Expression of WT1 gene in children with acute myeloid leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study WT1 gene expression in children with acute myeloid leukemia (AML) and its possible correlations to clinical outcomes.</p><p><b>METHODS</b>Bone marrow samples were collected from 45 children with AML (excluding acute promyelocytic leukemia, AML-M3) at different time points of AML treatment and follow-up. WT1 gene expression levels in bone marrow mononuclear cells were assayed by real-time fluorescence quantitative PCR. The correlation between WT1 expression and prognosis was retrospectively analyzed.</p><p><b>RESULTS</b>The WT1 expression level in AML children with bone marrow blast cell percentage of >60% was significantly higher than in those with bone marrow blast cell percentage of ≤ 60% (p<0.05). The lower WT1 expression level was documented in children with AML-M2 compared with in children with other non-M2 subtypes (p<0.05). WT1 expression level in patients in complete remission was significantly lower than that in patients at diagnosis or relapse (p<0.01). The 2-year disease-free survival (DFS) in patients with higher WT1 expression was significantly lower than in those with lower WT1 expression at the end of induction chemotherapy (p<0.05). The 2-year overall survival (OS) and DFS in patients with ≥1 log WT1 reduction range were significantly higher than those with <1 log reduction of WT1 expression level at the end of induction chemotherapy (p<0.05). WT1 expression levels tended to rise 2-3 months prior to bone marrow relapse.</p><p><b>CONCLUSIONS</b>WT1 expression level is closely correlated prognosis in children with AML. Dynamic monitoring of WT1 expression level is of great clinical importance in terms of individualized management, prognosis evaluation and relapse prediction.</p>

Measurement of serum growth differentiation factor 15 concentration in children with hemophagocytic lympohistiocytosis and implications in the development of hyperferritinemia / 中华实用儿科临床杂志

Objective To measure the serum growth differentiation factor (GDF15) levels in children with hemophagocytic lympohistiocytosis (HLH),and to explore its possible implications in the development of hyperferritinemia in HLH.Methods Twenty-eight children with newly-diagnosed HLH and 20 age-and-sex matched healthy children were enrolled in this study as research subjects and controls respectively.Serum GDF15 levels were measured by Quantikine ELISA assay (product of R&D Company,USA) according to manufacturer's instructions.Serum ferritin concentration and other biochemical parameters were determined by conventional methods.Comparison of serum GDF15 levels between HLH group and healthy control group were made by nonparametric Mann-Whitney test.Correlations between serum GDF15 concentration and hemobiochemical parameters (Hb,serum ferritin,fibrinogen,blood lipids,and liver and renal function tests) were made via Spearman correlation analysis.Results Serum GDF15 concentration was significantly higher in HLH group than that in healthy control group,with median concentrations and ranges of 1710 ng/L,190-2400 ng/L,and 260 ng/L,104-649 ng/L,respectively (P ＜ 0.001).Serum GDF15 concentration was correlated neither to Hb concentration at diagnosis nor to lowest Hb concentration before HLH-directed chemotherapy.Nevertheless it was positively correlated to serum level of total bilirubin at diagnosis and highest concentration of triglycerates during disease course (x2 =0.475,0.465 ; P =0.011,0.019,respectively),and negatively correlated to lowest levels of fibrinogen and albumin at diagnosis (x2 =-0.423,-0.399 ;P =0.031,0.039,respectively).Serum GDF15 level was not correlated to underlying etiology and mortality rate of children with HLH.Conclusions GDF15 has been documented as an upstream negative regulator of hepcidin,the central iron regulatory hormone produced primarily by hepatocytes,and is massively produced by activated macrophages in an autocrine fashion to suppress further activation of macrophages.This research finding that serum GDF15 level is significantly elevated in children with HLH suggests that GDF 15 is intimately implicated in the modulation of iron homeostasis and the development of hyperferritinemia in HLH.

TfR2 mRNA expression in bone marrow mononuclear cells of children with hyperplastic anemia and its implications / 中国实验血液学杂志

The aim of this study was to investigate the expression of transferrin receptor 2 (TfR2) mRNA in bone marrow mononuclear cells (BMMNC) of children with hyperplastic anemia (HA), to analyze the correlation of TfR2 mRNA expression level with Hb level, bone marrow erythroid hyperplasia, iron status in body and underlying diseases, and to evaluate the role of TfR2 in erythroid hemopoiesis and the useful value in diagnosis of HA. The experiment was divided into 2 groups: test group, in which 40 patients with HA were enrolled, and control group in which 10 patients without erythroid disorders and hematological malignancies confirmed by bone marrow examination were enrolled. The bone marrow samples of patients in mentioned above 2 groups were collected, the TfR2 mRNA expression in BMMNC of patients with HA was detected by fluorescence-quantitative PCR, the correlation of HA with bone marrow erythroid hyperplasia, iron status of body and underlying diseases was analyzed. The results showed that the relative level of TfR2 mRNA expression in HA patients was significantly higher than that in control patients. The TfR2 mRNA expression level negatively correlated with Hb level in peripheral blood (r = -0.715), while it positively correlated with ratio of bone marrow erythroblasts (r = 0.533). It is concluded that TfR2 mRNA expression in HA patients increases and closely correlates with hyperplasia status of bone marrow and anemia level in peripheral blood.

Detection of enterotoxigenic Escherichia coli by real-time polymerase chain reaction by using MGB-TaqMan probe technique / 中华预防医学杂志

<p><b>OBJECTIVE</b>To develop a real-time polymerase chain reaction(PCR) based on TaqMan technology by using a new MGB probe for detecting enterotoxigenic Escherichia coli (ETEC) in paper.</p><p><b>METHODS</b>Primers and MGB probe were designed in the ecoding region of heat-stable toxin of ETEC. Real-time PCR detected ETEC by using the exterior standard method with protracting standard curves. The specificity, sensitivity, accuracy, stability of real-time PCR system was evaluated. An internal negative antithesis was added to the real-time PCR system in order to get rid of the false positive of system. Using UNG enzyme expelled the contamination of PCR reaction.</p><p><b>RESULTS</b>Primers and MGB probe were suited to the Real-time PCR. The assay showed that the method was quick, special, sensitive and stable. The real-time PCR system could detect ETEC in a large scale. The assay might be finished in two hour.</p><p><b>CONCLUSION</b>These observations suggested that real-time PCR based on MGB probe should be an excellent candidate for a standard ETEC detection method.</p>

Expression of mitochondrial ferritin in K562 leukemic cell during TPA-induced cell differentiation / 中国实验血液学杂志

Mitochondrial ferritin (MtF), a new player in iron metabolism, first identified in 2001, is highly homologous to ferritin both structurally and functionally. Preliminary studies have suggested that MtF might play very important roles in the regulation of mitochondrial iron homeostasis. Leukemic cells, just like other malignant cells, demand more iron for their greater proliferation potential. However, little is known about what roles MtF might play in leukemic cell iron metabolism and cell proliferation. The aim of this study was to investigate the expression of MtF, transferrin receptor 1 (TfR1) and ferritin (Fn) mRNAs in K562 leukemic cells during TPA-induced cell differentiation and to explore the interrelationship between the expression levels of these iron metabolism-related molecules. K562 cells cultured with or without TPA (16 nmol/L) were collected at 24, 72 and 120 hours respectively. Cell differentiation toward monocyte lineage was confirmed by microscopic study (Wright's staining) and flow cytometry. Semiquantitative RT-PCR was performed to determine mRNA expression, with house-keeping gene beta-actin as control reference. This study revealed that over 95% of K562 cells showed morphological features of monocyte/macrophage, and the expression of CD64 on cell surface increased significantly at day 5 with TPA treatment. K562 cells could express a certain level of MtF before TPA-induced differentiation. With increase of TPA-induced cell differentiation, MtF mRNA expressions were downregulated progressively. After 5 days of induced cell differentiation, expression levels of MtF and TfR1 mRNA were just 50.3% and 68.2% of that before TPA treatment. While Fn mRNA expression increased to 1.97 folds of that before TPA treatment. It is concluded that MtF expression is downregulated during TPA-induced K562 cell differentiation, with concomitant downregulation of TfR1 and upregulation of Fn. The coordinated expression regulation of these key iron metabolism-related molecules during cell differentiation may in turn inhibit TfR1-mediated iron uptake via endocytosis and thus adversely affect cell proliferation potential.

Detection of the labile iron pool in leukemia cells and its significance / 中国实验血液学杂志

To explore a rapid and easy method to detect labile iron of pool (LIP) in cells, HL-60 and K562 cells were cultured at a concentration 1 x 10(6)/ml in RPMI 1640 containing 10% heat-inactivated fetal bovine serum. The iron deprivation was induced by adding desferrioxamine (DFO) 10 - 100 micromol/L for 0 - 48 hours. The intracellular LIP was measured by probe calcein-AM. Calcein fluorescence was monitored in 1420 multilabel counter. The results indicated that when HL-60 and K562 cells were incubated with different concentrations of DFO, the calcein fluorescence intensity was higher than that of control group at 12, 24 and 48 hours (P < 0.05). Fluorescence value of representing LIP in DFO groups was lower than that in the control group. In conclusion, DFO can decrease LIP in leukemia cells. The approach used in this study may provide a simple and reliable method for detection of intracellular iron homeostasis.

EGR-1 mRNA expression during 12-0-tetradecanoylphorbol-13-acetate-induced K562 cell differentiation / 中华儿科杂志

<p><b>OBJECTIVE</b>12-0-tetradecanoylphorbol-13 acetate (TPA) plays an important role in precipitating cell differentiation for various tumor cells, especially leukemic cells. Changes of many genes may be involved in this process. The purpose of this study was to observe the relationship between the EGR1mRNA expression and cell differentiation during TPA-induced K562 cell differentiation.</p><p><b>METHODS</b>Incubation of human K562 cells in vitro was applied to cultivate K562 cells. The cells were treated in two different ways. K562 cells of experiment group were treated with TPA and those of control group were treated without TPA. Using morphology (Wright's staining and NSE staining) and flow cytometry (FCM), the investigators observed the differentiation characteristics of K562 cells, cell-cycle and the differentiation antigen expressions of CD33 and CD14 on cell membranes. RT-PCR was carried out to assay EGR1 mRNA expression.</p><p><b>RESULTS</b>After treated with TPA for 7 d, the morphology of K562 cells obviously tended to mature differentiation, like monocytes. The differentiation rate of induced K562 cells was up to 95% in experiment group and 4.5% in control group, respectively. Using SPSS software, the above result showed statistical significance (P < 0.01). Using NSE staining, K562 cells showed positive reaction. Some of them were densely stained. The positive rate was up to 86%. More than half of the positive cells could be inhibited by NaF. The inhibiting rate of NaF was up to 58.72%, showing statistical difference when compared with that of control group. FCM analysis showed that most of K562 cells stimulated by TPA underwent G1/S phase cell-cycle arrest. The composing rate of cell-cycle in TPA-treated group showed that (53.7 +/- 1.25)% of cells were at G0 + G1 phase and (44.3 +/- 1.32)% were at S phase (P < 0.05). The level of CD33 expression on cell membranes was mildly decreased from 0.997% to 0.893% (P > 0.05). However, the level of CD14 expression was significantly increased from 0.049% to 0.387% (P < 0.05).</p><p><b>CONCLUSION</b>K562 cells could express EGR1mRNA during TPA-induced differentiation, which suggested that EGR1mRNA might participate in the process of K562 cells differentiating into monocyte/macrophages, and might play an important role in precipitating and maintaining cell differentiation for leukemic cells.</p>

Effect of truncated platelet-derived growth factor-alpha receptor on apoptosis and expression of c-sis mRNA of pulmonary artery smooth muscle cells / 中华儿科杂志

<p><b>OBJECTIVE</b>Platelet-derived growth factor (PDGF) plays an important role during the pathophysiological changes in vascular remodeling. The study aimed to investigate the effect of truncated PDGF-alpha receptor on apoptosis and expression of c-sis mRNA of pulmonary artery smooth muscle cells (VSMCs).</p><p><b>METHODS</b>Tissue mass culture was done to get vascular smooth muscle cells of pulmonary artery in newborn pigs. Two methods were used to interfere VSMCs: adding adenoviral recombined body (Ad5CMV-PalphaRtr, ACP) with three different concentrations of truncated PDGF-alpha receptor into the cultures, or adding three concentrations of PDGF-BB after the treatment with mid-concentration of ACP. VSMC apoptosis, cellular cycle and expression of c-sis were observed using flow-cytometry, and the expression of c-sis mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>ACP with mid- to- high concentrations could restrain the proliferation of VSMCs apparently with the increase of G(0)/G(1) cells. The apoptotic rate presented an ascending tendency. The differences among the groups were of statistically significant. Affected by mid- concentration of ACP, PDGF-BB did not exhibit a significantly accelerating effect on the changes of cellular cycle and VSMC apoptosis. The expression of c-sis mRNA was up-regulated under the effect of ACP. Affected by mid-concentration of ACP and PDGF-BB, c-sis mRNA expressed was down-regulated.</p><p><b>CONCLUSION</b>Mid- to- high concentration of ACP is a powerful inhibitor of cellular proliferation for pulmonary artery VSMCs. It can significantly increase cells in number in G(0)/G(1) phase, apoptosis and c-sis mRNA expression.</p>