MYCN downregulates integrin α1 to promote invasion of human reuroblastoma cells

Abstract

Neuroblastoma is a childhood tumor thought to arise through improper differentiation of neural crest cells. MYCN amplification is a prognostic factor that indicates a highly malignant disease and poor patient prognosis. Integrins are important regulators of neuroblastoma attachment and migration and participate in many aspects of metastasis. However, the role of integrins in neuroblastoma metastasis, the leading cause of death from this disease, remains less well understood. Screening of neuroblastoma cell lines for integrin mRNA expression showed that integrin α1 expression was higher in lines such as SK-N-SH and NB69 that do not have MYCN amplification than in cell lines such as IMR32, NB1, NB9 and NB19 that have MYCN amplification. A knockdown of MYCN in NB1 and NB19 cells resulted in increased expression of integrin α1, which correlated with enhanced attachment to the extracellular matrix and reduced migratory activity. In contrast, the overexpression of MYCN in SK-N-SH and NB69 cells resulted in decreased expression of integrin α1, which correlated with reduced attachment to the extracellular matrix and enhanced migratory activity. These results show that MYCN may limit cell adhesion to the extracellular matrix and promote cell migration by downregulating integrin α1.