Antisense src expression inhibits proliferation and erythropoietin-induced erythroid differentiation of K562 human leukemia cells.

We constructed a recombinant plasmid which expresses antisense src RNA in human cells and used it as a tool for investigating the role of pp60c-src in proliferation and differentiation of K562 human leukemia cells. In erythropoietin (EPO)-responsive cells, EPO induces rapid tyrosine phosphorylation of several cellular proteins including EPO receptor (EPOR) although EPOR has no tyrosine kinase domain. Here we show that antisense src RNA expression suppresses pp60c-src synthesis in the recombinant plasmid-transfected K562 cells, reduces the proliferation and inhibits hemoglobin synthesis and glycophorin A expression promoted by EPO in K562 cells. These findings suggest that pp60c-src plays crucial roles in the proliferation and EPO-induced erythroid differentiation of K562 cells.