Abstract
The effects of pituitary adenylate cyclase activating polypeptide (PACAP) analogs were investigated using breast cancer cells. 125I-PACAP-27 bound with high affinity (Kd = 5 nM) to T47D cells (Bmax = 29,000 per cell). Specific 125I-PACAP-27 binding was inhibited half maximally by PACAP-27, PACAP-38, PACAP(6-38) and PACAP(28-38) with IC50) values of 8, 17, 750 and >3000 nM, respectively. By RT-PCR, PACAP receptor mRNA was present in MCF-7 and T47D cell lines. Polyclonal antibodies to a PACAP receptor fragment (A-8-C) were elicited. The antibodies were affinity purified, recognized a 60-kDa protein by western blot, and stained malignant cells in breast cancer biopsy specimens by immunohistochemistry. PACAP-27 elevated the cAMP in T47D cells and the increase in cAMP caused by PACAP was inhibited by PACAP(6-38). PACAP-27 stimulated c-fos mRNA in T47D cells and the increase in c-fos gene expression caused by PACAP was reversed by PACAP(6-38). PACAP(6-38) inhibited colony formation using a soft agar assay and inhibited breast cancer xenograft growth in nude mice. These data suggest that PACAP(6-38) functions as a breast cancer PACAP receptor antagonist.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells
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Animals
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Breast Neoplasms / enzymology
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Breast Neoplasms / metabolism*
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Breast Neoplasms / pathology
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Cell Division / drug effects
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Female
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Growth Inhibitors / metabolism
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Growth Inhibitors / pharmacology
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Humans
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Mammary Neoplasms, Experimental / enzymology
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Mammary Neoplasms, Experimental / metabolism*
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Mammary Neoplasms, Experimental / pathology
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Mice
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Mice, Inbred BALB C
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Mice, Nude
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Neoplasm Transplantation
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Neuropeptides / antagonists & inhibitors
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Neuropeptides / metabolism
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Neuropeptides / pharmacology*
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Peptide Fragments / antagonists & inhibitors
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Peptide Fragments / metabolism
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Peptide Fragments / pharmacology*
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Pituitary Adenylate Cyclase-Activating Polypeptide
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Rabbits
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Pituitary Hormone / antagonists & inhibitors*
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Transplantation, Heterologous
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Tumor Cells, Cultured
Substances
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Growth Inhibitors
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Neuropeptides
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Peptide Fragments
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Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Pituitary Hormone
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pituitary adenylate-cyclase-activating-peptide (6-38)