Presence and significance of oxytocin receptors in human neuroblastomas and glial tumors.

To determine whether oxytocin (OT) could be added to the list of growth factors acting on neoplastic cells of nervous origin, we investigated the presence of oxytocin receptors (OTR) in human primary neuroblastomas and glioblastomas and related cell lines. OTR were demonstrated both at mRNA level (using a RT-PCR procedure) and at protein level (using immunocytochemical and immunofluorescence procedures). In order to clarify whether OT exerts any biological effect on these tumors through OTR, we also studied cell proliferation in 3 human neuroblastoma cell lines (SK-N-SH, SH-SY5Y, IMR-32) and one human anaplastic astrocytoma cell line (MOG-G-UVW) treated with OT 1 nM to 100 nM for 48 and 96 hr. At these doses, a dose-dependent inhibitory effect on cell proliferation was demonstrated. This inhibition was accompanied by a significant increase in the intracellular concentration of cAMP, which we have reported to be the intracellular mediator of the OT anti-proliferative effect in breast-carcinoma cell lines. Our data indicate that specific OTR are present in human neuroblastomas and glioblastomas. Through these receptors, OT could inhibit cell proliferation and modulate tumor growth.