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Berlin Brandenburg

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  • 1
    Language: English
    In: International Journal of Oncology, January 2002, Vol.20(1), pp.97-106
    Description: Valproic acid (VPA) has been shown to induce growth-arrest and differentiation of human neuroectodermal tumors similarly to several other fatty acids. In the present study, we show that continuous VPA treatment together with Interferon-α (INF-α) synergistically inhibited cell growth of a well-established model of neuroblastoma (NB) differentiation using the human N-myc amplified cell line BE(2)-C. Suppression of tumor growth was accompanied by morphological features of neuronal differentiation and inhibition of histone deacetylase activity. Furthermore, induction of differentiation was concomitant with altered expression of genes related to malignant phenotype such as down-regulation of N-myc, induction of bcl-2 and neural cell adhesion molecule. Production of inhibitors of angiogenesis like thrombospondin-1 and activin A was up-regulated in differentiated NB cells. Treatment with VPA alone decreased the ability of BE(2)-C cells to adhere to and penetrate human endothelium. All these effects of VPA were significantly enhanced when combined with INF-α which on its own had little or no effect. These results suggest that combination of VPA and INF-α may provide a novel therapeutic strategy for NB due to enhanced inhibition of tumor cell growth, induction of tumor differentiation and suppression of malignant biology by reduced angiogenic and decreased metastatic potentials.
    Keywords: Antineoplastic Agents -- Therapeutic Use ; Brain Neoplasms -- Drug Therapy ; Cell Differentiation -- Drug Effects ; Enzyme Inhibitors -- Therapeutic Use ; Interferon-Alpha -- Therapeutic Use ; Neuroblastoma -- Drug Therapy ; Valproic Acid -- Therapeutic Use;
    ISSN: 1019-6439
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  • 2
    Language: English
    In: Cancer research, 01 April 2003, Vol.63(7), pp.1508-14
    Description: Replication restricted oncolytic viruses such as multimutated herpes simplex virus type 1 (HSV-1) G207 represent a novel and attractive approach for cancer therapy, including pediatric solid tumors. Rhabdomyosarcoma is the most common soft-tissue sarcoma of childhood and is often diagnosed already as an advanced disseminated disease. Despite aggressive therapeutic approaches, the prognosis for patients with metastatic rhabdomyosarcoma remains grim. Therefore, there is a need for novel effective drugs with superior safety and efficacy profile. In this study, we showed marked in vitro activity of HSV-1 G207 against embryonal and alveolar rhabdomyosarcoma cells. All human embryonal (KF-RMS-1, RD, and CCA) and alveolar RMS (KFR, Rh28, Rh30, and Rh41) cell lines were highly sensitive to cytotoxic and replicative effects of G207 even at a multiplicity of infection of 0.01, except embryonal Rh1 rhabdomyosarcoma cells, which were efficiently killed only upon multiplicity of infection of 1.0. i.v. G207 treatment of xenotransplanted KFR and KF-RMS-1 tumors in mice led to significant tumor growth inhibition of both tumor entities, whereas intraneoplastic G207 treatment additionally resulted in complete tumor disappearance in 25% of animals. No difference has been found between alveolar and embryonal types of rhabdomyosarcoma. Combination treatment of both cell lines with G207 and vincristine led to strongly enhanced in vitro cytotoxicity without affecting infection efficiency and replication of G207 in KFR as well as in KF-RMS-1 cells. In vivo combination treatment using i.v. G207 and vincristine resulted in complete regression of alveolar rhabdomyosarcoma in five of eight animals and significant growth inhibition of embryonal rhabdomyosarcoma. Taking into consideration the proven safety of G207 in humans, we suggest that G207 alone and in combination with vincristine should be additionally evaluated as a potential agent against human rhabdomyosarcoma.
    Keywords: Antineoplastic Agents, Phytogenic -- Pharmacology ; Rhabdomyosarcoma -- Therapy ; Simplexvirus -- Physiology ; Vincristine -- Pharmacology
    ISSN: 0008-5472
    E-ISSN: 15387445
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 3
    Language: English
    In: International Journal of Cancer, 10 March 2003, Vol.104(1), pp.36-43
    Description: Cytotoxic drug treatment of neuroblastoma often leads to the development of drug resistance and may be associated with increased malignancy. To study the effects of long‐term cytotoxic treatment on malignant properties of tumor cells, we established 2 neuroblastoma cell sublines resistant to vincristine (VCR) and doxorubicin (DOX). Both established cell lines (UKF‐NB‐2VCR and UKF‐NB‐2DOX) were highly resistant to VCR, DOX and vice‐versa but retained their sensitivity to cisplatin. UKF‐NB‐2VCR and UKF‐NB‐2DOX expressed significant amounts of P‐glycoprotein, while parental cells were P‐glycoprotein negative. GD2 expression was upregulated, whereas NCAM expression was decreased in both resistant cells. Spectral karyotype (SKY) analysis revealed complex aberrant karyotypes in all cell lines and additional acquired karyotype changes in both resistant cells. All cell lines harbored high levels of N‐myc amplification. Compared to parental cells, UKF‐NB‐2VCR and UKF‐NB‐2DOX exhibited more than 2‐fold increase in clonal growth , accelerated adhesion and transendothelial penetration and higher tumorigenicity . We conclude that development of drug resistance and acquisition of certain karyotypic alterations is associated with an increase of additional malignant properties that may contribute to the poor prognosis in advanced forms of NB. The 2 novel neuroblastoma cell sublines also provide useful models for the study of drug resistance in aggressive forms of neuroblastoma. © 2002 Wiley‐Liss, Inc.
    Keywords: Neuroblastoma ; Drug Resistance ; Mdr‐1 ; Ncam ; Gd2 ; Karyotype
    ISSN: 0020-7136
    E-ISSN: 1097-0215
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  • 4
    Language: English
    In: International Journal of Oncology, October 2005, Vol.27(4), pp.1029-1037
    Description: Acquisition of P-gp-mediated multidrug-resistance does not always correlate with observed malignant behavior of NB. To characterize alterations accompanying development of multidrug-resistance in NB we established two neuroblastoma cell sublines resistant to vincristine (UKF-NB-3rVCR10) and doxorubicin (UKF-NB-3rDOX20). UKF-NB-3rVCR10 and UKF-NB-3rDOX20 overexpressed functional P-gp and developed an increased malignant phenotype: presented constitutive phosphorylation of AKT, resistance to γ-irradiation, and had increased survival in serum-free medium. Inhibition of P-gp restored chemosensitivity but did not affect increased survival in serum-free medium and sensitivity to γ-irradiation. Inhibition of AKT had no influence on chemoresistance but restored sensitivity to serum starvation. Both resistant cell lines acquired additional chromosomal changes. UKF-NB-3rVCR10 cells acquired a missense P53 mutation in exon 5, an increased MYCN amplification, an enhanced adhesion to endothelium, a decreased NCAM expression, a distinctly higher clonogenicity, and an increased in vivo tumorigenicity. We conclude that acquisition of increased malignant behavior in neuroblastoma occurs concomitantly with multidrug-resistance and is P-gp-independent.
    Keywords: Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; ATP Binding Cassette Transporter, Subfamily B, Member 1 -- Metabolism ; Neuroblastoma -- Pathology;
    ISSN: 1019-6439
    E-ISSN: 17912423
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  • 5
    Language: English
    In: Cancer Letters, 2007, Vol.250(1), pp.107-116
    Description: The efficacy of Onconase on the growth of a panel of chemosensitive and chemoresistant neuroblastoma cell lines was investigated. Onconase decreased cell viability of chemosensitive (IMR-32, UKF-NB-3) and chemoresistant neuroblastoma cell lines characterised by high expression of P-glycoprotein (P-gp) (UKF-NB-3 DOX ) or by high P-gp expression in combination with mutated p53 (UKF-NB-3 VCR , Be(2)-C), in a similar manner. Moreover, Onconase caused cell cycle block in G1 phase and induced caspase-independent cell death. Transmission electron microscope investigations suggested that Onconase-induced autophagy contributes to Onconase-induced cell death. Antitumour activity of Onconase against naïve and drug-resistant neuroblastoma xenografts was confirmed in animals.
    Keywords: Onconase ; Neuroblastoma ; Multi-Drug-Resistance ; P-Glycoprotein ; P53 ; Medicine
    ISSN: 0304-3835
    E-ISSN: 1872-7980
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  • 6
  • 7
    Language: English
    In: Molecular pharmacology, March 2004, Vol.65(3), pp.520-7
    Description: Valproic acid (VPA) is a widely used antiepileptic agent that is undergoing clinical evaluation for anticancer therapy. We assessed the effects of VPA on angiogenesis in vitro and in vivo. In human umbilical vein endothelial cells, therapeutically relevant concentrations of VPA (0.25 to 1 mM) inhibited proliferation, migration, and tube formation. VPA 1 mM inhibited endothelial cell proliferation by 51 +/- 5%, migration by 86 +/- 11%, and tube formation by 82 +/- 3%. These changes were preceded by the hyperacetylation of histone H4, indicating the inhibition of histone deacetylase (HDAC), and a decreased expression of the endothelial nitric-oxide synthase (eNOS). The inhibition of endothelial cell tube formation by VPA was prevented by addition of the nitric oxide donor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA NONOate). The anticonvulsive active VPA derivative 2-ethyl-4-methylpentanoic acid, which does not inhibit HDAC, did not affect endothelial cell proliferation, tube formation, or eNOS expression. VPA was also found to inhibit angiogenesis in vivo in the chicken chorioallantoic membrane assay and in a Matrigel plug assay in mice. Embryos from VPA-treated mice showed disturbed vessel formation. These results indicate that therapeutic plasma levels of VPA inhibit angiogenesis by a mechanism involving a decrease in eNOS expression preceded by HDAC inhibition.
    Keywords: Angiogenesis Inhibitors -- Pharmacology ; Endothelium, Vascular -- Drug Effects ; Neovascularization, Physiologic -- Drug Effects ; Valproic Acid -- Pharmacology
    ISSN: 0026-895X
    E-ISSN: 15210111
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