1, cell proliferation, and G1/S transition in breast cancer cells. In the mouse xenograft model of human breast carcinoma, tumor growth was significantly slower in animals injected with ClC-3-deficient cells compared with the growth of normal human breast cancer cells. In addition, silencing of ClC-3 attenuated the expression of proliferating cell nuclear antigen, Ki-67, cyclin D1, and cyclin E, as well as the activation of extracellular signal-regulated protein kinases (ERK) 1/2, both in vitro and in vivo. CONCLUSION: Together, our data suggest that upregulation of ClC-3 by IGF-1 contributes to cell proliferation and tumor growth in breast cancer, and ClC-3 deficiency suppresses cell proliferation and tumor growth via the IGF/IGF receptor/ERK pathway.