Constitutive activation of the neuregulin-1/erbB signaling pathway promotes the proliferation of a human peripheral neuroepithelioma cell line

Neuregulin-1 (NRG-1) proteins, acting through their erbB receptors, promote the differentiation, survival and/or proliferation of many cell types in the developing nervous system, including neural crest cells and neural crest-derived Schwann cells. We have recently found that the proliferation of a neoplastic Schwann cell line is dependent on constitutive activation of the NRG-1/erbB signaling pathway and that overexpression of NRG-1 in myelinating Schwann cells induces the formation of malignant peripheral nerve sheath tumors. These observations suggested that NRG-1 might similarly promote mitogenesis in a variety of neural neoplasms including peripheral neuroepitheliomas, aggressive neural crest-derived neoplasms that arise in nerves and soft tissues. To test this hypothesis, we examined the expression of NRG-1 and its erbB receptors in SK-N-MC neuroepithelioma cells. SK-N-MC cells expressed multiple NRG-1 proteins and mRNAs encoding several alpha and beta isoforms from the sensory and motor neuron-derived factor NRG-1 subfamily as well as the NRG-1 receptor subunits erbB2, erbB3, and erbB4. The erbB receptors expressed by SK-N-MC cells were constitutively tyrosine phosphorylated and inhibiting these kinases with the erbB specific inhibitor PD158780 reduced SK-N-MC DNA synthesis in a dose-dependent manner. We conclude that constitutive activation of the NRG-1/erbB signaling pathway promotes the proliferation of SK-N-MC neuroepithelioma cells in vitro and hypothesize that NRG-1/erbB autocrine, paracrine or juxtacrine signaling may contribute to the development and/or progression of neuroepitheliomas in vivo.