Integrated analysis of microRNA and transcription factors in the bone marrow of patients with acute monocytic leukemia.

Acutemonocytic leukemia (AMoL) is a distinct subtype of acute myeloid leukemia (AML) with poor prognosis. However, the molecular mechanisms and key regulators involved in the global regulation of gene expression levels in AMoL are poorly understood. In order to elucidate the role of microRNAs (miRNAs/miRs) and transcription factors (TFs) in AMoL pathogenesis at the network level, miRNA and TF expression level profiles were systematically analyzed by miRNA sequencing and TF array, respectively; this identified 285 differentially expressed miRNAs and 139 differentially expressed TFs in AMoL samples compared with controls. By combining expression level profile data and bioinformatics tools available for predicting TF and miRNA targets, a comprehensive AMoL-specific miRNA-TF-mediated regulatory network was constructed. A total of 26 miRNAs and 23 TFs were identified as hub nodes in the network. Among these hubs, miR-29b-3p, MYC, TP53 and NFKB1 were determined to be potential AMoL regulators, and were subsequently extracted to construct sub-networks. A hypothetical pathway model was also proposed for miR-29b-3p to reveal the potential co-regulatory mechanisms of miR-29b-3p, MYC, TP53 and NFKB1 in AMoL. The present study provided an effective approach to discover critical regulators via a comprehensive regulatory network in AMoL, in addition to enhancing understanding of the pathogenesis of this disease at the molecular level.

Integrated analysis of microRNA and transcription factor reveals important regulators and regulatory motifs in adult B-cell acute lymphoblastic leukemia.

B-cell acute lymphoblastic leukemia (B­ALL) is an aggressive hematological malignancy and a leading cause of cancer-related mortality in children and young adults. The molecular mechanisms involved in the regulation of its gene expression has yet to be fully elucidated. In the present study, we performed large scale expression profiling of microRNA (miRNA) and transcription factor (TF) by Illumina deep­sequencing and TF array technology, respectively, and identified 291 differentially expressed miRNAs and 201 differentially expressed TFs in adult B­ALL samples relative to their controls. After integrating expression profile data with computational prediction of miRNA and TF targets from different databases, we construct a comprehensive miRNA­TF regulatory network specifically for adult B­ALL. Network function analysis revealed 25 significantly enriched pathways, four pathways are well­known to be involved in B­ALL, such as PI3K­Akt signaling pathway, Jak­STAT signaling pathway, Ras signaling pathway and cell cycle pathway. By analyzing the network topology, we identified 28 hub miRNAs and 19 hub TFs in the network, and found nine potential B­ALL regulators among these hub nodes. We also constructed a Jak­STAT signaling sub­network for B­ALL. Based on the sub­network analysis and literature survey, we proposed a cellular model to discuss MYC/miR­15a­5p/FLT3 feed-forward loop (FFL) with Jak­STAT signaling pathway in B­ALL. These findings enhance our understanding of this disease at the molecular level, as well as provide putative therapeutic targets for B-ALL.

[Study on the effect and its mechanisms of genistein on the cell cycle of highly metastatic ovarian carcinoma HO-8910PM cells].

OBJECTIVE: To study the effect and its possible mechanism of genistein on the cell cycle of human highly metastatic ovarian carcinoma HO-8910PM cells. METHODS: Trypan blue stain assay was used to examine the effect of genistein on proliferation of HO-8910PM cells after 24 hours treatment. The cell cycle was assessed by flowcytometry (FCM). The expression level of NF-kappaB (p65) and the level of VEGF were assessed by Western blot analysis. RESULTS: Genistein could inhibit the proliferation of HO-8910PM cell and block the cell cycle at G1 phase. The expession level of NF-kappaB (P65) protein decreased obviously in HO-8910PM cells treated with 25 approximately 100 micromol/L genistein for 24 hours, and the effect appeared in the experssion of VEGF. CONCLUSION: The effect on cell cycle of genistein is involved in the decreasing expression of NF kappaB (p65) and the level of VEGF.

Homocysteine attenuates hemodynamic responses to nitric oxide in vivo.

Homocysteine is a significant but modifiable risk factor for vascular diseases. While several pathological processes may be involved, homocysteine can cause significant endothelial impairment and compromise vascular NO bioactivity. In the present study, we aimed to assess effects of homocysteine on NO-mediated hemodynamic responses in vivo. We created an acute hyperhomocysteinemia model (plasma homocysteine of 65-276 micromol/l) by continuous venous infusion of D,L-homocysteine to anaesthetized Sprague-Dawley rats. Vasodilators including NO donors: S-nitrosohomocysteine (SNOHcy), S-nitrosocysteine (SNOCys) and sodium nitroprusside (SNP), the endothelial NO synthase (eNOS) activator: acetylcholine (ACh), and calcium channel blocker: verapamil and nicardipine, were administered by one bolus injection to the homocysteinemic rats. While homocysteine infusion produced no change in the mean femoral arterial blood pressure, each of these vasodilators led to a rapid and substantial dose-dependent fall in blood pressure. Concurrent homocysteine infusion, however, attenuated the blood pressure lowering effects induced by NO donors (P<0.01), but not by the calcium channel blockers. Homocysteine inhibited not only the endothelial-derived NO as stimulated by ACh, but also the bioactivity of exogenously supplied NO by SNOHcy, SNOCys and SNP. Our findings indicate that homocysteine may have an effect on NO bioproduction and bioavailability. Vasodilating efficacy of commonly used NO donors such as nitroglycerine may be seriously compromised by hyperhomocysteinemia, which is common among ischemic heart disease patients.

Leukocytes extravasation in acute homocysteinemic rats.

Homocysteine may promote atherogenesis and thrombogenesis by enhancing leukocyte-endothelium interactions. We explored this hypothesis in an acute hyperhomocysteinemia rat model, which was created by a continuous venous homocysteine infusion (4 ml/h/kg body weight) with 2.5 and 10 mg/ml D,L-homocysteine upto 90 min. Venous homocysteine levels were monitored periodically and varied 65-276 micromol/l, a range observed frequently in homocysteinemic and homocystinuric patients. We measured hemodynamic parameters in mesentery by intravital microscopy in rats infused with homocysteine (N=5 for each dose) and saline (N=7). Homocysteine infusion for 90 min did not change the mean carotid arterial blood pressure, velocity of red blood cells and rolling leukocyte flux. However at the dose of 10 mg/ml the venular wall shear rate was reduced to 66-69% of the pre-infusion value (P<0.05). The leukocyte rolling velocity decreased to 78-82% (P<0.05). The number of leukocytes adhering to the venular wall increased 2.4-fold (P<0.05), and the leukocyte extravasation increased 4.7-fold (P<0.001). Each of these effects was time-dependent and homocysteine dose-dependent. But none were observed in saline infused rats. In conclusion, while homocysteine infusion did not change hemodynamic parameters, it significantly enhanced dose-dependent leukocyte-endothelium interactions, which may contribute to homocysteine induced endothelial dysfunction.