Humans ; Biomarkers, Tumor/metabolism* ; Claudins/analysis* ; Consensus ; Immunohistochemistry/methods* ; Stomach Neoplasms/diagnosis*

BACKGROUNDClaudin-5, claudin-9, and claudin-11 are expressed in endothelial cells to constitute tight junctions, and their deficiency may lead to hyperpermeability, which is the initiating process and pathological basis of cardiovascular disease. Although tongxinluo (TXL) has satisfactory antianginal effects, whether and how it modulates claudin-5, claudin-9, and claudin-11 in hypoxia-stimulated human cardiac microvascular endothelial cells (HCMECs) have not been reported.

METHODSIn this study, HCMECs were stimulated with CoCl2to mimic hypoxia and treated with TXL. First, the messenger RNA (mRNA) expression of claudin-5, claudin-9, and claudin-11 was confirmed. Then, the protein content and distribution of claudin-9, as well as cell morphological changes were evaluated after TXL treatment. Furthermore, the distribution and content histone H3K9 acetylation (H3K9ac) in the claudin-9 gene promoter, which guarantees transcriptional activation, were examined to explore the underlying mechanism, by which TXL up-regulates claudin-9 in hypoxia-stimulated HCMECs.

RESULTSWe found that hypoxia-suppressed claudin-9 gene expression in HCMECs (F = 7.244; P = 0.011) and the hypoxia-suppressed claudin-9 could be reversed by TXL (F = 61.911; P = 0.000), which was verified by its protein content changes (F = 29.142; P = 0.000). Moreover, high-dose TXL promoted the cytomembrane localization of claudin-9 in hypoxia-stimulated HCMECs, with attenuation of cell injury. Furthermore, high-dose TXL elevated the hypoxia-inhibited H3K9ac in the claudin-9 gene promoter (F = 37.766; P = 0.000), activating claudin-9 transcription.

CONCLUSIONSThe results manifested that TXL reversed the hypoxia-suppressed claudin-9 by elevating H3K9ac in its gene promoter, playing protective roles in HCMECs.

Cell Hypoxia ; Cells, Cultured ; Claudins ; analysis ; genetics ; Drugs, Chinese Herbal ; pharmacology ; Endothelial Cells ; drug effects ; metabolism ; Histones ; metabolism ; Humans ; Myocardium ; cytology ; metabolism ; Promoter Regions, Genetic

Background : Claudins are important components of the tight junctions in the intercellular barriers and cell polarity. Among them, claudin-7 is down-regulated in breast cancers compared with the normal breast epithelium. The aim of this study was to determine the expression pattern and prognostic value of claudin-7 in breast carcinomas. Methods : Claudin-7 expression was evaluated immunohistochemically in 42 cases of ductal carcinoma in situ (DCIS) and in 142 cases of invasive breast carcinoma (IBC) using a tissue microarray (TMA). Results : Claudin- 7 was strongly expressed in the normal luminal epithelial cells in the breast lobule. The level of claudin-7 expression was significantly lower or absent in 45.2% (19/42) of DCIS and 72.5% (103/142) of IBC. A loss or reduced expression of claudin-7 correlated with the invasiveness (p=0.001) of breast carcinomas and a high nuclear grade (p=0.013) in IBC. Conclusion: Claudin-7 is an important tight junction protein in the breast and a loss of expression may assist in the dissociation and invasion of tumor cells.
Breast Neoplasms* ; Breast* ; Carcinoma, Intraductal, Noninfiltrating ; Cell Polarity ; Claudins ; Epithelial Cells ; Epithelium ; Immunohistochemistry ; Microarray Analysis ; Phenobarbital ; Tight Junctions