Coronary artery disease results in progressive vascular stenosis associated with chronic myocardial ischemia. Vascular endothelial growth factor (VEGF) stimulates endothelial cell angiogenic responses to revascularize ischemic tissues; however, the effect of chronic hypoxia on the responsiveness of endothelial cells to VEGF remains unclear. We, therefore, investigated whether hypoxia alters VEGF-stimulated signaling and angiogenic responses in primary human coronary artery endothelial (HCAE) cells. Exposure of HCAE cells to hypoxia (1% O(2)) for 24 h decreased VEGF-stimulated endothelial cell migration ( approximately 82%), proliferation ( approximately 30%), and tube formation. Hypoxia attenuated VEGF-stimulated activation of endothelial nitric oxide (NO) synthase (eNOS) ( approximately 72%) and reduced NO production in VEGF-stimulated cells from 237 +/- 38.8 to 61.3 +/- 28.4 nmol/l. Moreover, hypoxia also decreased the ratio of phosphorylated eNOS to total eNOS in VEGF-stimulated cells by approximately 50%. This effect was not observed in thrombin-stimulated cells, suggesting that hypoxia specifically inhibited VEGF signaling upstream of eNOS phosphorylation. VEGF-induced activation of Akt, ERK1/2, p38, p70S6 kinases, and S6 ribosomal protein was also attenuated in hypoxic cells. Moreover, VEGF-stimulated phosphorylation of VEGF receptor-2 (KDR) at Y996 and Y1175 was decreased by hypoxia. This decrease correlated with a 70 +/- 12% decrease in KDR protein expression. Analysis of mRNA from these cells showed that hypoxia reduced steady-state levels of KDR mRNA by 52 +/- 16% and decreased mRNA stability relative to normoxic cells. Our findings demonstrate that chronic hypoxia attenuates VEGF-stimulated signaling in HCAE cells by specific downregulation of KDR expression. These data provide a novel explanation for the impaired angiogenic responses to VEGF in endothelial cells exposed to chronic hypoxia.

No abstract

No abstract

Compound 8 is the most cytotoxic against human lung adenocarcinoma A549 cells at hypoxic conditions. Hypoxia/normoxia cytotoxic coefficient of compound 8 (4.75) is close to hypoxia/normoxia cytotoxic coefficient of tirapazamine (5.59) - reference substance in our experiments and this parameter locates it between mitomycin C and 2-nitroimidazole (misonidazole). The screening test of the caspase-dependent apoptosis proved that the exposure of compounds 1-2 and 7-8 against A549 cells for a 48 h promote apoptotic cell death. Additionally, the test of the DNA damage established that compounds 1, 2, 7, 8 are specific agents for the hypoxia-selective cytotoxicity of nitrobenzimidazoles [6,26].

The immunomodulatory nature of lactoferrin (LF) derives from its ability to bridge innate and adaptive immunity in obtaining physiological equilibrium. LF is an attractive molecule for treatment of diseases that compromise immune homeostasis. Oral delivery is a preferable method for LF administration; however, its bioavailability is affected by protein degradation and absorption. The aim of this study was to evaluate the systemic effects of oral and intravenous (IV) administered recombinant human LF (rhLF) on blood cell transcriptome profiling. Rats were administered with a single dose of rhLF by gavage or IV. The transcriptome profiles from control and rhLF-treated rats after 3h, 6h and 24h were analyzed by Clariom D microarray. The results showed differentially expressed genes in response to IV as well as oral administered rhLF including coding and noncoding RNAs. Moreover, a comparison of the differentially expressed genes between oral and IV after 6h revealed that a majority (72.8%) of altered genes in response to oral rhLF administration was common with IV treatment. The pathway profiles showed similarities in up-regulation of specific genes involved in oxidative stress and inflammatory responses for both routes of treatments. These findings provide evidence of the systemic signal transduction effects of orally administered rhLF.