Proliferative Actions of Natriuretic Peptides on Neuroblastoma Cells: INVOLVEMENT OF GUANYLYL CYCLASE AND NON-GUANYLYL CYCLASE PATHWAYS

Abstract

To identify neural tumor cell lines that could be used as models to study growth-related natriuretic peptide actions, we determined the effects of these peptides on the proliferation of human and rodent neuroblastoma cell lines. Subnanomolar concentrations of atrial natriuretic peptide (ANP) and type C natriuretic peptide (CNP) stimulated proliferation in all four cell lines. These actions were associated with cGMP elevation and were blocked by a protein kinase G inhibitor. These data imply the involvement of guanylyl cyclase (GC)-coupled natriuretic receptors. However, higher concentrations of ANP and CNP, and low concentrations of des-[Gln(18),Ser(19),Gly(20),Leu(21),Gly(22)]-ANP(4-23)-NH(2) (desANP(4-23)) (analog for NPR-C receptor) exerted antiproliferative actions in three of the cell lines. These effects were insensitive to a protein kinase G inhibitor and to HS-142-1, suggesting that growth-inhibitory actions involved a non-GC receptor. They did not appear to involve cAMP, protein kinase A, protein kinase C, or calcium mobilization but were abolished when constitutive mitogen-activated protein kinase activity was inhibited. Radioligand binding experiments revealed the presence of a uniform class of binding sites in NG108 cells and multiple binding sites in Neuro2a cells. Northern and reverse transcriptase-polymerase chain reaction analyses revealed differential gene expression for NPR-A/B/C in NG108 and Neuro2a cells. The results indicate that natriuretic peptides stimulate neuroblastoma cell proliferation through type NPR-A/B (GC) receptors. Higher concentrations of ANP and CNP exerted a mitogen-activated protein kinase-dependent antiproliferative action mediated by a non-GC receptor that interacts with desANP(4-23) with relatively high affinity.