Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor implicated in many pathological processes. We investigated the regulation of 4 alternatively spliced isoforms (121, 165, 189 and 206 amino acids) by hypoxia, hypoglycemia, acidity, female reproductive hormones and vitamin D in breast carcinoma cell lines representing different tumor phenotypes. There was a 17-fold difference in total VEGF mRNA expression across the cell lines. The isoform expression, 121 > 165 > 189, was unchanged by different culture conditions. Hypoxia was the most potent stimulus, and the cell lines demonstrated a 1.4- to 6.9-fold range of VEGF induction, maintained when other hypoxically regulated genes (phosphoglycerate kinase 1 and glucose transporter 1) and a HIF-1-dependent reporter gene were examined. The relative inducibility of the genes was maintained in each cell line, but basal expression was independent of -fold induction. VEGF expression decreased under acidic conditions in 2 cell lines, but the hypoxia stimulus remained effective under acidic conditions. Hypoglycemia, female reproductive hormones and vitamin D exerted no effect on expression, nor did inhibitors of mutant ras. Our results show that VEGF expression varies widely between cell lines and that capacity to respond to hypoxia is also cell specific, relating mostly to the hypoxic sensing of the cell and the signal transduction mechanism. Such characteristics, if maintained in vivo, have implications for the angiogenic potential of different tumor cells under normal and hypoxic conditions.
 ...
PMID:Role of the hypoxia sensing system, acidity and reproductive hormones in the variability of vascular endothelial growth factor induction in human breast carcinoma cell lines. 949 38

Angiogenesis, the formation of new blood vessels, is crucial to the process of fracture healing. Vascular disruption after osseous injury results in an acidic, hypoxic wound environment. We have previously shown that osteoblasts can produce vascular endothelial growth factor (VEGF) in response to a variety of stimuli. In this study we examined pH and lactate concentration, two components of the putative fracture extracellular microenvironment, and determined their relative contribution to regulation of rat calvarial osteoblast VEGF production under both normoxic and hypoxic conditions. Our results demonstrate that pH and lactate concentration do independently affect osteoblast VEGF mRNA and protein production. Acidic pH (7.0) significantly decreased VEGF production, under normoxic and hypoxic conditions (P < 0.05), compared with neutral pH (7.4). This decrease was primarily transcriptionally regulated, because the rate of VEGF mRNA degradation was unchanged at pH 7.0 vs. 7.4. Similarly, an elevated lactate concentration (22 mM) also depressed osteoblast elaboration of VEGF at both neutral and acidic pH (P < 0.001). Furthermore, the effects of increasing acidity and elevated lactate appeared to be additive.
 ...
PMID:Osteoblast expression of vascular endothelial growth factor is modulated by the extracellular microenvironment. 1112 78