The in vitro effect of vincristine on the blast cell renewal in acute myeloblastic leukemia.

The goal of chemotherapy for acute myeloblastic leukemia (AML) may only be achieved by eradicating the self-renewal capacity of the blast progenitors. In this regard, chemotherapeutic drugs should be screened according to their effects against self-renewal. The present report was aimed to study the effect of the vinca alkaloid, vincristine (VCR), on the terminal divisions and self-renewal of the blast progenitors. A primary colony assay was utilized to reflect the former and a secondary colony assay and suspension culture to reflect the latter in AML patients. The results indicated that in many of the cases studied, VCR was considered to be almost equally toxic to terminal divisions and self-renewal of the blast progenitors. An almost equivalent cytotoxicity of VCR was also noted against normal hematopoietic cells, assessed by colony-forming unit granulocyte-macrophage (CFU-GM) assay. This study suggested that successful chemotherapy with VCR may be more easily achieved in combination with other drugs that are highly inhibitory to the self-renewal of the blast progenitors.