title: Reduction of intracellular pH inhibits the expression of VEGF in K562 cells after targeted inhibition of the Na+/H+ exchanger.
abstract: To explore the effect of inhibition of Na(+)/H(+) exchanger isoform 1 (NHE1) on the expression of vascular endothelial growth factor (VEGF) mRNA and protein in human myeloid K562 cells. The expression of VEGFmRNA was detected by RT-PCR technique. The levels of VEGF protein were measured by Western blotting and immunocytochemistry assay. pHi values were measured with fluorescence spectrophotometer. The three RT-PCR products detected were VEGF121, VEGF165, and VEGF189, respectively. Treatment of K562 cells either with amiloride (an inhibitor of NHE1) or with 5-(N-ethyl-N-isopropyl)-amiloride (EIPA, a selective inhibitor of NHE1) resulted in significant decrease of VEGF mRNA and VEGF protein levels. Either amiloride or EIPA decreased intracellular pH (pHi) values in K562 cells. These data strongly suggested that the expression of VEGF mRNA and protein in K562 cells was inhibited accompanying its reduction in pHi value after targeted inhibition of NHE1.
authors.affiliation: Pediatrics Department of Zhongnan Hospital, Wuhan University, East-lake Road, Wuhan, Hubei Province 430071, PR China. Heby2005@sina.com
authors.forename: Bingyan
authors.initials: B
authors.lastname: He
authors.forename: Changsheng
authors.initials: C
authors.lastname: Deng
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Dianding
authors.initials: D
authors.lastname: Zou
authors.forename: Min
authors.initials: M
authors.lastname: Xu
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D015153:Blotting, Western; D015870:Gene Expression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007124:Immunoenzyme Techniques; D020014:K562 Cells / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D017923:Sodium-Hydrogen Exchangers; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C069139:growth factor-activatable Na-H exchanger NHE-1; D000584:Amiloride; C039614:ethylisopropylamiloride