Effect and mechanism of gomisin D on the isoproterenol induced myocardial injury in H9C2 cells and mice.

We established myocardial injury models in vivo and in vitro to investigate the cardioprotective effect of gomisin D obtained from Schisandra chinensis. Gomisin D significantly inhibited isoproterenol-induced apoptosis and hypertrophy in H9C2 cells. Gomisin D decreased serum BNP, ANP, CK-MB, cTn-T levels and histopathological alterations, and inhibited myocardial hypertrophy in mice. In mechanisms research, gomisin D reversed ISO-induced accumulation of intracellular ROS and Ca2+. Gomisin D further improved mitochondrial energy metabolism disorders by regulating the TCA cycle. These results demonstrated that gomisin D had a significant effect on isoproterenol-induced myocardial injury by inhibiting oxidative stress, calcium overload and improving mitochondrial energy metabolism.

Predicting ventilator-associated pneumonia in elderly patients requiring mechanical ventilation through the detection in tracheal aspirates.

OBJECTIVE: In this study, we evaluated the clinical utility of tracheal aspirates α-amylase (AM), pepsin, and lipid-laden macrophage index (LLMI) in the early diagnosis of ventilator-associated pneumonia (VAP) in elderly patients on mechanical ventilation. METHODS: Within 96 hours of tracheal intubation, tracheal aspirate specimens were collected from elderly patients on mechanical ventilation; AM, pepsin, and LLMI were detected, and we analyzed the potential of each index individually and in combination in diagnosing VAP. RESULTS: Patients with VAP had significantly higher levels of AM, pepsin, and LLMI compared to those without VAP (P < 0.001), and there was a positive correlation between the number of pre-intubation risk factors of aspiration and the detection value of each index in patients with VAP (P < 0.001). The area under a receiver operating characteristic (ROC) curve (AUC) of AM, pepsin, and LLMI in diagnosis of VAP were 0.821 (95% CI:0.713-0.904), 0.802 (95% CI:0.693-0.892), and 0.621 (95% CI:0.583-0.824), the sensitivities were 0.8815, 0.7632, and 0.6973, the specificities were 0.8495, 0.8602, and 0.6291, and the cutoff values were 4,321.5 U/L, 126.61 ng/ml, and 173.5, respectively. The AUC for the combination of indexes in diagnosing VAP was 0.905 (95% CI:0.812-0.934), and the sensitivity and specificity were 0.9211 and 0.9332, respectively. In the tracheal aspirate specimens, the detection rate of AM ≥ cutoff was the highest, while it was the lowest for LLMI (P < 0.001). The detection rates of AM ≥ cutoff and pepsin ≥ cutoff were higher within 48 hours after intubation than within 48-96 hours after intubation (P < 0.001). In contrast, the detection rate of LLMI ≥ cutoff was higher within 48-96 hours after intubation than within 48 hours after intubation (P < 0.001). The risk factors for VAP identified using logistic multivariate analysis included pre-intubation aspiration risk factors (≥3), MDR bacteria growth in tracheal aspirates, and tracheal aspirate AM ≥ 4,321.5 U/L, pepsin ≥ 126.61 ng/ml, and LLMI ≥ 173.5. CONCLUSION: The detection of AM, pepsin, and LLMI in tracheal aspirates has promising clinical utility as an early warning biomarker of VAP in elderly patients undergoing mechanical ventilation.

Sustained Improvement of Appropriateness in Surgical Antimicrobial Prophylaxis with the Application of Quality Control Circle.

Purpose: Quality control circle (QCC) has acquired success in many fields in healthcare industry as a process management tool, whereas its efficacy in surgical antimicrobial prophylaxis (SAP) remains unknown. This study aimed to implement QCC interventions to improve the appropriateness of SAP. Methods: A QCC activity team was established to grasp the current situation of SAP in clean surgery procedure, set target, formulate corresponding countermeasures and implement and review them in stages. The plan-do-check-act (PDCA) method was cyclically applied. Results: The appropriateness of antibiotic prophylaxis before (January to December 2020) and after (January to December 2021) the implementation of QCC activities were evaluated based on relevant international and Chinese SAP guidelines. The overall SAP appropriateness was significantly improved from 68.72% before QCC to 93.7% post QCC implementation (P<0.01). A significant improvement (P<0.05) was also determined for each category: selection (from 78.82% to 96.06%), duration (from 90.15% to 96.46%), indication (from 94.09% to 97.64%), timing of first dose (from 96.55% to 99.21%), antimicrobial usage (from 96.8% to 99.41%), re-dosing of antimicrobial (from 96.55% to 99.21%). Conclusion: Implementation of a QCC program can optimize the use of antibiotics and improve the appropriateness of SAP and is of practical importance to their standardization.

Isolation and Screening of High-Yielding α-Amylase Mutants of Bacillus subtilis by Heavy Ion Mutagenesis.

To improve fermentative production of α-amylase, heavy-ion mutagenesis technology was used to irradiate Bacillus subtilis (B. subtilis) to obtain the high yielding mutants in this study. After continuous cultivation for 12 generations, eight mutants exhibited positive mutation rate with greater H/C. The α-amylase production was stable and obviously exceeded that by the parent strain, which shows that the mutants have a good genetic stability. Among the mutants, the α-amylase activity of B. subtilis KC-180-2 was 72.26 U·mL-1, which was 82.34% higher than that of the original strain. After optimization of fermentation conditions and media, the α-amylase activity of B. subtilis KC-180-2 reached a maximum of 156.83 U·mL-1 at 36 h in a bioreactor. In addition, the optimized fermentation temperature of B. subtilis KC-180-2 was increased to 49℃, indicating B. subtilis KC-180-2 possesses high-temperature resistance, which has great application prospects for industrial fermentation for α-amylase production.

Pharmacokinetics of Recombinant Human Coagulation Factor Ⅷ Preparations in Patients with Severe Hemophilia A / 中国实验血液学杂志

OBJECTIVE@#To calculate the pharmacokinetic parameters of recombinant human coagulation factor Ⅷ using myPKFiT in patients with severe hemophilia A, and provide an individualized treatment plan for patients.@*METHODS@#A total of 42 patients with severe hemophilia A who were treated with recombinant human coagulation factor Ⅷ were included from January 2021 to December 2021. myPKFiT was used to calculate the pharmacokinetic parameters of FⅧ, and the individualized treatment plan for hemophilia A patients was formulated.@*RESULTS@#The median age of 42 patients with severe hemophilia A was 31（16-50） years old, the average weight was 54.0±9.9 kg, the half-life of FⅧ was 12.05±1.6 h, the time to more than 1% of the baseline was 62.3±15.3 h, and the 0 bleeding rate after the guidance of myPKFiT was significantly increased from 39% to 49%, the Annual bleeding rate was reduced from 3.6±2.5 to 2.1±2.0, and the Annual joint bleeding rate was reduced from 3.2±2.2 to 1.9±0.9, all of which were statistically different (P<0.05).@*CONCLUSION@#Individualized therapy in patients with severe hemophilia A who were guided by myPKFiT assay of pharmacokinetics parameters can significantly reduce the annual bleeding rate and annual joint bleeding rate of patients.

Gas permeation rates of ultrathin graphite sealed SiO2 cavities.

Despite the proven impermeability of graphene toward most standard gases, graphene/graphite sealed SiO2 cavities always exhibit a nonzero leak rate, and the physical leakage mechanism is still unclear. By measuring leak rates of different gases for the same cavities sealed by ultrathin graphite under identical conditions, we find that the leak rates generally depend on the kinetic diameter of the gas molecules, which implies that the leakage is caused by a molecular sieving mechanism. By comparing different samples, we find that the leak rate of any gas in a particular sample is well predicted by the leak rate of N2 in that sample. In addition, we observe enhanced leak rates of water-soluble molecules. We infer that the leakage path (i.e., the graphene/graphite-SiO2 interface) favors hydrophilic species.

[Community-based Home Hospice Care Model under the Guidance of Tertiary Hospitals].

Community-based home hospice care provided by community service centers and family physician teams aims to alleviate the suffering of terminally ill patients and help them to receive end-of-life care and pass away at home.The Puhuangyu Community Health Service Center established the home hospice care model of PUMCH-Puhuangyu Coordination at the end of 2019.The model has been practiced and improved to date.This paper introduces this model of home hospice care.

[Experience of Community-based Home Hospice Care Practice for 24 Patients in Beijing Puhuangyu Community].

Objective To investigate the feasibility of home hospice care based on the practical experience in Puhuangyu community of Beijing.Methods We selected the patients assessed by hospice care team and receiving home hospice care from Puhuangyu Community Health Service Center of Beijing from January 1,2020 to December 31,2021.The clinical manifestations,hospice services received,and place of death of the patients were analyzed. Results A total of 24 patients were included in this study.They mainly suffered from malignant tumors(18 patients,75.0%),with pain as the most common symptom(12 patients,50.0%).The patients received a variety of hospice services through a combination of outpatient visits,home visits,and WeChat follow-up.The service time of each patient was(2.8±1.7) h each week on average and 57.9%(11/19) of the patients passed away at home. Conclusions The home hospice care in Puhuangyu community has a stable source of patients.The members of this hospice team can provide a variety of home hospice services.With this model,the wish to pass away at home can be achievable for most patients.Therefore,this model of community-based home hospice care is feasible.

SAF-248, a novel PI3Kδ-selective inhibitor, potently suppresses the growth of diffuse large B-cell lymphoma.

PI3Kδ is expressed predominately in leukocytes and overexpressed in B-cell-related malignances. PI3Kδ has been validated as a promising target for cancer therapy, and specific PI3Kδ inhibitors were approved for clinical practice. However, the substantial toxicity and relatively low efficacy as a monotherapy in diffuse large B-cell lymphoma (DLBCL) limit their clinical use. In this study, we described a novel PI3Kδ inhibitor SAF-248, which exhibited high selectivity for PI3Kδ (IC50 = 30.6 nM) over other PI3K isoforms at both molecular and cellular levels, while sparing most of the other human protein kinases in the kinome profiling. SAF-248 exhibited superior antiproliferative activity against 27 human lymphoma and leukemia cell lines compared with the approved PI3Kδ inhibitor idelalisib. In particular, SAF-248 potently inhibited the proliferation of a panel of seven DLBCL cell lines (with GI50 values < 1 µM in 5 DLBCL cell lines). We demonstrated that SAF-248 concentration-dependently blocked PI3K signaling followed by inducing G1 phase arrest and apoptosis in DLBCL KARPAS-422, Pfeiffer and TMD8 cells. Its activity against the DLBCL cells was negatively correlated to the protein level of PI3Kα. Oral administration of SAF-248 dose-dependently inhibited the growth of xenografts derived from Pfeiffer and TMD8 cells. Activation of mTORC1, MYC and JAK/STAT signaling was observed upon prolonged treatment and co-targeting these pathways would potentiate the activity of SAF-248. Taken together, SAF-248 is a promising selective PI3Kδ inhibitor for the treatment of DLBCL and rational drug combination would further improve its efficacy.

Reversal of Drug Resistance in K562/ADM Cells Caused by RA and the Related Mechanisms / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of ursane triterpenoids 3β,19α-dihydroxyursu-12-ene-23,28-dicarboxylic acid (Rotundioic acid, RA) on the sensitivity of adriamycin-resistant K562 cells (K562/ADM Cell) anti-tumor drug, and to explore the effect and mechanism of RA on the multidrug resistance of K562/ADM cells.@*METHODS@#CCK-8 method was used to detect the effect of RA on the sensitivity of K562 cells and K562/ADM cells to anti-tumor drug. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression level of mRNA and the protein in K562 and K562/ADM cells, and the effect of RA on the expression of MDR1 mRNA and P-gp in K562/ADM cells was also detected; Western blot was used to detect the expression of p-JNK, p-p38 and p-ERK1/2 in K562/ADM cells.@*RESULTS@#RA could increased the sensitivity of K562/ADM cells to adriamycin(the reversal factor was 1.61 times), the difference showed statistically significantly (P<0.05); the resistance factor of K562/ADM to ADM was 41.76 times. The expression of MDR1 mRNA in K562 cells was extremely low, and the protein product P-glycoprotein (P-gp) was almost not expressed; MDR1 mRNA and P-gp in K562/ADM cells were highly expressed; RA could down-regulate the expression levels of MDR1 and P-gp in K562/ADM cells. In addition, RA could upregulate the phosphorylation levels of p38 and ERK1/2 in K562/ADM cells, but it has no effect on the expression of p-JNK.@*CONCLUSION@#RA may participate in the regulation of MAPK signaling pathway by upregulating the expression levels of p-p38 and p-ERK1/2 in K562/ADM cells, and thus inhibit the transcription and translation levels of MDR1, and finally reverse the multidrug resistance of leukemia cells.

Transforming Growth Factor-ß Receptor III is a Potential Regulator of Ischemia-Induced Cardiomyocyte Apoptosis.

BACKGROUND: Myocardial infarction (MI) is often accompanied by cardiomyocyte apoptosis, which decreases heart function and leads to an increased risk of heart failure. The aim of this study was to examine the effects of transforming growth factor-ß receptor III (TGFßR3) on cardiomyocyte apoptosis during MI. METHODS AND RESULTS: An MI mouse model was established by left anterior descending coronary artery ligation. Cell viability, apoptosis, TGFßR3, and mitogen-activated protein kinase signaling were assessed by methylthiazolyldiphenyl-tetrazolium bromide assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunofluorescence, electron microscopy, and Western blotting. Our results demonstrated that TGFßR3 expression in the border region of the heart was dynamically changed during MI. After stimulation with H2O2, TGFßR3 overexpression in cardiomyocytes led to increased cell apoptosis and activation of p38 signaling, whereas TGFßR3 knockdown had the opposite effect. ERK1/2 and JNK1/2 signaling was not altered by TGFßR3 modulation, and p38 inhibitor (SB203580) reduced the effect of TGFßR3 on apoptosis, suggesting that p38 has a nonredundant function in activating apoptosis. Consistent with the in vitro observations, cardiac TGFßR3 transgenic mice showed augmented cardiomyocyte apoptosis, enlarged infarct size, increased injury, and enhanced p38 signaling upon MI. Conversely, cardiac loss of function of TGFßR3 by adeno-associated viral vector serotype 9-TGFßR3 short hairpin RNA attenuated the effects of MI in mice. CONCLUSIONS: TGFßR3 promotes apoptosis of cardiomyocytes via a p38 pathway-associated mechanism, and loss of TGFßR3 reduces MI injury, which suggests that TGFßR3 may serve as a novel therapeutic target for MI.

Arsenic trioxide and angiotensin II have inhibitory effects on HERG protein expression: Evidence for the role of PML SUMOylation.

The human ether-a-go-go-related gene (HERG) channel is a novel target for the treatment of drug-induced long QT syndrome, which causes lethal cardiotoxicity. This study is designed to explore the possible role of PML SUMOylation and its associated nuclear bodies (NBs) in the regulation of HERG protein expression. Both arsenic trioxide (ATO) and angiotensin II (Ang II) were able to significantly reduce HERG protein expression, while also increasing PML SUMOylation and accelerating the formation of PML-NBs. Pre-exposure of cardiomyocytes to a SUMOylation chemical inhibitor, ginkgolic acid, or the silencing of UBC9 suppressed PML SUMOylation, subsequently preventing the downregulation of HERG induced by ATO or Ang II. Conversely, knockdown of RNF4 led to a remarkable increase in PML SUMOylation and the function of PML-NBs, further promoting ATO- or Ang II-induced HERG protein downregulation. Mechanistically, an increase in PML SUMOylation by ATO or Ang II dramatically enhanced the formation of PML and Pin1 complexes in PML-NBs, leading to the upregulation of TGF-ß1 protein, eventually inhibiting HERG expression through activation of protein kinase A. The present work uncovered a novel molecular mechanism underlying HERG protein expression and indicated that PML SUMOylation is a critical step in the development of drug-acquired arrhythmia.

Manipulating PML SUMOylation via Silencing UBC9 and RNF4 Regulates Cardiac Fibrosis.

The promyelocytic leukemia protein (PML) is essential in the assembly of dynamic subnuclear structures called PML nuclear bodies (PML-NBs), which are involved in regulating diverse cellular functions. However, the possibility of PML being involved in cardiac disease has not been examined. In mice undergoing transverse aortic constriction (TAC) and arsenic trioxide (ATO) injection, transforming growth factor ß1 (TGF-ß1) was upregulated along with dynamic alteration of PML SUMOylation. In cultured neonatal mouse cardiac fibroblasts (NMCFs), ATO, angiotensin II (Ang II), and fetal bovine serum (FBS) significantly triggered PML SUMOylation and the assembly of PML-NBs. Inhibition of SUMOylated PML by silencing UBC9, the unique SUMO E2-conjugating enzyme, reduced the development of cardiac fibrosis and partially improved cardiac function in TAC mice. In contrast, enhancing SUMOylated PML accumulation, by silencing RNF4, a poly-SUMO-specific E3 ubiquitin ligase, accelerated the induction of cardiac fibrosis and promoted cardiac function injury. PML colocalized with Pin1 (a positive regulator for TGF-ß1 mRNA expression in PML-NBs) and increased TGF-ß1 activity. These findings suggest that the UBC9/PML/RNF4 axis plays a critical role as an important SUMO pathway in cardiac fibrosis. Modulating the protein levels of the pathway provides an attractive therapeutic target for the treatment of cardiac fibrosis and heart failure.

Research Progress on Long Non-Coding RNA in Hematological Malignancies--Review / 中国实验血液学杂志

Long non-coding RNA (LncRNA) is defined as a class of transcripts more than 200 nucleotides in length and without the protein-coding function. It has been found for years, however, that little is known about the potential role of LncRNA in humans. But recent studies showed that LncRNA can regulate the coding-gene expression and participate in effects of human body. Accumulating evidence demonstrated that LncRNA are involved in cancer incidence, development and progression.With further exploration on the mechanisms of tumors, the relationship between the long non-coding RNA and hematological malignancies increasingly become a hot research. This review focuses on the mechanisms of LncRNA in hematological malignancies.

Research Progress on Application of CRISPR/Cas Genome Editing Technology in Hematological Diseases -Review / 中国实验血液学杂志

CRISPR/Cas genome editing technology is a newly developed powerful tool for genetic manipulation, which can be used to manipulate the genome at specific locations precisely, to restore the function of genetic defect cells, and to develop various disease models. In recentl years, with the advances of precise genome manipulation, CRISPR/Cas technology has been applied to many aspects of diseases research and becomes an unique tool to investigate gene function and discover new therapeutic targets for genetic diseases. Nowadays, CRISPR/Cas technology has been a hot research point in agriculture, graziery, biotechnology and medicine. This review focuses on the recent advances in CRISPR/Cas technology and its application in hematological diseases.

Expression and Significance of NLRP3, ASC and AIM2 in Patients with Acute Leukemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the expression and significance of NLR family, pyrin domain containing 3 (NLRP3), apoptosis associated speck like protein containing a CRAD (ASC) and absent in melanoma 2 (AIM2) of patients with acute leukemia.</p><p><b>METHODS</b>The petipheral blood samples of 19 patients with ALL and 41 patients with ANLL as the AL group (each 20 cases of newly diagnosed, relapsed and complete remission group) and 20 cases of non-hematologic malignancies as the control group were collected from July 2013 to July 2014 in the First Affiliated Hospital of Gannan Medical University. The expression levels of NLRP3, ASC and AIM2 in peripheral blood plasma were determined by ELISA.</p><p><b>RESULTS</b>The expression levels of NLRP3, ASC and AIM2 in plasma of control and AL complete remission groups were significantly higher than those in newly diagnosed and relapsed groups, and were with statistical significance (P < 0.05), but there were no statistical signifirance between ALL and ANLL groups (P > 0.05).</p><p><b>CONCLUSION</b>The expression of NLRP3, ASC and AIM2 is down-regulated in the patients with acute leukemia, which maybe play a role of anti-leukemia, and provide a laboratory evidence for diagnosis and treatment of patients with acute leukemia.</p>

Formulation of intumescent flame retardant coatings containing natural-based tea saponin.

Natural product tea saponin (TS), extracted from the nutshell of camellia (Camellia oleifera Abel, Theaceae), was introduced into intumescent flame retardant formulations as blowing agent and carbon source. The formulations of the flame retardant system were optimized to get the optimum proportion of TS, and intumescent flame retardant coatings containing tea saponin (TS-IFRCs) were then prepared. It was found that TS can significantly affect the combustion behavior and the thermal stability of TS-IFRCs evaluated by cone calorimetry and simultaneous thermal analyzer, respectively. It was shown that TS, degraded to water vapor and carbon at high temperatures, can combine with other components to form a well-developed char layer. The char layer was supposed to inhibit erosion upon exposure to heat and oxygen and enhance the flame retardancy of TS-IFRCs. In addition, the smoke release of TS-IFRCs was also studied, which provided a low amount of smoke production.

Expression of HMGB1 and NF-κB in Patients with Acute Leukemia and Its Significance / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the expression of high mobility group box protein 1 (HMGB1) and nuclear factor-kappa B (NF-κB) in patients with acute leukemia and its significance.</p><p><b>METHOD</b>20 samples of bone marrow and peripheral blood from each acute leukemia groups (newly diagnozed, relapsed and complete remission groups) and 20 samples as control from patients with no-hematologic malignancies were collected. The expression level of HMGB1 in peripheral blood plasma was determined by ELISA; HMGB1 and NF-κB level in mononuclear cells were examined by RT-PCR. Western blot was used to determine HMGB1 and NF-κB protein levels. HMGB1 and NF-κB in bone marrow smears were determined by immnohistochemistry method (IHC).</p><p><b>RESULTS</b>The expression level of HMGB1 obviously increased in patients of newly diagnosed and relapsed groups, as compared with control group there was statistical significance (P < 0.05), but there was no obvious difference in expression level of HMGB1 between complete remission group and control group (P > 0.05). The expression level of HMGB1 and NF-kB in monnuclear cells of bone marrow in newly-diagnosed group and relapsed group was significantly higher than that in control group (P < 0.05), but the expression levels of HMGB1 and NF-kB in complete remisson group did not change (P > 0.05). The results of immnohistochemistry method indicated that the possitive expression of HMGB1 and NF-kB maily was found in bone marrow smears of newly diagnosed and relapsed groups.</p><p><b>CONCLUSION</b>HMGB1 is overexpressed in acute leukemia, which may be involved in the occurrence and development of acute leukemia by activating the NF-κB signaling pathway, HMGB1 may be a important index for observing therapeutic effectiveness and predicting recurrence of acute leukemia.</p>

Performance analysis of extracted rule-base multivariable type-2 self-organizing fuzzy logic controller applied to anesthesia.

We compare type-1 and type-2 self-organizing fuzzy logic controller (SOFLC) using expert initialized and pretrained extracted rule-bases applied to automatic control of anaesthesia during surgery. We perform experimental simulations using a nonfixed patient model and signal noise to account for environmental and patient drug interaction uncertainties. The simulations evaluate the performance of the SOFLCs in their ability to control anesthetic delivery rates for maintaining desired physiological set points for muscle relaxation and blood pressure during a multistage surgical procedure. The performances of the SOFLCs are evaluated by measuring the steady state errors and control stabilities which indicate the accuracy and precision of control task. Two sets of comparisons based on using expert derived and extracted rule-bases are implemented as Wilcoxon signed-rank tests. Results indicate that type-2 SOFLCs outperform type-1 SOFLC while handling the various sources of uncertainties. SOFLCs using the extracted rules are also shown to outperform those using expert derived rules in terms of improved control stability.

[Molecular mechanism of hydroxyurea enhances K562 cell apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand].

OBJECTIVE: To explore the molecular mechanism via which the chemotherapeutic drug hydroxyurea (HU) enhances K562 cell apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). METHODS: Chronic myelogenous leukemia-derived K562 and SVT-35 cells were treated with recombinant soluble TRAIL (rsTRAIL) alone or combined with HU for a time course, and the cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-4-sulfophenyl-2H-tetrazolium-phenazine methosulphate assay. Western blot was performed to analyze the activation of apoptosis-related protein kinases and the expression of apoptosis inhibitor molecules. RESULTS: The survival rates of SVT-35 and K562 cells treated with 1 µg/ml rsTRAIL for 24 hours were 32% and 93%, respectively. HU significantly increased the sensitivity of K562 cells to rsTRAIL cytotoxicity. Combination of rsTRAIL and HU resulted in the phosphorylation of rat sarcoma (RAS), mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase and in the significant reduction of apoptosis-inhibited molecule Fas associated death domain protein-like interleukin-1 beta-convening enzyme inhibitory protein and cellular inhibitor of apoptosis protein-1 in K562 cells. CONCLUSIONS: HU enhanced K562 cell sensitivity to rsTRAIL is mediated by Ras-MEK-ERK signaling pathway. Expression of antiapoptotic proteins cellular Fas associated death domain protein-like interleukin-1 beta-convening enzyme inhibitory protein and cellular inhibitor of apoptosis protein-1 is also down-regulated during this process. These results may through light on the therapeutic study of human chronic myelogenous leukemia.