Immunocytochemical identification of VPAC1, VPAC2, and PAC1 receptors in normal and neoplastic human tissues with subtype-specific antibodies.

Abstract

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.

• Authors: Solveig Schulz, Christoph Röcken, Christian Mawrin, Wolfgang Weise, Volker Höllt, Stefan Schulz
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 10 Issue 24 Pg. 8235-42 (Dec 15 2004) ISSN: 1078-0432 [Print] United States
• PMID: 15623599 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• ADCYAP1R1 protein, human
• Immunoglobulin G
• Peptide Fragments
• Receptors, Cell Surface
• Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
• Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I
• Receptors, Vasoactive Intestinal Peptide
• Receptors, Vasoactive Intestinal Peptide, Type II
• Receptors, Vasoactive Intestinal Polypeptide, Type I
• VIPR1 protein, human
• VIPR2 protein, human

Topics

• Animals
• Blood Vessels (metabolism)
• Blotting, Western
• Cell Membrane (metabolism)
• Gastrointestinal Tract (metabolism)
• Humans
• Immunoglobulin G (immunology)
• Muscle, Smooth (metabolism)
• Neoplasms (diagnosis, immunology, metabolism)
• Neurosecretory Systems (metabolism)
• Peptide Fragments (immunology)
• Rabbits
• Receptors, Cell Surface (metabolism)
• Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
• Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I
• Receptors, Vasoactive Intestinal Peptide (metabolism)
• Receptors, Vasoactive Intestinal Peptide, Type II
• Receptors, Vasoactive Intestinal Polypeptide, Type I