Decreasing circ_0014614 promotes the differentiation of bone marrow flineage cells into megakaryocytes in essential thrombocythemia via activiation of miR-138-5p/caspase3 axis.

BACKGROUND: Circular RNAs (circRNA) are pivotal in hematological diseases. Previous study showed that circ_0014614 (circDAP3) was significantly underexpressed in bone marrow-derived exosomes from essential thrombocythemia (ET) patients, affecting the differentiation of bone marrow lineage cells into megakaryocytes. METHODS: Fluorescence in situ hybridization (FISH) was used to display circ_0014614's primary cytoplasmic location in K562 cells. Cytoscape software was used to predict the circRNA-miRNA-mRNA networks, and their expression at the cellular level was detected by Quantitative reverse transcription-polymerase chain reaction (qRT-PCR). qRT-PCR was utilized to detect the expression levels of circ_0014614，miR-138-5p and caspase3 mRNA. Western blot was used to determine the protein levels of GATA-1, RUNX-1, NF-E2, CD41 and caspase3. The proliferation of K562 cells was assessed using the Cell Counting Kit-8 (CCK-8) Assay. Furthermore, the interplay between miR-138-5p and circ_0014614 or caspase3 was elucidated through a Dual-luciferase reporter assay. RESULTS: FISH assay indicated circ_0014614's primary cytoplasmic location in K562 cells. In ET bone marrow and K562 cells, circ_0014614 and caspase3 were down-regulated, whereas miR-138-5p saw a significant surge. Overexpressing circ_0014614 curtailed K562 cells' proliferation and differentiation. Further, circ_0014614 targeted miR-138-5p, with heightened miR-138-5p levels counteracting circ_0014614's inhibition. MiR-138-5p further targeted caspase3, and caspase3 silencing neutralized suppressed miR-138-5p's effects on K562 cell differentiation. CONCLUSION: Circ_0014614 was down-regulated in ET bone marrow and bone marrow lineage cells, and upregulating circ_0014614 can inhibit bone marrow lineage cells' proliferation and differentiation into megakaryocytes. Mechanistically, circ_0014614 functioned as ceRNA via sponging miR-138-5p and alleviated the inhibitory effect of miR-138-5p on its target caspase3, which potentially deters tumor activity in ET.

Risk factors contributing to postoperative surgical site infections in patients undergoing ankle fracture fixation: A systematic review and meta-analysis.

Surgical site infections (SSIs) following ankle fracture fixation pose significant challenges in patient recovery and healthcare management. Identifying risk factors contributing to SSIs can aid in developing targeted prevention and treatment strategies. This systematic review and meta-analysis were conducted according to the PRISMA guidelines and the PICO framework. A comprehensive literature search across major databases, including PubMed, Embase, Web of Science and the Cochrane Library, was completed on September 26, 2023. The inclusion criteria encompassed peer-reviewed studies of various designs that investigated risk factors for SSIs post-ankle fracture fixation. Quality assessment was performed using the Newcastle-Ottawa Scale. Statistical analyses assessed heterogeneity and calculated combined effect sizes using fixed- or random-effects models, depending on the heterogeneity observed. The initial search yielded 1250 articles, with seven meeting the inclusion criteria after rigorous screening and full-text review. The included studies, conducted between 2006 and 2019, predominantly utilized case-control designs. The meta-analysis identified diabetes, open fractures, smoking, age, alcohol consumption, ASA score ≥3, high BMI, contaminated incisions, fracture dislocation and heart disease as significant risk factors for postoperative SSIs. Publication bias assessment showed no significant bias across studies. The identification of key risk factors such as diabetes, open fractures, smoking, advanced age, alcohol consumption, high ASA score, elevated BMI, contaminated incisions, fracture dislocation and heart disease is essential in managing SSIs post-ankle fracture fixation. Targeted interventions addressing these risk factors are crucial to reduce the incidence of SSIs and improve overall patient outcomes.

Autophagy activation mediates resistance to FLT3 inhibitors in acute myeloid leukemia with FLT3-ITD mutation.

BACKGROUND: Autophagy plays a critical role in drug resistance in acute myeloid leukemia (AML), including the subtype with FLT3-ITD mutation. Yet how autophagy is activated and mediates resistance to FLT3 inhibitors in FLT3-ITD-positive AML remains unsure. METHODS: We detected the expression of autophagy markers in FLT3-ITD-positive leukemic cells after vs. before acquired resistance to FLT3 inhibitors; tested the stimulative effect of acquired D835Y mutation and bone marrow micro-environment (BME) on autophagy; explored the mechanism of autophagy mediating FLT3 inhibitor resistance. RESULTS: Sorafenib-resistant cells markedly overpresented autophagy markers in comparison with sorafenib-sensitive cells or the cells before sorafenib treatment. Both acquired D835Y mutation and BME activated cytoprotective autophagy to mediate FLT3 inhibitor resistance. Autophagy activation decreased the suppression efficacy of FLT3 inhibitors on FLT3 downstream signaling and then weakened their anti-leukemia effect. Inhibition of autophagy with CQ significantly enhanced the suppressive effect of FLT3 inhibitor on FLT3 downstream signaling, in the end overcame resistance to FLT3 inhibitors. CONCLUSIONS: Autophagy might be stimulated by acquired mutation or BME, and bypass activate FLT3 downstream signaling to mediate FLT3 inhibitor resistance in FLT3-ITD-positive AML. Targeting autophagy could be a promising strategy to overcome resistance.

Inhibition of EZH2 by chidamide exerts antileukemia activity and increases chemosensitivity through Smo/Gli-1 pathway in acute myeloid leukemia.

BACKGROUND: Epigenetic dysregulation plays important roles in leukemogenesis and the progression of acute myeloid leukemia (AML). Histone acetyltransferases (HATs) and histone deacetylases (HDACs) reciprocally regulate the acetylation and deacetylation of nuclear histones. Aberrant activation of HDACs results in uncontrolled proliferation and blockade of differentiation, and HDAC inhibition has been investigated as epigenetic therapeutic strategy against AML. METHODS: Cell growth was assessed with CCK-8 assay, and apoptosis was evaluated by flow cytometry in AML cell lines and CD45 + and CD34 + CD38- cells from patient samples after staining with Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI). EZH2 was silenced with short hairpin RNA (shRNA) or overexpressed by lentiviral transfection. Changes in signaling pathways were detected by western blotting. The effect of chidamide or EZH2-specific shRNA (shEZH2) in combination with adriamycin was studied in vivo in leukemia-bearing nude mouse models. RESULTS: In this study, we investigated the antileukemia effects of HDAC inhibitor chidamide and its combinatorial activity with cytotoxic agent adriamycin in AML cells. We demonstrated that chidamide suppressed the levels of EZH2, H3K27me3 and DNMT3A, exerted potential antileukemia activity and increased the sensitivity to adriamycin through disruption of Smo/Gli-1 pathway and downstream signaling target p-AKT in AML cells and stem/progenitor cells. In addition to decreasing the levels of H3K27me3 and DNMT3A, inhibition of EZH2 either pharmacologically by chidamide or genetically by shEZH2 suppressed the activity of Smo/Gli-1 pathway and increased the antileukemia activity of adriamycin against AML in vitro and in vivo. CONCLUSIONS: Inhibition of EZH2 by chidamide has antileukemia activity and increases the chemosensitivity to adriamycin through Smo/Gli-1 pathway in AML cells (Fig. 5). These findings support the rational combination of HDAC inhibitors and chemotherapy for the treatment of AML.

Effect of sorafenib on the outcomes of patients with FLT3-ITD acute myeloid leukemia undergoing allogeneic hematopoietic stem cell transplantation.

BACKGROUND: The objective of this study was to evaluate the effect of sorafenib on the outcomes of patients with acute myeloid leukemia (AML) with FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: A total of 144 patients with FLT3-ITD AML undergoing allo-HSCT between January 2012 and December 2015 were enrolled in this study. Depending on whether they were receiving sorafenib before transplantation or sorafenib maintenance after transplantation, patients were divided into 4 groups: patients receiving sorafenib before transplantation (group A; n = 36), patients receiving sorafenib after transplantation (group B; n = 32), patients receiving sorafenib both before and after transplantation (group C; n = 26), and patients receiving sorafenib neither before nor after transplantation (group D; n = 50). Outcomes were compared among these groups. RESULTS: The 3-year relapse rates were 22.2%, 18.8%, 15.8%, and 46.1% for groups A, B, C, and D, respectively (P = .006). The 3-year overall survival (OS) rates were 74.9%, 78.1%, 84.6%, and 50.9%, respectively (P = .023), and the 3-year leukemia-free survival (LFS) rates were 69.4%, 78.1%, 80.4%, and 34.8%, respectively (P < .001). The relapse rate was higher and the LFS was shorter in group D versus groups A, B, and C. The OS in group D was shorter than the OS in group C but was similar to the OS in groups A and B. A multivariate analysis revealed that sorafenib before transplantation, sorafenib maintenance after transplantation, and their combined application were protective factors for a lower relapse rate (hazard ratios [HRs], 0.436 [P = .048], 0.431 [P = .046], and 0.173 [P = .002], respectively) and longer LFS (HRs, 0.322 [P = .010], 0.343 [P = .014], and 0.187 [P = .001], respectively). CONCLUSIONS: Sorafenib before transplantation, sorafenib maintenance after transplantation, and their combined application all could improve the outcomes for patients with FLT3-ITD AML. Further study is needed to determine whether the use of sorafenib both before and after transplantation might be ideal. Cancer 2018;124:1954-63. © 2018 American Cancer Society.

Higher EZH2 expression is associated with extramedullary infiltration in acute myeloid leukemia.

Accumulating evidence indicates that enhancer of zeste homolog 2 (EZH2) promotes the metastatic ability of solid tumors, but the role of EZH2 in extramedullary infiltration (EMI) in acute myeloid leukemia (AML) has not been thoroughly explored. In the present study, we investigated the possible association between EZH2 and EMI. We found that the messenger RNA (mRNA) and protein expression levels of EZH2 in AML patients were both significantly higher than in idiopathic thrombocytopenic purpura (ITP) patients. Furthermore, a positive correlation between EZH2 mRNA expression and percentage of peripheral blood blasts wa s found in AML patients (r = 0.404, p = 0.009). The migratory capacities of Kasumi-1 and HL-60, which both show a high level of EZH2 expression, were markedly higher than those of U937 and KG-1α. In contrast, silencing of EZH2 resulted in reduction in proliferation and migration ability and an increase in apoptosis. The latter observation was accompanied by reduced expression of associated proteins p-ERK, p-cmyc, and matrix metalloproteinase 2 (MMP-2) and an increase in epithelial cadherin (E-cadherin). These data suggest that higher expression of EZH2 may be associated with extramedullary infiltration in acute myeloid leukemia and affect pathogenesis via activation of the p-ERK/p-cmyc/MMP-2 and E-cadherin signaling pathways.

Wilms' tumor 1 expression combined with genetic mutations for prognostic assessment in MDS.

Overexpression of Wilms' tumor (WT1) is frequently observed in myelodysplastic syndrome (MDS), which has been proposed as a prognostic marker. However, the prognostic role of WT1 expression in different contexts remains to be fully elucidated. We retrospectively assessed the relationships between WT1 levels and preexisting prognostic factors to further investigate its prognostic role under different contexts. In our study, WT1 expression was positively correlated with WHO 2016 classification and IPSS-R stratification. Lower WT1 expression was found in relation to TET2, TP53, CD101, or SRSF2 mutations, while mutant NPM1 patients possessed higher level. Notably, WT1 overexpression maintained its inferior prognostic effect on overall survival (OS) in TP53-wild patients but not in TP53-mutated group. In multivariate analysis, higher WT1 expression was a risk factors for OS in EB patients without TP53 mutations. Overall, WT1 expression was useful to predict prognosis for MDS and its prognostic role was impacted by some gene mutations.

Identifying prognostic biomarker related to immune infiltration in acute myeloid leukemia.

The immune cells of tumor microenvironment (TME) constitute a vital element of the tumor tissue. There is increasing evidence for their clinical significance in predicting prognosis and therapeutic outcomes. However, the TME immune cell infiltrating pattern of the bone marrow in acute myeloid leukemia (AML) patients remains unclear. Here, RNA-sequencing results of AML patients from TCGA database were used to quantify the abundance of 28 types of immune cells in the TME using the single-sample gene set enrichment analysis algorithm. We comprehensively evaluated the immune infiltration status in the TCGA-LAML cohort and defined two immunophenotypes: the immune hot and immune cold subtypes. Additionally, we constructed a TME score reflecting the immune infiltrating pattern of the patients using Cox regression algorithm. Subtypes with high TME score were characterized by over-activation of immune inflammation-related pathways, release of inflammatory factors, T-cell dysfunction, and poor prognosis. Subtypes with a low TME score were characterized by relatively low immune infiltration and immune exclusion. Our analysis indicated that patients in the low TME score group were more sensitive to chemotherapeutic drugs, and those in high TME score were more likely to respond to immunotherapy. Our study provides a new direction to evaluate anti-tumor therapy from immune infiltration of the TME, and the individualized scoring system in this study has important clinical significance in identifying patients who respond to immunotherapy.

[Effects of hOCT1 and ABCB1 gene on the efficacy of imatinib mesylate in chronic myelocytic leukemia].

OBJECTIVE: To detect the expression of hOCT1 and ABCB1 in marrow cells and examine the efficacy of imatinib mesylate (IM) in patients with chronic myelocytic leukemia (CML). METHODS: hOCT1 and ABCB1 gene in 90 samples with chronic phase CML diagnosed at our hospital from January 2008 and June 2011 were detected by taqman probe real-time reverse transcription-PCR (RT-PCR). The samples were divided into 3 groups: drug-resistant group (n = 17), partial cytological remission (PCyR) group (n = 11) and complete cytogenetic remission (CCR) group (n = 62) according to IM efficacy and 3 - 6, 7 - 12, 13 - 24, 25 - 48, > 48 months five groups (n = 21, 8, 15, 29, 17) according to IM treatment course. The relationship was explored between two genes and different disease states, course of treatment and time from first CCR. RESULTS: The hOCT1 gene mRNA expression of CCR group (-3.77 ± 0.55) was higher than drug-resistant group (-4.12 ± 0.47) and PCyR group (-4.24 ± 0.35) (P = 0.047, 0.019). The ABCB1 gene mRNA expression of drug-resistant group (-2.93 ± 0.49) was higher than CCR group (-3.02 ± 0.56) and PCyR group (-3.51 ± 0.45) (P = 0.045, 0.021). The hOCT1 and ABCB1 mRNA expressions showed no significant difference between five groups divided by IM treatment course (P = 0.270, 0.367). The median follow-up time was 30 (3 - 117) months. In same IM treatment course patients, the CCR rates in hOCT1 and ABCB1 low-expression groups were higher than that in high-expression groups separately (P = 0.006, 0.049). CONCLUSIONS: The expression levels of hOCT1 and ABCB1 vary in different disease states of patients on IM. And these two genes may influence the time from first CCR. But there is no significant relationship with course of the treatment.

hnRNPK/Beclin1 signaling regulates autophagy to promote imatinib resistance in Philadelphia chromosome-positive acute lymphoblastic leukemia cells.

This study sought to clarify the role of heterogeneous nuclear ribonucleoprotein K (hnRNPK) as a regulator of imatinib resistance in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Expression of hnRNPK was assessed in Ph+ ALL leukemia cells in vitro and in vivo, and imatinib susceptibility was assessed via CCK-8 assay. In cells in which hnRNPK levels had or had not been modulated, LC3Ⅰ/Ⅱ and mTOR/p-ERK/Beclin1 levels were assessed via Western blotting, while electron microscopy was used to evaluate autophagic vacuole formation. Interactions between hnRNPK and Beclin1 were assessed through an RNA binding protein immunoprecipitation assay. Imatinib-resistant Ph+ ALL cell lines and patient bone marrow samples exhibited significant hnRNPK overexpression. Knockdown of hnRNPK increased the imatinib sensitivity of these tumor cells and decreased in vivo tumor burden in a xenograft model system as evidenced by a reduction in tumor volume. Levels of LC3Ⅰ/Ⅱ and Beclin1, but not p-ERK and mTOR, were consistent with the regulatory activity of hnRNPK. Electron microscopy revealed that imatinib-resistant cells harbored significantly more autophagic vacuoles relative to wild-type cells, while hnRNPK knockdown reduced the number of these vacuoles. In an RNA-binding protein immunoprecipitation assay, anti-hnRNPK was able to precipitate the Beclin1 mRNA. These results suggest that the hnRNPK/Beclin1 signaling pathway may play a role in shaping imatinib resistance in Ph+ ALL cells.

Single-cell RNA sequencing to explore composition of peripheral blood NK cells in patients with chronic myeloid leukemia in treatment-free remission.

This study was to explore the role of NK cell subsets and gene expression in maintaining TFR status. We identified six types of NK cells in the PBMCs over both groups (healthy controls and patients with TFR). Gene Oncology analysis showed that up regulated genes were enriched in the categories of "immune response," "reaction to tumor cells," and "cytolysis." In addition, we found that the three NK cell subsets, mature and terminal NK cells, CD56 bright NK cells, and transitional NK cells, contained many significantly up regulated genes in both groups, and that CD56 bright NK cells and transitional NK cells in patients with CML-TFR were in a proliferating and activated state. Through single-cell RNA sequencing analysis, we confirmed that the mature and terminal, CD56 bright, and transitional subsets of NK cells play an indispensable role in maintaining TFR in patients with CML.

[Expression of Wilms' Tumor 1 Gene in Bone Marrow of Patients with Myelodysplastic Syndrome and Its Clinical Significance].

OBJECTIVE: To investigate the expression level and clinical significance of Wilms' tumor 1 (WT1) in bone marrow of patients with myelodysplastic syndromes (MDS). METHODS: The clinical data of 147 MDS patients who accepted real-time quantitative polymerase chain reaction (RT-PCR) to detect the expression level of WT1 in bone marrow before treated in Nanfang Hospital, Southern Medical University from January 2017 to April 2021 were retrospectively analyzed. According to the expression level of WT1, the patients were divided into WT1+ group and WT1- group, their clinical characteristics and prognosis were analyzed. RESULTS: The positive rate of WT1 in 147 MDS patients was 82.3%. There were significant differences in bone marrow blast count, aberrant karyotypes, WHO 2016 classification, and IPSS-R stratification between WT1+ group and WT1- group (all P<0.05). Furthermore, the higher the malignant degree of MDS subtype and the risk stratification of IPSS-R, the higher expression level of WT1. Compared with WT1- group, there were no differences in overall survival (OS) time and the time of transformation to AML in WT1+ group (both P>0.05). In patients who did not accept transplantation, the median OS time of WT1+ patients was significantly shorter than that of WT1- patients (P=0.049). Besides, regarding WT1+ group, patients who underwent transplantation had longer OS time and lower mortality than those who received hypomethylating agents (P=0.002, P=0.005). CONCLUSION: WT1 expression level directly reflects the disease progression, and it is also associated with prognosis of MDS patients.

De-escalation or discontinuation of tyrosine kinase inhibitor in patients with chronic myeloid leukemia: A multicentral, open-label, prospective trial in China.

Background: Long-term treatment-free remission (TFR) represents a new goal for chronic myeloid leukemia (CML). Optimizing dose of tyrosine kinase inhibitors (TKIs) in the CML treatment maybe a new challenge to maintain effective and improving patients' quality of life. We hypothesized that administration of low-dose TKIs does not compromise major molecular response (MMR) in patients with CML who have a deep molecular response (DMR). Methods: We did an open-label, randomized trial at eight hospitals in China. Eligible CML-CP patients (aged 18-70 years) had shown continuous response to TKI more than 5 years and maintained MR4.5 (BCR-ABLIS ≤ 0.0032%) in recent 18 months. Patients were randomly assigned (1:1) to the TKI de-escalation group or the discontinuation group. Randomization was done with permuted blocks (block size four) and implemented through an interactive web-based randomization system. Recurrence was defined as the single sample with real time Quantitative PCR (RT-qPCR) measurement greater than 0.1% (MMR). The primary endpoint was 12-month MMR rate in patients who received de-escalation or discontinuation of TKIs. This study was registered at ClinicalTrials.gov (NCT04143087). Results: Around 125 patients were enrolled between October 23, 2019 and October 31, 2020, 62 patients received dose de-escalation of TKIs, while 63 patients in the discontinuation group. In the de-escalation group, molecular recurrence-free survival at 12 months was 88.32% (95% CI 79%-98%), whereas molecular recurrence-free survival in the discontinuation group at 12 months was 59.98% (95% CI 47-73). No progressions occurred at the data cut-off date. All 29 recurrence cases restart TKI treatment returned to MMR. Cytolytic NK cells as a proportion of lymphocyte cells were significantly increased from baseline after 6 months whether in the de-escalation or TKIs cessation group (P = 0.048, 0.001, respectively); compared with the relapsing patients, Tregs proportion was decreased (P = 0.003), and higher proportion of NK cells were found in non-relapsing patients whether in TKI de-escalation or discontinuation group (P = 0.011, 0.007, respectively). We also found that the de-escalation group showed better disease-specific HRQOL in regards to its impact on emotional functioning, fatigue, pain, and financial difficulties. Conclusion: With 88.32% MMR in 12-months follow-up after de-escalation TKIs' treatment, dose-halving could become a new treatment paradigm for CML patients who with DMR under continuing maintenance therapy with TKIs.

miR-362-5p promotes cell proliferation and cell cycle progression by targeting GAS7 in acute myeloid leukemia.

Recently, miR-362-5p has attracted special interest as a novel prognostic predictor in acute myeloid leukemia (AML). However, its biological function and underlying molecular mechanism in AML remain to be further defined. Herein, we found that a significant increase in miR-362-5p expression was observed in AML patients and cell lines using quantitative real-time PCR. The expression of miR-362-5p was altered in THP-1 and HL-60 cells by transfecting with miR-362-5p mimic or inhibitor. A series of experiments showed that inhibition of miR-362-5p expression significantly suppressed cell proliferation, induced G0/G1 phase arrest and attenuated tumor growth in vivo. On the contrary, ectopic expression of miR-362-5p resulted in enhanced cell proliferation, cell cycle progression and tumor growth. Moreover, growth arrest-specific 7 (GAS7) was confirmed as a direct target gene of miR-362-5p and was negatively modulated by miR-362-5p. GAS7 overexpression imitated the tumor suppressive effect of silenced miR-362-5p on THP-1 cells. Furthermore, miR-362-5p knockdown or GAS7 overexpression obviously down-regulated the expression levels of PCNA, CDK4 and cyclin D1, but up-regulated p21 expression. Collectively, our findings demonstrate that miR-362-5p exerts oncogenic effects in AML by directly targeting GAS7, which might provide a promising therapeutic target for AML.

Integrative Genomic Analysis Reveals Cancer-Associated Gene Mutations in Chronic Myeloid Leukemia Patients with Resistance or Intolerance to Tyrosine Kinase Inhibitor.

INTRODUCTION: While the acquisition of mutations in the ABL1 kinase domain (KD) has been identified as a common mechanism behind tyrosine kinase inhibitor (TKI) resistance, recent genetic studies have revealed that patients with TKI resistance or intolerance frequently harbor one or more genetic alterations implicated in myeloid malignancies. This suggests that additional mutations other than ABL1 KD mutations might contribute to disease progression. METHODS: We performed targeted-capture sequencing of 127 known and putative cancer-related genes of 63 patients with CML using next-generation sequencing (NGS), including 42 patients with TKI resistance and 21 with TKI intolerance. RESULTS: The differences in the number of mutations between groups had no statistical significance. This could be explained in part by not all of the patients having achieved major molecular remission in the early period as expected. Overall, 66 mutations were identified in 96.8% of the patients, most frequently in the KTM2C (31.82%), ABL1 (31.82%), FAT1 (25.76%), and ASXL1 (22.73%) genes. CUX1, KIT, and GATA2 were associated with TKI intolerance, and two of them (CUX1, GATA2) are transcription factors in which mutations were identified in 82.61% of patients with TKI intolerance. ASXL1 mutations were found more frequently in patients with ABL1 KD mutations (38.1% vs 15.21%, P=0.041). Although the number of mutations was low, pairwise interaction between mutated genes showed that ABL1 KD mutations cooccurred with SH2B3 mutations (P<0.05). In Kaplan-Meier analyses, only TET2 mutations were associated with shorter progression-free survival (P=0.026). CONCLUSION: Our data suggested that the CUX1, KIT, and GATA2 genes may play important roles in TKI intolerance. ASXL1 and TET2 mutations may be associated with poor patient prognosis. NGS helps improving the clinical risk stratification, which enables the identification of patients with TKI resistance or intolerance in the era of TKI therapy.

Impact of FLT3-ITD allele ratio and ITD length on therapeutic outcome in cytogenetically normal AML patients without NPM1 mutation.

Mutations of internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD) contribute to poor prognosis in cytogenetically normal acute myeloid leukemia (CN-AML). Chemotherapy has limited effect, while allogeneic hematopoietic stem cell transplantation (allo-HSCT) plus sorafenib maintenance is a promising protocol to improve their therapeutic outcome. However, the prognostic significance of FLT3-ITD mutant status remains controversial. To investigate this, we detected FLT3-ITD mutant ratio (high and low) and length (long and short) in enrolled 184 CN-AML patients without NPM1 mutation, and evaluated their impact on complete remission (CR), overall survival (OS), relapse-free survival (RFS) and relapse risk (RR) after chemotherapy or allo-HSCT plus sorafenib maintenance. Our studies showed that FLT3-ITD mutation had negative impact on chemotherapeutic response, OS and RFS in CN-AML patients. There was no significant difference in CR rate between high and low ratio, or long and short length. Increasing ITD mutant ratio and length were associated with decreasing OS, and long length had shorter RFS and higher RR than the short after chemotherapy. Allo-HSCT plus sorafenib maintenance was an effective strategy to improve RFS and decrease relapse probability in FLT3-ITD AML patients, and benefited to these regardless of mutant ratio, and those with long length instead of the short.

Generation of an external guide sequence library for a reverse genetic screen in Caenorhabditis elegans.

BACKGROUND: A method for inhibiting the expression of particular genes using external guide sequences (EGSs) has been developed in bacteria, mammalian cells and maize cells. RESULTS: To examine whether EGS technology can be used to down-regulate gene expression in Caenorhabditis elegans (C. elegans), we generated EGS-Ngfp-lacZ and EGS-Mtgfp that are targeted against Ngfp-lacZ and Mtgfp mRNA, respectively. These EGSs were introduced, both separately and together, into the C. elegans strain PD4251, which contains Ngfp-lacZ and Mtgfp. Consequently, the expression levels of Ngfp-lacZ and Mtgfp were affected by EGS-Ngfp-lacZ and EGS-Mtgfp, respectively. We further generated an EGS library that contains a randomized antisense domain of tRNA-derived EGS ("3/4 EGS"). Examination of the composition of the EGS library showed that there was no obvious bias in the cloning of certain EGSs. A subset of EGSs was randomly chosen for screening in the C. elegans strain N2. About 6% of these EGSs induced abnormal phenotypes such as P0 slow postembryonic growth, P0 larval arrest, P0 larval lethality and P0 sterility. Of these, EGS-35 and EGS-83 caused the greatest phenotype changes, and their target mRNAs were identified as ZK858.7 mRNA and Lin-13 mRNA, respectively. CONCLUSION: EGS technology can be used to down-regulate gene expression in C. elegans. The EGS library is a research tool for reverse genetic screening in C. elegans. These observations are potentially of great importance to further our understanding and use of C. elegans genomics.

MicroRNA-144 targets APP to regulate AML1/ETO+ leukemia cell migration via the p-ERK/c-Myc/MMP-2 pathway.

Extramedullary infiltration (EMI) is common in patients with acute myeloid leukemia (AML) and is closely associated with the prognosis of disease. We previously reported that patients carrying the AML1/ETO (A/E) fusion gene and expressing the amyloid precursor protein (APP) tended to develop EMI, and had a poor prognosis. In the present study, the relapse-free survival (RFS) time and overall survival (OS) time were significantly lower in patients with EMI. The results demonstrated that the EMI incidence was significantly higher (P<0.05), while the RFS and OS rates were significantly lower (P<0.05), in patients with high APP expression. Kasumi-1 cells, which are A/E+, and the APP gene were used as the in vitro cell model to detect the mechanism of action in detail. Following the knockdown of APP expression, cell migration was significantly reduced (P<0.05). Furthermore, western blotting demonstrated that the protein expression of phosphorylated extracellular-signal-regulated kinase (p-ERK), matrix metalloproteinase-2 (MMP-2) and c-Myc was markedly reduced following interference of APP, while the expression of CXCR4 and MMP-9 was not altered. Kasumi-1 cells were co-cultured with p-ERK or c-Myc inhibitors and demonstrated that the APP/p-ERK/c-Myc/MMP-2 pathway was involved in signal transduction and regulation of cell migration. MicroRNA-144 (miR-144) mimics and transfected Kasumi-1 cells were generated. Reverse transcription-quantitative polymerase chain reaction and western blotting demonstrated that miR-144 was a negative regulator of APP. Taken together, the findings of the present study suggest that miR-144 negatively targets the APP gene and regulates cell migration via the APP/p-ERK/c-Myc/MMP-2 pathway.

Gene mutation profile and risk stratification in AML1­ETO­positive acute myeloid leukemia based on next­generation sequencing.

Gene mutations play an important role in the development and progression of AML1­ETO­positive acute myeloid leukemia (AE­AML). Nevertheless, the gene mutation profile in this subtype of leukemia remains unclear. In addition, the clinical and prognostic effects of different mutant genes may be underestimated. In the present study, gene sequencing was conducted at diagnosis and relapse with next­generation sequencing (NGS) in 64 patients with newly diagnosed AE­AML, and 44/64 (68.8%) patients were found to present with a median of 2 (1­10) recurrent mutations at diagnosis and 6/11 (54.5%) cases were found to present with genetic alterations at relapse. c­KIT mutation was the most common in this cohort, with an incidence of 27/64 (42.2%) at diagnosis, followed by ASXL1 (n=10, 15.6%), MET (n=8, 12.5%), MLH1 (n=6, 9.4%), TET2 (n=5, 7.8%), and FBXW7, TP53 and DNMT3A (n=5, 7.8%). Survival analysis showed that c­KIT (exon 8, 17) but not exon 10 adversely affected survival. In addition, ASXL1 and TP53 were poor impact factors for recurrence­free survival (RFS) (P<0.05), and ASXL1, MET, FBXW7 and TP53 had a negative impact on overall survival (OS) (P<0.05). Multivariate analysis showed that c­KIT (exon 8, 17) [RFS: hazard ratio (HR) 3.36, 95% confidence interval (CI) 1.54­7.34, P=0.002; OS: HR 2.84, 95% CI 1.20­6.71, P=0.018] and ASXL1 mutations (RFS: HR 3.13, 95% CI 1.34­7.32, P=0.009; OS: HR 3.94, 95% CI 1.62­9.61, P=0.003) were independent adverse factors for survival. Further, co­mutation of these two genes showed even worse effect on disease outcome. Collectively, additional gene mutations play critical role in AE­AML. C­KIT and ASXL1 mutations are the two most common mutations in this subtype of leukemia. C­KIT (exon 8, 17) but not exon 10, and also the ASXL1 mutation poorly affect the disease outcome of this disease.