Two Transcription Factors, E1AF and N‐myc, Correlate with the Invasiveness of Neuroblastoma Cell Lines

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Abstract
The ets transcription factor E1AF can activate several matrix‐degrading metalloproteinase (MMP) genes and is implicated in enhancement of tumor cell invasion. Here we compared the invasive activity of five human neuroblastoma cell lines (TGW, GOTO, SK‐N‐BE, SK‐N‐SH and SK‐N‐AS), which exhibit distinct levels of N‐myc amplification, together with the expression of E1AF. Extracellular matrix‐degrading proteases and their inhibitor proteins, which play an important role in local invasion, were also analyzed. The activity to invade through reconstituted basement membrane was high in cells (TGW, GOTO, and SK‐N‐BE) with N‐myc amplification, and these cells produced relatively large amounts of E1AF mRNA, correlating with the invasive activities. Of several matrix metalloproteinases (MMPs) and a tissue inhibitor of MMPs (TIMP), only membrane‐bound type 1 MMP (MT1‐MMP) was specifically detected in N‐myc‐amplified cells, suggesting a role of MT1‐MMP in neuroblastoma cell invasion. MMP‐2 (72 kD type IV collagenase), TIMP‐1 and TIMP‐2 were expressed in all five cell lines. Urokinase‐type plasminogen activator was undetectable. These findings indicate that the transcription factors E1AF and N‐myc are related to malignant phenotypes of neuroblastoma.