Hypoxia regulation of expression and angiogenic effects of vasoactive intestinal peptide (VIP) and VIP receptors in LNCaP prostate cancer cells.
Vascular endothelial growth factor (VEGF) is a main factor promoting neovascularization (angiogenesis) of solid tumours as prostate carcinoma. Hypoxia stimulates VEGF gene expression by activating the hypoxia-inducible factor-1 (HIF-1alpha). In the present study, the hypoxia-mimicking agent Ni(2+) induced vasoactive intestinal peptide (VIP) expression at both mRNA and peptide levels but it did not modify the expression of VIP receptors (VPAC(1), VPAC(2) and PAC(1) receptors) in androgen-dependent human LNCaP prostate cancer cells. VIP increased the mRNA levels of VPAC(1) and PAC(1) receptors whereas it decreased VPAC(2) receptor mRNA level. These features support that hypoxia up-regulation of VIP gene expression in prostatic carcinoma may lead to VIP regulation of the expression of its receptors by means of autocrine/paracrine mechanisms. Either VIP or hypoxia mimetics with Ni(2+) increased VEGF expression whereas both conditions together resulted in an additive response. It suggests two independent mechanisms for the observed pro-angiogenic activities of VIP and hypoxia. VIP did not stimulate HIF-1alpha mRNA expression but increased the translocation of HIF-1alpha from the cytosolic compartment to the cell nucleus. Moreover, VIP was unable to modify the expression of the HIF-1alpha inhibitor FIH-1 discarding the possibility of an indirect effect of VIP on HIF-1 transactivation.
Collado
Beatriz
B
Department of Biochemistry and Molecular Biology, Príncipe de Asturias Hospital, Alcalá de Henares 28871, Spain.
Sánchez-Chapado
Manuel
M
Prieto
Juan C
JC
Carmena
María J
MJ
D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D008297:Male; D006899:Mixed Function Oxygenases; D009532:Nickel / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D018005:Receptors, Vasoactive Intestinal Peptide / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000235:genetics / Q000378:metabolism*
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D018005:Receptors, Vasoactive Intestinal Peptide; D012097:Repressor Proteins; D014157:Transcription Factors; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D014660:Vasoactive Intestinal Peptide; C022838:nickel chloride; D009532:Nickel; D006899:Mixed Function Oxygenases; C439790:HIF1AN protein, human