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  • 1
    Abstract: Chronic lymphocytic leukemia is a malignancy of mature B cells that strongly depend on microenvironmental factors and their deprivation has been identified as promising treatment approach for this incurable disease. Cytokine array screening of 247 chronic lymphocytic leukemia serum samples revealed elevated levels of TNF receptor-1 which were associated with poor clinical outcome. We detected a microenvironment-induced expression of TNF receptor-1 in chronic lymphocytic leukemia cells in vitro and aberrantly high expression of this receptor in proliferation centers of patients' lymph nodes. Stimulation of TNF receptor-1 with TNF-alpha enhanced NFkappaB activity and viability of chronic lymphocytic leukemia cells which was inhibited by wogonin. Therapeutic effects of wogonin were analyzed in mice after adoptive transfer of Em-TCL1 leukemic cells. Wogonin treatment prevented leukemia development when given early after transplantation. Treatment of full-blown leukemia resulted in loss of TNF receptor-1 on chronic lymphocytic leukemia cells and their mobilization to blood. Targeting TNF receptor-1 signaling is therefore proposed for treatment of chronic lymphocytic leukemia.
    Type of Publication: Journal article epub ahead of print
    PubMed ID: 29326123
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  • 2
    Keywords: E ; TOCOPHEROL ; VITAMIN-E ; ALPHA-TOCOPHEROL ; CD95 ; LIGAND ; EXPRESSION ; CD95 ligand ; ALPHA
    Type of Publication: Book chapter
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  • 3
    Keywords: CELLS ; EXPRESSION ; tumor ; CELL ; Germany ; IN-VIVO ; INHIBITION ; VIVO ; DISEASE ; SITE ; SITES ; GENE ; transcription ; DIFFERENTIATION ; NF-KAPPA-B ; ACTIVATION ; FAMILY ; TRANSCRIPTION FACTOR ; AP-1 ; T cell ; T cells ; T-CELL ; T-CELLS ; BINDING ; RESPONSE ELEMENT ; TRANSCRIPTION FACTORS ; PROMOTER ; BETA ; immune response ; IMMUNE-RESPONSE ; LIVING CELLS ; CD28 ; C-REL ; T lymphocyte,transcription factor,cytokine
    Abstract: IL-4 plays a pivotal role in the development of the Th2 cell mediated humoral immune response and causes IgE-dependent allergic inflammatory diseases. Expression of IL-4 in differentiated Th2 cells is regulated by transcription factors such as NF-AT AP-1 and NF-IL6. Recently, increasing evidence indicates that the pro-inflammatory transcription factor NF-kappaB,13 may also participate in IL-4 expression. In this study, we show that the IL-4 promoter is synergistically activated by NF-kappaB, NF-AT and NF-IL6 at the NF-kappaB/NF-AT/NF-IL6 composite sites. In addition, we performed the chromatin immunoprecipitation technique to determine the functional relevance of NF-kappaB in the activation of the IL-4 gene in vivo. We demonstrate that NF-kappaB binds to the IL-4 promoter in vivo upon T cell activation. Inhibition of NF-kappaB nuclear translocation in living cells blocked binding of NF-kappaB to the IL-4 promoter. The data provide first evidence that NF-kappaB is directly involved in IL-4 transcription
    Type of Publication: Journal article published
    PubMed ID: 15048722
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  • 4
    Keywords: APOPTOSIS ; CELLS ; GROWTH ; IN-VITRO ; tumor ; BLOOD ; CELL ; Germany ; human ; IN-VIVO ; tumor growth ; VITRO ; GENE-EXPRESSION ; ACTIVATION ; MECHANISM ; mechanisms ; T cell ; T cells ; T-CELL ; T-CELLS ; NO ; MEMBRANE ; leukemia ; LYMPHOCYTES ; T-LYMPHOCYTES ; T lymphocyte ; ENDOPLASMIC-RETICULUM ; ANTICANCER DRUGS ; T lymphocytes ; signaling ; RE ; XENOGRAFTS ; TUMOR-GROWTH ; HYDROGEN-PEROXIDE ; USA ; HEPATOCELLULAR-CARCINOMA CELLS ; MEDICINE ; MITOCHONDRIAL PERMEABILITY TRANSITION ; PHOSPHOLIPASE C-GAMMA-1 ; CA2+ MOBILIZATION ; CYCLOPHILIN-D ; SCUTELLARIA-BAICALENSIS GEORGI
    Abstract: Herbs have successfully been used in traditional Chinese medicine for centuries. However, their curative mechanisms remain largely unknown. In this study, we show that Wogonin, derived from the traditional Chinese medicine Huang-Qin (Scutellaria baicalensis Georgi), induces apoptosis in malignant T cells in vitro and suppresses growth of human T-cell leukemia xenografts in vivo. Importantly, Wogonin shows almost no toxicity on T lymphocytes from healthy donors. Wogonin induces prolonged activation of PLC gamma 1 via H2O2 signaling in malignant T cells, which leads to sustained elevation of cytosolic Ca2+ in malignant but not normal T cells. Subsequently, a Ca2+ overload leads to disruption of the mitochondrial membrane. The selective effect of Wogonin is due to its differential regulation of the redox status of malignant versus normal T cells. In addition, we show that the L-type voltage-dependent Ca2+ channels are involved in the intracellular Ca2+ mobilization in T cells. Furthermore, we show that malignant T cells possess elevated amounts of voltage-dependent Ca2+ channels compared with normal T cells, which further enhance the cytotoxicity of Wogonin for malignant T cells. Taken together, our data show a therapeutic potential of Wogonin for the treatment of hematologic malignancies
    Type of Publication: Journal article published
    PubMed ID: 18070986
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  • 5
    Keywords: RECEPTOR ; APOPTOSIS ; CANCER ; EXPRESSION ; IN-VITRO ; TUMOR-CELLS ; carcinoma ; Germany ; PATHWAY ; THERAPY ; DEATH ; GENE ; GENE-EXPRESSION ; TUMORS ; LINES ; NF-KAPPA-B ; LIGAND ; breast cancer ; BREAST-CANCER ; TARGET ; p53 ; MEDIATED APOPTOSIS ; ENDOPLASMIC-RETICULUM STRESS ; T-cell leukemia
    Abstract: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent that kills various tumor cells without damaging normal tissues. However, many cancers remain resistant to TRAIL. To overcome TRAIL resistance, combination therapies using sensitizers of the TRAIL pathway would be an efficacious approach. To investigate potential sensitizers of TRAIL-induced apoptosis, we used TRAIL-resistant human T cell leukemia virus type 1 (HTLV-1)-associated adult T cell leukemia/lymphoma (ATL) cells as a model system. So far, HTLV-1-associated ATL is incurable by presently known therapies. Here, we show that wogonin and the structurally related natural flavones apigenin and chrysin break TRAIL resistance in HTLV-1-associated ATL by transcriptional down-regulation of c-FLIP, a key inhibitor of death receptor signaling, and by up-regulation of TRAIL receptor 2 (TRAIL-R2). This effect is mediated through transcriptional inhibition of the p53 antagonist murine double minute 2 (Mdm2), leading to an increase in p53 levels and, consequently, to up-regulation of the p53 target gene TRAIL-R2. We also show that these flavones can sensitize to TNFalpha- and CD95-mediated cell death. Furthermore, we show that wogonin, apigenin, and chrysin also enhance TRAIL-mediated apoptosis in other human cancer cell lines including breast cancer cell line MDA-MB-231, colon cancer cell line HT-29, hepatocellular carcinoma cell line HepG2, melanoma cell line SK-MEL-37, and pancreatic carcinoma cell line Capan-1 by the same mechanism. Thus, our study suggests the potential use of these flavones as an adjuvant for TRAIL-mediated anticancer therapy.
    Type of Publication: Journal article published
    PubMed ID: 22086925
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  • 6
    Keywords: RECEPTOR ; APOPTOSIS ; GROWTH-FACTOR ; DISEASE ; LINES ; REED-STERNBERG CELLS ; PATHOGENESIS ; B-CELLS ; Stat3 ; INTERLEUKIN-13
    Abstract: Hodgkin/Reed-Sternberg lymphoma (HL) is a clonal B-cell-related malignancy. Although many patients with HL can be cured by the current regimen of high-dose multi-agent chemotherapy, the treatment causes high risks of later pathologies including secondary malignancies. This fact highlights the demand to develop rational treatment for HL. Survival and growth of HL cells are largely dependent on their microenvironment. In this study, using the HL cell lines L1236 and KM-H2 as model systems, we investigated the role of IL-4/IL-13 signaling in regulation of drug sensitivity and resistance in HL. We show that specific blocking of IL-4 and IL-13-mediated STAT6 activation by either an IL-4-binding fusion protein APG598 or an IL-4R antagonist APG201 (R121D/Y124D) renders HL cells more prone to apoptotic killing by chemotherapeutic drugs such as Mitomycin C, 5-Fluorouracil, Etopside, Doxorubicin and Paclitaxel. This effect is due to inhibition of STAT6-mediated elevation of expression of the anti-apoptotic Bcl-2 family protein Bcl-xL. Employing ChIP analysis in combination with APG201 or STAT6-specific siRNA we identified a defined STAT6-binding site in the Bcl-xL promoter region from -1967 to -1957 of the transcription start site. Our data demonstrate that the IL-4/IL-13-STAT6-Bcl-xL axis may be an important target for HL treatment. This study also suggests that combination of classical chemotherapeutic drugs with the IL-4/IL-13 antagonists may enhance efficacy and reduce risks of toxicity from high dose of drugs in HL treatment.
    Type of Publication: Journal article published
    PubMed ID: 23553437
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  • 7
    Keywords: IN-VITRO ; PHASE-I ; BREAST-CANCER ; CARCINOMA-CELLS ; CHRONIC LYMPHOCYTIC-LEUKEMIA ; CANCER CELL-LINES ; MALIGNANT-CELLS ; SOLID TUMORS ; DEPENDENT KINASE INHIBITOR ; DINACICLIB SCH 727965
    Abstract: Tumor initiation, progression and resistance to therapies are tightly associated with over-expression of anti-apoptotic proteins Bcl-2, Bcl-x(L), Bcl-w and Mcl-1. ABT-263 (Navitoclax), an orally bio-available small-molecule mimetic of the Bcl-2 homology domain 3, inhibits Bcl-2, Bcl-x(L), and Bcl-w and has shown anti-cancer effects mainly on lymphomas and lymphocytic leukemia. Despite promising results obtained from the clinical trials, the use of ABT-263 in patients is dose-limited due to causing thrombocytopenia via inhibition of Bcl-x(L) in platelets. ABT-199 specifically inhibits Bcl-2; however, its use is limited to tumors over-expressing only Bcl-2. Besides, many tumors resist treatment due to high levels of Mcl-1 expression or develop resistance via up-regulation of Mcl-1 during long-term exposure. These obstacles highlight the demand to improve the ABT-263-based therapy. In this study, we show that anti-cancer flavones, e.g., wogonin, baicalein, apigenin, chrysin and luteolin enhance ABT-263-induced apoptosis in different cancer cell lines and in primary AML and ALL cells by down-regulation of Mcl-1 expression. Importantly, wogonin does not enhance the toxicity of ABT-263 to proliferating normal T cells and thrombocytes. Wogonin also potentiates the lethality of ABT-263 in cancer cells which have acquired resistance to ABT-263. Furthermore, we show that combination of wogonin with ABT-263 promotes in vivo tumor regression in a human T-cell leukemia xenograft mouse model. Our study demonstrates that wogonin (and related flavones) reduce the effective dose of ABT-263 thereby possibly decreasing the risk of adverse side effects.
    Type of Publication: Journal article published
    PubMed ID: 24895203
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  • 8
    Keywords: RHIZOPHORACEAE
    Abstract: Chemical examination of the barks of mangrove plant Ceriops tagal resulted in the isolation of six new dolabrane-type diterpenes with the trivial names of tagalenes A-F (1-6), together with 10 known analogues. The structures of new compounds were elucidated by extensive spectroscopic data analyses. Tagalenes A-C (1-3) are characterized by 18-nordolabrane scaffold, while tagalene F (6) featured by a 2,3-seco dolabrane derivative. Antitumor assay revealed that seven compounds exhibited potent inhibitory effects against a panel of tumor cell lines with IC50〈10muM, while tagalsin C (8) exerted the most potent activities in comparison with the IC50 values of the rest compounds. The primary structure-activity relationship is discussed. Tagalsin C also exerted the potent effects against a panel of drug-resistant human tumor cell lines, indicating it to be a promising molecule for further evaluation as an antitumor lead compound.
    Type of Publication: Journal article published
    PubMed ID: 25936771
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  • 9
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; tumor ; Germany ; DEATH ; transcription ; PATIENT ; NF-KAPPA-B ; INDUCTION ; T-CELLS ; PROGRESSION ; CELL-DEATH ; FAS-LIGAND EXPRESSION ; INDUCED APOPTOSIS ; UP-REGULATION ; LYMPHOCYTES ; IMMUNE-RESPONSE ; CALCIUM ; HUMAN-IMMUNODEFICIENCY-VIRUS ; T lymphocytes ; CD95 ; PROGRAM ; RE ; HYDROGEN-PEROXIDE ; CD95-MEDIATED APOPTOSIS ; BLOOD MONONUCLEAR-CELLS ; cell death ; AID ; Tat ; HYDROGEN ; KINASE-C-THETA ; CD95 APO-1/FAS LIGAND ; TAT PROTEIN
    Abstract: Termination of an immune response requires elimination of activated T lymphocytes by activation-induced cell death (AICD). In AICD, CD95 (Apo-1/Fas) ligand (L) triggers apoptosis of CD95-positive activated T lymphocytes. In AIDS patients, AICD is strongly enhanced and accelerated. We and others have previously shown that HIV-1 trans-activator of transcription (HIV-1 Tat) sensitizes T cells toward CD95-mediated apoptosis and up-regulates CD95L expression by affecting the cellular redox balance. In this study, we show that it is hydrogen peroxide (11202) that functions as an essential second messenger in TCR signaling. The 11,02 signal combined with simultaneous calcium (Ca2(+)) influx into the cytosol constitutes the minimal requirement for induction of CD95L expression. Either signal alone is insufficient. We further show that HIV-1 Tat interferes with TCR signaling and induces a H2O2 signal. H2O2 generated by HIV-1 Tat combines with CD4-dependent calcium influx and causes massive T cell apoptosis. Thus, our data provide an explanation for CD4(+) T lymphocyte depletion during progression of AIDS
    Type of Publication: Journal article published
    PubMed ID: 15843521
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  • 10
    Keywords: CELLS ; IRRADIATION ; tumor ; Germany ; PATHWAY ; PATHWAYS ; GENE-EXPRESSION ; transcription ; NF-KAPPA-B ; ACTIVATION ; RESPONSES ; IFN-GAMMA ; MECHANISM ; TRANSCRIPTION FACTOR ; INDUCTION ; T-CELL ; T-CELLS ; C-JUN ; PHOSPHORYLATION ; PROTEIN-KINASE ; SUPPRESSION ; cytokines ; IMMUNE-RESPONSES ; TRANSCRIPTION FACTORS ; c-Fos ; UP-REGULATION ; SIGNALING PATHWAY ; SIGNALING PATHWAYS ; TISSUE FACTOR ; IMMUNE-RESPONSE ; KAPPA-B ; IL-2 ; TNF-ALPHA ; SKIN-CANCER ; signaling ; PROGRAM ; RE ; ULTRAVIOLET ; JNK ; SUPPRESSOR ; EVENTS ; ERK ; APC ; EGR-1 EXPRESSION ; JNK PATHWAY ; OZONE DEPLETION ; TRICHINELLA-SPIRALIS ; UV-IRRADIATION
    Abstract: UV irradiation is carcinogenic and immunosuppressive. Previous studies indicate that UV-mediated alteration of APCs and induction of suppressor T cells play a critical role in UV-induced immune suppression. In this study, we show that UV irradiation can directly (independently of APCs and suppressor T cells) inhibit T cell activation by blocking TCR-mediated phosphorylation of ERK and I kappa B via overactivation of the p38 and JNK pathways. These events lead to the down-modulation of c-Jun, c-Fos, Egr-1, and NF-kappa B transcription factors and thereby inhibit production of cytokines, e.g., IL-2, IL-4, IFN-gamma, and TNF-alpha, upon TCR stimulation. We also show that UV irradiation can suppress preactivated T cells, indicating that UV irradiation does not only impair T cell function in response to T cell activation, but can also have systemic effects that influence ongoing immune responses. Thus, our data provide an additional mechanism by which UV irradiation directly suppresses immune responses
    Type of Publication: Journal article published
    PubMed ID: 16081779
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