Cytotoxicity of the novel anti-cancer drug rViscumin depends on HER-2 levels in SKOV-3 cells

Abuharbeid, Shaker; Apel, Jürgen; Sander, Martin; Fiedler, Babette; Langer, Martin; Zuzarte, Marylou; Czubayko, Frank; Aigner, Achim

doi:10.1016/j.bbrc.2004.06.160

Cited by 31 publications

(16 citation statements)

References 34 publications

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“…39 Briefly, cell lines were plated in quadruplicates into 96-well plates at 200 cells/well and cultivated in IMDM/10% FCS, which was changed every 24 hr, in a humidified incubator under standard conditions. Numbers of viable cells were assessed using a colorimetric assay according to the manufacturer's protocol (Cell Proliferation Reagent WST-1; Roche Molecular Biochemicals, Mannheim, Germany).…”

Section: Growth Assaysmentioning

confidence: 99%

Ribozyme‐targeting reveals the rate‐limiting role of pleiotrophin in glioblastoma

Grzelinski

Bader

Czubayko

et al. 2005

Intl Journal of Cancer

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Glioblastomas (GBMs) are the most frequent malignant brain tumors with very limited treatment options and nearly all GBM patients dying within 1 year. Pleiotrophin (PTN, HB-GAM, HBNF, OSF-1) is a secreted growth factor that shows mitogenic, chemotactic and transforming activity. While PTN expression is tightly regulated during embryogenesis and very limited in normal adult tissues, a marked PTN upregulation is seen in tumors including glioblastomas. Targeting of the PTN receptors, ALK and RPTP-zeta, indicates a contribution of PTN-activated signaling pathways in glioblastomas. However, the relevance of PTN expression itself is unknown especially since, besides PTN, at least one more growth factor, midkine (MK), signals through ALK and is expressed in glioblastoma. Here we demonstrate the biologic relevance of PTN in 2 glioblastoma cell lines in vitro and in vivo. We show that stable ribozyme-targeting leads to a robust reduction of PTN mRNA and protein levels. This results in decreased cell proliferation, cell migration and soft agar colony formation in vitro. Comparing clonal ribozyme-transfected cells with different residual PTN levels, we establish a PTN gene-dose effect of glioblastoma cell proliferation. In a subcutaneous tumor xenograft mouse model, in vivo growth is markedly reduced upon PTN depletion, which is paralleled by decreased PTN serum levels. Furthermore, the immunohistochemical analysis of the tumors shows reduced angiogenesis in PTN-depleted tumors. We conclude that PTN is a rate-limiting growth factor in glioblastoma. Since PTN is overexpressed in glioblastomas but rarely found in normal tissue, PTN may represent an attractive therapeutic target. ' 2005 Wiley-Liss, Inc.Key words: pleiotrophin; PTN; glioblastoma; ribozyme-targeting; tumor growth; tumor angiogenesis Gliomas are the most common primary CNS tumors in humans, which are subdivided according to the WHO into low-grade astrocytomas (grade 2), anaplastic astrocytomas (grade 3) and glioblastomas (GBMs; grade 4). Glioblastomas, which can arise de novo or progress from lower-grade gliomas, are the most frequent and most malignant brain tumors, with nearly all GBM patients dying within 1 year despite aggressive treatment.1 Clearly, an insight into the molecular basis of glioblastoma growth may provide new therapeutic strategies.Pleiotrophin (PTN), also referred to as heparin-binding growthassociated molecule (HB-GAM), heparin-binding growth factor 8, heparin-binding neurotrophic factor (HBNF), or osteoblast-specific protein-1 (OSF-1), is a 15.3 kDa secreted protein that was originally purified from human breast cancer cells, 2 bovine uterus, 3 as well as neonatal rat brain. 4,5 Based on its time-and tissuespecific expression pattern during rodent development, PTN represents a developmentally regulated cytokine whose expression gets increasingly restricted with progressing organ differentiation and drops after the perinatal phase. In the CNS, PTN expression is high in neuroepithelial progenitor cells as well as in glial cells and neurons du...

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Section: Growth Assaysmentioning

confidence: 99%

Ribozyme‐targeting reveals the rate‐limiting role of pleiotrophin in glioblastoma

Grzelinski

Bader

Czubayko

et al. 2005

Intl Journal of Cancer

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“…Western blotting of cell lysates confirmed the Northern blot results and showed an even more pronounced 65-75% reduction of HER-2 protein levels at days 2 and 3 after treatment ( Figure 2b). Concomitanty, p42/44 activation (phosphorylation), which has been shown recently to be reduced upon ribozyme-mediated HER-2 downregulation in SKOV-3 cells, 23 was decreased indicating alterations of molecules downstream in the HER-2 signaling pathways upon siRNA-mediated HER-2 targeting (Figure 2b). The biological relevance of this robust HER-2 downregulation was demonstrated in soft agar assays.…”

mentioning

confidence: 90%

“…Western blot analysis of equal amounts of cell lysates was performed as described. 23,33 (a) By Northern blotting, a B50% reduction of HER-2 mRNA was observed after 48 or 72 h, which resulted in a 65-75% decrease of HER-2 protein levels as determined by Western blotting at the same time points (b). Concomitanty, p42/44 activation (phosphorylation) was decreased indicating alterations of molecules downstream in the HER-2 signaling pathways (b, lower panel).…”

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confidence: 99%

RNAi-mediated gene-targeting through systemic application of polyethylenimine (PEI)-complexed siRNA in vivo

et al. 2004

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RNA interference (RNAi) represents a powerful, naturally occurring biological strategy for inhibition of gene expression. It is mediated through small interfering RNAs (siRNAs), which trigger specific mRNA degradation. In mammalian systems, however, the application of siRNAs is severely limited by the instability and poor delivery of unmodified siRNA molecules into the cells in vivo. In this study, we show that the noncovalent complexation of synthetic siRNAs with low molecular weight polyethylenimine (PEI) efficiently stabilizes siRNAs and delivers siRNAs into cells where they display full bioactivity at completely nontoxic concentrations. More importantly, in a subcutaneous mouse tumor model, the systemic (intraperitoneal, i.p.) administration of complexed, but not of naked siRNAs, leads to the delivery of the intact siRNAs into the tumors. The i.p. injection of PEI-complexed, but not of naked siRNAs targeting the c-erbB2/neu (HER-2) receptor results in a marked reduction of tumor growth through siRNA-mediated HER-2 downregulation. Hence, we establish a novel and simple system for the systemic in vivo application of siRNAs through PEI complexation as a powerful tool for future therapeutic use.

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“…It is now accepted that chemotherapy for ovarian cancer is limited by significant interindividual variations, which are often associated with genetic variations (polymorphisms) in specific genes (23,24). The present findings support the hypothesis that the CXCL12-3'A polymorphism has a strong influence on the outcome of ovarian cancer in patients treated with cisplatin/ paclitaxel chemotherapy, indicating that mean survival rates and the progression-free interval are influenced by CXCL12-3'A genotype subgroups (A carrier and GG) in early stages (I/II) of the disease (P=0.017 and 0.009, respectively).…”

Section: Discussionmentioning

confidence: 99%

CXCL12 chemokine genotypes as predictive biomarkers of ovarian cancer outcome

Coelho

Pereira²,

Nogal³

et al. 2008

Mol Med Rep

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Abstract. Ovarian cancer is an aggressive disease with high mortality. The CXCL12 chemokine has been associated with the development of this neoplasia. The aim of this study was to evaluate the genetic influence of the CXCL12-3'A polymorphism as a prognostic/predictive factor in ovarian cancer patients treated with platinum/paclitaxel chemotherapy. The mean survival rates for early stages (I/II) of the disease were statistically different according to patient genotype (96 months for GG and 57 months for A carrier genotypes; p=0.017). The mean progression-free interval was statistically lower in patients with early stages (I/II) of the tumour carrying the A allele (55 months) than in those carrying the GG genotype (91 months; P=0.009). The CXCL12-3'A polymorphism leads to a poorer response to chemotherapy with cisplatin/paclitaxel, and diminishes the mean survival rate and the progression-free interval in patients with ovarian cancer. CXCL12-3'A may therefore serve as an important predictive biomarker for the determination of outcome in ovarian cancer. IntroductionOvarian cancer is the sixth most common type of cancer and ranks seventh as the most frequent cause of cancer-related death in women (4.0% of cases and 4.2% deaths) (1). At diagnosis, the majority of ovarian cancers have already progressed to stage III or IV, which results in poor long-term patient survival and quality of life (2). Standard treatment involves cytoreductive surgery followed by systemic platinumbased chemotherapy (3). Paclitaxel combinations with either cisplatin or carboplatin are first-line chemotherapy regimens, each combination producing similar responses (4). This therapy results in variable efficacy rates, with frequent recurrences at even early stages of the disease, and with most tumours eventually becoming resistant to chemotherapy (5).The biological mechanisms responsible for chemotherapy resistance remain unclear, but it is now widely accepted that the apoptotic capacity of cancer cells is pivotal in determining response to chemotherapeutic targets (6). Phosphatidylinositol 3-kinase (PI3K)/Akt (serine/threonine kinase subfamily) is a major cell survival pathway, and several targets of Akt, such as proapoptotic protein BAD and caspase-9, have roles in the regulation of apoptosis; phosphorylation by Akt inhibits their function (7).Akt overexpression or activation is correlated with poor prognosis in several tumour types, including gastric and hepatocellular carcinoma, breast and pancreatic cancer and melanoma (8). Previous studies have proposed that PI3K/Akt activation in ovarian cancer cells promotes resistance to cisplatin-induced apoptosis, serving as a mediator in chemoresistance (6,7). This activation may occur due to a variety of stimuli in different types of tumours. It has been suggested that one such stimulus is the chemokine CXCL12 (9-12).The chemokine receptor CXCR4 and its sole ligand, SDF-1/CXCL12 (stromal cell-derived factor-1), play important roles in inflammation and hematopoiesis by acting as chemoattractants for...

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Cytotoxicity of the novel anti-cancer drug rViscumin depends on HER-2 levels in SKOV-3 cells

Cited by 31 publications

References 34 publications

Ribozyme‐targeting reveals the rate‐limiting role of pleiotrophin in glioblastoma

Ribozyme‐targeting reveals the rate‐limiting role of pleiotrophin in glioblastoma

RNAi-mediated gene-targeting through systemic application of polyethylenimine (PEI)-complexed siRNA in vivo

CXCL12 chemokine genotypes as predictive biomarkers of ovarian cancer outcome

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