Bidirectional Eph-Ephrin signaling as a focal point of research in cell-cell communications is critical for generation of nerves and vesssels as well as invation and metastasis of tumor cells. The roles for Ephrin-Eph bidirectional signaling in bone remodeling were important. EphrinB2 is expressed on osteoblasts and EphB4 is expressed on osteoclasts. Forward signaling through the EphB4 receptor into mesenchymal precursors promotes osteoblast differentiation, while reverse signaling through the EphrinB2 ligand into osteoclast suppresses differentiation. Signaling between the ligand EphrinB2 and the receptors EphB4 explains bidirectional signaling between osteoblasts and osteoclasts,bone absorption and remodeling, which may lay a theoretical foundation for identifying drug targeting and preventing and treating bone loss.
Animals ; Bone Remodeling ; physiology ; Ephrin-B2 ; physiology ; Humans ; Osteoblasts ; cytology ; Osteoclasts ; cytology ; Receptor, EphB4 ; physiology ; Signal Transduction ; physiology

The aim of the present study was to examine the effects of suppression of EphB4 and/or mTOR on the biological behaviors of ovarian cancer cells, and the potential regulatory pathways. Antisense EphB4 vectors and shRNA vectors targeting mammalian target of rapamycin (mTOR) were constructed and transfected into A2780 and SKOV3 cells (two ovarian cancer cell lines). The effects of the antisense EphB4 vectors and the shRNA vectors on the proliferation, apoptosis and invasion of ovarian cancer cells were measured, and the expression of EphB4, mTOR and Akt detected. The results showed that transfection with mTOR shRNA could inhibit growth, induce apoptosis, and reduce invasive ability of ovarian cancer cells, which was accompanied by downregulation of EphB4, mTOR and Akt. The inhibitory effects on cell growth caused by mTOR shRNA alone were weaker than those by antisense pEGFP-C1-EphB4. In the antisense pEGFP-C1-EphB4-transfected cells, it was found that EphB4 knockdown could decrease the mTOR expression and slightly reduce the Akt phosphorylation. Significant suppressive effects on cell growth were observed in cells co-transfected with antisense pEGFP-C1-EphB4 and mTOR shRNA. In co-transfection group, the expression levels of EphB4, mTOR and Akt were distinctly lower than those in other groups. It was concluded that suppression of EphB4 may inhibit the growth of ovarian cancer cells by downregulation of the PI3K/Akt/mTOR pathway, and reverse Akt phosphorylation induced by mTOR shRNA. Inhibition of EphB4 and mTOR combined may cooperatively suppress the biological behaviors of ovarian cancer cells.
Apoptosis ; genetics ; Cell Line, Tumor ; Cell Proliferation ; Down-Regulation ; genetics ; Female ; Humans ; Ovarian Neoplasms ; pathology ; physiopathology ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Receptor, EphB4 ; genetics ; metabolism ; Suppression, Genetic ; genetics

Adult ; Aged ; Aged, 80 and over ; Carcinoma, Non-Small-Cell Lung ; genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Lung Neoplasms ; genetics ; Male ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Polymorphism, Single Nucleotide ; Receptor, EphB4 ; genetics

OBJECTIVETo study the regulation of methylation inhibitor 5-aza-2'-deoxycytidine on transcription of EphB4 gene and effects on the proliferation and apoptosis of human acute lymphocyte leukemia cell line CEM.

METHODSBisulfite sequencing PCR was used to detect CpG island methylation density in EphB4 promoter. The expression of EphB4 mRNA and protein was determined by Q-PCR and Western blot. MTS assay and flow cytometry were used to detect the apoptosis of CEM cells after treatment with different concentrations of 5-aza-2'-deoxycytidine (1.0, 2.5 and 5 μmol/L).

RESULTSMethylation of EphB4 gene promoter was detected in CEM cells (31.4%). The methylation level of EphB4 gene was down-regulated after treatment with various concentrations of 5-aza-2'-deoxycytidine. The EphB4 mRNA and protein expression in CEM cells increased after 5-aza-2'-deoxycytidine treatment. 5-Aza-2'-deoxycytidine significantly inhibited the cell growth in dose and time dependent manners. Early apoptosis rates of CEM cells increased from 4.1% to 24.8% 96 hrs after 5-aza-2'-deoxycytidine treatment. CEM cells in G1 phase decreased from 62.4% to 46.8%, cells in G2 phase increased from 2.1% to 16.2%, and CEM cells were arrested in G2 phase after treatment with 5 μmol/L 5-aza-2'-deoxycytidine for 96 hrs.

CONCLUSIONS5-Aza-2'-deoxycytidine, an inhibitor of specific methylation transferase, can induce expression of the silent EphB4 gene in CEM cells, inhibit the proliferation of leukemia cells and induce cell apoptosis.

Apoptosis ; drug effects ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Methylation ; DNA Modification Methylases ; antagonists & inhibitors ; Humans ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; drug therapy ; pathology ; RNA, Messenger ; analysis ; Receptor, EphB4 ; genetics

OBJECTIVETo evaluate the effect of Xuefu Zhuyu Capsule ()-containing serum (XFZY-CS) on EphB4/ephrinB2 and its reverse signal in human microvascular endothelial cell-1 (HMEC-1).

METHODSXFZY-CS and the blank control serum were collected. HMEC-1 cells were randomly assigned to 6 groups including the concentration 1.25%, 2.5%, and 5% XFZY-CS groups and their blank serum control ones. The angiogenesis effect of XFZY-CS was tested with an in vitro tube formation assay and the best condition of pro-angiogenesis was determined. The effect of XFZY-CS on EphB4/ephrinB2 and the reverse signal were determined by Western blot and real-time quantitative polymerase chain reaction, respectively; we also confifirmed the results through activating and inhibiting the reverse signal by EphB4/fc and pyrophosphatase/ phosphodiesterase2 (PP2).

RESULTSXFZY-CS promoted angiogenesis at the concentration of 2.5% corresponding serum after being cultured for 48 h, while inhibited angiogenesis at the concentration of 5% after culturing for 48 and 72 h. Under the 2.5% serum concentration, XFZY up-regulated the expression of EphB4-mRNA at 12 h (P<0.05), and down-regulates its expression at 24 h (P<0.01). Protein expression of EphB4 was apparently up-regulated at 12 h and down-regulated at 24 h. The phosphorylation of ephrinB2 increased at 9 h (P<0.05). In addition, 2.5% XFZY-CS played a similar role as the reverse signaling activator EphB4/Fc ranging from 0.5 to 5 μg/mL (P>0.05). XFZY-CS also reduced the inhibitive effect of PP2 in limited periods.

CONCLUSIONSEphB4/ephrinB2 was the upstream signal in the process of angiogenesis and its reverse signaling was responsible for XFZY's effect on promoting angiogenesis.

Adult ; Capsules ; Drugs, Chinese Herbal ; pharmacology ; Endothelial Cells ; drug effects ; metabolism ; Ephrin-B2 ; metabolism ; Gene Expression Regulation ; drug effects ; Humans ; Male ; Microvessels ; pathology ; Middle Aged ; Neovascularization, Physiologic ; drug effects ; genetics ; Phosphoric Diester Hydrolases ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Receptor, EphB4 ; genetics ; metabolism ; Serum ; metabolism ; Time Factors ; Young Adult

OBJECTIVETo investigate the role of the expression of ephrinB2 and EphB4 in non-small cell lung cancer (NSCLC), and their relationship with multi-slice spiral CT pulmonary perfusion imaging.

METHODSThirty-one nodules with pathologically proven NSCLC underwent CT perfusion scan. The perfusion parameters including blood flow (BF), blood volume (BV), peak enhancement image (PEI) were collected. The expression of ephrinB2 and EphB4 in tumor cells and interstitial vasculature were detected by immunohistochemistry. Correlation analysis and trend test were used to assess the relationship between ephrinB2/EphB4 expression and clinicopathological features, and between ephrinB2/EphB4 expression and perfusion parameters.

RESULTSPositive expression of ephrinB2 and EphB4 in the NSCLC group was 83.9% and 71.0%, respectively, significantly higher than that in the internal control group (P < 0.01). The expression of ephrinB2 and EphB4 was consistently in tumor parenchyma but differently in tumor vessels. The expressions of ephrinB2 and EphB4 were positively correlated with lymphatic metastasis (P < 0.05). The expression of EphB4 was negatively correlated with blood flow (BF) and blood volume (BV), respectively (P < 0.05). There was a significant positive correlation between ephrinB2 expression and BF (r = 0.516, P = 0.003), and a positive correlation between ephrinB2 expression and BV (r = 0.448, P = 0.013). The expressions of ephrinB2 and EphB4 were not correlated with PEI (P > 0.05). The values of BF and BV in the high and moderate EphB4 expression groups were significantly decreased compared with that in the negative group (P < 0.01). The value of BF in the high ephrinB2 expression group was significantly increased compared with that in the moderately positive group and negative group (P < 0.01). The value of BV in the high ephrinB2 expression group was significantly increased compared with that in the negative group (P < 0.01).

CONCLUSIONThe CT pulmonary perfusion imaging reflects the density difference of blood vessels with functional lumen, and such difference also depends on the quantity and quality of vasculature with functional lumen.

Adult ; Aged ; Blood Volume ; Carcinoma, Non-Small-Cell Lung ; blood supply ; diagnostic imaging ; metabolism ; pathology ; physiopathology ; Ephrin-B2 ; metabolism ; Female ; Humans ; Lung Neoplasms ; blood supply ; diagnostic imaging ; metabolism ; pathology ; physiopathology ; Lymphatic Metastasis ; Male ; Middle Aged ; Perfusion Imaging ; Pulmonary Circulation ; Receptor, EphB4 ; metabolism ; Tomography, Spiral Computed ; methods