Increased N-Myc Mrna Expression Associated with Dibutyryl Cyclic amp Induced Neuroblastoma Differentiation

Abstract

The N-myc cellular oncogene is frequently amplified and expressed at a high level in neuroectodermal tumor cells such as neuroblastoma and retinoblastoma. We examined N-TMVC expression in NCB-20 hybrid (N18TG2 neuroblastoma x embryonic Chinese Hamster brain) cells. After five days of culture, cells treated with 1 mM db cAMP show extensive neurite outgrowth and secrete acetylcholinesterase into the media at a level three times higher tha untreated control. In situ hybridizations, dot blots, and Northern analyses reveal four- to eight-fold higher levels of N-myc mRNA in the treated, differentiated cells than in the untreated, undifferentiated controls. Our results show that the highly differentiated state is not incompatible with a high level of ti-myc mRNA.

Key Words:

• oncogene
• acetylcholinesterase
• neuron
• NCB-20
• in situ hybridization