The PU.1-Modulated MicroRNA-22 Is a Regulator of Monocyte/Macrophage Differentiation and Acute Myeloid Leukemia.

MicroRNA-22 (miR-22) is emerging as a critical regulator in organ development and various cancers. However, its role in normal hematopoiesis and leukaemogenesis remains unclear. Here, we detected its increased expression during monocyte/macrophage differentiation of HL-60, THP1 cells and CD34+ hematopoietic stem/progenitor cells, and confirmed that PU.1, a key transcriptional factor for monocyte/macrophage differentiation, is responsible for transcriptional activation of miR-22 during the differentiation. By gain- and loss-of-function experiments, we demonstrated that miR-22 promoted monocyte/macrophage differentiation, and MECOM (EVI1) mRNA is a direct target of miR-22 and MECOM (EVI1) functions as a negative regulator in the differentiation. The miR-22-mediated MECOM degradation increased c-Jun but decreased GATA2 expression, which results in increased interaction between c-Jun and PU.1 via increasing c-Jun levels and relief of MECOM- and GATA2-mediated interference in the interaction, and thus promoting monocyte/macrophage differentiation. We also observed significantly down-regulation of PU.1 and miR-22 as well as significantly up-regulation of MECOM in acute myeloid leukemia (AML) patients. Reintroduction of miR-22 relieved the differentiation blockage and inhibited the growth of bone marrow blasts of AML patients. Our results revealed new function and mechanism of miR-22 in normal hematopoiesis and AML development and demonstrated its potential value in AML diagnosis and therapy.

Clinical trial on the effects of thalidomide on hemoglobin synthesis in patients with moderate thalassemia intermedia.

To investigate the efficacy and safety of thalidomide in patients with thalassemia intermedia (TI). Patients with a confirmed diagnosis of TI who met the trial criteria and signed consent forms were prescribed oral thalidomide 50 mg qn for 3 months from February 2017. Complete blood counts, Hb analysis, and liver and kidney functions were monitored monthly during treatment and any differences were compared before and after treatment. Patients with Hb increments > 2.0 g/dL were termed main responders (MaR), and those with Hb increments between 1.0 and 2.0 g/dL as minor responders (MiR), otherwise they were termed non-responders. Relevance analysis was performed to explore parameters predicting Hb increments after treatment. Adverse effects during treatment were carefully recorded. The overall response rate (ORR = MaR + MiR) and MaR rates were 78.6 and 50% after 1 month of treatment, respectively, and 85.7 and 71.4% after 3 months treatment. At the end of the treatment period, Hb and HbF increased by 2.5 ± 1.8 g/dL and 2.5 ± 1.6 g/dL, while bilirubin, lactate dehydrogenase, and the nucleated red blood cell count (NRBC) were significantly decreased, while the reticulocyte count significantly increased. Correlation analysis showed that the Hb increments correlated significantly with the ratio of HbF before treatment (r = 0.683, P = 0.007) rather than age, Hb, reticulocyte count, and NRBC before treatment. Adverse events during treatment were mild, and drug reduction or withdrawal from the trial was not required. Thalidomide had rapid and significant effects in patients with TI, and also, it is safe and convenient. But larger scale clinical trials will be required to confirm our conclusions. TRIAL REGISTRATION: NCT02995707, https://www.clinicaltrials.gov/ct2/show/NCT03184844?term=thalidomide+thalassemia&rank=1 .

Nutlin-3-induced redistribution of chromatin-bound IFI16 in human hepatocellular carcinoma cells in vitro is associated with p53 activation.

AIM: Interferon-γ inducible protein 16 (IFI16), a DNA sensor for DNA double-strand break (DSB), is expressed in most human hepatocellular carcinoma cell (HCC) lines. In this study we investigated the re-localization of chromatin-bound IFI16 by Nutlin-3, a DNA damage agent, in HCC cells in vitro, and the potential mechanisms. METHODS: Human HCC SMMC-7721 (wild-type TP53), Huh-7 (mutant TP53), Hep3B (null TP53) and normal fetal liver L02 cell lines were examined. DSB damage in HCC cells was detected via γH2AX expression and foci formation assay. The expression of IFI16 and IFNB mRNA was measured using RT-PCR, and subcellular localization and expression of the IFI16 protein were detected using chromatin fractionation, Western blot analysis, and fluorescence microscopy. RESULTS: Treatment of SMMC-7721 cells with Nutlin-3 (10 µmol/L) or etoposide (40 µmol/L) induced significant DSB damage. In SMMC-7721 cells, Nutlin-3 significantly increased the expression levels of IFI16 and IFNB mRNA, and partially redistributed chromatin-bound IFI16 protein to the cytoplasm. These effects were blocked by pretreatment with pifithrin-α, a p53 inhibitor. Furthermore, Nutlin-3 did not induce ectopic expression of IFI16 protein in Huh-7 and Hep3B cells. Moreover, the association of IFI16 with chromatin and Nutlin-3-induced changes in localization were not detected in L02 cells. CONCLUSION: Nutlin-3 regulates the subcellular localization of IFI16 in HCC cells in vitro in a p53-dependent manner.

MicroRNA-29a and microRNA-142-3p are regulators of myeloid differentiation and acute myeloid leukemia.

Although microRNAs (miRNAs) are increasingly linked to various physiologic processes, including hematopoiesis, their function in the myeloid development is poorly understood. We detected up-regulation of miR-29a and miR-142-3p during myeloid differentiation in leukemia cell lines and CD34(+) hematopoietic stem/progenitor cells. By gain-of-function and loss-of-function experiments, we demonstrated that both miRNAs promote the phorbol 12-myristate 13-acetate-induced monocytic and all-trans-retinoic acid-induced granulocytic differentiation of HL-60, THP-1, or NB4 cells. Both the miRNAs directly inhibited cyclin T2 gene, preventing the release of hypophosphorylated retinoblastoma and resulting in induction of monocytic differentiation. In addition, a target of miR-29a, cyclin-dependent kinase 6 gene, and a target of miR-142-3p, TGF-ß-activated kinase 1/MAP3K7 binding protein 2 gene, are involved in the regulation of both monocytic and granulocytic differentiation. A significant decrease of miR-29a and 142-3p levels and an obvious increase in their target protein levels were also observed in blasts from acute myeloid leukemia. By lentivirus-mediated gene transfer, we demonstrated that enforced expression of either miR-29a or miR-142-3p in hematopoietic stem/progenitor cells from healthy controls and acute myeloid leukemia patients down-regulated expression of their targets and promoted myeloid differentiation. These findings confirm that miR-29a and miR-142-3p are key regulators of normal myeloid differentiation and their reduced expression is involved in acute myeloid leukemia development.

Pulmonary hypertension risk in patients with hemoglobin h disease: low incidence and absence of correlation with splenectomy.

Pulmonary hypertension (PHT) is a common complication for patients with ß thalassemia intermediate (TI), especially splenectomized patients. However, the frequency and risk factors of PHT in patients with hemoglobin H (HbH) disease is unknown. The purpose of this study was to identify the prevalence of PHT risk manifested as tricuspid regurgitant jet velocity (TRV) ≥2.5 m/s in patients with HbH disease and its correlation with splenectomy. One hundred and ninety-eight patients with HbH disease who visited the 303rd Hospital of the People's Liberation Army (Nanning, China) were investigated. Thirteen subjects (6.5%) were diagnosed as having a risk of PHT. Regression analyses showed that the prevalence of PHT risk was correlated only with age (r = 0.195, p = 0.006) and not with splenectomy. The risk of PHT in patients older than 35 years was 5.7 times (range 1.8-18.6) greater than that for patients younger than 35 years. For splenectomized patients compared to those with HbH disease, patients with TI had a higher frequency of PHT risk, higher nucleated red blood cell counts (46.03 ± 41.11 × 10(9)/l vs. 0.18 ± 1.19 × 10(9)/l, p < 0.001) and a higher platelet counts (837.6 ± 178.9 × 10(9)/l vs. 506.7 ± 146.2 × 10(9)/l, p < 0.001). PHT risk is low in patients with HbH disease and does not correlate with splenectomy. Patients older than 35 years should be monitored regularly.

[Predictors of Hematologic Responses in Patients with Non-Transfusion-Dependent ß-Thalassemia Receiving Thalidomide Therapy].

OBJECTIVE: To explore the predictors of hematologic responses of non-transfusion-dependent ß-thalassemia (NTDT) to thalidomide. METHODS: 33 patients with NTDT who treated with thalidomide in the 923rd Hospital of the Joint Logistics Support Force of the People's Liberation Army from May 2016 to June 2019 were included in the study. The basic data, hematological indexes, degree of treatment response and genetic background of the patients were analyzed. RESULTS: The baseline fetal hemoglobin (HbF) level of main responders (MaR) was significantly higher than that of minor responders (MiR) and no responders (NR) (P=0.001). And the baseline HbF level was positively correlated with hemoglobin increment after treatment (r=0.601). Genetic background analysis showed that the frequencies of the genotype CT of HBG2 rs7482144 (P=0.031), the genotypes CT/CC (P=0.030) and the minor allele C (P=0.015) of HBS1L-MYB rs9399137, the genotypes AT/TT (P=0.030) and the minor allele T (P=0.028) of HBS1L-MYB rs4895440, the genotypes AG/GG (P=0.030) and the minor allele G (P=0.028) of HBS1L-MYB rs4895441 (P=0.030) in MaR group were significantly higher than those in MiR and NR groups. Comparing the area under the ROC curve (AUC) of the above indicators to predict the main response, the results demonstrated that the predictive value of baseline HbF level was significantly better than rs7482144 (0.91 vs 0.72, P=0.003), rs9399137 (0.91 vs 0.74, P=0.022), rs4895440 (0.91 vs 0.74, P=0.023) and rs4895441 (0.91 vs 0.74, P=0.023), but there was no significant difference in the predictive value between combined single nucleotide polymorphisms (SNPs) (0.91 vs 0.88, P=0.658）and baseline HbF combined SNPs (0.91 vs 0.97, P=0.132). The AUC value of baseline HbF predicting the efficacy of thalidomide as the main response was 0.91, the cut-off value was 27.4%, the sensitivity was 100%, and the specificity was 58.3% (P=0.001). CONCLUSION: The hematologic response of NTDT to thalidomide is variable and complex. Compared to genetic background, baseline HbF may be a simpler and more efficient tool to predict efficacy response.

A case report of concomitant paroxysmal nocturnal hemoglobinuria and heterozygous ß-thalassemia.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal blood disorder that presents chronic intravascular hemolysis. PNH concomitant with inherited hemolytic anemia has been rarely reported. Here, we report an interesting PNH patient who was misdiagnosed with iron deficiency anemia due to concomitant heterozygous ß-thalassemia. The patient experienced dizziness, fatigue, and restricted physical activity for the previous 3 years. Thalassemia gene analysis revealed heterozygous ß-thalassemia. Iron staining of the bone marrow demonstrated the absence of stainable iron and sideroblasts. The patient was diagnosed with iron deficiency anemia. Iron supplementation treatment was performed, but the anemia remained unresolved. The patient became transfusion dependent 1 year later and was admitted to our hospital in March 2010. Flow cytometry of the patient's peripheral blood demonstrated that 7.9% and 11.9% of the erythrocytes were CD59 and CD55 deficient, respectively. The patient was finally diagnosed with concomitant PNH and heterozygous ß-thalassemia.

Treatment and complications of thalassemia major in Guangxi, Southern China.

BACKGROUND: ß-Thalassemia is extremely prevalent in Guangxi province, Southern China. However, little is known about the treatment and complications of patients with thalassemia major (TM) in Guangxi. The first thalassemia center in China was opened in Guangxi in 2003. Since that time, more than 400 patients have been enrolled. PROCEDURE: From December 2009 to February 2010, data was collected from TM patients visiting the thalassemia center including the circumstances of diagnosis, biological and clinical data, markers of iron overload and treatment. RESULTS: Data on 231 patients (median age, 5 years; range, 5 months to 21 years) were recorded. Only 44.6% of patients maintained their hemoglobin levels >9.0 g/dl. In 186 patients with ferritin levels >1,000 ng/ml, an iron chelator was used regularly in 44.6%, irregularly in 26.9%, and was not used in 28.5%. The mean serum ferritin level was 3,143 ng/ml and levels increased with age. Height and weight retardation were found in 48.3% and 11.1% patients, respectively. Compared to patients treated outside of the center, patients completing treatment in the thalassemia center had a higher hemoglobin level before transfusion, higher height and weight SD score, and less splenomegaly, but a similar ratio of regular or irregular iron chelation. Six (18.2%) of 33 patients >10 years of age (14.3 ± 2.8 years; range, 11-19 years) were diagnosed as hypothyroid. CONCLUSIONS: Although survival status of patients with TM in Guangxi has improved since the opening of the thalassemia center, TM complications remain high and with an early onset.

Refractory platelet transfusion in a patient with CD36 deficiency due to pseudothrombocytopenia.

Type I CD36 deficiency is defined by the absence of CD36 on both platelets and monocytes. Pseudothrombocytopenia (PTCP) is characterized by a false reduction in the number of platelets in ethylenediaminetetraacetic acid (EDTA)-anticoagulated blood. Here we report a rare case of concomitant CD36 deficiency and PTCP. The patient was a 7-year-old boy who suffered comminuted fractures of the left humeral condyle. In the pre-operative examination, he was found to have thrombopenia and assumed to have idiopathic thrombocytopenic purpura. After immunotherapy and platelet transfusion, the platelet count remained low, suggesting that the patient was refractory to platelet transfusion. Serum was collected for the detection of platelet antibodies, and antibodies against CD36 were found. Flow cytometry verified the absence of CD36 on both the platelets and monocytes of this patient. However, the platelet count was normal when capillary blood smears were analysed; in addition, platelet coagulation was noted under the microscope when EDTA-anticoagulated peripheral blood was used. The patient underwent surgery without platelet transfusion and recovered uneventfully.

[Clinical Efficiency of Rituximab Combined with Autologous Hematopoietic Blood Stem Cell Transplantation for Treatment of CD20+ B non.Hodgkin Lymphoma].

AbstractObjective: To investigate the effeciency of autologous hematopoietic stem cell transplantation (auto.HSCT) combined with rituximab(R) to treat CD20+ B non.Hodgkin lymphoma(B.NHL). METHODS: From January 2005 to December 2013, 83 patients with refractory/recurrent CD20+ B.NHL who were treated with auto.HSCT in our department were enrolled. The patients were divided into 2 groups: 57 patients in Rituximab group, and 26 patients in control group(without Rituximab). All the patients received chemotherapy and auto.HSCT. For the patients in treatment group, Tituximab was used before transplantation of the stem cells, and for some patients Rituximab was used after transplantation. For the patients in control group, the induction, enhancement and transplantation were the same as those in treatment group. The clinical efficiency of the patients in treatment group according to the time and frequency of R was analyzed in subgroups and compared with the control group. The deadline of follow.up was April 30 2014. RESULTS: All the patient achieved complete response. The median follow.up time was 39 months. Both the two groups collected peripheral blood stem cells successfully, and had no difference in hematopoietic reconstitution time. Three patients in treatment group and six patients in control group relapsed and the three year overall survival and EFS in treatment group was significantly higher than that in control group, that is（93.0% vs 73.1%, P=0.037） and （89.5% vs 65.4%, P=0.034）, respectively. Subgroup analysis showed that: compared with the treatment group in which using R in the whole courses(before and after transplantation, and collection of stem cells) was superior to the control group in both OS and EFS, with the OS 97% vs 87.5% (P>0.05) and EFS 97% vs 76.2% (P=0.05) respectively. While stratified by the different courses of rituximab, the OS was 88.9% (1-2 courses, 9 cases), 93.1% (3-4 courses, 29 cases), 94.7%(more than 5 courses,19 cases), and EFS was 77.8%, 89.7% and 94.7%, respectively. CONCLUSION: For the patients with refractory/recurrent CD20+ B.NHL, the combination of R and inducing chemotheraphy, purify in body before transplantation, as well as continue with R after auto.HSCT could obviously improve the OS and EFS of patients. For the patients who with R before and after transplantation, their EFS is better than the patients with R before transplantation only.

Endophthalmitis associated with fungal keratitis and penetrating injuries in North China.

PURPOSE: To report the laboratory findings, management strategies, and visual outcomes of culture-proven exogenous fungal endophthalmitis in North China. METHODS: The microbiological and treatment records of patients with culture-positive exogenous fungal endophthalmitis who visited the Affiliated Hospital of Qingdao University from January 2012 to December 2016 were reviewed. RESULTS: A total of 39 eyes (39 patients) were identified over a 5-year period. Exogenous fungal endophthalmitis was associated with penetrating trauma in 22 eyes (56.4%), fungal keratitis in 15 eyes (38.5%), and intraocular surgery in 2 eyes (5.1%). Hyphae were found in 29 of 37 smear samples (78.4%) by direct microscopic examination. Fungal pathogens cultured from 39 samples were identified as 10 genera and 15 species. Filamentous fungi (molds) accounted for 94.9% (37 samples), including Fusarium (19, 48.7%) and Aspergillus (11, 28.2%). Most keratitis cases were caused by Fusarium (11 of 15; 73.3 %). Aspergillus was isolated from nine penetrating ocular trauma cases (9 of 22; 40.9%). Three eyes receiving evisceration had fungal and bacteria coinfection (3 of 39, 7.7%) with Aspergillus and Bacillus. At least, one surgical intervention was performed in all 39 eyes and 28 (71.8%) eyes underwent two or more procedures, including surgeries and intraocular injections. Twenty-nine patients received intraocular antifungal therapy with amphotericin B and/or voriconazole. Visual acuity at discharge from the hospital was significantly better than the initial visual acuity (p < 0.001). Final vision of 20/400 or better was achieved in 22 (56.4%) eyes. CONCLUSIONS: This study highlighted the differences between clinical categories of exogenous fungal endophthalmitis. Trauma was the major etiological factor. Molds were the most common pathogens, with Fusarium ranking first, followed by Aspergillus. Fungal and bacterial coinfection mostly occurred after metal penetrating trauma, and Bacillus was the primary bacterial pathogen. Coinfection may be one reason of evisceration. Immediate intravitreal antifungal therapy combined with vitrectomy was effective for exogenous fungal endophthalmitis. Amphotericin B and voriconazole were commonly used antifungal agents.

lncRNA PCAT-1 interacting with FZD6 contributes to the malignancy of acute myeloid leukemia cells through activating Wnt/ß-catenin signaling pathway.

Accumulating evidence has suggested the involvement of long noncoding RNAs (lncRNAs) on the acute myeloid leukemia (AML). Therefore, this study aimed to investigate the unknown function of lncRNA Prostate cancer-associated transcript-1 (PCAT-1) in AML cells. Our data found that PCAT-1 was highly expressed in AML-M1/2 and AML-M3 patients than normal controls and its expression was significantly up-regulated in AML cell lines Kasumi-6 and HL-60. The functional experiments demonstrated that knockdown of PCAT-1 remarkably inhibited proliferation, arrested cell cycle progression and triggered apoptosis of AML cells. Mechanistically, we revealed that PCAT-1 could directly interact with FZD6 protein to regulate its stability. Overexpression of FZD6 partly abolished the effects of PCAT-1 silencing on AML cells. Our integrated experiments then suggested that PCAT-1 could activate the Wnt/ß-catenin signaling pathway in an FZD6-dependent manner. Taken together, the present study indicated that PCAT-1 interacting with FZD6 to activate Wnt/ß-catenin signaling, which may play an important role in the pathogenesis of AML.

Detection of drug resistance-associated genes of multidrug-resistant Acinetobacter baumannii.

The beta-lactamase (BLA) genes, the genes for aminoglycosides-modifying enzymes (AMEs), disinfectant-sulfanilamide resistance (qacEDelta1-sul1) genes, class 1 integrase (intl1) gene, and the qnr gene associated with plasmid-mediated quinolone resistance were analyzed using PCR and verified by DNA sequencing for 31 clinical isolates of multidrug-resistant Acinetobacter baumannii (MDRAB). The organism typing was performed by pulsed-field gel electrophoresis (PFGE). The positive rate of ADC, TEM, PER, and DHA of BLA genes were 100%, 61.3%, 19.4%, and 3.2%, respectively; however, the genes of SHV, OXA-23 group, OXA-24 group, GES, VIM, IMP, and qnr gene were negative. The positive rate of the genes of AMEs for aac (3)-I, aac (6')-I, ant (3")-I, ant (2")-I, aac (3)-II, and aac (6')-II were 67.7%, 45.2%, 29.0%, 22.6%, 12.9%, and 3.2%, respectively. The positive rate of qacEDelta1-sul1 and intl1 were 80.6% and 58.1%, respectively. Six different PFGE clones were found, of which two dominated. The findings show that clinical isolates of MDRAB harbor various kinds of resistance genes.

[Oxidative Stress Status and Its Effect on Regulation of Hepcidin in Patients with HbHCS].

OBJECTIVE: To investigate the oxidative stress status and its effects on hepcidin in patients with hemoglobin H Constant Spring disease (HbH-CS). METHODS: A total of 35 patients were enrolled in the study, including 15 splenectomized cases and 20 non-splenectomized cases. 20 healthy volunteers were selected as controls. Serum superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG) levels, erythropoietin (EPO), serum free transferrin receptor (sFTR), growth differentiation factor 15 (GDF15) as well as the level of hepcidin were detected. Correlation analysis and multiple factor regression analysis were performed to investigate the factors affecting the iron metabolism and erythropoiesis. RESULTS: Compared with healthy control, the SOD and GSH levels in patients with HbHCS decreased, while MDA and GSSG levels increased. The levels of SOD, MDA, GSG and GSSG were not significantly different between the patients with splenectomy and those without splenectomy. Correlation analysis showed that inpatients with HbHCS, EPO, sFTR and GDF15 correlated negatively with SOD level and positively with MDA level. EPO and sFTR levels negatively correlated with Hepcidin. CONCLUSION: Excessive oxidative stress is present in patients with HbHCS, and hepcidin is inhibited by the upregulation of EPO and sFTR, and hence involved in iron overload in patients.

[Microbiology and clinical analysis of six cases of hospital-acquired pneumonia caused by Acinetobacter baumannii].

OBJECTIVE: To study the microbiology, clinical features and treatment outcomes of hospital-acquired pneumonia (HAP) caused by Acinetobacter baumannii. METHODS: Six cases of HAP, caused by Acinetobacter baumannii producing PER-1 type extended-spectrum beta-lactamase verified by molecular biological methods, were studied in Bethune International Peace Hospital, from January to August 2005. Clinical data were collected and analyzed. Pulsed-field gel electrophoresis (PFGE) were used to analyze the homology of these strains. The genes of beta-lactamase (BLA), aminoglycoside-modifying enzymes (AME), resistant to disinfectant-sulfanilamide (qacEDelta1-sul1), and class 1 integrase (intl1) were analyzed using PCR and verified by DNA sequencing. RESULTS: Among these 6 strains of Acinetobacter baumannii, five were susceptible only to imipenem, and 4 were susceptible to meropenem. The PFGE types identified from these isolates were A1 (n=2) and A2-A5 (n=1, respectively). They all were positive for PER-1, TEM-1, and genes of qacEDelta1-sull and intl1. Three of them harbored genes of aac (3)-I and aac (6')-I. Two had aac (3)-I and ant (3'')-I. One had aac (3)-I. All the patients had severe underlying diseases, and had received mechanical ventilation. They all had received broad spectrum antibiotics within 15 days before Acinetobacter baumannii were identified. Although carbapenem and/or cefoperazone/sulbactam had been used, only 3 patients survived. CONCLUSION: The 6 PER-1 type extended-spectrum beta-lactamase-producing Acinetobacter baumannii isolates were closely related and had complex mechanisms of drug resistance. The prognosis of patients infected by them was poor.

A test of homogeneity of Hardy-Weinberg disequilibrium across strata.

For genotype data being sampled from several strata with different allele frequencies, it is necessary to verify the assumption of homogeneity of Hardy-Weinberg disequilibrium across strata before testing Hardy-Weinberg law across strata. In practice, disequilibrium can be measured via fixation coefficients (ie, ratios of genotypic frequencies) or disequilibrium coefficients (ie, differences of genotypic frequencies). Test for homogeneity of Hardy-Weinberg disequilibrium using data from several populations has been derived according to fixation coefficients. In this article, using the likelihood score theory extended to nuisance parameters, we derive a homogeneity score test for comparing disequilibrium coefficients across several independent strata. Simulation results demonstrate that the homogeneity score test performs satisfactorily in the sense that its empirical size seldom exceeds the pre-chosen nominal level by more than 10% even for small sample sizes. Corresponding power and sample size formulae are provided as well. We illustrate our test with a real glyoxalase genotype data set.

[Quantification for biofilm formation of pseudomonas aeruginosa isolates and their genotypic analysis].

OBJECTIVE: To probe the correlation between the ability of biofilm formation of Pseudomonas aeruginosa isolates and their genotypes. METHODS: Forty-eight Pseudomonas aeruginosa isolates were tested for their biofilm formation with a modified microtiter test and were analyzed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). The percent similarity between their genetic fingerprints and cluster analysis was performed and worked out using computer software. RESULTS: Forty-eight Pseudomonas aeruginosa isolates demonstrated different abilities of biofilm formation in vitro. And the 48 isolates with different abilities of biofilm formation showed different genotypes in fingerprints by ERIC-PCR. Among the 48 isolates of Pseudomonas aeruginosa tested, five clusters (A, B, C, D, E), were identified at the 17% genetic similarity level. The isolates with strong ability of biofilm formation were in D cluster at the 42% genetic similarity level. CONCLUSION: Most of the 48 PA isolates tested formed strong biofilm, and their genotypes were of correlation.

c-Myc suppresses miR-451⊣YWTAZ/AKT axis via recruiting HDAC3 in acute myeloid leukemia.

Aberrant activation of c-Myc plays an important oncogenic role via regulating a series of coding and non-coding genes in acute myeloid leukemia (AML). Histone deacetylases (HDACs) can remove acetyl group from histone and regulate gene expression via changing chromatin structure. Here, we found miR-451 is abnormally down-regulated in AML patient samples; c-Myc recruits HDAC3 to form a transcriptional suppressor complex, co-localizes on the miR-451 promoter, epigenetically inhibits its transcription and finally induces its downregulation in AML. Furthermore, our in vitro and in vivo results suggest that miR-451 functions as a tumor suppressor via promoting apoptosis and suppressing malignant cell proliferation. The mechanistic study demonstrated that miR-451 directly targets YWHAZ mRNA and suppresses YWHAZ/AKT signaling in AML. Knockdown of c-Myc results in restoration of miR-451 and inhibition of YWHAZ/AKT signaling. In AML patients, low level of miR-451 is negatively correlated with high levels of c-Myc and YWHAZ, while c-Myc level is positively related to YWHAZ expression. These results suggested that c-Myc⊣miR-451⊣YWHAZ/AKT cascade might play a crucial role during leukemogenesis, and reintroduction of miR-451 could be as a potential strategy for AML therapy.