PACAP-27 tyrosine phosphorylates mitogen activated protein kinase and increases VEGF mRNAs in human lung cancer cells

Abstract

The effects of pituitary adenylate cyclase activating polypeptide (PACAP) on human lung cancer cell line NCI-1299 mitogen activated protein kinase (MAPK) tyrosine phosphorylation and vascular endothelial cell growth factor (VEGF) expression were investigated. PACAP-27 (100 nM) increased MAPK tyrosine phosphorylation 3-fold, 5 min after addition to NCI-H1299 cells. PACAP caused tyrosine phosphorylation in a concentration-dependent manner being half-maximal at 10 nM PACAP-27. PACAP-27 or PACAP-38 (100 nM) but not PACAP28-38 or VIP caused increased MAPK tyrosine phosphorylation using NCI-H1299 cells. Also, the increase in MAPK tyrosine phosphorylation caused by PACAP-27 was totally inhibited by 10 microM PACAP(6-38), a PAC(1) receptor antagonist or 10 microM PD98059, a MAPKK inhibitor. These results suggest that PAC(1) receptors regulate tyrosine phosphorylation of MAPK in a MAPKK-dependent manner. PACAP-27 (100 nM) caused increased VEGF mRNA in NCI-H1299 cells after 8 h. The increase in VEGF mRNA caused by PACAP-27 was partially inhibited by PACAP(6-38), PD98059 and H-89. Addition of VIP to NCI-H1299 cells caused increased VEGF mRNA, which was totally inhibited by H89, a PKA inhibitor. These results suggest that PAC(1) and VPAC(1) receptors regulate VEGF expression in lung cancer cells.

Ras-mutant Cancer Cells Display B-Raf Binding to Ras That Activates Extracellular Signal-regulated Kinase and Is Inhibited by Protein Kinase A Phosphorylation

“…This block was also seen after incubation with the peptide hormone PACAP38 (pituitary adenylate cyclase activating peptide-38) (Fig. 4C), presumably acting through the PAC1 receptor that is expressed on these cells (28). PAC1 receptor is a G proteincoupled receptor linked to the production of cAMP and activation of PKA.…”

Pituitary Adenylate Cyclase-Activating Polypeptide Causes Increased Tyrosine Phosphorylation of Focal Adhesion Kinase and Paxillin

“…VIP stimulated the growth of lung cancer cells lines and the growth was inhibited by the VPAC1R antagonist VIPhybrid (Moody et al 1993b). Subsequently, VIP-chemotherapuetic conjugates were developed which were cytotoxic for lung cancer cells (Moody et al 2002b). These results indicate that the VPAC1-R is a molecular target for lung cancer.…”

Pituitary Adenylate Cyclase-Activating Polypeptide Causes Tyrosine Phosphorylation of the Epidermal Growth Factor Receptor in Lung Cancer Cells

“…In lung cancer cells gefitinib blocked the increase in EGFR and ERK tyrosine phosphorylation caused by the addition of PACAP to NCI-H838 cells. It remains to be determined whether gefitinib blocks additional signal transduction caused by PACAP such as increased c-fos and vascular endothelial growth factor mRNA (Moody et al, 2002).…”

“…The increase in PI 4,5-bisphosphate metabolism caused by phospholipase C results in diacylglycerol (activates protein kinase C) and inositol 1,4,5-trisphosphate (elevates cytosolic Ca 2ϩ ). The addition of PACAP to NCI-H838 cells causes ERK phosphorylation, increases c-fos mRNA, and in-creases vascular endothelial growth factor expression (Draoui et al, 1996;Moody et al, 2002). PACAP stimulates the growth of lung cancer (NCI-H345 cells; Moody et al, 1993), pancreatic carcinoma (AR42-J cells; Buscail et al, 1992), and colon cancer (Bon cells; Germano et al, 2009).…”