Oxidative stress levels in myelodysplastic syndrome patients: their relationship to serum ferritin and haemoglobin values.

Reactive oxygen species (ROS) and serum ferritin levels are both considered to be important biological factors in the pathogenesis of myelodysplastic syndrome (MDS). This study evaluated the levels of ROS in 40 patients with MDS (19 males and 21 females) using the Free Radical Analytical System, FRAS4, and derivatives of reactive oxygen metabolite kits. The patients' mean age was 67.3 years (range 58 - 86 years). The sera of 34 (85%) patients exhibited higher levels of oxidative stress than the reference range. There was a positive correlation between ROS levels and serum ferritin levels, and a negative correlation between ROS levels and haemoglobin levels. There was a negative relationship between serum haemoglobin and ferritin levels. The results indicated that iron accumulation or severe anaemia could contribute to oxidative stress in MDS patients. Iron chelation and antioxidant therapy may be suitable for the management of MDS.

Troglitazone inhibits cell growth and induces apoptosis of B-cell acute lymphoblastic leukemia cells with t(14;18).

Peroxisome proliferator-activated receptor-gamma (PPARgamma), a member of the nuclear receptor superfamily, has been detected in several human leukemia cells. Recent studies reported that PPARgamma ligands inhibit cell proliferation and induce apoptosis in both normal and malignant B-lineage cells. We investigated the expression of PPARgamma and the effects of PPARgamma ligands on UTree-O2, Bay91 and 380, three B-cell acute lymphoblastic leukemia (B-ALL) cell lines with t(14;18), which show a poor prognosis, accompanying c-myc abnormality. Western blot analysis identified expression of PPARgamma protein and real-time PCR that of PPARgamma mRNA on the three cell lines. Troglitazone (TGZ), a synthetic PPARgamma ligand, inhibited cell growth in these cell lines in a dose-dependent manner, which was associated with G(1) cell cycle arrest and apoptosis. We also found this effect PPARgamma independent since PPARgamma antagonists failed to reverse this effect. We assessed the expression of c-myc, an apoptosis-regulatory gene, since c-myc abnormality was detected in most B-ALL cells with t(14;18). TGZ was found to dose-dependently downregulate the expression of c-myc mRNA and c-myc protein in the three cell lines. These results suggest that TGZ inhibits cell growth via induction of G(1) cell cycle arrest and apoptosis in these cell lines and that TGZ-induced apoptosis, at least in part, may be related to the downregulation of c-myc expression. Moreover, the downregulation of c-myc expression by TGZ may depend on a PPARgamma-independent mechanism. Further studies indicate that PPARgamma ligands may serve as a therapeutic agent in B-ALL with t(14;18).

Quantitative nested reverse transcriptase PCR vs. real-time PCR for measuring AML1/ETO (MTG8) transcripts.

A quantitative nested reverse transcriptase polymerase chain reaction (QN-RT-PCR) method was developed using a plasmid cDNA containing the AML1/ETO (MTG8) fusion transcript from Kasumi-1 cells, an acute-myelogenous leukemia cell line with the t(8;21) translocation. In this method, the plasmid was detectable at a concentration of 10(-17) m. The fusion transcript in a mixture of 10(7) Rice94 (Burkitt lymphoma cell line) cells containing two Kasumi-1 cells was detectable at 10(-17) m. In a previously published real-time PCR method, the plasmid containing the fusion transcript was detectable at 10(-16) m or higher, and 20 or more Kasumi-1 cells were detectable in 10(7) Rice94 cells. Thus, this QN-RT-PCR method is more sensitive than the real-time PCR. When the same samples were examined by real-time PCR and our QN-RT-PCR method, in one patient in clinical remission after chemotherapy and allogeneic-bone marrow transplantation (BMT), the transcript was detected by QN-RT-PCR 60 days prior to hematological relapse, in contrast to 10 days before hematological relapse by real-time PCR. The transcript level was below 10(-17) m (undetectable) with this QN-RT-PCR in patients in clinical remission after chemotherapy and BMT, while it was 10(-15)-10(-16) m in patients in clinical remission after chemotherapy alone. The quantitative difference of the transcript level in minimal residual disease (MRD) between these two different types of clinical remission was estimated to be at least 10(2)-fold. This QN-RT-PCR method is useful for predicting hematological relapse and for quantitatively estimating MRD in different types of clinical remission.