Inhibition of Proliferation by c-myb Antisense RNA and Oligodeoxynucleotides in Transformed Neuroectodermal Cell Lines1

Transfection of a neuroblastoma cell line with expression vectors containing two different segments of human c-mybcomplementary DNA in antisense orientation yielded far fewer transfectant clones than did the transaction with the identical segments in sense orientation. In cell clones expressing c-myb antisense RNA, levels of the c-myb protein were down-regulated and the proliferation rate was slower than that of cells transfected with sense constructs or the untransfected parental cell line. Treatment of neuroblastoma and neuroepithelioma cell lines with a c-myb antisense oligodeoxynucleotide strongly inhibited cell growth. These data indicate a definite involvement of c-myh in the proliferation of neuroectodermal tumor cells extending the role of this protooncogene beyond the hematopoietic system. The availability of cell clones that transcribe c-myh antisense RNA provides a useful tool to study the involvement of other genes in the proliferation and differentiation of neuroblastoma cells.