Doh Yu Hwang

Aurora A kinase expression is increased in leukemia stem cells, and a selective Aurora A kinase inhibitor enhances Ara-C-induced apoptosis in acute myeloid leukemia stem cells.

Background The overexpression of Aurora A kinase (AurA) has been reported in various malignancies, including acute myeloid leukemia (AML). However, the expression of AurA and the effects of AurA inhibition in cancer stem cells are not yet fully understood. We investigated the expression and inhibition of AurA in AML stem cells (CD34+/CD38-). Methods Expression of AurA was investigated in cell lines (NB4 and KG1) that express high levels of CD34 and low levels of CD38. Primary AML cells were harvested from 8 patients. The expression of AurA and cell death induced by inhibition of AurA were analyzed in CD34+/CD38- cells. Results AurA was shown to be overexpressed in both primary AML cells and leukemia stem cells (LSCs) compared to normal hematopoietic stem cells. Inhibition of AurA plus cytarabine treatment in LSCs resulted in increased cytotoxicity compared to cytarabine treatment alone. Additional stimulation with granulocyte-colony stimulating factor (G-CSF) increased the cell death caused by AurA inhibition plus cytarabine treatment. Conclusion To our knowledge, this is the first report describing increased expression of AurA in LSCs. Our results suggest that selective AurA inhibition may be used to reduce LSCs, and this reduction may be enhanced by stimulation with G-CSF. Further exploration of relationship between nuclear factor kappa-B and AurA inhibition and the potential of AurA inhibition for use in leukemia treatment is needed.

Clinical significance of B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) in acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Background BAFF (B cell-activating factor) and APRIL (a proliferation-inducing ligand) are members of the tumor necrosis factor family and promote B cell survival and proliferation. We evaluated the correlation between serum concentration of BAFF or APRIL and severity of acute graft-versus-host disease (GVHD). Methods Fifteen patients who received allogeneic hematopoietic stem transplantation for leukemia and developed acute GVHD were enrolled. We determined serum concentrations of BAFF and APRIL at the onset of the first clinical manifestation of GVHD by enzyme-linked immunosorbent assay. Results Nine patients had grade 2 acute GVHD, and 6 had grade 3-4 acute GVHD. The BAFF serum concentration was higher in patients with grade 3-4 acute GVHD (1,093.42 in grade 2 vs. 2,171.99 pg/mL in grade 3-4), although the difference was not significant (P=0.077). However, the ratio of BAFF serum concentration to absolute lymphocyte count (ALC) (BAFF/ALC) was significantly higher in patients with grade 3-4 acute GVHD (P=0.045). The APRIL serum concentration and APRIL/ALC ratio showed similar results (P=0.077 and P=0.013, respectively). Conclusion Patients with grade 3-4 acute GVHD had higher BAFF/ALC and APRIL/ALC ratios than patients with grade 2 acute GVHD. These findings suggest that B cells might play an important role in the development of acute GVHD, and that the BAFF and APRIL concentrations in serum might be significant predictive factors for estimating the severity of acute GVHD. Their clinical significance should be further evaluated in a larger patient population.

High pre-transplant serum ferritin and busulfan-thiotepa conditioning regimen as risk factors for hepatic sinusoidal obstructive syndrome after autologous stem cell transplantation in patients with malignant lymphoma

Few studies have evaluated the risk factors for hepatic sinusoidal obstructive syndrome (SOS) in patients with malignant lymphoma receiving autologous stem cell transplantation (ASCT). We retrospectively analyzed 132 malignant lymphoma patients who underwent ASCT. Intravenous busulfan-based conditioning regimens were used in 108 (81.8%) patients. The combination of heparin and ursodeoxycholic acid was used for prophylaxis of SOS. Hepatic SOS was developed in 10 (7.6%) patients at a median of 30 days post-ASCT. In nine (90.0%) patients, SOS was diagnosed after 20 days post-ASCT. Two patients developed severe SOS and eventually died from multiple organ failure. In multivariate analysis, the use of the busulfan-thiotepa conditioning regimen (p = 0.003) and a high pre-transplant serum ferritin level (≥ 950 ng/mL) (p = 0.003) were risk factors for hepatic SOS. The evaluation of pre-transplant serum ferritin may be helpful in determining the most appropriate conditioning regimen with a lower risk of SOS.