Antisense inhibition of single copy N-myc expression results in decreased cell growth without reduction of c-myc protein in a neuroepithelioma cell line.

The N-myc gene is transiently expressed during normal embryonic development and abnormally expressed in several tumors of neuroendocrine origin. Little is known of the function of the N-myc gene product in either normal or neoplastic tissue. We utilized synthetic antisense oligodeoxynucleotides to specifically inhibit N-myc gene expression in the neuroepithelioma cell line CHP100. These cells contain single copy N-myc alleles but overexpress c-myc. N-myc antisense oligomer treatment was found to be growth inhibitory without affecting levels of c-myc protein. N-myc antisense oligomer-treated cells also lost the characteristic cellular heterogeneity displayed by CHP100 in vitro.