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ABSTRACT: This paper reports a new approach towards the construction of a multifunctional periodic mesoporous organosilica (PMO), which integrates a range of advantages, such as mesoporous structural order, selective nucleobase-recognition properties, stimuli-responsive site-specific delivery of anticancer agents to cancer tissues, and Cu2+ adsorption, into a single entity. First, the appropriate organic-functional-receptor precursor was synthesized by a chemical process and used to fabricate a multifunctional pyridine-containing PMO material (DMPy-PMO) by a hydrolysis and condensation route. The designed organic–inorganic hybrid mesoporous silica chemosensor showed an intrinsic selective recognition of nucleobase, specifically thymidine, through multipoint hydrogen-bonding interactions with suitably arrayed receptor sites loaded into the rigid silica framework. An in vitro cytotoxicity test showed that the designed chemosensor materials have good biocompatibility and, therefore, could be promising candidates for the delivery of a range of therapeutic agents. Confocal laser scanning microscopy (CLSM) confirmed that the material can be internalized effectively by cancer cells (MCF-7 cells). In addition, the DMPy-PMOs showed efficient Cu2+ ion removal capacity at pH 5.0 with significantly high levels of adsorption (0.95 mmol g–1). These results suggest that the prepared multifunctional PMO hybrid has potential use as a smart material for a range of applications, such as biomolecule recognition, biomedical applications, and as an efficient adsorbent for the removal of metal ions.
European Journal of Inorganic Chemistry 04/2013; · 3.05 Impact Factor
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ABSTRACT: Dendritic cells (DCs) are potent antigen-presenting cells that can be matured in vitro from immature dendritic cells (iDCs) in the presence of several biological agents such as cytokine cocktail, CD40L, TNF-a and antigen loading, which are necessary and achieved using various protocols, such as lipofection, passive pulse or electroporation. However, these DCs maturation protocols may cause with a significant loss of cells because of cellular attachment and spreading during culturing. Some biomaterials that influence adhesion and development of cells have been used in cell culture techniques, and it was thought that they might be applied on the culture of DCs. In this study, we used polyHEMA, which is a hydrogel coating biomaterial that prevents DCs from adherence, and investigated whether hydrogel coating affects the maturation of iDCs. The efficiency in the generation of mDCs was improved through hydrogel coating procedure and a dendritic cell maturation marker, CD83, was significantly increased in hydrogel-coated culture condition. The antigen-loaded mDCs from electroporation were further expressed the CD83. The mDCs generated in the hydrogel-coated culture condition showed more, longer and thicker dendrites, and produced more amounts of cytokines such as IL-12 and IFN-γ. Therefore, it was suggested that the hydrogel-coated culture condition could improve function of mDCs. Cheol-Hun Son and Jae-Ho Bae contributed equally to this work.
Immunological Investigations 03/2013; · 1.47 Impact Factor
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ABSTRACT: In this study, we investigated the role of c-Myc/ATF4/CHOP signaling pathway in sensitization of human hepatoma HepG2 cells to TRAIL. Knockdown of SIRT1 or treatment with SIRT1 inhibitor caused the up-regulation of DR5 and down-regulation of c-FLIP through modulation of c-Myc/ATF4/CHOP pathway, and subsequently enhanced the cytotoxic and apoptotic effects of TRAIL on HepG2 cells. Interestingly, SIRT1 interacted directly with c-FLIP(L) and Ku70, and treatment with SIRT1 inhibitor enhanced acetylation of Ku70 and subsequently decreased its binding to c-FLIP. And this was followed by degradation of c-FLIP. Moreover, Ku70(-/-) MEF and Ku70-knockdown HepG2 cells showed the increased levels of c-Myc, ATF4, CHOP, and DR5 and decreased level of c-FLIP. These results were followed by increased sensitivity of Ku70(-/-) MEF cells and Ku70-knockdown HepG2 cells to TRAIL compared with their control cells. These findings reveal for the first time that SIRT1 inhibition increases Ku70 acetylation, and the acetylated Ku70 with a decreased function mediates the induction of DR5 and the down-regulation of c-FLIP by up-regulating c-Myc/ATF4/CHOP pathway, and consequently promotes the TRAIL-induced apoptosis of HepG2 cells. This study provides important mechanistic insight of the synergism exhibited by SIRT1 inhibition and TRAIL.
The international journal of biochemistry & cell biology 12/2012; · 4.89 Impact Factor
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ABSTRACT: Recently, chemotherapy and radiotherapy are known to directly affect some immunosuppressive barriers within a tumor microenviroment. We used cyclophosphamide (CTX), which is known to enhance the immune response by suppressing CD4CD25 regulatory T cells (Treg cells) when used at a low dose, as a chemotherapeutic agent to provide a synergic effect in the irradiation and dendritic cells (DC) combination therapy. Some previous studies observed that a single-dose CTX treatment significantly reduced the number of Treg cells in 3-5 days, however, the reduced Treg cells increased rapidly after 5 days. To overcome the disadvantages of a single-dose CTX, we used 30 mg/kg dose of CTX, which was treated intraperitoneally to mice 3 days before every immature DC (iDC) injection (known as "metronomic schedule CTX"). Irradiation was applied at a dose of 10 Gy to the tumor on the right thigh by a linear accelerator. Then, iDC was intratumorally injected into the irradiated tumor site. Growth of a distant tumor on the right and left flank was suppressed by an injection of iDC into the irradiated tumor, and this effect was increased by the metronomic schedule CTX. Also, combinations treated with the metronomic schedule CTX and ionizing radiation (IR)/iDC, showed the longest survival time compared with other groups. This antitumor immune response of IR/iDC was improved by metronomic schedule CTX and this result was associated with decreasing the proportion of CD4CD25 Treg cells and increasing the number of tumor-specific interferon-γ-secreting T cells. Our results demonstrated that metronomic schedule CTX improves the antitumor effect of immunization with an injection of DC s into the irradiated tumor.
Journal of immunotherapy (Hagerstown, Md.: 1997) 10/2012; 35(8):607-14. · 3.20 Impact Factor
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ABSTRACT: Many types of cancer cells remain resistant towards TRAIL-induced cytotoxicity by the blockade of apoptotic signaling cascades. Thus, sensitizers are needed to enhance the effect of TRAIL-based cancer therapies. Although synergistic tumor cell death has been reported when various HDAC inhibitors were administered with TRAIL in a variety of human cancers, the effect of inhibitors of Class III HDAC such as SIRT1 have not been reported. We reported here for the first time that inhibition of SIRT1 augmented the cytotoxic and apoptotic effects of TRAIL on human leukemic K562 cells. Knockdown of SIRT1 or treatment with amurensin G, a potent new SIRT1 inhibitor, up-regulated the levels of DR5 and c-Myc and down-regulated the level of c-FLIP(L/S). Furthermore, knockdown of SIRT1 or treatment with amurensin G augmented the molecular responses to TRAIL, including activation of caspase-8, -9 and -3, PARP cleavage, up-regulation of Bax, and down-regulation of Bcl-2. Amurensin G-enhanced TRAIL-induced apoptosis was abrogated by caspase inhibitor Z-VAD-FMK. These findings suggest that the suppression of SIRT1 with siRNA or amurensin G sensitize the TRAIL-resistant K562 cell to TRAIL-induced apoptosis, possibly by the up-regulation of c-Myc and DR5 surface expression and the down-regulations of c-FLIP and Mcl-1. In addition, amurensin G, a potent new SIRT1 inhibitor, would be used as a sensitizer of TRAIL in TRAIL-resistant leukemic cells.
Biochemical pharmacology 03/2012; 84(3):402-10. · 4.25 Impact Factor
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ABSTRACT: Magnetic particles have become very promising materials for drug delivery. However, preparation of magnetite particles with high surface area, biocompatibility, strong magnetic response, and suitable particle size still remains a major challenge. In this report, magnetite nanocrystal clusters with high surface areas were fabricated through a solvothermal process by introducing ammonium acetate as a porogen and trisodium citrate as a surface modification agent. The porosity, which was controlled by the reactant concentration, has been investigated in detail. The surface area of the nanocrystal clusters was as high as 141 m(2) g(-1). Ibuprofen, as a model drug, was entrapped into the magnetite carriers. The interfacial interaction between the carboxylic groups on the drug molecules and the carboxylate groups on the carriers enhanced the loading efficiency. Low cytotoxicity in MCF-7 cell and in vitro constant drug release behavior combined with the high drug loading efficiency and high saturation magnetization values demonstrated the potential of the as-synthesized magnetite materials in targeted drug release systems.
Chemistry 09/2011; 17(45):12802-8. · 5.93 Impact Factor
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ABSTRACT: We have previously shown that inhibition of intracellular signaling pathways by treatment with quercetin induced the expression of natural killer cell group 2D (NKG2D) ligands on cancer cells and made the cells sensitive to natural killer (NK)-cell mediated cytotoxicity. In the present study, we investigated whether epidermal growth factor receptor (EGFR) inhibitors could induce the expression of NKG2D ligands in colon cancer cells. Treatment with EGFR inhibitors predominantly increased the levels of mRNA transcripts and surface protein of UL16-binding protein-1 (ULBP1) in various colon cancer cells, including KM12, Caco-2, HCT-15, and HT-29, which express EGFR, and increased susceptibility of these colon cancer cells to NK-92 cells. The expression of ULBP1 was not induced by inhibitors of nuclear factor-κB, phosphatidylinositol 3 kinase, and MAPK, but was induced by inhibitors of PKC, and the induction of ULBP1 expression with EGFR inhibitors was prevented by treatment with PMA in colon cancer cells. A transcription factor, activator protein-2 alpha (AP-2α), which has a suppressive effect on ULBP1 transcription, was prevented from binding to the ULBP1 promoter by treatment with EGFR inhibitors. The present study suggests that EGFR inhibitors can enhance the susceptibility to NK cell-mediated lysis of colon cancer cells by induction of ULBP1 via inhibition of the PKC pathway.
Cancer Science 09/2011; 103(1):7-16. · 3.33 Impact Factor
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ABSTRACT: In this study, we investigated the role of c-Myc in overcoming multidrug resistance (MDR) in human ovarian and breast cancer cells by TRAIL. We showed that P-gp expressing MDR variants (Hey A8-MDR and MCF7-MDR cells) with high level of c-Myc were highly susceptible to TRAIL treatment when compared to their drug-sensitive parental human ovarian cancer Hey A8 and breast MCF-7 cells, respectively. Up-regulation of DR5 TRAIL receptor and down-regulation of c-FLIP and the promotion of caspase-dependent cell death, which contribute to TRAIL sensitization of MDR cells, were regulated by the over-expressed c-Myc in the MDR cells. After targeted inhibition of c-Myc with specific siRNA, these responses to TRAIL disappeared and TRAIL-induced apoptosis was also suppressed in MCF7-MDR cells. Treatment with TRAIL significantly reduced P-glycoprotein (P-gp)-mediated efflux of rhodamine123 in both Hey A8-MDR and MCF7-MDR cells. Furthermore, TRAIL significantly potentiated the cytotoxicity of vinblastine, vincristine, doxorubicin and VP-16 that are P-gp substrate anticancer drugs in both MDR cells, which resulted in the reversal effect of TRAIL on the MDR phenotype. The present study shows for the first time that elevated c-Myc expression in the MDR cells plays a critical role in overcoming MDR by TRAIL that can act as a specific sensitizer for P-gp substrate anticancer drug.
Biochimica et Biophysica Acta 07/2011; 1812(7):796-805. · 4.66 Impact Factor
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ABSTRACT: As quercetin, which can inhibit phosphatidylinositol 3-kinase, nuclear factor-kappa B, and protein kinase C (PKC) pathways, induced expression of natural killer group 2, member D (NKG2D) ligands on cancer cells and made the cells sensitive to NK -cell-mediated killing; inhibition of epidermal growth factor receptor (EGFR) pathway might lead to induction of NKG2D ligands. In this study, it was investigated whether EGFR inhibitors, including erlotinib or gefitinib, could regulate expression of NKG2D ligands in various lung cancer cells including A549, NCI-H23, and SW-900. The EGFR inhibitors predominantly increased transcription and surface expression of ULBP1, and subsequently increased susceptibility of the cancer cells to NK-92 cells. When the selective inhibitors of nuclear factor-kappa B, phosphatidylinositol 3-kinase, mitogen-activated protein kinases, and PKC were treated to discriminate downstream signaling of EGFR pathway, expression of ULBP1 in the cancer cells was induced by inhibition of PKC. Treatment with phorbol 12-myristate 13-acetate restored the EGFR inhibitor-induced ULBP1 transcription. Binding activity to ULBP1 promoter region of AP-2α, which suggested as suppressor of expression of ULBP1, was decreased by treatment with EGFR inhibitors, and restored by pretreatment with phorbol 12-myristate 13-acetate in A549 and SW-900. Rottlerin, a PKCδ inhibitor, also decreased the binding activity of AP-2α in dose-dependent manner. This study suggests that EGFR inhibitors enhanced the susceptibility to NK cell-mediated lysis of lung cancer cells by induction of ULBP1 by inhibition of PKC pathway and therapeutic efficacy of EGFR inhibitors in lung cancer may be mediated in part by increased susceptibility to NK cell-mediated cytotoxicity.
Journal of immunotherapy (Hagerstown, Md.: 1997) 05/2011; 34(4):372-81. · 3.20 Impact Factor
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ABSTRACT: Growth of a tumor on the left flank was suppressed by direct injection of immature DCs (iDCs) into the irradiated tumor on the right thigh (IR/DC). This antitumor immune effect of IR/DC was enhanced by pretreatment with CTX (CTX+IR/DC) and this effect was related with increased number of tumor-specific IFN-γ secreting T cells and decreased ratio of CD4(+)CD25(+)/CD4(+) T cells. The treatment with CTX+IR/DC increased or decreased the levels of IL-2 or IL-10, respectively. These results demonstrated that antitumor effect of IR/DC could be augmented by pretreatment with low-dose CTX, suggesting a new antitumor therapeutic modality of chemoradioimmunotherapy.
Immunological Investigations 02/2011; 40(4):383-99. · 1.47 Impact Factor
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ABSTRACT: Natural killer (NK) cells are important innate effector cells which can irradicate tumor cells through specific interactions between activating receptors on NK cells and their cognate ligands on cancer cells. Recently, it has been known that induction of activating NKG2D ligands including MHC class I chain-related (MIC) and UL16-binding protein (ULBP) families on tumor cells by various stresses makes them more susceptible to NK cell-mediated cytotoxicity. Therefore, it was investigated whether sublethal dose of hematoporphyrin-based photodynamic therapy (PDT) could up-regulate NKG2D ligands on tumor cells and increase the susceptibility of cancer cells against NK cells. Treatment with sublethal dose of hematoporphyrin-based PDT increased mRNA transcription and surface expression of ULBP1 and ULBP2 genes in SNU-1 human gastric tumor cell line and MICA/B, ULBP1, ULBP2 and ULBP3 genes in SW-900 human lung cancer cell line. These results were followed by increased susceptibility of cancer cells to NK cell-mediated cytotoxicity after sublethal PDT, which was abolished by addition of a blocking NKG2D mAb. Therefore, it could be suggested that the effect of hematoporphyrin-based PDT might be mediated in part by the increased susceptibility to NK cells via induction of NKG2D ligands on tumor cells, which survived after treatment with PDT.
Immunological Investigations 02/2011; 40(4):367-82. · 1.47 Impact Factor
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ABSTRACT: Tumor recurrence and metastasis develop as a result of tumors' acquisition of anti-apoptotic mechanisms and therefore, it is necessary to develop novel effective therapeutics against metastatic cancers. In this study, we showed the differential TRAIL responsiveness of human prostate adenocarcinoma PC3 and human colon carcinoma KM12 cells and their respective highly metastatic PC3-MM2 and KM12L4A sublines and investigated the mechanism underlying high susceptibility of human metastatic cancer cells to TRAIL.
PC3-MM2 and KM12L4A cells with high level of c-Myc and DNA-PKcs were more susceptible to TRAIL than their poorly metastatic primary PC3 and KM12 cells, which was associated with down-regulation of c-FLIPL/S and Mcl-1 and up-regulation of the TRAIL receptor DR5 but not DR4 in both metastatic cells. Moreover, high susceptibility of these metastatic cells to TRAIL was resulted from TRAIL-induced potent activation of caspase-8, -9, and -3 in comparison with their primary cells, which led to cleavage and down-regulation of DNA-PKcs. Knockdown of c-Myc gene in TRAIL-treated PC3-MM2 cells prevented the increase of DR5 cell surface expression, caspase activation and DNA-PKcs cleavage and attenuated the apoptotic effects of TRAIL. Moreover, the suppression of DNA-PKcs level with siRNA in the cells induced the up-regulation of DR5 and active caspase-8, -9, and -3. We also found that 4,5-dimethoxy-2-nitrobenzaldehyde (DMNB), a specific inhibitor of DNA-PK, potentiated TRAIL-induced cytotoxicity and apoptosis in relatively TRAIL-insensitive PC3 and KM12 cells and therefore functioned as a TRAIL sensitizer.
This study showed the positive relationship between c-Myc expression in highly metastatic human prostate and colon cancer cells and susceptibility to TRAIL-induced apoptosis and therefore indicated that TRAIL might be used as an effective therapeutic modality for advanced metastatic cancers overexpressing c-Myc and combination of TRAIL therapy with agent that inhibits the DNA-PKcs/Akt signaling pathway might be clinically useful for the treatment of relatively TRAIL-insensitive human cancers.
Molecular Cancer 01/2011; 10:46. · 3.99 Impact Factor
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ABSTRACT: The inhibitory effect of Dryopteris crassirhizoma on the proliferation of human metastatic prostate PC3-MM2 cells and the mechanism of action were examined to identify its anti-cancer properties. The effect of the extract on cell cycle progression and its combined cytotoxic effect with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on PC3-MM2 cells were also investigated.
The anti-proliferative effects of Dryopteris crassirhizoma were examined by culturing PC3-MM2 cells in the presence or absence of various concentrations of Dryopteris crassirhizoma extract, and the inhibitory effects on cell proliferation were determined by Cell Counting Kit (CCK)-8 analysis. The quantities of apoptosis-inducing proteins were measured by western blotting analysis. Cell cycle progression was analyzed by PI staining using flow cytometry.
Dryopteris crassirhizoma (50 and 100 microg/ml) inhibited markedly the proliferation of PC-3 and PC3-MM2 cells without cytotoxicity to normal (spleen) cells from BALB/C mice. Dryopteris crassirhizoma (100 microg/ml) effectively induced apoptosis through the activation of caspase-3, -8, -9, bid, and PARP in PC3-MM2 cells. The cells exposed to Dryopteris crassirhizoma increased significantly the accumulation of the DNA contents in the G0/G1 phase and sub-G1 phase in contrast to the control. The combined cytotoxic effects of Dryopteris crassirhizoma and TRAIL induced the increased activity of 29% in contrast to the sum of the inhibitory effects of each agent alone.
Dryopteris crassirhizoma has anti-cancer properties by inducing cell cycle arrest and apoptosis through the extrinsic and intrinsic pathway in PC3-MM2 cells. The extract also showed a combined effect with TRAIL on the inhibition of proliferation in the cells. These findings suggest that possibly its extract could be used for treating androgen-independent prostate cancer with minimal side effects.
Journal of ethnopharmacology 05/2010; 130(2):248-54. · 2.32 Impact Factor
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Jae-Ho Bae,
Joo-Young Kim,
Mi-Ju Kim,
Sung-Ho Chang,
You-Soo Park,
Cheol-Hun Son,
Soo-Jung Park,
Joo-Seop Chung,
Eun-Yup Lee,
Sun-Hee Kim,
Chi-Dug Kang
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ABSTRACT: It is known that treatments with heat shock, some anticancer drugs, and ionizing radiation increase the expression of heat-shock proteins (HSPs) and natural killer group 2D (NKG2D) ligands in tumor cells. The increased HSPs may make the tumor cells resistant to apoptosis and reduction of HSPs may make the tumor cells more susceptible to natural killer (NK)-cell mediated lysis of tumor cells. In this study, we investigated whether quercetin which has inhibitory activities against heat-shock factor, protein kinase C, nuclear factor-kappaB, and phosphatidyl inositol 3-kinase, can modulate the expression of NKG2D ligands and suppress the HSPs in tumor cells. The results of this study showed that quercetin significantly induced the expression of several NKG2D ligands including major histocompatibility complex class I-related chain B, UL16-binding protein 1, and UL16-binding protein 2 in K562, SNU1, and SNU-C4 cells. The quercetin-treated K562, SNU1, and SNU-C4 cells showed an enhanced susceptibility to NK-92 cells through induction of NKG2D ligands. This increased expression of NKG2D ligands seemed to be due to the inhibition of the nuclear factor-kappaB and phosphatidyl inositol 3-kinase pathways. The findings of this study suggest that the induced NKG2D ligands with the decrease of HSP70 protein by quercetin may provide an attractive strategy to improve the effectiveness of NK cell-based cancer immunotherapy.
Journal of immunotherapy (Hagerstown, Md.: 1997) 04/2010; 33(4):391-401. · 3.20 Impact Factor
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Sung HoChang,
Eun Jung Jung,
Youn Hee Park,
Dong Gyun Lim,
Na Young Ko,
Wahn Soo Choi,
Erk Her,
Soo Hyun Kim,
Kang Duk Choi, Jae Ho Bae,
Sun Hee Kim,
Chi Dug Kang,
Duck Jong Han,
Song Cheol Kim
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ABSTRACT: Objectives The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4+CD25- T cells and antigen-expanded regulatory T cells.Methods CD4+CD25- T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [3H]thymidine and, after harvesting the cells, [3H] thymidine incorporation was measured. For analysis of interleukin-2 and interferon- secreted from CD4+CD25- T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4+CD25- T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography–mass spectrometry.Key findingsA. princeps (30 μg/ml) effectively suppressed proliferation of CD4+CD25- T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon- in anti-CD3/CD28-stimulated CD4+CD25- T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3.Conclusions The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4+CD25- T cells and increasing activity of expanded regulatory T cells.
Journal of Pharmacy and Pharmacology. 01/2010; 61(8):1043 - 1050.
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ABSTRACT: The development of new modulator possessing high efficacy, low toxicity and high selectivity is a pivotal approach to overcome P-glycoprotein (P-gp) mediated multidrug resistance (MDR) in cancer treatment. In this study, we suggest a new molecular mechanism that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) down-regulates P-glycoprotein (P-gp) through inhibition of DNA-PKcs/Akt/GSK-3beta pathway and activation of caspases and thereby sensitize MDR cells to MDR-related drugs.
MDR variants, CEM/VLB10-2, CEM/VLB55-8 and CEM/VLB100 cells, with gradually increased levels of P-gp derived from human lymphoblastic leukemia CEM cells, were gradually more susceptible to TRAIL-induced apoptosis and cytotoxicity than parental CEM cells. The P-gp level of MDR variants was positively correlated with the levels of DNA-PKcs, pAkt, pGSK-3beta and c-Myc as well as DR5 and negatively correlated with the level of c-FLIPs. Hypersensitivity of CEM/VLB100 cells to TRAIL was accompanied by the activation of mitochondrial apoptotic pathway as well as the activation of initiator caspases. In addition, TRAIL-induced down-regulation of DNA-PKcs/Akt/GSK-3beta pathway and c-FLIP and up-regulation of cell surface expression of death receptors were associated with the increased susceptibility to TRAIL of MDR cells. Moreover, TRAIL inhibited P-gp efflux function via caspase-3-dependent degradation of P-gp as well as DNA-PKcs and subsequently sensitized MDR cells to MDR-related drugs such as vinblastine and doxorubicin. We also found that suppression of DNA-PKcs by siRNA enhanced the susceptibility of MDR cells to vincristine as well as TRAIL via down-regulation of c-FLIP and P-gp expression and up-regulation of DR5.
This study showed for the first time that the MDR variant of CEM cells was hypersensitive to TRAIL due to up-regulation of DR5 and concomitant down-regulation of c-FLIP, and degradation of P-gp and DNA-PKcs by activation of caspase-3 might be important determinants of TRAIL-induced sensitization of MDR cells to MDR-related drugs. Therefore, combination of TRAIL and chemotherapeutic drugs may be a good strategy for treatment of cancer with multidrug resistance.
Molecular Cancer 01/2010; 9:199. · 3.99 Impact Factor
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Sung Ho Chang,
Eun Jung Jung,
Youn Hee Park,
Dong Gyun Lim,
Na Young Ko,
Wahn Soo Choi,
Erk Her,
Soo Hyun Kim,
Kang Duk Choi, Jae Ho Bae,
Sun Hee Kim,
Chi Dug Kang,
Duck Jong Han,
Song Cheol Kim
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ABSTRACT: The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells and antigen-expanded regulatory T cells.
CD4(+)CD25(-) T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [(3)H]thymidine and, after harvesting the cells, [(3)H]thymidine incorporation was measured. For analysis of interleukin-2 and interferon-gamma secreted from CD4(+)CD25(-) T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4(+)CD25(-) T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography-mass spectrometry.
A. princeps (30 microg/ml) effectively suppressed proliferation of CD4(+)CD25(-) T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon-gamma in anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3.
The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4(+)CD25(-) T cells and increasing activity of expanded regulatory T cells.
Journal of Pharmacy and Pharmacology 09/2009; 61(8):1043-50. · 2.17 Impact Factor
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ABSTRACT: Despite the fact that many cancer cells are sensitive to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, human K562 leukemic cells showed resistance to TRAIL-induced apoptosis. Interestingly, K562/R3 cells, a stable TRAIL-sensitive variant isolated from K562 cells, showed down-regulation of DNA-PK/Akt pathway and a high responsiveness to TRAIL-mediated growth inhibition and apoptosis. We revealed that siRNA-mediated suppression of DNA-PKcs led to decreased phosphorylation of Akt and Bad, a target molecule of Akt, and increased expression of DR4/DR5. Also, we found that suppression of DNA-PKcs using siRNA down-regulated c-FLIP and sensitized K562 cells to TRAIL-induced apoptosis through activation of caspase-8, -9 and -3. In addition, we revealed that treatment with DMNB, a specific inhibitor of DNA-PK, resulted in an increase of DR4/DR5 mRNA levels and their surface expression and a decrease of c-FLIP mRNA levels in K562 cells. DMNB potentiated TRAIL-induced cytotoxicity and apoptosis through inhibition of DNA-PK/Akt pathway and activation of caspase-8, -9 and -3 in K562 cells. This study is the first to show that a protective role of DNA-PK/Akt pathway against TRAIL-induced apoptosis and thus TRAIL in combination with agents that inhibit DNA-PK/Akt pathway would have clinical applicability in treating TRAIL-insensitive human leukemic cells. This model may provide a novel framework for overcoming TRAIL resistance of other cancer cells with agents that inhibit DNA-PK/Akt pathway.
Biochemical pharmacology 06/2009; 78(6):573-82. · 4.25 Impact Factor
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ABSTRACT: TRAIL-resistant cancer cells can be sensitized to TRAIL by combination therapy. In this study, we investigated the effect of trichostatin A (TSA), a histone deacetylase inhibitor, to overcome the TRAIL resistance in human ovarian cancer cells. Co-treatment of human ovarian cancer cells with TSA and TRAIL synergistically inhibited cell proliferation and induced apoptosis. The combined treatment of ovarian cancer SKOV3 cells with TSA and TRAIL significantly activated caspase-8 and truncated Bid, resulting in the cytosolic accumulation of cytochrome c as well as the activation of caspase-9 and -3. Moreover, we found that down-regulation of c-FLIP(L) might contribute to TSA-mediated sensitization to TRAIL-induced apoptosis in SKOV3 cells, and this result was supported by showing that down- or up-regulation of c-FLIP(L) with transfection of siRNA or plasmid sensitized or made SKOV3 cells resistant to TRAIL-induced apoptosis, respectively. TSA or co-treatment with TSA alone and TRAIL also resulted in down-regulation of EGFR1/2 and dephosphorylation of its downstream targets, AKT and ERK. Treatment of SKOV3 cells with PKI-166 (EGFR1/2 inhibitor), LY294002 (AKT inhibitor), and PD98059 (ERK inhibitor) decreased c-FLIP(L) expression and co-treatment with TRAIL further reduced the level of c-FLIP(L,) respectively, as did TSA. Collectively, our data suggest that TSA-mediated sensitization of ovarian cancer cells to TRAIL is closely correlated with down-regulation of c-FLIP(L) via inhibition of EGFR pathway, involving caspase-dependent mitochondrial apoptosis, and combination of TSA and TRAIL may be an effective strategy for treating TRAIL-resistant human ovarian cancer cells.
Biochemical pharmacology 05/2009; 77(8):1328-36. · 4.25 Impact Factor
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ABSTRACT: TNF-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic cytokine that is capable of inducing apoptosis in a wide variety of cancer cells but not in normal cells. Although many cancer cells are sensitive to TRAIL-induced apoptosis, chronic myeloid leukemia (CML) develops resistance to TRAIL. In this study, we investigated whether apicidin, a novel histone deacetylase inhibitor, could overcome the TRAIL resistance in CML-derived K562 cells. Compared to treatment with apicidin or TRAIL alone, cotreatment with apicidin and TRAIL-induced apoptosis synergistically in K562 cells. This combination led to activation of caspase-8 and Bcl-2 interacting domain (Bid), resulting in the cytosolic accumulation of cytochrome c from mitochondria as well as an activation of caspase-3. Treatment with apicidin resulted in down-regulation of Bcr-Abl and inhibition of its downstream target, PI3K/AKT-NF-kappaB pathway. In addition, apicidin decreased the level of NF-kappaB-dependent Bcl-x(L), leading to caspase activation and Bid cleavage. These results suggest that apicidin may sensitize K562 cells to TRAIL-induced apoptosis through caspase-dependent mitochondrial pathway by regulating expression of Bcr-Abl and its related anti-apoptotic proteins. Therefore, the present study suggests that combination of apicidin and TRAIL may be an effective strategy for treating TRAIL-resistant Bcr-Abl expressing CML cells.
Experimental Cell Research 04/2009; 315(11):1809-18. · 3.58 Impact Factor
