[Efficacy, Prognosis and Safety of Decitabine Combined with Low-Dose Cytarabine in the Treatment of Elderly Patients with Relapsed/Refractory Acute Myeloid Leukemia].

OBJECTIVE: To investigate the efficacy, prognosis and safety of decitabine combined with low-dose CAG regimen in the treatment of elderly patients with acute myeloid leukemia （AML）. METHODS: The clinical data of 40 elderly patients with relapsed/refractory AML （69-85 years old） admitted to our hospital from January 2014 to August 2016 were analyzed retrospectively. 40 patients were divided into combination therapy group and CAG group according to different treatment methods. 20 patients of the combination therepy group were treated with decitabine combined with low-dose CAG （decitabine, 15 mg/m2, d 1; aclarithromycin, 10 mg/m2, d 3-6; Cytidine, 10 mg/m2, d 1-14; recombinant human granulocyte macrophage colony-stimulating factor （G-CSF） for injection, 200 µg/（m2·d）, d 1-14）. 20 patients of CAG group were treated by the standard CAG protocol （acralmycin 20 mg/m2, d 1-4; cytarabine for injection, 15 mg/m2, d 1-14; G-CSF 400 µg/（m2·d）, d 1-14）. One course of treatment lasted for 2 weeks, after 2 courses of continuous medication, the complete remission rate （CR）, overall remission rate （ORR）, overall survival （OS）, 1-year survival rate, hemoglobin, white blood cells, platelets improvement, and incidence of adverse reactions were compared. RESULTS: In combination therapy group the CR was 55.00% （11/20）, OR was 85.00% （17/20）, but in the CAG group CR was 30.00% （6/20）, and OR was 50.00% （10/20）. Till to February 2018, out of 40 patients 17 survived, 20 died, and 3 failed to be followed-up. The median follow-up time was 12 （2 to 35） months; the median survival time in the comtination therapy group was 13 （2-35） months, and the 1-year OS rate was 70.00%, and the median survival time of the CAG group was 10 （2-31） months, and the 1-year OS rate was 50.00%, without staistical significance between the 2 groups （P>0.05）. After treatment, the WBC and Plt counts in the combination therapy group were higher than those in the CAG group, but the Hb level was lower than that in the CAG group with statistically significant difference （P<0.05）. In the combination therapy group, the incidence of lung infection, nausea and vomiting was higher than that of the CAG group （65.00% vs 25.00%, 50.00% vs 20.00%）, with statistically significant difference （P<0.05）. CONCLUSION: Decitabine combined with low-dose CAG regimen is effective for the treatment of relapsed/refractory AML in the elderly. Compared with the standard CAG regimen, the long-term efficacy of this regimen is not different significantly, but its adverse reactions are increase, thus the preventive treatment should be given in time.

Identification of DEAD-Box RNA Helicase DDX41 as a Trafficking Protein That Involves in Multiple Innate Immune Signaling Pathways in a Zebrafish Model.

DDX41 is an important sensor for host recognition of DNA viruses and initiation of nuclear factor-κB (NF-κB) and IFN signaling pathways in mammals. However, its occurrence and functions in other vertebrates remain poorly defined. Here, a DDX41 ortholog [Danio rerio DDX41 (DrDDX41)] with various conserved structural features to its mammalian counterparts was identified from a zebrafish model. This DrDDX41 was found to be a trafficking protein distributed in the nucleus of resting cells but transported into the cytoplasm under DNA stimulation. Two nuclear localization signal motifs were localized beside the coiled-coil domain, whereas one nuclear export signal motif existed in the DEADc domain. DrDDX41 acts as an initiator for the activation of NF-κB and IFN signaling pathways in a Danio rerio STING (DrSTING)-dependent manner through its DEADc domain, which is a typical performance of mammalian DDX41. These observations suggested the conservation of DDX41 proteins throughout the vertebrate evolution, making zebrafish an alternative model in understanding DDX41-mediated immunology. With this model system, we found that DrDDX41 contributes to DrSTING-Danio rerio STAT6 (DrSTAT6)-mediated chemokine (Danio rerio CCL20) production through its DEADc domain. To the best of our knowledge, this work is the first report showing that DDX41 is an upstream initiator in this newly identified signaling pathway. The DrDDX41-mediated signaling pathways play important roles in innate antibacterial immunity because knockdown of either DrDDX41 or DrSTING/DrSTAT6 significantly reduced the survival of zebrafish under Aeromonas hydrophilia or Edwardsiella tarda infection. Our findings would enrich the current knowledge of DDX41-mediated immunology and the evolutionary history of the DDX41 family.

Essential Roles of TIM-1 and TIM-4 Homologs in Adaptive Humoral Immunity in a Zebrafish Model.

TIM-1 and TIM-4 proteins have become increasingly attractive for their critical functions in immune modulation, particularly in CD4(+) Th2 cell activation. Thus, these proteins were hypothesized to regulate adaptive humoral immunity. However, further evidence is needed to validate this hypothesis. This study describes the molecular and functional characteristics of TIM-1 and TIM-4 homologs from a zebrafish (Danio rerio) model (D. rerio TIM [DrTIM]-1 and DrTIM-4). DrTIM-1 and DrTIM-4 were predominantly expressed in CD4(+) T cells and MHC class II(+) APCs under the induction of Ag stimulation. Blockade or knockdown of both DrTIM-1 and DrTIM-4 significantly decreased Ag-specific CD4(+) T cell activation, B cell proliferation, Ab production, and vaccinated immunoprotection against bacterial infection. This result suggests that DrTIM-1 and DrTIM-4 serve as costimulatory molecules required for the full activation of adaptive humoral immunity. DrTIM-1 was detected to be a trafficking protein located in the cytoplasm of CD4(+) T cells. It can translocate onto the cell surface under stimulation by TIM-4-expressing APCs, which might be a precise regulatory strategy for CD4(+) T cells to avoid self-activation before APCs stimulation. Furthermore, a unique alternatively spliced soluble DrTIM-4 variant was identified to exert a negative regulatory effect on the proliferation of CD4(+) T cells. The above findings highlight a novel costimulatory mechanism underlying adaptive immunity. This study enriches the current knowledge on TIM-mediated immunity and provides a cross-species understanding of the evolutionary history of costimulatory systems throughout vertebrate evolution.

Characterization of γδ T Cells from Zebrafish Provides Insights into Their Important Role in Adaptive Humoral Immunity.

γδ T cells represent an evolutionarily primitive T cell subset characterized by distinct T cell receptors (TCRs) and innate and adaptive immune functions. However, the presence of this T cell subset in ancient vertebrates remains unclear. In this study, γδ T cells from a zebrafish (Danio rerio) model were subjected to molecular and cellular characterizations. The constant regions of zebrafish TCR-γ (DrTRGC) and δ (DrTRDC) were initially identified. Zebrafish γδ T cells accounted for 7.7-20.5% of the total lymphocytes in spleen, head kidney, peripheral blood, skin, gill, and intestine tissues. They possess typical morphological features of lymphocytes with a surface phenotype of γ+δ+CD4-CD8+. Zebrafish γδ T cells functionally showed a potent phagocytic ability to both soluble and particulate antigens. They can also act as an antigen-presenting cell to initiate antigen (KLH)-specific CD4+ TKLH cell activation and to induce B cell proliferation and IgM production. Particularly, zebrafish γδ T cells also play a critical role in antigen-specific IgZ production in intestinal mucus. These findings demonstrated that γδ T cells had been originated as early as teleost fish, which providing valuable insights into the evolutionary history of T cell subset. It is anticipated that this study would be used as a guide to develop a zebrafish model for the cross-species investigation of γδ T cell biology.

TaUBA, a UBA domain-containing protein in wheat (Triticum aestivum L.), is a negative regulator of salt and drought stress response in transgenic Arabidopsis.

KEY MESSAGE: TaUBA functions as a negative regulator of salt and drought stress response in transgenic Arabidopsis, either the UBA domain or the zinc finger domain is crucial for TaUBA's function. TaUBA (DQ211935), which is a UBA domain-containing protein in wheat, was cloned and functionally characterized. Southern blot suggested that TaUBA is a low copy gene in common wheat. qRT-PCR assay showed that the expression of TaUBA was strongly induced by salt and drought stress. When suffering from drought and salt stresses, lower proline content and much higher MDA content in the TaUBA overexpressors were observed than those of the wild-type control, suggesting TaUBA may function as a negative regulator of salt and drought stress response in plants. To study whether the UBA domain or the zinc finger domain affects the function of TaUBA, TaUBAΔUBA (deletion of UBA domain) and TaUBA-M (Cys464Gly and Cys467Gly) overexpression vectors were constructed and transformed into Arabidopsis. Upon drought and salt stresses, the TaUBAΔUBA-and TaUBA-M-overexpressed plants accumulated much more proline and lower MDA than the wild-type control, the TaUBA-overexpressors lost water more quickly than TaUBAΔUBA-and TaUBA-M-overexpressed plants as well as the wild-type control, suggesting that overexpression of TaUBAΔUBA or TaUBA-M improved the drought and salt tolerance of transgenic Arabidopsis plants and the possibility of ubiquitination role in the regulation of osmolyte synthesis and oxidative stress responses in mediating stress tolerance. qRT-PCR assay of stress-related genes in transgenic plants upon drought and salt stresses suggested that TaUBA may function through down-regulating some stress related-transcription factors and by regulating P5CSs to cope with osmotic stress.

[Effects of H3K27 methylation inhibitor EPZ005687 on apoptosis, proliferation and cell cycle of U937 cells and normal CD34 positive cells].

The aim of this study was to investigate the effects of H3K27 methylation inhibitor EPZ005687 on the apoptosis, proliferation and cell cycle of U937 cells and normal CD34⁺ cells. The U937 cells and normal CD34⁺ cells were treated with different concentration of EPZ005687 at different time points. The apoptosis rate was determined by Annexin V/PI staining. The cell proliferation and cell cycle was determined using WST-1 assay and 7-AAD assay, respectively. The activity of H3K27 methylation was detected by chemiluminescent immunoassay. The results showed that the EPZ005687 induced an obvious apoptosis of U937 cells. The apoptotic rate was 3.96% ± 0.79%,5.74% ± 0.73%,13.34% ± 1.77% and 25.24% ± 2.55% in U937 cells treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 for 48 hours, respectively. However, EPZ005687 had rare effect on normal bone marrow(NBM) CD34⁺ cells. The apoptotic rate was 3.64% ± 0.62%,4.28% ± 0.99%,6.18% ± 1.19% and 7.56% ± 1.34% after U937 cells were treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 for 48 hours, respectively. EPZ005687 inhibited obviously the proliferation of U937 cells but had weak effect on the proliferation of NBMCD34⁺ cells. The inhibitory effect of EPZ005687 on U937 cells was time-dependent after treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 from 12 to 96 hours. EPZ005687 induced G1 phase blocking (G1%, 64.18% ± 13.27% vs 49.43% ± 12.54%) and decreased the percentage of cells in S phase (9.67% ± 2.61% vs15.26% ± 5.58%) in U937 cells. However, EPZ005687 had no effect on the cell cycle of NBMCD34⁺ cells. In addition, EPZ005687 produced obviously depletion of H3K27 methylation in U937 cells (P < 0.05), but hardly had effect on the H3K27 methylation of NBMCD34⁺ cells. It is concluded that the EPZ005687 inhibites proliferation, induces apoptosis and cell cycle blocking in G1 phase in leukemia cells. This agent may have potential value in clinical application.

[Expression of BCR/ABL fusion gene in circulating endothelial cells from chronic myelogenous leukemia patients and its clinical significance].

Several studies have shown that the tumor endothelial cells are different from the normal tissue endothelial cells. These tumor endothelial cells may contribute to tumor neo-vasculogenesis. This study was purposed to analyze the biologic features and determine the expression level of CD133 and BCR/ABL fusion gene in circulating endothelial cells (CEC) isolated from peripheral blood of CML patients, as well as to investigate the role of CEC in disease progression. Mononuclear cells were isolated from peripheral blood by density gradient centrifugation; CEC were sorted by MACS and harvested in the endothelial growth medium. The morphologic features of CEC were observed by microscopy, the cell growth rate was calculated by cell counting, and the cells were identified by immunofluorescence staining for the expression of CD31,CD34,VWF and CD133. The expression of BCR/ABL fusion gene was examined by FISH in 12 CML patients. The results indicated that the isolated CEC displayed the typical cobble-stone morphology. These cells could be identified by the positive immunofluorescence staining for CD31, CD34 and VWF, and showed more increased proliferative potential as compared to that of healthy donors. It was found that the positive rate of CD133 was 31.29% in CML patients, which was significantly different from that of healthy donors (P < 0.05). In 12 CML patients, CEC carried the same chromosome aberration as the leukemia cells (10.77%). Higher expression level of CD133 and BCR/ABL fusion gene positively correlated with progression of disease. It is concluded that the CEC may participate in invasion and angiogenesis in patients with CML and possibly correlate to the spreading and progression of the disease.

[Clinical investigation of homoharringtonine in combination with all-transretinoic acid and arsenic trioxide for acute promyelocytic leukemia].

OBJECTIVE: To study the clinical outcome, adverse effect and treatment cost of homoharringtonine (HHT) in combination with all-trans retinoic acid (ATRA) and arsenic trioxide (AS2O3) for newly diagnosed with patients acute promyelocytic leukemia (APL). METHODS: Clinical data of treatment of newly diagnosed patients with APL in experimental group (HHT + ATRA + AS2O3, n = 14) and control group \[Idarubicin (IDA) + ATRA + AS2O3, n = 21\] were analyzed retrospectively. The therapeutic effects, side effects and costs during induction therapy were compared between the two groups. RESULTS: (1) The complete remission (CR) rate were 92.9% (13/14) and 95.2% (20/21) in experimental group and control group, respectively. The time to achieve CR were (28.1 ± 3.8) and (31.7 ± 4.2) days, respectively (P > 0.05). The negative rate of PML-RARα fusion gene at the time of CR were 76.9% (10/13) and 75.0% (15/20), respectively, and that in CR patient at the end of the first cycle treatment were 100.0% (13/13) and 95.0% (19/20), respectively (P > 0.05). (2) 5-year overall survival (OS) rate were (92.6 ± 0.6)% and (89.9 ± 0.5)%, respectively (P > 0.05), 5-year disease free survival (DFS) rate were 100.0% and (86.8 ± 0.6)%, respectively (P > 0.05). (3) During induction therapy, the incidence of infection in experimental and control group were 23.1% (3/13), 60.0% (12/20), respectively (P < 0.05). The amount of platelet transfusion were (54.7 ± 29.6) and (76.5 ± 25.6) units, respectively (P > 0.05), and that of fresh frozen plasma were (1157.1 ± 238.4) and (1423.5 ± 324.6) ml, respectively (P > 0.05). The total medical costs (excluding HHT and IDA) in experimental and control group were (36074.9 ± 1245.6) and (50564.5 ± 3658.4)CNY, respectively (P < 0.05). CONCLUSION: HHT in combination with ATRA and AS2O3 regimen for newly diagnosed APL has a better efficacy, a higher long-term survival rate, and a lower costs, which is one of the reasonable choice.

[Relationship between expression of chemokine receptor and curative effect of multiple myeloma].

This study was purposed to explore the correlation of CXCR4, CCR1, CCR2 expression with curative effect of multiple myeloma (MM). Flow cytometry was used to detect the expressions of CXCR4, CCR1, CCR2 on cell surface of bone marrow from 48 newly diagnosed MM patients. These patients were divided into two groups: one group with expression of chemokine receptor (group I) and another group without expression of chemokine receptor (group II). The group I was consisted of 34 patients, but 3 out of them could not be continuously followed up. The group II was consisted of 14 patients. The MM patients of 2 groups were treated with chemotherapeutic drugs for 3 and 6 months, the curative efficacy of 2 groups were compared. The results showed that after treating for 3 and 6 months the effective rates of group I and group II were 80.6% (25/31) vs 50% (7/14) and 83.9% (26/31) vs 50% (7/14) respectively, which suggested that curative efficacy of group I was better than that of group II (p < 0.05). It is concluded that CXCR4, CCR1, CCR2 may be used as indexes for evaluating curative effect of MM patients.