Immunocytochemical identification of VPAC1, VPAC2, and PAC1 receptors in normal and neoplastic human tissues with subtype-specific antibodies.
Human tumors frequently overexpress receptors for vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP). However, none of the VIP/PACAP receptor proteins has been visualized individually in human tumors. Here, we developed and characterized a panel of antipeptide antibodies to the carboxyl-terminal regions of the VIP/PACAP receptor subtypes vasoactive intestinal peptide receptor (VPAC)1, VPAC2, and pituitary adenylate cyclase-activating peptide receptor (PAC)1. Specificity of the antisera was shown by the following: (1) detection of broad bands migrating at Mr 50,000 to 70,000 in Western blots of membranes from receptor-expressing tumors and receptor-transfected cells; (2) cell surface staining of VIP/PACAP receptor-transfected cells; (3) translocation of VIP/PACAP receptor immunostaining in transfected cells after agonist exposure; and (4) abolition of tissue immunostaining by preadsorbtion of the antibodies with their immunizing peptides. The distribution of VIP/PACAP receptors was investigated in 98 human tumors and their tissues of origin. VPAC1, VPAC2, and PAC1 receptors were clearly located at the plasma membrane of the tumor cells in a variety of human neoplasms. In the gastrointestinal tract, VPAC1 receptor immunoreactivity was abundant in the mucosa and myenteric neurons; VPAC2 receptor immunoreactivity was detected in neuroendocrine cells, blood vessels, and smooth muscle; and PAC1 receptor immunoreactivity was found in myenteric neurons. This is the first localization of all of the VIP/PACAP receptor subtypes in human formalin-fixed, paraffin-embedded tissues. VIP/PACAP receptor visualization with this simple and rapid immunohistochemical method will facilitate identification of tumors with a sufficient receptor overexpression for diagnostic or therapeutic intervention.
Schulz
Solveig
S
Department of Obstetrics and Gynecology, Otto-von-Guericke-University, Magdeburg, Germany. Stefan.Schulz@Medizin.Uni-Magdeburg.de
Röcken
Christoph
C
Mawrin
Christian
C
Weise
Wolfgang
W
Höllt
Volker
V
Schulz
Stefan
S
D000818:Animals; D001808:Blood Vessels / Q000378:metabolism; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D009130:Muscle, Smooth / Q000378:metabolism; D009369:Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism*; D009490:Neurosecretory Systems / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology*; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000378:metabolism*; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I
C495503:ADCYAP1R1 protein, human; D007074:Immunoglobulin G; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; C495506:VIPR1 protein, human; C495509:VIPR2 protein, human