The organic arsenic derivative GMZ27 induces PML-RARα-independent apoptosis in myeloid leukemia cells

Arsenic trioxide (ATO) is an inorganic arsenic derivative that is very effective against acute promyelocytic leukemia. However, organic arsenic derivatives (OAD) have a more favorable toxicity profile than ATO. We herein characterized dipropil-S-glycerol arsenic (GMZ27), a novel OAD. GMZ27 had potent antiproliferative activity against human acute myeloid leukemia (AML) cell lines that was higher than that of ATO. In contrast to ATO, GMZ27 only marginally induced maturation of leukemia cells and had no effect on the cell cycle. The anti-leukemia activity of GMZ27 against AML cells was independent of the presence of the PML-RARα fusion protein. GMZ27 dissipates mitochondrial transmembrane potential, and induces cleavage of caspase 9 and activation of caspase 3 without altering the expression levels of (BCL-2), BAX and BCL-xl. GMZ27 induces the formation of intracellular superoxide, a reactive oxygen species (ROS) which plays a major role in the antileukemia activity of this OAD. In addition to ROS generation, GMZ27 concomitantly reduces intracellular glutathione which markedly weakens the cellular antioxidant capacity, thus enhancing the detrimental intracellular effects of ROS production. These results indicate that GMZ27 induces apoptosis in AML cells in a PML-RARα-independent fashion, through the induction of ROS production. This activity provides the rationale for the testing of GMZ27 in patients with AML

COLONY-FORMING UNIT ASSAY AS A POTENCY TEST FOR HEMATOPOIETIC STEM/PROGENITOR CELL PRODUCTS

Colony-forming unit (CFU) assay is a short-term culture assay used for the detection of functionally active hematopoietic progenitor cells (HPCs) in the in vitro setting. This potency assay enables the identification of colony-producing HPCs in any type of hematopoietic stem cell/progenitor product (HSC/P) including bone marrow (BM), cord blood (CB) and mobilized peripheral blood (MPB). It has been shown that the frequency of HPCs in BM, MPB and CB cellular products directly correlates with the engraftment of both neutrophils and platelets as well as with the overall survival of recipients following hematopoietic stem cell transplantation which makes the CFU assay a good quality parameter for the prediction of engraftment success. The aim of this article is to provide an overview of different approaches to setting up the CFU assay with an emphasis on different sample preparation techniques, cell plating density and colony identification and enumeration used by different laboratories