Peptide containing the BCR oligomerization domain (AA 1-160) reverses the transformed phenotype of p210^bcr–abl positive 32D myeloid leukemia cells

Abstract

We first showed that the introduction of a bcr–abl transcription unit into the 32D murine myeloid cell line (P210bcrabl32D) converts this cell line from an IL3 dependent cell line to an IL3 growth independent cell line. We next cloned a fragment of the bcr–abl cDNA, which codes for the bcr oligomerization domain and neighboring regions. To test for a transformation inhibitory effect of this oligomerization inhibitory peptide transcription unit on the p210^bcr–abl mediated IL3 independent growth of the P210bcrabl32D cell line, we transiently co-electroporated into the growth factor dependent 32D cells, mixtures of plasmids which contained varying ratios of the plasmid expression vectors for the bcr oligomerization inhibitory peptide along with a smaller amount of the plasmid expression vector for the full length p210^bcr–abl. (The P210^bcr–abl protein converts the 32D from a growth factor dependent into a growth factor independent cell line.) We then showed that the oligomerization domain containing fragment from the bcr and bcr–abl proteins, can be used to inhibit the IL3 independent growth of p210^bcr–abl positive 32D cells. These studies may be of eventual interest for those investigators whose goal is to design molecular therapeutic approaches to CML based on the use of peptidomimetic chemical functionalities, which mimic the structure and the inhibitory binding properties of the oligomerization domain containing fragment so as to inhibit the transforming function of the P210^bcr–abl oncoprotein.