Clinical and microbiological features of a cohort of patients with Acinetobacter baumannii bloodstream infections.

PURPOSE: Acinetobacter baumannii is emerging as a pathogen that is a focus of global concern due to the frequent occurrence of the strains those are extensively resistant to antibiotics. This study was aimed to analyze the clinical and microbiological characteristics of a cohort of patients with A. baumannii bloodstream infections (BSIs) in western China. METHODS: A retrospective study of the patients at West China Hospital of Sichuan University with A. baumannii BSIs between Jan, 2018 and May, 2023 was conducted. Antimicrobial susceptibility of A. baumannii isolates was tested by microdilution broth method. Whole-genome sequencing and genetic analysis were also performed for these isolates. RESULTS: Among the 117 patients included, longer intensive care unit stay, higher mortality, and more frequent invasive procedures and use of more than 3 classes of antibiotics were observed among the carbapenem-resistant A. baumannii (CRAB)-infected group (n = 76), compared to the carbapenem-susceptible A. baumannii (CSAB)-infected group (n = 41, all P ≤ 0.001). Twenty-four sequence types (STs) were determined for the 117 isolates, and 98.7% (75/76) of CRAB were identified as ST2. Compared to non-ST2 isolates, ST2 isolates exhibited higher antibiotic resistance, and carried more resistance and virulence genes (P < 0.05). In addition, 80 (68.4%) isolates were CRISPR-positive, showed higher antibiotic susceptibility, and harbored less resistance and virulence genes, in comparison to CRISPR-negative ones (P < 0.05). Phylogenetic clustering based on coregenome SNPs indicated a sporadic occurrence of clonal transmission. CONCLUSION: Our findings demonstrate a high frequency of ST2 among A. baumannii causing BSIs, and high antibiotic susceptibility of non-ST2 and CRISPR-positive isolates. It is necessary to strengthen the surveillance of this pathogen.

scRNA-Seq and Bulk-Seq Analysis Identifies S100A9 Plasma Cells as a Potentially Effective Immunotherapeutic Agent for Multiple Myeloma.

Purpose: Immunological regimens are an important area of research for treating multiple myeloma (MM). Plasma cells play a crucial role in immunotherapy. Patients and Methods: In our study, we used both single-cell RNA sequencing (scRNA-seq) and bulk sequencing techniques to analyze MM patients. We analyzed each sample using gene set variation analysis (GSVA) based on immune-related gene sets. We also conducted further analyses to compare immune infiltration, clinical characteristics, and expression of immune checkpoint molecules between the H-S100A9 and L-S100A9 groups of MM patients. Results: We identified eight subpopulations of plasma cells, with S100A9 plasma cells being more abundant in patients with 1q21 gain and 1q21 diploid. CellChat analysis revealed that GAS and HGF signaling pathways were prominent in intercellular communication of S100A9 plasma cells. We identified 14 immune-related genes in the S100A9 plasma cell population, which allowed us to classify patients into the H-S100A9 group or the L-S100A9 group. The H-S100A9 group showed higher ESTIMATE, immune and stroma scores, lower tumor purity, and greater immune checkpoint expression. Patients with 1q21 gain and four or more copies had the lowest ESTIMATE score, immune score, stroma score, and highest tumor purity. Drug sensitivity analysis indicated that the H-S100A9 group had lower IC50 values and greater drug sensitivity compared to the L-S100A9 group. Quantitative reverse transcription (RT-q) PCR showed significantly elevated expression of RNASE6, LYZ, S100A8, S100A9, and S100A12 in MM patients compared to the healthy control group. Conclusion: Our study has identified a correlation between molecular subtypes of S100A9 plasma cells and the response to immunotherapy in MM patients. These findings improve our understanding of tumor immunology and provide guidance for developing effective immunotherapy strategies for this patient population.

Additional Impact of Aortic Regurgitation on Left Ventricular Strain and Remodeling in Essential Hypertension Patients Evaluated Using MRI.

BACKGROUND: Understanding the impact of aortic regurgitation (AR) on hypertensive patients' hearts is important. PURPOSE: To assess left ventricular (LV) strain and structure in hypertensive patients and investigate the relationship with AR severity. STUDY TYPE: Retrospective. POPULATION: 263 hypertensive patients (99 with AR) and 62 controls, with cardiac MRI data. FIELD STRENGTH/SEQUENCE: Balanced steady-state free precession (bSSFP) sequence at 3.0T. ASSESSMENT: AR was classified as mild, moderate, or severe based on echocardiographic findings. LV geometry was classified as normal, concentric remodeling, eccentric hypertrophy, or concentric hypertrophy based on MRI assessment of LV mass/volume ratio and LV Mass index (LVMI). LV global radial peak strain (GRPS), global circumferential peak strain (GCPS), and global longitudinal peak strain (GLPS) were obtained by post-processing bSSFP cine datasets using commercial software. STATISTICAL TESTS: ANOVA, Kruskal-Wallis test, Spearman's correlation coefficients (r), chi-square test, and multivariable linear regression analysis. A P value <0.05 was considered statistically significant. RESULTS: Hypertensive patients with AR had significantly lower LV myocardial strain and higher LVMI than the group without AR (GRPS 26.25 ± 12.23 vs. 34.53 ± 9.85, GCPS -17.4 ± 5.84 vs. -20.57 ± 3.57, GLPS -9.86 ± 4.08 vs. -12.95 ± 2.94, LVMI 90.56 ± 38.56 vs.58.84 ± 17.55). Of the 99 patients with AR, 56 had mild AR, 26 had moderate AR and 17 had severe AR. The degree of AR was significantly negatively correlated to the absolute values of LV GRPS, GCPS and GLPS (r = -0.284 - -0.416). LV eccentric hypertrophy increased significantly with AR severity (no AR 21.3%, mild AR 42.9%, moderate AR 73.1%, severe AR 82.4%). In multivariable analysis, the degree of AR was an independent factor affecting LV global strain and LVMI even after considering confounding factors (ß values for global myocardial strain were -0.431 to -0.484, for LVMI was 0.646). DATA CONCLUSION: Increasing AR severity leads to decreased cardiac function and worse ventricular geometric phenotypes in hypertensive patients. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 3.

The selective activator protein-1 inhibitor T-5224 regulates the IRF4/MYC axis and exerts cooperative antimyeloma activity with bortezomib.

The activating protein-1 (AP-1) transcription factors (TFs) have been associated with many different cancer types and are promising therapeutic targets in logical malignancies. However, the mechanisms of their role in multiple myeloma (MM) remain elusive. The present study determined and compared the mRNA and protein expression levels of the AP-1 family member JunB in CD138+ mononuclear cells from MM patients and healthy donors. Herein, we investigated the effect of T-5224, an inhibitor of JUN/AP-1, on MM. We found that the cytotoxicity of T-5224 toward myeloma is due to its ability to induce cell apoptosis, inhibit proliferation, and induce cell cycle arrest by increasing the levels of cleaved caspase3/7 and concomitantly inhibiting the IRF4/MYC axis. We also noticed that siJunB-mediated deletion of JunB/AP-1 enhanced MM cell apoptosis and affected cell proliferation. The software PROMO was used in the present study to predict the AP-1 TF that may bind the promoter region of IRF4. We confirmed the correlation between JunB/AP-1 and IRF4. Given that bortezomib (BTZ) facilitates IRF4 degradation in MM cells, we applied combination treatment of BTZ with T-5224. T-5224 and BTZ exerted synergistic effects, and T-5224 reversed the effect of BTZ on CD138+ primary resistance in MM cells, in part due to suppression of the IRF4/MYC axis. Our results suggest that targeting AP-1 TFs is a promising therapeutic strategy for MM. Additionally, targeting both AP-1 and IRF4 with T-5224 may be a synergistic therapeutic strategy for this clinically challenging subset of MM.

[Preliminary study on the regulation of acute myeloid leukemia by FLT3 gene expression].

OBJECTIVE: To assess the influence of FLT3 expression on the prognosis of patients with acute myeloid leukemia (AML) by cell experiment and clinical data analysis. METHODS: Models for FLT3 over-expression and interference-expression in AML cells were constructed. The level of BAK gene expression and its protein product was determined, along with the proliferation and apoptosis of leukemia cells. FLT3 gene expression and FLT3-ITD variant were determined among patients with newly diagnosed AML. RESULTS: Compared with the interference-expression group, the level of BAK gene expression and its protein in FLT3 over-expression AML cells was significantly lower (P < 0.001), which also showed significantly faster proliferation (P < 0.001) and lower rate of apoptosis (P < 0.001). The expression level of FLT3 gene among patients with newly diagnosed AML was also significantly higher compared with the healthy controls (P < 0.001). The FLT3 gene expression of FLT3-ITD positive AML patients was higher than that of FLT3-WT patients (P = 0.002). Survival analysis showed that AML patients with high FLT3 expression in the medium-risk group had a lower complete remission rate and overall survival rate compared with those with a low FLT3 expression (P < 0.001). CONCLUSION: Over-expression of FLT3 may influence the course of AML by promoting the proliferation of leukemia cells and inhibiting their apoptosis, which in turn may affect the prognosis of patients and serve as a negative prognostic factor for AML.

Enhancing the Cycle Performance of Lithium-Sulfur Batteries by Coating the Separator with a Cation-Selective Polymer Layer.

Lithium-sulfur batteries are believed to possess the feasibility to power electric vehicles in the future ascribed to the competitive energy density. However, soluble polysulfides continuously shuttle between the sulfur electrode and lithium anode across the separator, which dramatically impairs the battery's capacity. Herein, the surface of a polypropylene separator (PP film) is successfully modified with a delicately designed cation-selective polymer layer to suppress the transport of polysulfides. In principle, since bis-sulfonimide anions groups on the backbone of the polymer are immobilized, only cations can pass through the polymer layer. Furthermore, plenty of ethoxy chains in the polymer can facilitate lithium-ion mobility. Consequently, in addition to obstructing the movement of negatively charged polysulfides by the electrostatic repulsive force of fixed anions, the coated multi-functional layer on the PP film also guarantees the smooth conduction of lithium ions. The investigations demonstrate that the battery with the pristine PP film only delivers 228.5 mAh g-1 after 300 cycles at 2 C with a high capacity fading rate of 60.9 %. By contrast, the polymer-coated sample can release 409.4 mAh g-1 under the identical test condition and the capacity fading rate sharply declines to 43.2 %, illustrating superior cycle performance.

CD38-targeted and erythrocyte membrane camouflaged nanodrug delivery system for photothermal and chemotherapy in multiple myeloma.

Multiple myeloma (MM) is a malignant and incurable disease. Chemotherapy is currently the primary treatment option for MM. However, chemotherapeutic drugs can interrupt treatment because of serious side effects. Therefore, development of novel therapeutics for MM is essential. In this study, we designed and constructed an innovative nanoparticle-based drug delivery system, P-R@Ni3P-BTZ, and investigated its feasibility, effectiveness, and safety both in vitro and in vivo. P-R@Ni3P-BTZ is a nanocomposite that consists of two parts: (1) the drug carrier (Ni3P), which integrates photothermal therapy (PTT) with chemotherapy by loading bortezomib (BTZ); and (2) the shell (P-R), a CD38 targeting peptide P-modified red blood cell membrane nanovesicles. In vitro and in vivo, it was proven that P-R@Ni3P-BTZ exhibits remarkable antitumor effects by actively targeting CD38 + MM cells. P-R@Ni3P-BTZ significantly induces the accumulation of intracellular reactive oxygen species (ROS) and increases the apoptosis of MM cells, which underlies the primary mechanism of its antitumor effects. In addition, P-R@Ni3P exhibits good biocompatibility and biosafety, both in vitro and in vivo. Overall, P-R@Ni3P-BTZ is a specific and efficient MM therapeutic method.

[Epidemiological Analysis of Carbapenem-Resistant Enterobacteriaceae Strains in the Clinical Specimens of a Hospital].

Objective: To analyze the detection rate, in vitro susceptibility to antibiotics, and carbapenemase types of carbapenem-resistant Enterobacteriaceae (CRE) strains in the clinical samples of a hospital and to provide support for the prevention, control and treatment of CRE-related infections. Methods: Clinical specimens were examined according to the operating procedures of bacteriological tests. Species identification and in vitro drug susceptibility testing were performed on the isolated strains. Carbapenemase inhibitor enhancement testing, which combined the use of 3-aminobenzeneboronic acid and ethylenediaminetetraacetic acid, was conducted to identify the types of carbapenemase in the CRE strains. Results: In 2021, 2215 CRE strains were isolated from 157196 clinical samples collected in this hospital, presenting a detection rate of 1.4% (2215/157196). A total of 1134 non-repetitive strains of CRE were isolated from 903 patients. The main sources of samples were respiratory tract (494/1134, 43.6%), secretion (191/1134, 16.8%) and blood (173/1134, 15.3%) samples. The cases with the same CRE strain isolated from the samples of two, three and four sites accounted for 12.5%, 4.9%, and 1.1%, respectively. The most common species was Klebsiella pneumoniae (883/1134, 77.9%), followed by Enterobacter cloacae complex (107/1134, 9.4%) and Escherichia coli (96/1134, 8.5%). The rates of resistance to polymyxin B and tigecycline of different species of CRE strains were not significantly different ( P<0.05). Serine carbapenemase-producing strains, metallo-ß-lactamase-producing strains, and those producing both enzymes accounted for 82.6% (809/979), 17.2% (168/979), and 0.2% (2/979), respectively. Conclusion: CRE strains are frequently isolated from samples collected from the respiratory tract, secretion, and blood. The most common strain is serine carbapenemase-producing K. pneumoniae, which has a high resistance rate to various antimicrobial drugs, and risk factors of its associated infections deserve more attention.

Incremental Effect of Mitral Regurgitation on Left Atrial Dysfunction and Atrioventricular Interaction in Hypertensive Patients by MRI.

BACKGROUND: Mitral regurgitation may occur when hypertension causes left ventricular (LV) and left atrial (LA) remodeling. However, its role in LA function in hypertensive patients remains unclear. PURPOSE: To explore how mitral regurgitation affects LA function in hypertension and to investigate atrioventricular interaction in hypertensive patients with mitral regurgitation. STUDY TYPE: Retrospective. POPULATION: A total of 193 hypertensive cases and 64 controls. FIELD STRENGTH/SEQUENCE: A 3.0 T/balanced steady-state free precession. ASSESSMENT: LA volume (LAV), LA strain (reservoir, conduit, and active), LA ejection fraction, and LV strain (global peak longitudinal [GLS], circumferential [GCS], and radial strain [GRS]) were evaluated and compared among groups. Regurgitant fraction (RF) was evaluated in regurgitation patients and used to subdivide patients into mild (RF: 0%-30%), moderate (RF: 30%-50%), and severe (RF: >50%) regurgitation categories. STATISTICAL TESTS: One-way analysis of variance, Spearman and Pearson's correlation coefficients (r), and multivariable linear regression analysis. A P value <0.05 was considered statistically significant. RESULTS: Hypertensive patients without mitral regurgitation showed significantly impaired LA reservoir and conduit functions and significantly decreased LV GLS but preserved pump function and LAV compared to controls (P = 0.193-1.0). Hypertensive cases with mild regurgitation (N = 22) had significantly enlarged LAV and further reduced LA reservoir function, while the group with moderate regurgitation (N = 20) showed significantly reduced LA pump function, further impaired conduit function, and significantly reduced LV strain. The severe regurgitation (N = 13) group demonstrated significantly more severely impaired LA and LV functions and LAV enlargement. Multivariable linear regression showed that regurgitation degree, GRS, GCS, and GLS were independently correlated with the LA reservoir, conduit, and active strain in hypertensive patients with mitral regurgitation. DATA CONCLUSION: Mitral regurgitation may exacerbate LA and LV impairment in hypertension. Regurgitation degree, LV GRS, GCS, and GLS were independent determinants of the LA strain in hypertensive patients with mitral regurgitation, which demonstrated atrioventricular interaction. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 3.

Additive effects of mitral regurgitation on left ventricular strain in essential hypertensive patients as evaluated by cardiac magnetic resonance feature tracking.

Objectives: Hypertension is one of the leading risk factors for cardiovascular disease. Mitral regurgitation (MR) is a heart valve disease commonly seen in hypertensive cases. This study aims to assess the effect of MR on left ventricle (LV) strain impairment among essential hypertensive cases and determine factors that independently impact the global peak strain of the LV. Materials and methods: We enrolled 184 essential hypertensive patients, of which 53 were patients with MR [HTN (MR +) group] and 131 were without MR [HTN (MR-) group]. Another group of 61 age-and gender-matched controls was also included in the study. All participants had received cardiac magnetic resonance examination. The HTN (MR +) group was classified into three subsets based on regurgitation fraction, comprising mild MR (n = 22), moderate MR (n = 19), and severe MR (n = 12). We compared the LV function and strain parameters across different groups. Moreover, we performed multivariate linear regression to determine the independent factors affecting LV global radial peak strain (GRS), circumferential peak strain (GCS), and global longitudinal peak strain (GLS). Results: HTN (MR-) cases exhibited markedly impaired GLS and peak diastolic strain rate (PDSR) but preserved LV ejection fraction (LVEF) compared to the controls. However, HTN (MR +) patients showed a decrease in LVEF and further deteriorated GRS, GCS, GLS, PDSR, and the peak systolic strain rate (PSSR) compared to the HTN (MR-) group and controls. With increasing degrees of regurgitation, the LV strain parameters were gradually reduced in HTN (MR +) patients. Even the mild MR group showed impaired GCS, GLS, PDSR, and PSSR compared to the HTN (MR-) group. Multiple regression analyses indicated that the degree of regurgitation was independently associated with GRS (ß = -0.348), GCS (ß = -0.339), and GLS (ß = -0.344) in HTN (MR +) patients. Conclusion: GLS was significantly impaired in HTN (MR-) patients. MR may further exacerbate the deterioration of LV strain among essential hypertensive cases. Besides, the degree of regurgitation was independently correlated with GRS, GCS, and GLS in HTN (MR +) patients.

Comparison of Silicosis and Tuberculosis Involving Mediastinal Lymph Nodes Based on Contrast-Enhanced Multidetector-Row Computed Tomography.

PURPOSE: To investigate the different imaging features of contrast-enhanced multidetector-row-computed tomography (MDCT) for distinguishing between silicosis and tuberculosis involving the mediastinal lymph nodes. METHODS: 86 silicosis patients and 61 tuberculosis patients with mediastinal lymphadenopathy based on contrast-enhanced MDCT were included. The enhanced patterns, anatomical distribution and calcification features of the enlarged lymph nodes were retrospectively compared between the groups using the Pearson chi-square test or Fisher's exact test. RESULTS: Homogeneous enhancement of the mediastinal lymph nodes was more commonly observed in silicosis (94.2%, 81/86) than in tuberculosis (19.7%, 12/61). Peripheral enhancement was more frequent in tuberculosis (n = 44, 72.1%) than in silicosis involving the mediastinal lymph nodes (n = 1, 1.2%), and multilocular appearance was more frequent in TB than in silicosis. Tuberculosis was more likely to affect regions 1R, 2R, 2L, 3A, 5 and 6 than silicosis (all p < 0.05), especially region 2R. Calcification of the lymph nodes was more common in the silicosis group than in tuberculosis group. The sensitivity, specificity, and accuracy of silicosis with lymphadenopathy with homogeneous enhanced pattern were 94.2%, 80.3% and 88.4%, respectively. The sensitivity, specificity, and accuracy of tuberculosis lymphadenopathy with peripheral enhanced pattern were 72.1%, 98.8%, and 87.7%, respectively. CONCLUSION: The predominant enhanced patterns, anatomical distribution, and calcification features of mediastinal lymph nodes were different between tuberculosis and silicosis. These radiographic features might help differentiate tuberculosis from silicosis, which provides imaging information for the differential diagnosis of the two diseases in a clinical setting.

Effect of BCLAF1 on HDAC inhibitor LMK-235-mediated apoptosis of diffuse large B cell lymphoma cells and its mechanism.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of adult lymphoma. It is a group of malignant tumors with a large number of clinical manifestations and prognoses. Therefore, it is necessary to explore its unknown potential therapeutic targets. Histone deacetylase inhibitor (HDACi) is a novel drug for the treatment of DLBCL, however pan-HDACis cannot be ignored because of their clinical efficacy. By contrast, specific HDACi is well-tolerated, and LMK-235 is a novel HDACi that is a specific inhibitor of HDAC4 and HDAC5. In this study, we investigated the up-regulation of BCLAF1 through NF-κB signaling pathways in LMK-235, mediating the apoptosis of two diffuse large B-cell lymphoma cell lines, OCI-LY10 and OCI-LY3. Further studies showed that BCLAF1 expression was increased in DLBCL cells after treatment with the NF-κB inhibitor Bay11-7082. The combination of Bay11-7082 and siRNA si-HDAC4 significantly increased BCLAF1 expression and further increased apoptosis. These results indicate that BCLAF1 plays an important role in LMK-235-mediated apoptosis and may be a potential target for the treatment of diffuse large B-cell lymphoma.

Up-regulation of HO-1 promotes resistance of B-cell acute lymphocytic leukemia cells to HDAC4/5 inhibitor LMK-235 via the Smad7 pathway.

PURPOSE: HDAC4/5 and Smad7 are potential therapeutic targets for the onset and progression of B-cell acute lymphocytic leukemia (B-ALL) and indices for clinical prognosis. In contrast, HO-1 (heat shock protein 32) plays a key role in protecting tumor cells from apoptosis. METHODS: HDAC4/5, HO-1 and Smad7 expressions in 34 newly diagnosed B-ALL cases were detected by real-time PCR and Western blot. Lentivirus and small interference RNA were used to transfect B-ALL cells. The expression of Smad7 was detected after treatment with LMK-235 or Hemin and ZnPP. Apoptosis and proliferation were evaluated by flow cytometry, CCK-8 assay and Western blot. RESULTS: HDAC4/5 was overexpressed in B-ALL patients with high HO-1 levels. Increasing the concentration of HDAC4/5 inhibitor LMK-235 induced the decrease of Smad7 and HO-1 expressions and the apoptosis of B-ALL cells by suppressing the phosphorylation of AKT (Protein kinase B). Up-regulating HO-1 alleviated the decrease of Smad7 expression and enhanced B-ALL resistance to LMK-235 by activating p-AKT which reduced the apoptosis of B-ALL cells and influenced the survival of leukemia patients. Silencing Smad7 also augmented the apoptosis rate of B-ALL cells by suppressing p-AKT. CONCLUSION: HO-1 played a key role in protecting tumor cells from apoptosis, and HDAC4/5 were related with the apoptosis of B-ALL cells. LMK-235 may be able to improve the poor survival of leukemia patients.

Low expression of GFI-1 Gene is associated with Panobinostat-resistance in acute myeloid leukemia through influencing the level of HO-1.

To improve the treatment outcomes of acute myeloid leukemia (AML), epigenetic modification has been widely tested and used in recent years. However, drug-resistance is still a choke point to cure the malignancy. The growth factor independent 1 transcriptional repressor (GFI-1), as a zinc-finger transcriptional repressor, can bind histone deacetylases to allow the transcriptional repression. According to the finding of our study, AML patients with low level of GFI-1 not only implicated poor prognosis but also caused Panobinostat-resistance. In our prevent study revealed that heme oxygenase-1(HO-1) was one of the main factors leading to chemotherapy sensitivity to AML. Thus, this study tried to test the correlation between GFI-1 and HO-1. Our study discovered that AML patients with lower expression of GFI-1 had higher level of HO-1, HDAC1, HDAC2 and HDAC3, which resulted in poor prognosis in AML. The results of the in vitro study were the same. Panobinostat is a promising new class of anti-cancer drugs in AML. However, knocking down GFI-1 by siRNA could eliminate the Panobinostat-induced cell apoptosis. Subsequently, we utilized ZnPP to down regulate the level of HO-1, finding that the Panobinostat-resistance between the low level of GFI-1 and empty vector had eased. After further exploring the mechanism, it could be found that with knock down GFI-1, the phosphorylation of Akt and PI3K could be activated. Subsequently, Akt pathway and HO-1 inhibitor were utilized respectively and the resistance was reversed. It suggested that the resistance of Panobinostat to AML cells at low level of GFI-1 was mainly due to up-regulated level of HO-1 through the PI3K-Akt pathway.

Crucial role of HO-1/IRF4-dependent apoptosis induced by panobinostat and lenalidomide in multiple myeloma.

Inhibition of histone deacetylase (HDAC) is a promising therapeutic strategy for various hematologic cancers. Panobinostat has been approved for treating patients with multiple myeloma (MM) by the FDA. Since the mechanism for the resistance of panobinostat to MM remains elusive, we aimed to clarify this mechanism and the synergism of panobinostat with lenalidomide. The mRNA and protein of transcription factor IRF4 were overexpressed in CD138+ mononuclear cells from MM patients compared with in those from healthy donors. Given that direct IRF4 inhibitors are clinically unavailable, we intended to explore the mechanism by which IRF4 expression was regulated in MM. Heme oxygenase-1 (HO-1) promotes the growth and drug resistance of various malignant tumors, and its expression is positively correlated with IRF4 mRNA and protein expression levels. Herein, panobinostat induced acetylation of histone H3K9 and activation of caspase-3 in MM cells, being inversely correlated with the reduction of HO-1/IRF4/MYC protein levels. Adding Z-DEVD-FMK, a caspase-3 inhibitor, abolished the HO-1/IRF4 reduction by panobinostat alone or in combination with lenalidomide, suggesting that caspase-3-mediated HO-1/IRF4/MYC degradation occurred. Given that lenalidomide stabilized cereblon and facilitated IRF4 degradation in MM cells, we combined it with LBH589, an HDAC inhibitor. LBH589 and lenalidomide exerted synergistic effects, and LBH589 reversed the efficacy of lenalidomide on the resistance of CD138+ primary MM cells, in part due to simultaneous suppression of HO-1, IRF4 and MYC. The results provide an eligible therapeutic strategy for targeting MM depending on the IRF4 network and clinical testing of this drug combination in MM patients.

Histone deacetylase inhibitor BG45-mediated HO-1 expression induces apoptosis of multiple myeloma cells by the JAK2/STAT3 pathway.

Multiple myeloma (MM) is a hematological malignancy that is characterized by the clonal expansion of plasma cells in the bone marrow. Histone deacetylases (HDACs) represent a new type of molecular targeted therapy for different types of cancers and promising targets for myeloma therapy. We showed that HDAC3 mRNA and protein levels of CD138 mononuclear cells from MM patients were higher than those in healthy donors. Therefore, we investigated the effects of a novel class I HDAC inhibitor BG45 on MM cells in vitro. BG45 downmodulated heme oxygenase 1 (HO-1) when class I HDACs decreased in MM cells. HO-1 is a target for the treatment of MM. Moreover, BG45 induced hyperacetylation of histone H3 and inhibited the growth, especially the apoptosis of MM cell lines. Treatment with BG45 induced apoptosis by downregulating bcl-2 and Bcl-xl, upregulating Bax and other antiapoptotic proteins and activating poly(ADP-ribose)polymerase, and decreasing protein levels of p-JAK2 and p-STAT3. These effects were partly blocked by HO-1. Correspondingly, BG45 led to an accumulation in the G0/G1 phase, accompanied by decreased levels of CDK4 and phospho-retinoblastoma protein, an increased level of p21, and a moderately reduced level of CDK2. Clinical use of single agents was limited because of toxic side effects and drug resistance. However, combining BG45 with lenalidomide exerted synergistic effects. In conclusion, we verified the potent antimyeloma activity of this novel HDAC inhibitor and that the combination of BG45 and lenalidomide is a new method for MM treatment. Thus, BG45 may be applicable to the treatment of MM and other hematological malignancies.

Silencing heme oxygenase-1 increases the sensitivity of ABC-DLBCL cells to histone deacetylase inhibitor in vitro and in vivo.

Heme oxygenase-1 (HO-1) can promote tumor growth and reinforce the resistance of diffuse large B-cell lymphoma (DLBCL) cells to chemotherapeutic drug vincristine. We herein found that HO-1 protein expression was higher in high-risk DLBCL patients than in low-risk ones. Silencing HO-1 gene expression resisted vorinostat-induced apoptosis and arrested cell cycle in the G0/G1 phase of LY-10 cells. Western blot, co-immunoprecipitation and chromatin immunoprecipitation assays confirmed that the possible mechanisms may be increased cleaved caspase-3 protein expression, decreased phospho-histone deacetylase 3 protein expression, and activated histone acetylation of P27Kip1 promoter. Moreover, silencing HO-1 gene expression enhanced vorinostat-induced tumor cell apoptosis, prolonged survival time and promoted P27Kip1 protein expression in a xenograft mouse model. In conclusion, HO-1 is a potential therapeutic target of DLBCL. The findings provide a valuable preclinical evidence for sensitizing DLBCL patients with poor prognosis to histone deacetylase inhibitors.

[The Transmission of KPC-2 Gene in Klebsiella Species].

OBJECTIVES: To explore the mechanisms of imipenem resistance inKlebsiella spp. and the transmission of Klebsiella pneumoniae Carbapenemase-2(KPC-2) gene in Klebsiella species. METHODS: The imipenem resistant Klebsiella pneumoniae and Klebsiella oxytoca were isolated in the West China Hospital of Sichuan University in 2009/2010 and 2012/2013. Their minimal inhibitory concentration (MIC) was determined by agar dilution method. CARB ChromID plate and improved Hodge test were undertaken to detect carbapenemases resistant phenotype. PCR method was used for detecting KPC-2 gene. Plasmid transmission was detected by plasmid conjugation tests. The homology of the plasmids and the strains was analyzed using random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus PCR(ERIC-PCR) methods. RESULTS: Three strains of Klebsiella oxytoca collected in 2009/2010 and 7 Klebsiella pneumoniae collected in 2012/2013 developed carbapenemases resistance, all of which carried KPC-2 gene. The 3 KPC-2 positive plasmids isolated from Klebsiella oxytoca transited to recipient organisms and showed homology with the 7 KPC-2 gene positive plasmids isolated from Klebsiella pneumoniae. The ERIC-PCR showed homology of the 7 KPC positive Klebsiella pneumoniae. CONCLUSIONS: Carbapenemases inKlebsiella spp with expressed KPC-2 gene contribute to the development of resistance in this hospital. The transmission of KPC-2 plasmid in Klebsiella oxytoca may cause imipenem resistance in Klebsiella pneumonia. The horizontal transmission may be the main mechanism in the spread of imipenem resistance inKlebsiella spp.

[FLT3 Gene Expression and Its Clinical Significance in Acute Myeloid Leukemia.]

OBJECTIVES: To determine the correlation between fms-like tyrosine kinase 3 gene (FLT3) expression and FLT3-internal tandem duplication (ITD) mutations in acute myeloid leukemia patients,and the association between expression of FLT3 gene and clinical and laboratory features of patients. METHODS: The expression of FLT3 mRNA in bone marrow (BM) leukemic cells of 128 acute myeloid leukemia (AML) patients was measured by real-time PCR.The patients were divided into two groups using the 35% FLT3 expression as a cut-off point.The associations between the expression level of FLT3 and clinical and laboratory features of patients were analyzed. RESULTS: The patients had a FLT3 gene expression level of 0.01-180.68 (mean 14.65) at the initial diagnosis,with AML-M1 the most expressed and AML-M6 the least expressed,but without statistical significance.The patients with a high level of FLT3 gene expression had higher peripheral blood white blood cell count (WBC) (P<0.01) and were more likely to become anemic and febrile (P<0.05).WBC [regression coefficient (B)=1.508,odds ratio (OR)=4.518,95% confidence interval(CI):1.465-13.390,P=0.009] and anemia (B=2.142,OR=8.513,95%CI:3.201-22.644,P<0.001)were predictors of higher expression of FLT3.The patients with high levels of FLT3 gene expression had lower complete remission rate (32/83),compared with those (36/44) with low levels of FLT3 gene expression (P<0.05).The Cox regression analysis showed that the patients with higher levels of FLT3 gene expression had a higher risk of death (B=1.338, relative risk=3.810, 95%CI:1.820-7.947,P<0.001).The Kaplan-Meier analysis showed that the patients with higher levels of FLT3 gene expression had lower survival time (56.63%) than those with lower levels of FLT3 expression (70.45%,P<0.05). CONCLUSIONS: FLT3 gene has adverse impacts on complete remission of AML.High expression of FLT3 gene is associated with poor prognosis of patients with AML.