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  • 1
    In: BMC Research Notes, Springer Science and Business Media LLC, Vol. 7, No. 1 ( 2014-12)
    Type of Medium: Online Resource
    ISSN: 1756-0500
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2014
    detail.hit.zdb_id: 2413336-X
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  • 2
    Online Resource
    Online Resource
    Frontiers Media SA ; 2014
    In:  Journal of Pharmacy & Pharmaceutical Sciences Vol. 17, No. 1 ( 2014-03-10), p. 92-
    In: Journal of Pharmacy & Pharmaceutical Sciences, Frontiers Media SA, Vol. 17, No. 1 ( 2014-03-10), p. 92-
    Abstract: PURPOSE: The prominent ATP-binding cassette (ABC) transporters ABCB1, ABCC1, and ABCG2 are involved in substance transport across physiological barriers and therefore in drug absorption, distribution, and elimination. They also mediate multi-drug resistance in cancer cells. Different flavonoids are known to interfere with different ABC transporters. Here, the effect of the furanoflavonol karanjin, a potential drug with antiglycaemic, gastroprotective, antifungal, and antibacterial effects, was investigated on ABCB1, ABCC1, and ABCG2-mediated drug transport in comparison to the flavonoids apigenin, genistein, and naringenin. METHODS: Cells expressing the relevant transporters (ABCB1: UKF-NB-3ABCB1, UKF-NB-3rVCR10; ABCC1: G62, PC-3rVCR20; ABCG2: UKF-NB-3ABCG2) were used in combination with specific fluorescent and cytotoxic ABC transporter substrates and ABC transporter inhibitors to study ABC transporter function. Moreover, the effects of the investigated flavonoids were determined on the ABC transporter ATPase activities. RESULTS: Karanjin interfered with drug efflux mediated by ABCB1, ABCC1, and ABCG2 and enhanced the ATPase activity of all three transporters. Moreover, karanjin exerted more pronounced effects than the control flavonoids apigenin, genistein, and naringenin on all three transporters. Most notably, karanjin interfered with ABCB1 at low concentrations being about 1µM. CONCLUSIONS: Taken together, these findings should be taken into account during further consideration of karanjin as a potential drug for different therapeutic indications. The effects on ABCB1, ABCC1, and ABCG2 may affect the pharmacokinetics of co-administered drugs. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.METHODS: Cells expressing the relevant transporters (ABCB1: UKF-NB-3ABCB1, UKF-NB-3rVCR10; ABCC1: G62, PC-3rVCR20; ABCG2: UKF-NB-3ABCG2) were used in combination with specific fluorescent and cytotoxic ABC transporter substrates and ABC transporter inhibitors to study ABC transporter function. Moreover, the effects of the investigated flavonoids were determined on the ABC transporter ATPase activities.RESULTS: Karanjin interfered with drug efflux mediated by ABCB1, ABCC1, and ABCG2 and enhanced the ATPase activity of all three transporters. Moreover, karanjin exerted more pronounced effects than the control flavonoids apigenin, genistein, and naringenin on all three transporters. Most notably, karanjin interfered with ABCB1 at low concentrations being about 1µM.CONCLUSIONS: Taken together, these findings should be taken into account during further consideration of karanjin as a potential drug for different therapeutic indications. The effects on ABCB1, ABCC1, and ABCG2 may affect the pharmacokinetics of co-administered drugs.
    Type of Medium: Online Resource
    ISSN: 1482-1826 , 1482-1826
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2014
    detail.hit.zdb_id: 1422972-9
    SSG: 15,3
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  • 3
    In: Journal of Pharmacy & Pharmaceutical Sciences, Frontiers Media SA, Vol. 17, No. 1 ( 2014-04-06), p. 154-
    Abstract: PURPOSE: The clinically approved oncogenic BRAF inhibitor PLX4032 (vemurafenib) was shown to be a substrate of the ATP-binding cassette (ABC) transporter ABCB1. Here, we compared PLX4032 and its structurally closely related precursor compound PLX4720 for their interference with ABCB1 and the ABCB1-mediated compound transport using docking and cell culture experiments. METHODS: For the docking study of PLX4032 and PLX4720 with ABCB1, we analysed binding of both compounds to mouse Abcb1a and to human ABCB1 using a homology model of human ABCB1 based on the 3D structure of Abcb1a. Naturally ABCB1 expressing cells including V600E BRAF-mutated and BRAF wild-type melanoma cells and cells transduced with a lentiviral vector encoding for ABCB1 were used as cell culture models. ABCB1 expression and function were studied by the use of fluorescent and cytotoxic ABCB1 substrates in combination with ABCB1 inhibitors. RESULTS: Docking experiments predicted PLX4032 to interact stronger with ABCB1 than PLX4720. Experimental studies using different cellular models and structurally different ABCB1 substrates confirmed that PLX4032 interfered stronger with ABCB1 function than PLX4720. For example, PLX4032 (20µM) induced a 4-fold enhanced rhodamine 123 accumulation compared to PLX4720 (20µM) in ABCB1-transduced UKF-NB-3 cells and reduced the IC50 for the cytotoxic ABCB1 substrate vincristine in this model by 21-fold in contrast to a 9-fold decrease induced by PLX4720. CONCLUSIONS: PLX4032 exerted stronger effects on ABCB1-mediated drug transport than PLX4720.  This indicates that small changes in a molecule can substantially modify its interaction with ABCB1, a promiscuous transporter that transports structurally different compounds.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.PURPOSE: The clinically approved oncogenic BRAF inhibitor PLX4032 (vemurafenib) was shown to be a substrate of the ATP-binding cassette (ABC) transporter ABCB1. Here, we compared PLX4032 and its structurally closely related precursor compound PLX4720 for their interference with ABCB1 and the ABCB1-mediated compound transport using docking and cell culture experiments. METHODS: For the docking study of PLX4032 and PLX4720 with ABCB1, we analysed binding of both compounds to mouse Abcb1a and to human ABCB1 using a homology model of human ABCB1 based on the 3D structure of Abcb1a. Naturally ABCB1 expressing cells including V600E BRAF-mutated and BRAF wild-type melanoma cells and cells transduced with a lentiviral vector encoding for ABCB1 were used as cell culture models. ABCB1 expression and function were studied by the use of fluorescent and cytotoxic ABCB1 substrates in combination with ABCB1 inhibitors. RESULTS: Docking experiments predicted PLX4032 to interact stronger with ABCB1 than PLX4720. Experimental studies using different cellular models and structurally different ABCB1 substrates confirmed that PLX4032 interfered stronger with ABCB1 function than PLX4720. For example, PLX4032 (20µM) induced a 4-fold enhanced rhodamine 123 accumulation compared to PLX4720 (20µM) in ABCB1-transduced UKF-NB-3 cells and reduced the IC50 for the cytotoxic ABCB1 substrate vincristine in this model by 21-fold in contrast to a 9-fold decrease induced by PLX4720. CONCLUSIONS: PLX4032 exerted stronger effects on ABCB1-mediated drug transport than PLX4720.  This indicates that small changes in a molecule can substantially modify its interaction with ABCB1, a promiscuous transporter that transports structurally different compounds. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
    Type of Medium: Online Resource
    ISSN: 1482-1826 , 1482-1826
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2014
    detail.hit.zdb_id: 1422972-9
    SSG: 15,3
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  • 4
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 5814-5814
    Abstract: Introduction Infection is one of the main causes of mortality and morbidity after allogeneic stem cell transplantation, especially in patients who received T cell depleted haploidentical stem cells. Reactivation or de novo infection of cytomegalovirus (CMV) is amongst the most frequent complications and occur due to a lack of virus-specific T cells post-transplant. Pre-emptive immunotherapy may support both reconstitution of viral specific responses on one hand and may prevent impending leukemic relapse on the other hand. Therefore we established a protocol to generate CMV-specific cytokine-induced killer cells (CIKpp65) with dual cytolytic function against CMV and AML. Protocol CIK cells were generated in vitro from peripheral blood mononuclear cells (PBMC) of CMV-seropositive healthy donors using IFN-γ, activating monoclonal anti-CD3 antibody (MAb), interleukin (IL)-2 and IL-15. An additional single stimulation with human CMVpp65 protein was adequate to increase the amount of cytotoxic CMV-specificcells within CIK cells up to 23%. In total the CMVpp65 stimulation resulted in up to 11.0-fold increased frequency of CMV-dextramer+CD8+cells after 15 days of expansion (n=12). Results Cytotoxicity Next we investigated cell-mediated cytotoxicity against leukemic cell lines THP-1 and K562, pp65 loaded cell line T2 and CMV-infected primary fibroblasts. CIK cell cytotoxicity is described as mediated by activating NK-cell receptor NKG2D. This receptor was blocked in order to determine the specific MHC-mediated cytotoxicity in experiments targeting pp65 loaded cells. The lysis of pp65 loaded cells by CIKpp65 cells was significant higher as compared to conventional CIK cells (effector to target cell ratio of 5:1, 39.9±21.6% to 13.6±10.6%, P 〈 0.01). CIKpp65 cells also induced high cytotoxicity in infected fibroblasts (up to 55%, 10:1 E:T ratio). The anti-leukemic effect was retained in CIKpp65 cells. CIKpp65 cells revealed a mean cytotoxicity of 71.5%, 60.7% and 37.8% against THP-1 and 55.0%, 50.0%, 20.5% against K562 in 40:1, 20:1 and 5:1 E:T ratio, respectively. In contrast, the reactivity against allogeneic PBMC remained low (18% lysis, 40:1 E:T ratio) and allogeneic mock-infected fibroblasts were not lysed at all. This clearly indicates towards the low alloreactive potential of CIKpp65 cells. Phenotype Furthermore we characterized subpopulation and memory phenotype of CIKpp65 cells in detailed flow cytometric analyses and examined the cytokine secretion pattern by cytometric bead array. After expansion the population mainly consisted of a CD3+CD56- T cell (77.6±4.5%) and CD3+CD56+ T-NK cell phenotype (20.0±12.6%). The T-NK cells additionally co-expressed high amounts of CD8 cytotoxic antigen (63.8±16.8%). Interestingly, the T-NK cell compartment contained higher amounts CMV-specific CD8+ cells (mean 5.5%) than the T cell compartment (mean 1.3%). Expression of activating NKG2D and CD25 receptor was strongly positive in both cell fractions. Remarkably, almost 30% of T-NK cells expressed γδ+ T cell receptor, whereas T cells only expressed 4.5% of this receptor type. The cytotoxic T cells within the CIKpp65 cells consisted of a mixed naïve (CD45RA+CD62L+), central memory (CD45RO+CD62L+) and effector memory (CD45RO+CD62L-) phenotype, the cytotoxic T-NK cells mainly of effector memory and EMRA (CD45RA+CD62L-) phenotype. Cytokine secretion (granzyme B, IFN-γ, MIP-1α, TNF-α, Fas-L, IP-10, IL-10, IL-6 and IL-4) were measured during the expansion period and cytotoxic assays and resulting data confirmed the cytotoxic nature of the cells and indicated towards a mainly TH1 cell type character. Conclusion In conclusion CIKpp65 cells can easily be generated from donor PBMC and might represent advantage to conventional CIK cells. Our pre-clinical data demonstrate the concomitant cytotoxicity of generated cells against leukemia cells and CMV, as well as low alloreactivity and limited risk to induce GvHD. Therefore CIKpp65 cells may represent an effective tool for pre-emptive immunotherapy in patients which have both an apparent risk of CMV reactivation and leukemic relapse after allogeneic stem cell transplantation. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 5
    In: European Journal of Cardio-Thoracic Surgery, Oxford University Press (OUP), Vol. 46, No. 5 ( 2014-11), p. 877-886
    Type of Medium: Online Resource
    ISSN: 1873-734X , 1010-7940
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2014
    detail.hit.zdb_id: 1500330-9
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  • 6
    Online Resource
    Online Resource
    Portland Press Ltd. ; 2014
    In:  Biochemical Society Transactions Vol. 42, No. 4 ( 2014-08-01), p. 752-757
    In: Biochemical Society Transactions, Portland Press Ltd., Vol. 42, No. 4 ( 2014-08-01), p. 752-757
    Abstract: Various experimental strategies aim to (re)activate p53 signalling in cancer cells. The most advanced clinically are small-molecule inhibitors of the autoregulatory interaction between p53 and MDM2 (murine double minute 2). Different MDM2 inhibitors are currently under investigation in clinical trials. As for other targeted anti-cancer therapy approaches, relatively rapid resistance acquisition may limit the clinical efficacy of MDM2 inhibitors. In particular, MDM2 inhibitors were shown to induce p53 mutations in experimental systems. In the present article, we summarize what is known about MDM2 inhibitors as anti-cancer drugs with a focus on the acquisition of resistance to these compounds.
    Type of Medium: Online Resource
    ISSN: 0300-5127 , 1470-8752
    Language: English
    Publisher: Portland Press Ltd.
    Publication Date: 2014
    SSG: 12
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  • 7
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