[The Effect of TCP1 Expression on the Proliferation and the Accumulation of Intracellular Drug of HL60/A and HL60 Cell and Its Mechanism].

OBJECTIVE: To investigate the effect of TCP1 expression on the proliferation and the accumulation of intracellular drug of HL60/A and HL60 cells and its possible molecular mechanism. METHODS: Lentiviral transfection technology was used to construct HL60/A and HL60 cells with knocked down or overexpressed TCP1 and their control cells. The efficiency of knockdown and overexpression was evaluated by Western blot. The cell proliferation was detected by CCK-8 assay. The intracellular drug accumulation was detected by laser confocal detection and flow cytometry. The expression levels of MRP1, P-gP and p-AKT were evaluated by flow cytometry and Western blot. RESULTS: After TCP1 was knocked down,the proliferation ability of HL60/A cells was significantly reduced, the accumulation of intracellular drug was significantly increased and the expression of MRP1 and P-gP protein were decreased. After TCP1 was overexpressed, the proliferation ability of HL60 was significantly increased, the accumulation of intracellular drug was significantly decreased and the expression of MRP1 and P-gP protein were increased. Intervention of LY294002 significantly antagonized the promotion on cell proliferation, the inhibition on intracellular drug accumulation and the expression of MRP1 and P-gP mediated by TCP1 overexpressing in HL60 cells. CONCLUSION: TCP1 can promote cell proliferation, improve the expression of MRP1 and P-gP by activating PI3K/AKT signal, and reduce intracellular drug accumulation.

Extraction and Surface Functionalization of Cellulose Nanocrystals from Sugarcane Bagasse.

The present study aimed to optimize the process for extracting cellulose nanocrystals (CNCs) from sugarcane bagasse through ultrasonic-assisted sulfuric acid hydrolysis and its subsequent modification with L-malic acid and silane coupling agent KH-550. The effects of the different modification methods and the order of modification on the structures and properties of bagasse CNCs were explored. The results indicated that the optimal process conditions were achieved at an acid-digestion temperature of 50 °C, a reaction time of 70 min, an ultrasonic power of 250 W, and a volume fraction of 55%. The modified CNCs were analyzed using infrared spectral, X-ray diffraction, and thermogravimetric techniques, which revealed that L-malic acid was attached to the hydroxyl group on the CNCs via ester bond formations, and the silane coupling agent KH-550 was adsorbed effectively on the CNCs' surfaces. Moreover, it was observed that the modification of the CNCs by L-malic acid and the KH-550 silane coupling agent occurred only on the surface, and the esterification-crosslinking modification method provided the best thermal stability. The performance of self-made CNC was found to be superior to that of purchased CNC based on the transmission electron microscopy analysis. Furthermore, the modified esterified-crosslinked CNCs exhibited the best structure and performance, thereby offering a potential avenue for the high-value utilization of sugarcane bagasse, a byproduct of sugarcane sugar production, and the expansion of the comprehensive utilization of sugarcane bagasse.

Successful treatment with HLA-matched peripheral hematopoietic stem cell transplantation for very severe hepatitis-associated aplastic anemia complicated with multidrug-resistant bacterial and fungal infections: A case report.

Hepatitis-associated aplastic anemia (HAAA) is a life-threatening hematologic disorder characterized by bone marrow failure. Allogeneic hematopoietic stem cell transplantation (HSCT) is the first-line treatment for HAAA. Severe infection and complications in patients with very severe aplastic anemia are the challenges to the efficacy of HSCT. We report a rare case of successful transplantation with HLA-matched peripheral hematopoietic stem cells for a 15-year-old girl suffering from HAAA with multidrug-resistant bacterial and fungal infections. Through effectively controlling infection and optimal timing of transplantation by adjusting the conditioning regimen, the allo-HSCT was successfully performed for the patient. Updated data of following-up 26 months after transplantation showed that the patient was still in complete remission with a good quality of life. This case provided a reference for treating severely infected patients with HAAA before HSCT.

High Efficacy of Stem Cell Mobilization With Etoposide+Cytarabine Plus G-CSF in Patients With Multiple Myeloma.

BACKGROUND: Efficient mobilization of CD34+ hematopoietic stem cells plays a vital role in successful autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM), especially in cases with high-risk cytogenetic recommended for tandem ASCT. However, the optimal mobilization strategy remains a matter of debate in the era of lenalidomide. The combination of etoposide with Cytarabine plus G-CSF as a novel mobilization regimen in MM has not been reported previously. METHODS: This research retrospectively studied mobilization efficacy and safety using etoposide combined with Cytarabine (etoposide 50-100 mg/m2, qd d1-3; AraC 0.5 g/m2, q12h d1~3) plus G-CSF (5 µg/kg/day, from d5 until the day of apheresis) in 128 patients with MM. 70(54.7%) patients received lenalidomide-based induction regimens treatment. RESULTS: A median of 27.75×106 CD34+ cells/kg was collected in the first apheresis, and 28.23×106 CD34+ cells/kg were collected overall. Of the 128 patients, all achieved adequate collection (≥2×106 CD34+ cells/kg), 121(94.5%) achieved optimal collection for single ASCT (≥5×106 CD34+ cells/kg), and 114(89.1%) harvested optimal collection for tandem ASCT (≥10×106 CD34+ cells/kg). In particular, the target yield of optimal collection for tandem ASCT was reached in 82.8% (106/128) by a single apheresis procedure. 14 patients obtained deeper response post mobilization. In multivariate analysis, cycles of prior chemotherapy independently affected the optimal achievement of CD34+ cells (p=0.004, OR 0.695, 95% CI 0.544~0.888). Previous lenalidomide exposure did not significantly impair CD34+ cells collection. Although 68% episodes of antibiotic usage were observed, no severe infection or treatment-related mortality occurred. CONCLUSION: Stem cell mobilization with Etoposide + Cytarabine plus G-CSF was highly efficient and safe in patients with MM, which could be considered in high-risk MM patients who were referred for tandem ASCT.

Sequential Transplantation of Haploidentical Stem Cell and Unrelated Cord Blood With Using ATG/PTCY Increases Survival of Relapsed/Refractory Hematologic Malignancies.

Allogeneic haploidentical HSCT (haplo-HSCT) and unrelated umbilical cord blood transplantation(UCBT)are used in patients lacking HLA-identical sibling or unrelated donors. With myeloablative condition and GVHD prophylaxis of using low-dose ATG and post-transplantation cyclophosphamide (PTCY), we conducted a prospective clinical trial. Of eligible 122 patients from February 2015 to December 2019 in the study, 113 patients were involved. Forty-eight patients were in the group of sequential haplo-cord transplantation (haplo-cord HSCT), and 65 patients were in the group of single UCBT. The primary endpoint of 2-year disease-free survival (DFS) was no statistical difference between groups (64.1 vs. 56.5%), p>0.05. The analysis of subgroup patients with relapsed/refractory showed haplo-cord HSCT was associated with better OS (HR 0.348, 95% CI, 0.175-0.691; p=0.0025), DFS (HR 0.402, 95% CI, 0.208-0.779; p=0.0069), and GRFS (HR 0.235, 95% CI, 0.120-0.457, p<0.0001) compared to the single cord group. The 2-year's probability in OS, DFS, and GRFS was 64.9 vs. 31.6%, 64.5 vs. 31.6%, and 60.8 vs. 15.0% in the haplo-cord group and single cord group, respectively. III-IV acute GVHD 8.3 vs. 6.2%, chronic GVHD 25.8 vs. 13.7%, and extensive chronic GVHD 5.3 vs. 1.8% were shown in corresponding group, p>0.05. The patients engrafted persistently with UCB showed better survival outcomes. Our sequential Haplo-cord HSCT with ATG/PTCY improved the survival of patients and might be an alternative transplantation approach for patients with relapsed/refractory hematologic malignancies.

TCP1 increases drug resistance in acute myeloid leukemia by suppressing autophagy via activating AKT/mTOR signaling.

T-complex protein 1 (TCP1) is one of the subunits of chaperonin-containing T complex (CCT), which is involved in protein folding, cell proliferation, apoptosis, cell cycle regulation, and drug resistance. Investigations have demonstrated that TCP1 is a factor being responsible for drug resistance in breast and ovarian cancer. However, the TCP1 role in acute myeloid leukemia (AML) remains elusive. In the present study, we discovered that the TCP1 expression was elevated in AML patients and high TCP1 expression was associated with low complete response rate along with poor overall survival. TCP1 showed higher expression in the adriamycin-resistant leukemia cell line HL60/A and K562/A, comparing to their respective parent cells HL60 and K562 cells. TCP1 inhibition suppressed drug resistance in HL60/A and K562/A cells, whereas TCP1 overexpression in HL60 cells incremented drug resistance, both in vitro and in vivo. Mechanistic investigations revealed that TCP1 inhibited autophagy and adriamycin-induced cell apoptosis, and TCP1-mediated autophagy inhibition conferred resistance to adriamycin-induced cell apoptosis. Furthermore, TCP1 interacted with AKT and mTOR to activate AKT/mTOR signaling, which negatively regulates apoptosis and autophagy. Pharmacological inhibition of AKT/mTOR signal particularly activated autophagy and resensitized TCP1-overexpressing HL60 cells to adriamycin. These findings identify a novel role of TCP1 regarding drug resistance in AML, which advise a new strategy for overcoming drug resistance in AML through targeting TCP1/AKT/mTOR signaling pathway.

New Insights into the Quantitative Relationship between Surface Chemistry of Fullerene (C60) and Solubility Parameters and Compatibility with Polymers.

The quantitative relationship between the surface chemistry of carbon materials and the compatibility with polymers is a fundamental and vital physical chemistry problem in the field of polymer nanocomposites. Traditional experimental methods are difficult to solve this problem, so no theory has been formed to guide the functionalization of carbon materials. In this work, the quantitative relationship between functional groups and Hildebrand (δT) and transformed Hansen (δvdW and δele) solubility parameters of fullerene (C60) was determined by molecular dynamics simulation. Besides, which solubility parameter can more accurately predict the compatibility between C60 and three typical polymers with different polarity as a function of grafting ratio is investigated. Very interestingly, no matter which group is grafted, δT and δvdW of C60 show a slight increase first and then a decrease with the grafting ratio, whereas δele first increases abruptly and then decreases slightly. The introduction of polar groups (-OH, -COOH, and -NH2) is conducive to improving the compatibility between C60 and polymers, whereas the introduction of the nonpolar group (-CH3) is not. In terms of predicting compatibility, the Hildebrand solubility parameter is better than the Hansen solubility parameter due to the nonpolar nature of the polymers, even for nitrile butadiene rubber. Finally, the optimum grafting ratios corresponding to the maximum binding energies of C60/polymers mixtures were obtained. This study provides a new understanding of the functionalization of C60 at the molecular level and promotes the development of the theory of the thermodynamics of mixing.

A combined experimental and molecular dynamics simulation study of an intrinsic self-healing polyurethane elastomer based on a dynamic non-covalent mechanism.

An intrinsic self-healing polyurethane (PU) elastomer with excellent self-healing efficiency was prepared. The self-healing properties of this elastomer as well as the temperature dependence of self-healing can be tailored by regulating the molar ratio of hard to soft segments. The self-healing efficiency of 92.5% is the highest when the molar ratio of 4,4-methylenedicyclohexyl diisocyanate (HMDI) to polypropylene carbonate polyol (PPC) is 1.3 and the temperature is 25 °C. In situ temperature swing infrared spectra and low-field nuclear magnetic resonance reveal that the soft segment, PPC, endows PU with a dense dynamic hydrogen bond network, and the dissociation and reconstruction of the hydrogen bond network enable the PU to heal. To date, the exchange of hydrogen bonds has not been observed intuitively through experimental means. Therefore, the number, type, strength, lifetime, and the exchange of hydrogen bonds in the self-healing process at different temperatures were investigated by molecular dynamics (MD) simulation. The simulated results show that the type of hydrogen bond exchange between functional groups will be affected by temperature. The hydrogen bonds between urethane and urea groups play a leading role in the self-healing properties due to the high strength and a large number of hydrogen bonds at both 25 and 50 °C. The stronger strength, longer lifetime, and greater number of effective hydrogen bonds at 25 °C make the self-healing efficiency of PU higher than at 50 °C.

Molecular Dynamics Simulation Study on Two-Component Solubility Parameters of Carbon Nanotubes and Precisely Tailoring the Thermodynamic Compatibility between Carbon Nanotubes and Polymers.

Solubility parameters play an important role in predicting compatibility between components. The current study on solubility parameters of carbon materials (graphene, carbon nanotubes, and fullerene, etc.) is unsatisfactory and stagnant due to experimental limitations, especially the lack of a quantitative relationship between functional groups and solubility parameters. Fundamental understanding of the high-performance nanocomposites obtained by carbon material modification is scarce. Therefore, in the past, the trial and error method was often used for the modification of carbon materials, and no theory has been formed to guide the experiment. In this work, the effect of defects, size, and the number of walls on the Hildebrand solubility parameter (δT) of carbon nanotubes (CNTs) was investigated by molecular dynamics (MD) simulation. Besides, three-component Hansen solubility parameters (δD, δp, δH) were transformed into two-component solubility parameters (δvdW, δelec). The quantitative relation between functional groups and two-component solubility parameters of single-walled carbon nanotubes (SWCNTs) was then given. An important finding is that the δT and δvdW of SWCNTs first decrease, reach a minimum, and then increase with increasing grafting ratio. The thermodynamic compatibility between functionalized SWCNTs and six typical polymers was investigated by the Flory-Huggins mixing model. Two-component solubility parameters were proven to be able to effectively predict their compatibility. Importantly, we theoretically gave the optimum grafting ratio at which the compatibility between functionalized SWCNTs and polymers is the best. The functionalization principle of SWCNTs toward good compatibility between SWCNTs and polymers was also given. This study gives a new insight into the solubility parameters of functionalized SWCNTs and provides theoretical guidance for the preparation of high-performance SWCNTs/polymers composites.

Emergency Combination of Four Drugs for Bloodstream Infection Caused by Carbapenem-Resistant Enterobacteriaceae in Severe Agranulocytosis Patients with Hematologic Malignancies after Hematopoietic Stem Cell Transplantation.

Bloodstream infection (BSI) caused by multidrug-resistant (MDR) bacteria or extensively drug-resistant (XDR) bacteria is a global threat. However, an effective treatment regimen is still controversial and inadequate due to the rapid deterioration caused by the bacteria. In immunocompromised and neutropenic patients, MDR-BSI is an emergency, which causes treatment-related mortality. In this study, four agranulocytosis patients with hematologic malignancies after HSCT receiving treatment for carbapenem-resistant Enterobacteriaceae- (CRE-) BSI were included. Conventional treatment using two to three combined antibiotics was administered in the first and second patients. Combination treatment using four drugs, polymyxin B, high-dose tigecycline, fosfomycin, and double-dose carbapenem, was administered in the third and fourth patients. None of the patients receiving conventional treatment survived. Both patients receiving combination treatment using four drugs survived. Therefore, four-drug combination therapy may be needed in CRE-BSI patients who experienced severe agranulocytosis after HSCT. The efficacy of the four-drug combination treatment for CRE-BSI patients as well as the adverse effects need to be further studied.

Molecular dynamics simulation insight into the temperature dependence and healing mechanism of an intrinsic self-healing polyurethane elastomer.

An intrinsic self-healing polyurethane (PU) elastomer was synthesized in our previous work. In this work, three-dimensional (3D) micro-crack models based on experimental samples were further introduced to investigate their self-healing behavior, mechanism, and temperature dependence by molecular dynamics (MD) simulations. In particular, the number, type, strength, and lifetime of hydrogen bonds as well as the microscopic behavior of molecular diffusion in the self-healing process were investigated. It was found that the self-healing capacity of PU mainly results from intermolecular electrostatic interactions, and the hydrogen bond plays a key role in electrostatic interactions. There is an optimum ratio of soft and hard segments at which the number of hydrogen bonds is appropriate and the self-healing capacity is optimum. Besides, the temperature has an optimal value at which the self-healing rate of PU is the fastest. The exchanges of hydrogen bonds, which endowed PU with self-healing capacity, were further revealed intuitively. We found that the exchanges of hydrogen bonds are reversible and more likely to occur on the urethane groups. This study deepened the understanding of the self-healing character of PU at the molecular level.

The role of the novel LincRNA uc002jit.1 in NF-kB-mediated DNA damage repair in acute myeloid leukemia cells.

The roles and therapeutic potential of long noncoding RNAs (lncRNAs) in acute myeloid leukemia (AML) have attracted increased attention. However, many lncRNAs have not been annotated in AML, and their predictive value for AML therapy remains unclear. In this study, we identified a novel large intergenic noncoding RNA uc002jit.1 (D43770) from a lncRNA microarray. We first proved uc002jit.1 is a target gene of nuclear factor kappa B/RELA, RELA regulated uc002jit.1 transcription by binding to its promoter. Additionally, uc002jit.1 knockdown impaired the stability of poly (ADP-ribose) polymerase 1 (PARP1) mRNA, and then reduced PARP1 protein content and PARylation level upon DNA damage, thus inhibiting DNA damage repair in AML cells. Moreover, uc002jit.1 knockdown significantly inhibited AML cells proliferation and increased the sensitivity to chemotherapeutic drugs in vitro as well as in a mouse model in vivo. Overall, our study indicated that uc002jit.1 may be associated with the occurrence and prognosis of AML and could be a new diagnostic/prognostic biomarker and therapeutic target for AML.

NF-κB and Poly (ADP-ribose) Polymerase 1 Form a Positive Feedback Loop that Regulates DNA Repair in Acute Myeloid Leukemia Cells.

NF-κB mediates acquired resistance in acute myeloid leukemia (AML) cells treated with DNA-damaging agents. Because DNA repair is the major molecular shift that alters sensitivity to DNA-damaging agents, we explored whether activation of the NF-κB pathway promotes AML cell survival by regulating DNA repair after chemotherapy. Our results showed that RELA, an important subunit of NF-κB, regulated DNA repair by binding to the promoter region of the PARP1 gene and affecting PARP1 gene transcription. Conversely, PARP1 knockdown reduced NF-κB activity, indicating that NF-κB and PARP1 create a positive feedback loop in DNA repair. Simultaneous treatment with the NF-κB inhibitor BMS-345541 and the PARP1 inhibitor olaparib resulted in robust killing of AML cells. This dual inhibition significantly suppressed tumor growth and extended survival times in xenograft tumor models. IMPLICATIONS: RELA and PARP1 form a positive feedback loop to regulate DNA damage repair, simultaneous inhibition of NF-κB and PARP1 increases the antileukemic efficacy of daunorubicin in vitro and in vivo, broadening the use of PARP1 inhibitors.

Temperature dependence of the interfacial bonding characteristics of silica/styrene butadiene rubber composites: a molecular dynamics simulation study.

Based on our previous studies on the modification of in-chain styrene butadiene rubber (SBR) using 3-mercaptopropionic acid as well as its composites filled with silica, we further constructed two types of models (amorphous and layered) to investigate the temperature dependence of the interfacial bonding characteristics of silica/SBR composites via molecular dynamics (MD) simulation. The competing effects of rubber-rubber interactions and filler-rubber interactions were identified, and the relationship between the competing effects and the temperature was determined. Besides this, the effect of temperature on the mobility and distribution of SBR chains on the surface of silica was investigated. It was found that the stronger the interfacial interactions, the less sensitive the motion of SBR chains to temperature. Finally, the number and length of hydrogen bonds as a function of temperature were analyzed. These simulated results deepened the understanding of interface temperature dependence of the silica/SBR composites and gave a molecular level explanation for the existence of an optimum modifier content (14.2 wt%) that is temperature independent.

Recombinant C-terminal heparin-binding domain of fibronectin polypeptide protects against liver damage, reduces serum inflammatory cytokines, and decreases mortality in acute liver failure.

This study aimed to evaluate the effect of recombinant C-terminal heparin-binding domain of fibronectin (FNCHBD) polypeptide on live-damage protection, inflammation, and mortality in acute liver failure (ALF) mice. 25 mice were randomly divided into five groups: normal controls, lipopolysaccharide (LPS)/D-galactosamine (GalN), 5 mg/kg FNCHBD, 10 mg/kg FNCHBD and 20 mg/kg FNCHBD groups. Blood samples were obtained at 9 h after treatment for measurement of liver indexes and inflammatory cytokine levels, and livers were acquired for H&E and TUNEL staining assays. 90 mice (18 mice in each group) were randomly divided into five groups for mortality assessment after LPS/GalN administration at 48 h. Compared to LPS/GalN group, levels of blood liver indexes including AST, ALT and TBIL were decreased in FNCHBD polypeptide-treated groups. H&E staining disclosed FNCHBD polypeptide protected cell morphology and histomorphology, and necrosis rates in FNCHBD polypeptide-treated groups were lower compared to LPS/GalN group. TUNEL staining assay revealed cell apoptosis was inhibited in FNCHBD polypeptide-treated groups compared to LPS/GalN group. Serum inflammatory cytokines including TNF-α, IL-1ß, and IL-6 were reduced in FNCHBD polypeptide-treated groups compared to LPS/GalN group. As to mortality rate, it was only decreased in 10 mg/kg FNCHBD and 20 mg/kg FNCHBD groups but not in 5 mg/kg FNCHBD compared to LPS/GaIN group. In addition, most effects of FNCHBD presented in a dose-dependent manner. FNCHBD polypeptide protects against liver damage, inhibits elevation of serum inflammatory cytokines, and decreases mortality in ALF.

Mutual benefit for foreign medical students and Chinese postgraduates: A mixed team-based learning method overcomes communication problems in hematology clerkship.

Hematology is difficult for students to learn. A beneficial education method for hematology clerkship training is required to help students develop clinical skills. Foreign medical students often encounter communication issues in China. To address this issue, Chinese post-graduates from our institute are willing to assist with educating foreign students. Therefore, we propose a mixed team-based learning method (MTBL) which might overcome communication problems in hematology clerkship. Twenty-two foreign medical Students attended a 2-week hematology clerkship in Fujian Medical University Union Hospital. Twenty-one foreign African medical students were assigned randomly into two groups. Fourteen foreign African medical students were assigned to MTBL group. Each MTBL team included two foreign African medical students and one Chinese post-graduate. Seven foreign African medical students were assigned to lecture-based learning method (LBL) group, which had a foreign medical classmate from Hong Kong or Chinese intern volunteers to serve as translators. The practice test scores of MTBL were significantly higher than LBL group (p < 0.05). The MTBL group had increased motivation to prepare before class, an engaged classroom atmosphere, and an improvement in their understanding of difficult topics. Interestingly, the Chinese post-graduates also benefited from this setting, as they found that this interaction improved their communication in the English language. The mixed team-based learning method overcomes communication problems in hematology clerkship. Foreign medical students and Chinese post-graduates alike can benefit from MTBL. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(2):93-96, 2017.

Hsp90 N- and C-terminal double inhibition synergistically suppresses Bcr-Abl-positive human leukemia cells.

Heat shock protein 90 (Hsp90) contains amino (N)-terminal domain, carboxyl(C)-terminal domain, and middle domains, which activate Hsp90 chaperone function cooperatively in tumor cells. One terminal occupancy might influence another terminal binding with inhibitor. The Bcr-Abl kinase is one of the Hsp90 clients implicated in the pathogenesis of chronic myeloid leukemia (CML). Present studies demonstrate that double inhibition of the N- and C-terminal termini can disrupt Hsp90 chaperone function synergistically, but not antagonistically, in Bcr-Abl-positive human leukemia cells. Furthermore, both the N-terminal inhibitor 17-AAG and the C-terminal inhibitor cisplatin (CP) have the capacity to suppress progenitor cells; however, only CP is able to inhibit leukemia stem cells (LSCs) significantly, which implies that the combinational treatment is able to suppress human leukemia in different mature states.

A novel synthetic novobiocin analog, FM-Nov17, induces DNA damage in CML cells through generation of reactive oxygen species.

OBJECTIVES: To investigate the cytotoxicity of FM-Nov17 against chronic myeloid leukemia (CML) cells, we explored its underlying mechanisms mediating the induction of DNA damage and apoptotic cell death by reactive oxygen species (ROS). METHODS: MTT assays were used to measure the proliferation-inhibition ratio of K562 and K562/G01 cells. Flow cytometry (FCM) was used to test the level of extracellular ROS, DNA damage, cell cycle progression and apoptosis. Western blotting was used to verify the amount of protein. RESULTS: FM-Nov17 significantly inhibited the proliferation of K562 cells, with an IC50 of 58.28±0.304µM, and K562/G01 cells, with an IC50 of 62.36±0.136µM. FM-Nov17 significantly stimulated the generation of intracellular ROS, followed by the induction of DNA damage and the activation of the ATM-p53-r-H2AX pathway and checkpoint-related signals Chk1/Chk2, which led to increased numbers of cells in the S and G2/M phases of the cell cycle. Furthermore, FM-Nov17 induced apoptotic cell death by decreasing mitochondrial membrane potential and activating caspase-3 and PARP. The above effects were all prevented by the ROS scavenger N-acetylcysteine. CONCLUSIONS: FM-Nov17-induces DNA damage and mitochondria-dependent cellular apoptosis in CML cells. The process is mediated by the generation of ROS.

A Novobiocin Derivative, XN4, Inhibits the Proliferation of Chronic Myeloid Leukemia Cells by Inducing Oxidative DNA Damage.

XN4 might induce DNA damage and apoptotic cell death through reactive oxygen species (ROS). The inhibition of proliferation of K562 and K562/G01 cells was measured by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide). The mRNA levels of NADPH oxidase 1-5 (Nox1-5) genes were evaluated by qRT-PCR. The levels of extracellular reactive oxygen species (ROS), DNA damage, apoptosis, and cell cycle progression were examined by flow cytometry (FCM). Protein levels were analyzed by immunoblotting. XN4 significantly inhibited the proliferation of K562 and K562/G01 cells, with IC50 values of 3.75±0.07 µM and 2.63±0.43 µM, respectively. XN4 significantly increased the levels of Nox4 and Nox5 mRNA, stimulating the generation of intracellular ROS, inducing DNA damage and activating ATM-γ-H2AX signaling, which increased the number of cells in the S and G2/M phase of the cell cycle. Subsequently, XN4 induced apoptotic cell death by activating caspase-3 and PARP. Moreover, the above effects were all reversed by the ROS scavenger N-acetylcysteine (NAC). Additionally, XN4 can induce apoptosis in progenitor/stem cells isolated from CML patients' bone marrow. In conclusion, XN4-induced DNA damage and cell apoptosis in CML cells is mediated by the generation of ROS.