• BMB Reports
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• v.49 no.1
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• pp.63-68
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• 2016

The serine/threonine kinase mTOR is essential for the phosphoinositide 3-kinases (PI3K) signaling pathway, and regulates the development and function of immune cells. Aberrant activation of mTOR signaling pathway is associated with many cancers including leukemia. Here, we report the contributions of mTOR signaling to growth of human leukemic cell lines and mouse T-cell acute leukemia (T-ALL) cells. Torin, an ATP-competitive mTOR inhibitor, was found to have both cytotoxic and cytostatic effects on U-937, THP-1, and RPMI-8226 cells, but not on Jurkat or K-562 cells. All cells were relatively resistant to rapamycin even with suppressed activity of mTOR complex 1. Growth of T-ALL cells induced by Notch1 was profoundly affected by torin partially due to increased expression of Bcl2l11 and Bbc3. Of note, activation of Akt or knockdown of FoxO1 mitigated the effect of mTOR inhibition on T-ALL cells. Our data provide insight on the effect of mTOR inhibitors on the survival and proliferation of leukemic cells, thus further improving our understanding on cell-context-dependent impacts of mTOR signaling. [BMB Reports 2016; 49(1): 63-68]

• Journal of Life Science
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• v.26 no.3
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• pp.376-386
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• 2016

Apoptosis induction has been proposed as an efficient mechanism by which malignant tumor cells can be removed following chemotherapy. The intrinsic mitochondria-dependent apoptotic pathway is frequently implicated in chemotherapy-induced tumor cell apoptosis. Since DNA-damaging agent (DDA)-induced apoptosis is mainly regulated by the tumor suppressor protein p53, and since more than half of clinical cancers possess inactive p53 mutants, microtubule-damaging agents (MDAs), of which apoptotic effect is mainly exerted via p53-independent routes, can be promising choice for cancer chemotherapy. Recently, we found that the apoptotic signaling pathway induced by MDAs (nocodazole, 17α-estradiol, or 2-methoxyestradiol) commonly proceeded through mitotic spindle defect-mediated prometaphase arrest, prolonged Cdk1 activation, and subsequent phosphorylation of Bcl-2, Mcl-1, and Bim in human acute leukemia Jurkat T cells. These microtubule damage-mediated alterations could render the cellular context susceptible to the onset of mitochondria-dependent apoptosis by triggering Bak activation, Δψm loss, and resultant caspase cascade activation. In contrast, when the MDA-induced Bak activation was inhibited by overexpression of anti-apoptotic Bcl-2 family proteins (Bcl-2 or Bcl-xL), the cells in prometaphase arrest failed to induce apoptosis, and instead underwent mitotic slippage and endoreduplication cycle, leading to formation of populations with 8N and 16N DNA content. These data indicate that cellular apoptogenic mechanism is critical for preventing polyploid formation following MDA treatment. Since the formation of polyploid cells, which are genetically unstable, may cause acquisition of therapy resistance and disease relapse, there is a growing interest in developing new combination chemotherapies to prevent polyploidization in tumors after MDA treatment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1441-1447
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• 2003

The purpose of this research was to investigate the effects of Chungjokupye-tang(CJKPT) on the anti-carcinogenic action. The cell viability of mouse spienocytes and thymocytes were enhanced by the addition of CJKPT. CJKPT were increased of splenic and thymic T lymphocytes, such as T/sub H/ cells were markedly increased by the treatment of CJKPT in vivo. CJKPT treatment induced the apoptotic cell death of Jurkat and HL60 leukemia cells. CJKPT reduced mitochondrial transmembrane potential and increased the expression of ICE, c-myc and p53 gene in Molt-4cells dose dependant manner. These results suggest that CJKPT have an anti-carcinogenic action via immunoregulatory mechanism.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1193-1198
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• 2011

Encapsulation of biological material in the permiselective membrane allows to construct a system separating cells from their products, which may find biotechnological as well as biomedical applications in biological processes regulation. Application of a permiselective membrane allows avoiding an attack of the implanted microorganisms on the host. Our aim was to evaluate the performance of Bacillus subtilis encapsulated in an elaborate membrane system producing listeriolysin O, a cytolysin from Listeria monocytogenes, with chosen eukaryotic cells for future application in anticancer treatment. The system of encapsulating in membrane live Bacillus subtilis BR1-S secreting listeriolysin O was proven to exert the effective cytotoxic activity on eukaryotic cells. Interestingly, listeriolysin O showed selective cytotoxic activity on eukaryotic cells: more human leukemia Jurkat T cells were killed than human chronic lymphocytic B cells leukemia at similar conditions in vitro. This system of encapsulated B. subtilis, continuously releasing bacterial products, may affect selectively different types of cells and may have future application in local anticancer treatment.

• BMB Reports
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• v.34 no.6
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• pp.578-583
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• 2001

As a prototypic Thl vs Th2 cytokine, IFN-$\gamma$ and IL-4 activate distinct STAT proteins, STAT1 and STATE, respectively. In cytokine-producing Jurkat T cells, IL-4 is effectively rescued from cell death that is induced by dexamethasone, but IFN-$\gamma$ failed to do so. Since the Ras/MAPK pathway is known to play an important role in cytokine-induced cell survival, we investigated the mechanism of T cell survival through the analysis of functional cross-talk between Ras/MAPK and distinct STAT proteins that are activated by IL-4 and IFN-$\gamma$. Although IL-4 and IFN-$\gamma$ each induced the activation of STATE and STATI. in Jurkat T cells, respectively, only IL-4 was capable of inducing MAPK. Along with tyrosine kinase inhibitors, MEK/MAPK inhibitors also caused a significant suppression of the IL-4-induced STATE activity. This suggests a positive regulation of STATE by MAPK during IL-4 signal transduction. Furthermore, transfection studies with dominant active (da) vs dominant negative (dn) Ras revealed that daRas, but not dnRas, selectively up-regulated the expression and activity of STATE with a concomitant increase in MAPK activity. These results, therefore, suggest that there is a functional cross-talk between the Ras/MAPK and Jak/STAT6 pathways, which may have a role in the IL-4-induced T cell survival.

• BMB Reports
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• v.45 no.2
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• pp.85-90
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• 2012

Our previous study demonstrated that CopA3, a disulfide dimer of the coprisin peptide analogue (LLCIALRKK), has antibacterial activity. In this study, we assessed whether CopA3 caused cellular toxicity in various mammalian cell lines. CopA3 selectively caused a marked decrease in cell viability in Jurkat T, U937, and AML-2 cells (human leukemia cells), but was not cytotoxic to Caki or Hela cells. Fragmentation of DNA, a marker of apoptosis, was also confirmed in the leukemia cell lines, but not in the other cells. CopA3-induced apoptosis in leukemia cells was mediated by apoptosis inducing factor (AIF), indicating induction of a caspase-independent signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.208-214
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• 2009

Steroid hormones have long been known to have a profound influence on the immune system. Although the functions of the nuclear receptors in the development of T cells are fairly well studied, the differential expression of these receptors in T helper cells is poorly understood. Here, we investigated the differential expression of nuclear receptors and coregulators in Th1 and Th2 cells by genome-wide micro array analysis. The result showed that several nuclear receptors and coregulators are differentially expressed in these cells. The result was confirmed by RT-PCR. The result showed that $RXR{\alpha}$ is highly expressed in Th2 cells. Overexpression of $RXR{\alpha}$ in a Jurkat human T cell line induced IL4 but not IFN-${\gamma}$ gene expression, suggesting that $RXR{\alpha}$ plays a selective role in Th1 and Th2 differentiation. In summary, these results suggest that Th1/Th2 differentiation is influenced by differential regulation of nuclear receptors and coregulators.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.546-554
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• 2006

To understand antitumor activity of Zanthoxylum schinfolium, which has been used as an aromatic and medicinal plant in Korea, the cytotoxic effect of various organic solvent extracts of its leaves on human tumor cells were investigated. Among these extracts such as methanol extract (SL-13), methylene chloride extract (SL-14), ethyl acetate extract (SL-15), n-butanol extract (SL-16), and residual fraction (SL-17), SL-14 appeared to contain the most cytotoxic activity against leukemia and breast cancer cells tested. The methylene chloride extra.1 (SL-14) possessed an apoptogenic activity causing apoptotic DNA fragmentation of human acute leukemia Jurkat T cells via mitochondrial cytochrome c release into cytoplasm, subsequent activation of caspase-9 and caspase-3, and cleavage of PARP, which could be negatively regulated by antiapoptotic protein Bcl-xL. The GC-MS analysis of SL-14 revealed that the twenty-two ingredients of SL-14 were 9,19-cyclolanost-24-en-3-ol (15.1%), 2-a-methyl-17, b-hop-21-ene (15.1%), 15-methyl-2,3-dihydro-1H benzazepin (11.95%), phytol (10.38%), lupeol (9.92%), 12-methylbenzofuran (8.23%), hexadecanoic acid (5.96%), cis,cis,cis-9,12,15-octadecatrienoic acid-methyl-ester (5.49%), 9,12,15-octadecatrienoic acid-methylester (3.59%), 15-methyl-4-(1-methylethylidene)-2-(4-nitrophenyl) (3.36%), hexadecanoic acid methyl ester (1.93%), vitamine E (1.88%), beta-amyrin (0.96%), and auraptene (0.89%). These results demonstrate that the cytotoxicity of the methylene chloride extract of the leaves of Z. schinifolium toward Jurkat T cells is mainly attributable to apoptosis mediated by mitochondria-dependent caspase cascade regulated by Bcl-xL, and provide an insight into the mechanism underlying antitumor activity of the edible plant Z. schinifolium.

• Journal of Haehwa Medicine
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• v.22 no.1
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• pp.145-170
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• 2013

Objectives : This study was carried out to investigate the anti inflammatory and anti allergy effects of Vitex rotundifolia Linne fil. extract(VRE). Results : 1. In vitro test, VRE was used to determine the modulation of cytokine secretion, the activation of inflammatory and allergic factor and the inhibition of gene expression. The cell survival rate of Raw 264.7 and Jurkat T cells didn't decrease and accordingly cytotoxicity wasn't observed. In anti-allergic assay, the secretion of IL-2, TNF-${\alpha}$, IL-4, IL-5 and IFN-${\gamma}$ were suppressed on Jurkat T cells induced by dust mites. And the gene expression of COX-2 was suppressed in HMC-1 stimulated by calcium ionophore A23187. In anti-inflammatory assay, the gene expression of TNF-${\alpha}$, COX-2 were suppressed on LPS-activated Raw 264.7 cells. And the secretion of IL-6 and IL-8 were suppressed on EoL-1 cells induced by dust mites. P38 and ERK activation of MAPK decreased generally. VRE showed potent inhibitory activity of NO production. 2. In vivo test, we used NC/Nga mouse induced by atopic dermatitis to observe the effects of VRE on the weight, water and feed, blood test, weight of organs, total IgE and histological change of main organs. Quantity of water and feed were not changed, therefore it didn't affect the weight directly, and no change was observed in related main organs, thus maybe there is no organ toxicity by test substances. And the symptoms were decreased significantly, and the thickness of epithelial cell layer and the number of mast cells were inhibited significantly by the difference of dosage. The number of total complete blood cells and IgE in serum were not changed significantly. Conclusion : These results suggest that VRE has anti-inflammatory and anti-allergic effects. Therefore VRE could be used effectively on improvement or treatment of atopic dermatitis. However, further study is needed to prove which component of VRE indicates effective pharmacological action.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.93-100
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• 2014

Background: Curcumin has has been reported to exert anti-inflammatory, anti-oxidation and anti-angiogenic activity in various types of cancer. It has also been shown to induce apoptosis in leukemia cells. We aimed to unravel the role of the redox pathway in Curcumin mediated apoptosis with a panel of human leukemic cells. Materials and Methods: In this study in vitro cytotoxicity of Curcumin was measured by MTT assay and apoptotic effects were assessed by annexin V/PI, DAPI staining, cell cycle analysis, measurement of caspase activity and PARP cleavage. Effects of Curcumin on intracellular redox balance were assessed using fluorescent probes like $H_2DCFDA$, JC1 and an ApoGSH Glutathione Detection Kit respectively. Results: Curcumin showed differential anti-proliferative and apoptotic effects on different human leukemic cell lines in contrast to minimal effects on normal cells. Curcumin induced apoptosis was associated with the generation of intracellular ROS, loss of mitochondrial membrane potential, intracellular GSH depletion, caspase activation. Conclusions: As Curcumin induces programmed cell death specifically in leukemic cells it holds a great promise as a future therapeutic agent in the treatment of leukemia.