Reversible Regulation of the Transformed Phenotype of Ornithine Decarboxylase- and Ras-Overexpressing Cells by Dominant-Negative Mutants of c-Jun

Kielosto, Mari; Nummela, Pirjo; Katainen, Riikka; Leaner, Virna D.; Birrer, Michael J.; Hölttä, Erkki

doi:10.1158/0008-5472.can-3188-2

Cited by 23 publications

(25 citation statements)

References 55 publications

(44 reference statements)

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“…Unlike the fourfold increase in ODC activity in ODC transformants (Moshier et al, 1993), ODC activity was increased only twofold in the AZI-overexpressing cells. Furthermore, there may be other functions of ODC which have not yet been fully elucidated, such as the ability of ODC to modulate downstream kinases and transcription factors (Gilmour et al, 1999;Kielosto et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Regulation of cell proliferation by the antizyme inhibitor: evidence for an antizyme-independent mechanism

Kim

Mangold

Waghorne

et al. 2006

Journal of Cell Science

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The antizyme inhibitor was discovered as a protein that binds to the regulatory protein antizyme and inhibits the ability of antizyme to interact with the enzyme ornithine decarboxylase (ODC). Blocking antizyme activity subsequently leads to increased intracellular levels of ODC and increased ODC enzymatic activity. We now report that antizyme inhibitor is a positive modulator of cell growth. Overexpression of antizyme inhibitor in NIH-3T3 mouse fibroblasts or in AT2.1 Dunning rat prostate carcinoma cells resulted in an increased rate of cell proliferation and an increase in saturation density of the cultured cells. This was accompanied by an increase in intracellular levels of the polyamine putrescine. In AT2.1 cells, antizyme inhibitor overexpression also increased the ability of the cells to form foci when grown under anchorage-independent conditions. In order to determine the role of antizyme on antizyme inhibitor activity we created an antizyme inhibitor mutant, AZIΔ117-140, which lacks the putative antizyme-binding domain. We show that this mutant fails to bind to antizyme, but remains capable of inducing increased rates of cell proliferation, suggesting that antizyme inhibitor has antizyme-independent functions. Silencing antizyme inhibitor expression leads to diminished levels of cyclin D1 and to reduced cell proliferation. Antizyme inhibitor is capable of preventing cyclin D1 degradation, and this effect is at least partially independent of antizyme. We show that wild-type antizyme inhibitor and the AZIΔY mutant are capable of direct interaction with cyclin D1 suggesting a potential mechanism for the antizyme-independent effects. Together, our data suggest a novel function for antizyme inhibitor in cellular growth control.

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Section: Discussionmentioning

confidence: 99%

Regulation of cell proliferation by the antizyme inhibitor: evidence for an antizyme-independent mechanism

Kim

Mangold

Waghorne

et al. 2006

Journal of Cell Science

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“…It was established that cell transformation induced by ODC and c-Ha-ras oncogene is accompanied by constitutively increased phosphorylation of c-Jun (Kielosto, 2004).…”

Section: Ornithine Decarboxylase Under Mucosa Malignancymentioning

confidence: 99%

The ornithine decarboxylase, NO-synthase activitiesand phospho-c-Jun content under experimental gastric mucosa malignancy

et al. 2016

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Abstract-Introduction:Ornithine decarboxylase is the first and key regulatory enzyme in synthesis of polyamines, which are essential for cell proliferation and differentiation, so its aberrant regulation is reported to play a role in neoplastic transformation and tumours growth. That's why, there were analysed some major links of metabolic pathways that are closely related to tumorigenesis: ornithine decarboxylase, and the NADPH-dependent enzyme nitric oxide synthase, the nuclear phosphoprotein c-Jun, that could play an important role in the development of gastric cancer malignancy. Methods: Thegastric carcinogenesis was initiated in rats by 10-week replacement of drinking water by 0.01% N-methyl-N'-nitro-N-nitrosoguanidine solution, at the same time they were redefined on the diet containing 5% NaCl. After this period expired, the animals were fed with standard diet till the end of the 24 th week. The gastric mucosa cells were extracted at the end of the 4 th , 6 th , 8 th , 10 th , 12 th , 18 th and 24 th week and underwent biochemical examinations. It was established the elevated phospho-c-Jun content, ornithine decarboxylase and inducible nitric oxide synthase activities from 6 th to 24 th week of gastric cancer development compared to the control references. Results: The increasing of ornithine decarboxylase activity could probably be caused by the growth of phospho-c-Jun, it is also belonging to an ornithine decarboxylase transactivation effects. Thus, it was shown that the increase of ornithine decarboxylase and inducible nitric oxide synthase activities, phospho-c-Jun and nitrite-ions accumulation in gastric mucosa epithelial cells were associated with the gastric malignant progression. Conclusion: The complex relationships between the examined enzymes and transcription activator that pointed to an aggravation of pathological disturbances due to reciprocal action between ornithine decarboxylase and c-Junand nitric oxide synthase participation.

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“…An Amdc cell line stably transfected with the tetracycline-inducible expression system of the c-Jun deletion mutant TAM67 (Amdc-pLRT-TAM67) was generated similarly to that previously described for the ODCand ras-transformed cell lines. 21 Amdc-pLRT-TAM67 cells were cultured in MEM alpha medium supplemented with gentamycin (50 lg/ml) and 5% TET System Approved FBS (all from Invitrogen). For induction of TAM67 expression, 1 lg/ml doxycycline (Sigma, St. Louis, MO) was added the day after plating.…”

Section: Cell Culturementioning

confidence: 99%

“…The membranes were then immunoblotted as previously described, 21 using primary antibodies detailed in Supporting Information Table II and horseradish peroxidase-conjugated swine anti-rabbit IgGs, rabbit anti-rat IgGs (both from DAKO, Glostrup, Denmark), or goat anti-mouse IgG/IgM (Chemicon International, Temecula, CA). These are the genes downregulated most in AdoMetDC-transformed NIH3T3 cells expressing a tetracycline-inducible TAM67 vector (AmdcpLRT-TAM67 cells; induction for 3 and 6 days), that were previously found to be upregulated in the parental Amdc cells as compared with normal NIH3T3 fibroblasts (for direct comparison, the folds of increase of the respective genes in Amdc cells are 3.2, 3.1, 5.1, 8.3, 2.7, 23.5, 2.4, 6.8, 4.1, 2.2, 3.8, 12.1, 7.3, and 2.3, respectively, as analyzed with Incyte Genomics' arrays).…”

Section: Western Blottingmentioning

confidence: 99%

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Identification of integrins α6 and β7 as c‐Jun‐ and transformation‐relevant genes in highly invasive fibrosarcoma cells

Kielosto

Nummela

Järvinen

et al. 2009

Intl Journal of Cancer

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Understanding the mechanisms of tumor cell invasion is essential for our attempts to prevent cancer deaths. We screened by DNA microarrays the c-Jun-and transformation-related gene expression changes in S-adenosylmethionine decarboxylase (AdoMetDC)-overexpressing mouse fibroblasts that are highly invasive in vivo, and their derivatives expressing a tetracycline-inducible dominant-negative mutant of c-Jun (TAM67) or c-Jun shRNA. Among the small set of target genes detected were integrins a6 and b7, cathepsin L and thymosin b4, all upregulated in the AdoMetDC-transformed cells and downregulated upon reversal of transformation by TAM67 or c-Jun shRNA. The upregulation of integrin a6 subunit, pairing with integrin b1, endowed the transformed cells with the capability to attach to basement membrane laminin and to spread. Further, inhibition of integrin a6 or b1 function with neutralizing antibodies blocked the invasiveness of AdoMetDC-transformants and human HT-1080 fibrosarcoma cells in three-dimensional Matrigel. Moreover, immunohistochemical analyses showed strong integrin a6 staining in high-grade human fibrosarcomas. Our data show that c-Jun can regulate all three key steps of invasion: cell adhesion (integrin a6), basement membrane/extracellular matrix degradation (cathepsin L) and cell migration (thymosin b4). In addition, this is the first study to associate integrin b7, known as a leukocyte-specific integrin binding to endothelial/epithelial cell adhesion molecules, with the transformed phenotype in cells of nonleukocyte origin. As tumor cell invasion is a prerequisite for metastasis, the observed critical role of integrin a6b1 in fibrosarcoma cell invasion/spreading allures testing antagonists to integrin a6b1, alone or combined with inhibitors of cathepsin L and thymosin b4, as chemotherapeutic agents. ' 2009 UICC

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Reversible Regulation of the Transformed Phenotype of Ornithine Decarboxylase- and Ras-Overexpressing Cells by Dominant-Negative Mutants of c-Jun

Cited by 23 publications

References 55 publications

Regulation of cell proliferation by the antizyme inhibitor: evidence for an antizyme-independent mechanism

Regulation of cell proliferation by the antizyme inhibitor: evidence for an antizyme-independent mechanism

The ornithine decarboxylase, NO-synthase activitiesand phospho-c-Jun content under experimental gastric mucosa malignancy

Identification of integrins α6 and β7 as c‐Jun‐ and transformation‐relevant genes in highly invasive fibrosarcoma cells

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