TPCK Induces Apoptosis in Human Acute Myeloid Leukemia U-937 Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4478-4478
Author(s):  
Julia Mazar ◽  
Alexandra Lichtenstein ◽  
Leora Katz ◽  
Ofer Shpilberg ◽  
Itai Levi ◽  
...  

Abstract Many types of antitumor therapy in general and AML in particular exert their effect by activating apoptosis. Apoptosis of AML cells can be induced by cytostatic drugs, corticosteroids, and radiation. Recently, the role of different proteases as possible targets for chemotherapy was described. N-tosyl-L-phenylalanine chloromethyl ketone (TPCK), a chymotrypsin-like protease (CLP) inhibitor was shown to exert a dual effect on leukemic cells: proapoptotic and antiapoptotic. In the present study the mechanism of its proapoptotic effect was addressed. It was found that the CLP inhibitors, TPCK and 3,4 dichloroisicoumarine induced apoptosis in a time- and concentration-dependent manner. Apoptosis was accompanied by a decrease in mitochondrial membrane potential, cytochrome c release, caspase-3 (but not caspase-8) activation, PS flip-flop (measured by Annexin-V staining followed by flow cytometry analysis) and chromatin condensation, but not fragmentation (detected by acridine orange/ethidium bromide staining). All apoptotic processes induced by TPCK were completely inhibited by cycloheximide. The ability of cycloheximide to inhibit TPCK-induced cell death suggests that protein synthesis plays a role in TPCK-induced apoptosis. Additionaly, the proapoptotic effect of TPCK was abolished by elimination of glucose from the medium. The data supports the role of mitochondria in this process. In the present study the apoptotic pathway driven by inhibition of CLP was demonstrated. Moreover, these findings suggest possible ways of preventing the proapoptotic activity of TPCK and thereby enhancimg its antiapoptotic action.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2981-2981
Author(s):  
Chris Pepper ◽  
Chris Fegan ◽  
Paul Brennan ◽  
Ken Mills ◽  
Alan K. Burnett

Abstract Chronic lymphocytic leukemia (CLL) has a variable clinical course but once treatment is required the development of drug resistance often ensues. Therefore, delineation of the biological mechanisms of drug resistance and the development of novel therapies designed to overcome this is an important goal of research into this condition. We have recently shown that the transcription factor NF-κB plays a central role in regulating CLL cell survival and this is mediated, at least in part, through the transactivation of a number of anti-apoptotic genes including Bcl-2. In this pre-clinical study we evaluated the cytotoxic effects of the novel parthenolide analog, LC-1 (Leuchemix Inc.), in primary tumor cells derived from 49 CLL patients (20 treated, 29 untreated). LC-1 induced apoptosis, as assessed by the Annexin V assay, in a concentration-dependent manner (0.1 – 10 μM) in all the CLL samples tested with a mean LD50 value (the concentration of drug required to kill 50% of the cells) of 2.9 μM. The induction of apoptosis was preceded by a marked loss of NF-κB activity, as evidenced by electrophoretic mobility shift assay, and a down regulation in Bcl-2 protein expression. Caspase-3 activation was a consistent feature of LC-1-induced apoptosis pointing to the involvement of the intrinsic apoptotic pathway. Importantly, CD38+ samples (> 30% expression) and those derived from patients with unmutated VH genes were more sensitive to LC-1 (LD50 values = 2.3 μM versus 3.4 μM and 2.4 μM versus 3.2 μM; P = 0.0003 and 0.01 respectively) suggesting that these CLL cells have a disproportionate reliance on NF-κB activity to maintain their survival and proliferative advantage. Taken together our data clearly demonstrates that LC-1 preferentially targets CLL cells from poor prognostic subsets. This unique cytotoxicity profile warrants further investigation and supports the use of this agent in early clinical trials for patients with CLL.


Drug Research ◽  
2019 ◽  
Vol 69 (12) ◽  
pp. 665-670 ◽  
Author(s):  
Mohammad Jalili-Nik ◽  
Hamed Sabri ◽  
Ehsan Zamiri ◽  
Mohammad Soukhtanloo ◽  
Mostafa Karimi Roshan ◽  
...  

AbstractGlioblastoma multiforme (GBM) is the fatal type of astrocytic tumors with a survival rate of 12 months. The present study, for the first time, evaluated the cytotoxic impacts of Ferula latisecta (F. latisecta) hydroalcoholic extract on U87 GBM cell line. The MTT assay measured the cellular toxicity following 24- and 48 h treatment with various doses of F. latisecta (0–800 μg/mL). Apoptosis was evaluated by an Annexin V/propidium iodide (PI) staining 24 h after treatment by F. latisecta. Moreover, to determine the cellular metastasis of U87 cells, we used a gelatin zymography assay (matrix metalloproteinase [MMP]-2/-9 enzymatic activity). The outcomes showed that F. latisecta mitigated the viability of U87 cells in a concentration- and time-dependent manner with IC50 values of 145.3 and 192.3 μg/mL obtained for 24- and 48 h treatments, respectively. F. latisecta induced apoptosis in a concentration-dependent manner after 24 h. Also, MMP-9 activity was significantly decreased following 24 h after treatment concentration-dependently with no change in MMP-2 enzymatic activity. This study showed that F. latisecta induced cytotoxicity and apoptosis, and mitigated metastasis of U87 GBM cells. Hence, F. latisecta could be beneficial as a promising natural herb against GBM after further studies.


2020 ◽  
Vol 38 (6) ◽  
pp. 1664-1676
Author(s):  
Małgorzata Opydo-Chanek ◽  
Iwona Cichoń ◽  
Agnieszka Rak ◽  
Elżbieta Kołaczkowska ◽  
Lidia Mazur

Summary One of the key features of acute myeloid leukemia (AML) is the arrest of differentiation at the early progenitor stage of myelopoiesis. Therefore, the identification of new agents that could overcome this differentiation block and force leukemic cells to enter the apoptotic pathway is essential for the development of new treatment strategies in AML. Regarding this, herein we report the pro-differentiation activity of the pan-Bcl-2 inhibitor, obatoclax. Obatoclax promoted differentiation of human AML HL-60 cells and triggered their apoptosis in a dose- and time-dependent manner. Importantly, obatoclax-induced apoptosis was associated with leukemic cell differentiation. Moreover, decreased expression of Bcl-2 protein was observed in obatoclax-treated HL-60 cells. Furthermore, differentiation of these cells was accompanied by the loss of their proliferative capacity, as shown by G0/G1 cell cycle arrest. Taken together, these findings indicate that the anti-AML effects of obatoclax involve not only the induction of apoptosis but also differentiation of leukemic cells. Therefore, obatoclax represents a promising treatment for AML that warrants further exploration.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Bin Chen ◽  
Ying Teng ◽  
Xingguang Zhang ◽  
Xiaofeng Lv ◽  
Yanling Yin

Both diabetes and hyperinsulinemia are confirmed risk factors for Alzheimer’s disease. Some researchers proposed that antidiabetic drugs may be used as disease-modifying therapies, such as metformin and thiazolidinediones, although more evidence was poorly supported. The aim of the current study is to investigate the role of metformin in Aβ-induced cytotoxicity and explore the underlying mechanisms. First, the experimental results show that metformin salvaged the neurons exposed to Aβin a concentration-dependent manner with MTT and LDH assay. Further, the phosphorylation levels of JNK, ERK1/2, and p38 MAPK were measured with western blot analysis. It was investigated that Aβincreased phospho-JNK significantly but had no effect on phospho-p38 MAPK and phospho-ERK1/2. Metformin decreased hyperphosphorylated JNK induced by Aβ; however, the protection of metformin against Aβwas blocked when anisomycin, the activator of JNK, was added to the medium, indicating that metformin performed its protection against Aβin a JNK-dependent way. In addition, it was observed that metformin protected the neurons via the suppression of apoptosis. Taken together, our findings demonstrate that metformin may have a positive effect on Aβ-induced cytotoxicity, which provides a preclinical strategy against AD for elders with diabetes.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1276-1276
Author(s):  
Hein Schepers ◽  
Marjan Geugien ◽  
Marco van der Toorn ◽  
Anton L. Bryantsev ◽  
Harm H. Kampinga ◽  
...  

Abstract In the present study, expression and function of Heat Shock Protein 27 (HSP27) was analyzed in acute myeloid leukemia (AML), since HSP27 expression is linked to unfavourable prognosis. HSP27 protein was predominantly expressed in monocytic blasts (M4-M5, 91%, N = 11) and absent in myeloid leukemic blasts (M1-M2, N = 5). A similar lineage restricted expression was observed in normal hematopoietic cells: high expression in normal CD34+ cells and monocytes, and absent in granulocytes. To study the functional role of HSP27, RNA interference (RNAi) studies were performed in the leukemic TF-1 cell line. These experiments demonstrated a twofold increase in VP-16-induced apoptosis after HSP27 siRNA. In contrast, CD95 Fas-induced apoptosis remained the same, as a result of CD95 Fas-mediated upregulation of HSP27. Additional investigations demonstrated that the increased VP-16-induced apoptosis after HSP27 RNAi, was associated with an enhanced phosphorylation of p38 and c-Jun. This VP-16-induced phosphorylation was subsequently followed by the release of cytochrome c into the cytoplasm, which increased twofold after siRNA treatment. These results indicate that HSP27 plays an important role in the protection against VP-16-induced apoptosis through the modulation of p38 and JNK activation, probably through interference with DAXX-mediated ASK1 activation. This was further underscored by co-immunoprecipitation studies, demonstrating complex formation of DAXX and HSP27 in an ASK1-dependent manner. However, in the investigated AML samples, VP-16-mediated apoptosis correlated moderately with HSP27 expression, although HSP27 was highly expressed and phosphorylated and activated in primitive monocytic AML blasts. This is likely due to the co-expression of p21Waf1/Cip1, which is in the majority of the monocytic AML M4-M5 blasts constitutively localised in the cytoplasm and interferes with apoptosis via the DAXX-ASK1-dependent pathway. Preliminary data indicate that overexpression of a cytoplasmic form of p21 is able to reduce the VP-16-induced apoptosis after RNAi for HSP27 as compared to controls, suggesting a predominant anti-apoptotic role of p21 over HSP27. In summary, we demonstrate a role for HSP27 in the survival of leukemic cells by modulation of the DAXX/p38/JNK apoptosis pathway. This survival advantage can further be promoted by the co-expression of cytoplasmic localised p21Waf1/Cip1 protein, indicating that strategies in AML treatment should be focused on targeting multiple signal transduction pathways.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2304-2304 ◽  
Author(s):  
Teresa McQueen ◽  
Marina Konopleva ◽  
Michael Andreeff

Abstract In hematological malignancies, there are reciprocal interactions between leukemic cells and cells of the bone marrow (BM) microenvironment such as mesenchymal stem cells (MSC). It is speculated that specific BM niches may provide a sanctuary for subpopulations of leukemic cells to evade chemotherapy-induced death and allow acquisition of a drug-resistant phenotype. In this study, we compared anti-leukemia effects of Ara-C and various signal transduction and apoptosis inhibitors in a co-culture system of primary AML and human bone marrow-derived MSC. AML blasts from 11 primary AML samples with high (>70%) blast count were co-cultured with MSC for 24 hours, after which they were exposed to the indicated concentrations of inhibitors for 48–96 hrs. Concentrations were selected on the basis of preliminary cell line studies which determined efficient inhibition of drug targets. Induction of apoptosis was analyzed by Annexin V flow cytometry after gating on the CD90 APC(−) (non-MSC) population. MSC protected leukemic blasts from spontaneous apoptosis in all 11 samples studied (mean annexinV positivity, 49.5±7.2% vs 25.3±4.8%, p<0.001) and from Ara-C-induced cytotoxicity in 6 out of 11 samples (p=0.02). No difference in the degree of protection was noted when MSC from older vs. younger donors were used (not shown). Co-culture of leukemic cells with MSC resulted in significant (p<0.03) suppression of inhibitor-induced apoptosis for all agents tested (Table 1), however PI3K/AKT inhibitors seemed to overcome MSC-mediated resistance. In addition, specific inhibitors of Bcl-2 and MDM2 induced apoptosis not only in suspension, but also in the MSC co-culture system, while Raf-1/MEK inhibitors were less effective. The AKT inhibitor A443654 caused apoptosis induction not only in leukemic cells, but also in MSC, which likely accounted for its high efficacy in stromal co-cultures (53±6% annexin V+). In a different study (Tabe et al, ASH 2005), we report that interactions of leukemic and BM stromal cells result in the activation of PI3K/ILK/AKT signaling in both, leukemic and stromal cells. We therefore propose that disruption of these interactions by specific PI3K/AKT inhibitors represents a novel therapeutic approach to eradicate leukemia in the BM microenvironment via direct effects on leukemic cells and by targeting activated BM stromal cells. Furthermore, Bcl-2 and MDM2 inhibitors appear to retain their efficacy in stroma-cocultured AML cells, while the efficacy of chemotherapy and Raf/MEK inhibitors in these conditions may be reduced. Further studies are aimed at the elucidation of the role of the BM microenvironment and its ability to activate specific signaling pathways in the pathogenesis of leukemias and on efforts to disrupt the MSC/leukemia interaction (Zeng et al, ASH 2005). Focus on this stroma-leukemia-stroma crosstalk may result in the development of strategies that enhance the efficacy of therapies in hematological malignancies and prevent the acquisition of a chemoresistant phenotype. Table 1. Leukemia Cell Apoptosis in a MSC/AML Co-Culture System Target Bcl-2/XL MDM2 PI3K AKT Raf-1 MEK Apoptosis was determined as percentage of Annexin V(+)CD90(−) cells, and calculated by the formula: % specific apoptosis = (test − control) x 100 / (100 − control). Compound, concentration Ara-C, 1 μM ABT-737, 0.1 μM Nutlin-3A, 2.5 μM LY294002, 10 μM A443654, 1 μM BAY43-9006, 2.5 μM CI1040, 3 μM AML 28±7 69±7 45±7 53.8±13.3 75±7 35±11 27±11 AML + MSC 16±4 38±6 28±6 31.2±6.9 53±6 18±8 15±5


2015 ◽  
Vol 34 (11) ◽  
pp. 1096-1105
Author(s):  
H-H Cheng ◽  
C-T Chou ◽  
T-K Sun ◽  
W-Z Liang ◽  
J-S Cheng ◽  
...  

Naproxen is an anti-inflammatory drug that affects cellular calcium ion (Ca2+) homeostasis and viability in different cells. This study explored the effect of naproxen on [Ca2+]i and viability in Madin-Darby canine kidney cells (MDCK) canine renal tubular cells. At concentrations between 50 μM and 300 μM, naproxen induced [Ca2+]i rises in a concentration-dependent manner. This Ca2+ signal was reduced partly when extracellular Ca2+ was removed. The Ca2+ signal was inhibited by a Ca2+ channel blocker nifedipine but not by store-operated Ca2+ channel inhibitors (econazole and SKF96365), a protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, and a PKC inhibitor GF109203X. In Ca2+-free medium, pretreatment with 2,5-di-tert-butylhydroquinone or thapsigargin, an inhibitor of endoplasmic reticulum Ca2+ pumps, partly inhibited naproxen-induced Ca2+ signal. Inhibition of phospholipase C with U73122 did not alter naproxen-evoked [Ca2+]i rises. At concentrations between 15 μM and 30 μM, naproxen killed cells in a concentration-dependent manner, which was not reversed by prechelating cytosolic Ca2+ with the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid acetoxymethyl. Annexin V/propidium iodide staining data suggest that naproxen induced apoptosis. Together, in MDCK renal tubular cells, naproxen induced [Ca2+]i rises by inducing Ca2+ release from multiple stores that included the endoplasmic reticulum and Ca2+ entry via nifedipine-sensitive Ca2+ channels. Naproxen induced cell death that involved apoptosis.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2584-2584
Author(s):  
Julie C. Watt ◽  
Marina Konopleva ◽  
Rooha Contractor ◽  
Ismael Samudio ◽  
David Harris ◽  
...  

Abstract GX15-070 is a novel cycloprodigiosin derived small molecule BH3 inhibitor that binds with moderate affinity to all antiapoptotic Bcl-2 family members, including Mcl-1, and is currently undergoing Phase I clinical trials in leukemias. In this study, we investigated the activity of GX15-070 in acute myeloid leukemia (AML) cell lines and primary AML samples. GX15-070 inhibited cell growth of HL-60, U937, OCI-AML3 and KG-1 cell lines at IC50’s of 0.1, 0.5, 0.5 and 2.5μM, respectively, at 72 hours. Neither overexpression of Bcl-2 or Bcl-XL nor loss of expression of Bax conferred resistance to GX15-070. GX15-070 inhibited Bim/Bcl-2 heterodimerization and induced association of activated Bak with Bax in OCI-AML3 cells, as demonstrated by co-immunoprecipitation studies using CHAPS buffer. This was associated with cytosolic release of cytochrome c followed by an increase in annexin positivity, caspase activation and a decrease in mitochondrial inner membrane potential. Notably, GX15-070 induced cytochrome c release from isolated mitochondria of leukemic cells. GX15-070 synergized with both AraC and the novel BH3 mimetic ABT-737 to induce apoptosis in OCI-AML3 cells, a notoriously chemoresistant cell line (GX15-070 and ABT-737 average CI value 0.3; GX15-070 and AraC average CI value 0.36). In 6/7 primary AML samples, GX15-070 induced apoptosis in CD34+ progenitor cells at an average IC50 of 3.6±1.2μM at 24 hours. GX15-070 potently inhibited clonogenic ability of AML blasts at sub-micromolar doses (58.5±10.6% CFU-Blast at 0.1μM and 38.1±10.5% at 0.25μM, n=7). In summary, BH3 inhibitor GX15-070 induces apoptosis in AML cells via inhibition of association of pro-survival Bcl-2 family proteins and BH3-only proteins, followed by Bax/Bak activation and initiation of the intrinsic apoptotic pathway. Hence, GX15-070 alone or in combination with chemotherapeutic agents may have utility in AML therapy.


2001 ◽  
Vol 280 (5) ◽  
pp. H2292-H2299 ◽  
Author(s):  
Guang-Wu Wang ◽  
Zhanxiang Zhou ◽  
Jon B. Klein ◽  
Y. James Kang

To study possible mechanisms for metallothionein (MT) inhibition of ischemia-reperfusion-induced myocardial injury, cardiomyocytes isolated from MT-overexpressing transgenic neonatal mouse hearts and nontransgenic controls were subjected to 4 h of hypoxia (5% CO2-95% N2, glucose-free modified Tyrode's solution) followed by 1 h of reoxygenation in MEM + 20% fetal bovine serum (FBS) (5% CO2-95% air), and cytochrome c-mediated caspase-3 activation apoptotic pathway was determined. Hypoxia/reoxygenation-induced apoptosis was significantly suppressed in MT-overexpressing cardiomyocytes, as measured by both terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling and annexin V-FITC binding. In association with apoptosis, mitochondrial cytochrome c release, as determined by Western blot, was observed to occur in nontransgenic cardiomyocytes. Correspondingly, caspase-3 was activated as determined by laser confocal microscopic examination with the use of FITC-conjugated antibody against active caspase-3 and by enzymatic assay. The activation of this apoptotic pathway was significantly inhibited in MT-overexpressing cells, as evidenced by both suppression of cytochrome c release and inhibition of caspase-3 activation. The results demonstrate that MT suppresses hypoxia/reoxygenation-induced cardiomyocyte apoptosis through, at least in part, inhibition of cytochrome c-mediated caspase-3 activation.


2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Gomathi Chan ◽  
Muhamad Noor Alfarizal Kamarudin ◽  
Daniel Zin Hua Wong ◽  
Nor Hadiani Ismail ◽  
Faizuri Abdul Latif ◽  
...  

This study was aimed to isolate and evaluate neuroprotective compounds from the hexane extract of the bark ofMesua kunstleri(Clusiaceae) on H2O2-induced apoptosis in NG108-15 cells. Five 4-phenylcoumarins were isolated by using various chromatographic techniques via neuroprotective activity-guided fractionation and isolation from the active hexane extract. The chemical structures of the isolated compounds were confirmed by NMR spectroscopic data interpretation and comparison with literature values. Cell viability data demonstrated that mesuagenin C3significantly increased cell viability. Hoechst 33342/PI staining illustrated mesuagenin C3was able to abate the nuclear shrinkage, chromatin condensation and formation of apoptotic bodies. Pretreatment with mesuagenin C3reduced total annexin V positive cells and increased the level of intracellular glutathione (GSH). Mesuagenin C3attenuated membrane potential (Δψm), reduced Bax/Bcl-2 ratio and inactivated of caspase-3/7 and -9. These results indicated that mesuagenin C3could protect NG108-15 cells against H2O2-induced apoptosis by increasing intracellular GSH level, aggrandizingΔψm, and modulating apoptotic signalling pathway through Bcl-2 family and caspase-3/7 and -9. These findings confirmed the involvement of intrinsic apoptotic pathway in H2O2-induced apoptosis and suggested that mesuagenin C3may have potential therapeutic properties for neurodegenerative diseases.


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