Pituitary adenylate cyclase-activating peptide/vasoactive intestinal peptide receptors in human normal mammary gland and breast cancer tissue.
Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) bind similarly to VPAC1 and VPAC2 receptors, whereas PACAP binds with higher affinity than VIP to PAC1 receptors. Here we demonstrate by different approaches the expression of the three subclasses of PACAP/VIP receptors in human normal and malignant breast tissue. At the mRNA level, reverse transcription-polymerase chain reaction experiments showed VPAC1 and VPAC2 receptors as well as various isoforms (null, hip/hop) of PAC1 receptors due to alternative splicing. At the protein level, Western blot experiments revealed the three subclasses of receptor although no conclusive differences could be established when comparing control, peritumoral and tumoral tissue samples. Immunohistochemistry showed the distribution of these receptors: they were located at epithelial cells in normal and cancer conditions but also in leukocytes at the stromal level in carcinomatous tissue. A weaker immunostaining of PAC1 receptors in normal tissue and a strong density of the three PACAP/VIP receptor subclasses in cancer tissue may be related to differential expression patterns during breast tumor progression but more samples need to be studied to validate this hypothesis. PAC1, VPAC1 and VPAC2 receptors were functional, as shown by their coupling to adenylate cyclase stimulation: VIP, PACAP-27 and PACAP-38 behaved similarly at this level, whereas both VPAC receptors acted alike as shown by means of specific peptide agonists and antagonists. The present results together with the known presence of PACAP and VIP in the mammary gland support a paracrine/autocrine involvement of both peptides at this level in physiological and pathological conditions, i.e. during malignant transformation.
García-Fernández
M Olga
MO
Department of Biochemistry and Molecular Biology, University of Alcalá, E-28871 Alcalá de Henares, Spain.
Collado
Beatriz
B
Bodega
Guillermo
G
Cortés
Joaquin
J
Ruíz-Villaespesa
Antonio
A
Carmena
Maria J
MJ
Prieto
Juan Carlos
JC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism*; D016022:Case-Control Studies; D002471:Cell Transformation, Neoplastic; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D042361:Mammary Glands, Human / Q000378:metabolism*; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D018005:Receptors, Vasoactive Intestinal Peptide / Q000235:genetics / Q000378:metabolism*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D020133:Reverse Transcriptase Polymerase Chain Reaction
C495503:ADCYAP1R1 protein, human; D012333:RNA, Messenger; 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