PACAP(6-38) is a PACAP receptor antagonist for breast cancer cells.
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.
Leyton
J
J
Department of Cell and Cancer Biology, Medicine Branch, National Cancer Institute, Rockville, MD 20850, USA.
Gozes
Y
Y
Pisegna
J
J
Coy
D
D
Purdom
S
S
Casibang
M
M
Zia
F
F
Moody
T W
TW
D016475:3T3 Cells; D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D005260:Female; D006131:Growth Inhibitors / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011817:Rabbits; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000037:antagonists & inhibitors*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
D006131:Growth Inhibitors; D009479:Neuropeptides; D010446:Peptide Fragments; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; C075647:pituitary adenylate-cyclase-activating-peptide (6-38)