The effect of modulation of glutathione cellular content on busulphan-induced cytotoxicity on hematopoietic cells in vitro and in vivo

Abstract

Summary:Busulphan is used in conditioning regimens prior to SCT. A relationship between exposure to busulphan, expressed as an area under the plasma concentration time curve (AUC), and effect and/or adverse effects, such as veno-occlusive disease (VOD), was reported. Exhaustion of glutathione (GSH) contributes to VOD and modulation of intracellular levels of GSH influences bulsulphan-induced toxicity in hepatocytes. Thus, increase of GSH might serve as prophylaxis against VOD. However, it should not interfere with the myeloablative effects of busulphan. We investigated the relationship between exposure to busulphan, and its in vitro toxicity to CD34 + hematopoietic progenitors from volunteers using clonogenic assays. Busulphan inhibited colony formation by CD34 + cells in an AUC-dependent manner. Myeloid progenitors were more sensitive than erythroid progenitors, expressed as 100% inhibition of colony formation (68.7 ؎ 7.5 g.h/ml and 140.3 ؎ 35.7, respectively). The observed exposure corresponds to the total AUC obtained in patients treated with busulphan (1 mg/kg/day) for 4 days. Secondly, we studied the effect of modulation of GSH cellular levels on busulphaninduced toxicity in vitro in CD34 + cells from volunteers, and in vivo in bone marrow cells from Balb/c mice. The intracellular concentration of GSH was increased or decreased by treatment with N-acetylcysteine or buthionine sulfoximine, respectively. Neither in vitro nor in vivo treatment with GSH modulators affected the hematological toxicity of busulphan. Thus, N-acetylcysteine would not interfere with the myeloablative effect of busulphan and therefore it is a potential candidate for VOD prophylaxis during busulphan-based conditioning regimens.

GVHD after chemotherapy conditioning in allogeneic transplanted mice

“…30,31 Thus the lack of donor alloreactivity against host residual cells and/or the high dose of BU may explain the lack of need of CY. In our previous studies, 32,33 we have shown that similar myeloablative effects of BU were obtained after the administration of BU as i.v. or i.p., therefore, BU was administered i.p.…”

Busulfan-induced senescence is dependent on ROS production upstream of the MAPK pathway

“…It has been shown that the major route of BU metabolism is through GSH-S-transferase catalyzed conjugation to GSH [18,19]. Therefore, treatment of cells with BU can lead to GSH depletion.…”

“…It has been demonstrated that ROS can function as a signal molecule to stimulate the Erk-p38 MAPK pathway [17]. BU has the ability to increase ROS production in part by depletion of intracellular GSH [18,19]. Therefore, we hypothesized that BU may activate Erk and p38 by inducing oxidative stress.…”

“…Oxidative stress is also a well-documented inducer of cellular senescence [16]. Several reports have shown that BU forms conjugates with glutathione (GSH) leading to GSH depletion and oxidative stress [18,19]. In addition, a recent study found that BU can inhibit thioredoxin reductase, which also plays an important role in regulation of oxidative stress in a cell [20].…”

Incidence, characteristics and risk factors of marked hyperbilirubinemia after allogeneic hematopoietic cell transplantation with reduced-intensity conditioning

“…Hence, hepatocytes would be more susceptible to injury caused by other drugs following BU administration. 38 Indirect evidence supporting this hypothesis comes from the studies suggesting a lower risk of sinusoidal injury when BU is given last in order in the BU/CY regimen. 39 Several strategies have been developed in an attempt to reduce the impact of liver dysfunction on mortality after SCT, including the use of danaparoid, defibrotide and N-acetylcysteine.…”