Yunxiao Xu

Use of all-trans retinoic acid in combination with arsenic trioxide for remission induction in patients with newly diagnosed acute promyelocytic leukemia and for consolidation/maintenance in CR patients.

In the present study, 90 patients with newly diagnosed acute promyelocytic leukemia (APL) were studied for all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) combination treatment in remission induction and postremission therapy. In addition, 20 APL patients who had achieved complete remission (CR) with an ATRA-based regimen received ATRA/As2O3 combination for consolidation and maintenance were also enrolled. The results showed that ATRA/As2O3 combination therapy yielded a high CR rate of 93.3% and a significantly shorter time to enter CR (median: 31 days; range: 18–59 days) compared to the ATRA-based regimen (n = 72; median: 39 days; range: 25–62 days). With the ATRA/As2O3 combination for CR maintaining, regardless of the way by which CR was attained, the relapse-free survival was significantly better than with an ATRA plus cytotoxic chemotherapy regimen (92.9 ± 3.2% vs. 72.4 ± 7.6%, for the 3-year Kaplan-Meier estimate of relapse-free survival). The drug toxicity profile showed that with the use of As2O3, the incidence of hepatotoxicity was obviously high during remission induction but decreased significantly during postremission treatment. We conclude that APL patients may benefit from the early use of the combination of ATRA and As2O3, in either remission induction or consolidation/maintenance.

Decreased 5-hydroxymethylcytosine levels are associated with TET2 mutation and unfavorable overall survival in myelodysplastic syndromes

Abstract The clinical significance and mechanisms of TET2 are not well defined in myeloid malignancies. We detected TET2 mutations and assayed its catalyzing conversion product 5-hydroxymethylcytosine (5-hmC) in 61 Chinese patients with MDS. Ten patients were identified to have TET2 mutations (16.4%). 5-hmC levels in patients with MDS with TET2 mutations were significantly lower than in those without mutations, and CD34+ cells of patients with MDS exhibited a lower 5-hmC content than that of controls. TET2 expression and 5-hmC in patients with MDS with P15 methylation were both significantly lower than in those without P15 methylation. We did not observe a correlation between TET2 mutations and overall survival (OS) in MDS. Interestingly, we found that patients with MDS with higher 5-hmC levels or in lower risk groups of the Revised International Prognostic Scoring System (IPSS-R) had a longer overall survival, suggesting that 5-hmC levels may be a new molecular marker for prognostic assessment of MDS and that revised IPSS criteria are also applicable to the risk categories of Chinese patients with MDS.

Deregulation of Mitochondrial ATPsyn-β in Acute Myeloid Leukemia Cells and with Increased Drug Resistance

The mechanisms underlying the development of multidrug resistance in acute myeloid leukemia are not fully understood. Here we analyzed the expressions of mitochondrial ATPsyn-β in adriamycin-resistant cell line HL-60/ADM and its parental cell line HL-60. Meanwhile we compared the differences of mitochondrial ATPsyn-β expression and ATP synthase activity in 110 acute myeloid leukemia (AML, non-M3) patients between relapsed/refractory and those in remission. Our results showed that down-regulation of ATPsyn-β expression by siRNA in HL-60 cells increased cell viability and apoptotic resistance to adriamycin, while up-regulation of mitochondrial ATPsyn-β in HL-60/ADM cells enhanced cell sensitivity to adriamycin and promoted apoptosis. Mitochondrial ATPsyn-β expression and ATP synthase activity in relapsed/refractory acute myeloid leukemia patients were downregulated. This downregulated ATPsyn-β expression exhibited a positive correlation with the response to adriamycin of primary cells. A lower expression of ATPsyn-β in newly diagnosed or relapsed/refractory patients was associated with a shorter first remission duration or overall survival. Our findings show mitochondrial ATPsyn-β plays an important role in the mechanism of multidrug resistance in AML thus may present both a new marker for prognosis assessment and a new target for reversing drug resistance.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Ameliorates Hippocampal Synaptic Impairment after Transient Global Ischemia

Recent studies have found that administration of stem cells or extracellular vehicles (EVs) derived from stem cells exert neuroprotective effects after transient global ischemia. However, the underlying mechanisms of this effect remain unclear, especially at the level of synaptic functions. In this study, we compared the suppressive effects on cyclooxygenase-2 (COX-2) upregulation by EVs derived from bone marrow mesenchymal stem cells (BMSC-EV), adipose tissue MSC (AdMSC-EV) and serum (serum-EV). Then we examined whether BMSC-EVs could restore functional integrity of synaptic transmission and plasticity. Mice were randomly assigned to four groups: sham, sham with EV treatment, ischemia and ischemia with EV treatment. EVs were administered by intracerebroventricular injection (ICVI). We examined the consequence of transient global ischemia on pre- and post-synaptic functions of the hippocampal CA3-CA1 synapses at basal level, and long-term potentiation (LTP), an activity-dependent form of synaptic plasticity. Then we tested the therapeutic effects of EVs on these synaptic deficits. Meanwhile, Morris water maze (MWM) test was performed to examine the efficacy of EVs in rescuing ischemia-induced impairments in spatial learning and memory. EV treatment significantly restored impaired basal synaptic transmission and synaptic plasticity, and improved spatial learning and memory compared with the control group. In addition, EVs significantly inhibited ischemia-induced pathogenic expression of COX-2 in the hippocampus. EVs exert ameliorating effects on synaptic functions against transient global cerebral ischemia, which may be partly attributed to suppression of COX-2 pathogenic expression.

Analysis of clinical and laboratory characteristics in 42 patients with thrombotic thrombocytopenic purpura from a single center in China.

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease characterized by microvascular platelet deposition and thrombus formation with resulting microangiopathic hemolytic anemia. Deficiency of the von Willebrand factor cleavage protease, also known as ADAMTS 13, has been implicated as an important etiological factor in TTP. Little studies were obtained on Chinese patients with TTP until now. Our aim was to analyze the clinical features, outcome and laboratory characteristics of Chinese TTP patients, and determine whether plasma ADAMTS 13 activity is decreased in TTP and its diagnostic value for TTP. Forty-two TTP patients (29 females; 13 males) admitted to our hospital from 1998 to 2010 were analyzed. There were 34 patients (81%) with the triad of TTP, including hemolytic anemia, thrombocytopenia and neurologic abnormalities; 7 (16.7%) had the classical pentad of TTP. Major etiologic factors were acquired autoimmunological abnormalities (31%); no familial TTP was identified in this series. The schistocytes of peripheral blood smears were present in all cases with a mean frequency of 4.6% (range from 0.3% to 13.4%). Plasma ADAMTS 13 activity was determined in 22 patients with the FRET-vWF86 assay. Only 4 idiopathic TTP patients (18.2%) had severe ADAMTS 13 deficiency (activity<10%); 9 (40.9%) had moderate decrease of ADAMTS 13 activity (activity: 10-40%); another 9 (40.91%) had normal ADAMTS 13 activity (>40%). T lymphocyte subpopulation was measured in 23 TTP patients with FACS Calibur; 14 of the 23 (60.9%) had significantly decreased CD4 cells count and CD4/CD8 ratio, suggesting cellular immune dysfunction may be involved in the pathogenesis of TTP. In the studies, plasmapheresis is the main therapeutic method. 26 of 31 patients (83.9%) accepting plasmapheresis achieved complete remission; those patients who only underwent plasma infusion had low remission rate (18.2%) and high mortality (9/11; 81.8%). Four patients with packed RBC infusion manifested transient exacerbation of neurologic or psychiatric symptoms. In conclusion, the diagnosis of TTP in China is still based on clinical features including evidence of microangiopathic hemolysis. Severe ADAMTS 13 activity deficiency might be a valuable indicator for idiopathic TTP diagnosis. Further studies are needed to determine the real value of ADAMTS 13 activity for TTP diagnosis and whether T lymphocytes subset dysregulation plays important role in TTP pathogenesis.

Characterization of an acquired factor VIII inhibitor and plasmapheresis therapy in a patient with bullous pemphigoid.

Characterization of an acquired factor VIII inhibitor and plasmapheresis therapy in a patient with bullous pemphigoid -

Preservation of neuronal functions by exosomes derived from different human neural cell types under ischemic conditions

Stem cell‐based therapies have been reported in protecting cerebral infarction‐induced neuronal dysfunction and death. However, most studies used rat/mouse neuron as model cell when treated with stem cell or exosomes. Whether these findings can be translated from rodent to humans has been in doubt. Here, we used human embryonic stem cell‐derived neurons to detect the protective potential of exosomes against ischemia. Neurons were treated with in vitro oxygen–glucose deprivation (OGD) for 1 h. For treatment group, different exosomes were derived from neuron, embryonic stem cell, neural progenitor cell and astrocyte differentiated from H9 human embryonic stem cell and added to culture medium 30 min after OGD (100 μg/mL). Western blotting was performed 12 h after OGD, while cell counting and electrophysiological recording were performed 48 h after OGD. We found that these exosomes attenuated OGD‐induced neuronal death, Mammalian target of rapamycin (mTOR), pro‐inflammatory and apoptotic signaling pathway changes, as well as basal spontaneous synaptic transmission inhibition in varying degrees. The results implicate the protective effect of exosomes on OGD‐induced neuronal death and dysfunction in human embryonic stem cell‐derived neurons, potentially through their modulation on mTOR, pro‐inflammatory and apoptotic signaling pathways.

A TET2 rs3733609 C/T genotype is associated with predisposition to the myeloproliferative neoplasms harboring JAK2V617F and confers a proliferative potential on erythroid lineages

Common germline single-nucleotide polymorphisms (SNPs) at JAK2 locus have been associated with Myeloproliferative neoplasms (MPN). And, the germline sequence variant rs2736100 C in TERT is related to risk of MPN, suggesting a complex association between SNPs and the pathogenesis of MPN. Our previous study (unpublished data) showed that there was a high frequency distribution in rs3733609 C/T genotype at Ten-Eleven Translocation 2 (TET2) locus in one Chinese familial primary myelofibrosis. In the present study, we evaluate the role and clinical significance of rs3733609 C/T genotype in JAK2V617F-positive sporadic MPN (n = 181). TET2 rs3733609 C/T genotype had a higher incidence (13.81%; 25/181) in JAK2V617F-positive sporadic MPN patients than that in normal controls (n = 236) (6.35%; 15/236), which was predisposing to MPN (odds ratio(OR) = 2.361; P = 0.01). MPN patients with rs3733609 C/T genotype had increased leukocyte and platelets counts, elevated hemoglobin concentration in comparison with T/T genotype. Thrombotic events were more common in MPN patients with rs3733609 C/T than those with T/T genotype (P < 0.01). We confirmed that rs3733609 C/T genotype downregulated TET2 mRNA transcription, and the mechanism may be involved in a disruption of the interaction between CCAAT/enhancer binding protein alpha (C/EBPA) and TET2 rs3733609 C/T locus.TET2 rs3733609 C/T genotype stimulated the erythroid hematopoiesis in MPN patients. Altogether, we found a novel hereditary susceptible factor-TET2 rs3733609 C/T variant for the development of MPN, suggesting the variant may be partially responsible for the pathogenesis and accumulation of MPN.

(-)-Epigallocatechin-3-gallate induces cell apoptosis in chronic myeloid leukemia by regulating Bcr/Abl-mediated p38-MAPK/JNK and JAK2/STAT3/AKT signaling pathways

Epigallocatechin‐3‐gallate (EGCG), a major polyphenolic constituent of green tea, possesses remarkable chemopreventive and therapeutic potential against various types of cancer, including leukaemia. However, the molecular mechanism involved in chronic myeloid leukaemia (CML), especially imatinib‐resistant CML cells, is not completely understood. In the present study, we investigated the effect of EGCG on the growth of Bcr/Abl+ CML cell lines, including imatinib‐resistant cell lines and primary CML cells. The results revealed that EGCG could inhibit cell growth and induce apoptosis in CML cells. The mechanisms involved inhibition of the Bcr/Abl oncoprotein and regulation of its downstream p38‐MAPK/JNK and JAK2/STAT3/AKT pathways. In conclusion, we documented the anti‐CML effects of EGCG in imatinib‐sensitive and imatinib‐resistant Bcr/Abl+ cells, especially T315I‐mutated cells.

A gain-of-function mutation in TNFRSF13B is a candidate for predisposition to familial or sporadic immune thrombocytopenia

Essentials Positive family histories suggest the existence of hereditary immune thrombocytopenia (ITP). The predisposing gene for familial ITP was screened in two familial ITP patients. The G76S mutation on TNFRSF13B led to immune dysfunction and induced megakaryocyte apoptosis. The G76S mutation on TNFRSF13B is a gain‐of‐function mutation and a predisposing variant for ITP.