FCM - Instituto de Genética Experimental

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Examinando FCM - Instituto de Genética Experimental por Materia "Animals"

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    Lovastatin enhances in vitro radiation-induced apoptosis of rat B-cell lymphoma cells
    (BioMed Central; "Regina Elena" National Cancer Institute, Italy, 1905-06-27) Rozados, Viviana R.; Hinrichsen, Lucila Isabel; McDonnel, José; Scharovsky, O. Graciela
    Our previous demonstration of an antimetastatic effect of lovastatin, both in rat sarcoma and lymphoma tumor-models, as well as the fact that lovastatin and radiation are able to stop the cell cycle in different phases, suggested the feasibility of a combined treatment. We studied the effect of the in vitro combined treatment of a B-cell rat lymphoma (L-TACB) with lovastatin and irradiation. The results herein obtained provide new information about the role of statins as radiosensitizers. The antitumor effect of the combined treatment was higher than that elicited by either treatment alone. This effect could be a consequence, at least in part, of an enhanced apoptosis.
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    Paradoxical antiproliferative effect by a murine mammary tumor-derived epithelial cell line
    (BioMed Central, 2007-10-01) Gurzov, Esteban N.; Nabha, Sanaa M.; Yamamoto, Hamilto; Meng, Hong; Scharovsky, O. Graciela; Bonfil, R. Daniel
    Background Despite significant advancement in breast cancer therapy, there is a great need for a better understanding of the mechanisms involved in breast carcinogenesis and progression, as well as of the role of epigenetic contributions from stromal cells in mammary tumorigenesis. In this study, we isolated and characterized murine mammary tumor-derived epithelial and myofibroblast cell lines, and investigated the in vitro and in vivo effect of cellular soluble factors produced by the epithelial cell line on tumor cells. Methods Morphology, immunophenotype, cytogenetics, invasiveness, and tumorigenicity of epithelial (LM-234ep) and myofibroblast (LM-234mf) cell lines isolated from two murine mammary adenocarcinomas with common ancestor were studied. The in vitro effects of LM-234ep conditioned medium on proliferation, cell cycle distribution, and expression of cell cycle proteins, were investigated in LM-234mf cells, mouse melanoma cells (B16-F10), and human cervical adenocarcinoma cells (HeLa). The in vivo anti-tumor activity of LM-234ep conditioned media was evaluated in subcutaneous tumors formed in nude mice by B16-F10 and HeLa cells. Results LM-234ep cells were found to be cytokeratin positive and hipertriploid, whereas LM-234mf cells were α-smooth muscle actin positive and hypohexaploid. Chromosome aberrations were found in both cases. Only LM-234mf revealed to be invasive in vitro and to secrete active MMP-2, though neither of the cell types were able to produce progressing tumors. LM-234ep-derived factors were able to inhibit the in vitro growth of LM-234mf, B16-F10, and HeLa cells, inducing cell cycle arrest in G0/G1 phase. The administration of LM-234ep conditioned medium inhibited the growth of B16-F10 and HeLa tumors in nude mice. Conclusion Our data suggest the existence of epithelial cell variants with tumor suppressive properties within mammary tumors. To our knowledge, this is the first report showing antiproliferative and antineoplastic activities induced by tumor-derived epithelial cells.
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    ÍtemAcceso Abierto
    Regulatory T cells but not NKT I cells are modulated by a single low-dose cyclophosphamide in a B cell lymphoma tumor-model
    (MORION LLC, 2012-03) Rico, María José; Rozados, Viviana R.; Mainetti, Leandro Ernesto; Zacarías Fluck, Mariano; Matar, Pablo; Scharovsky, O. Graciela
    Aim: Experimental and clinical studies showed that the administration of cyclophosphamide (Cy) in low doses leads to an enhancement of the antitumor immune response. Our objective was to study the modulation, if any, by low dose Cy, of T regulatory (Treg) and natural killer T (NKT) I cells, two cell populations of the innate immune response with opposing effects on the tumors, in a rat B cell lymphoma model. Methods: Inbred e rats were challenged s.c. with L-TACB lymphoma and on day 14 animals were distributed in two groups. Treated: injected i.p. with cyclophosphamide (10mg/kg of body weight) and Control: injected i.p. with saline. Blood samples were taken from days 0 to 21 and the percentage of T regulatory and natural killer T I cells were determined by flow cytometry. Results: We found that the increase of natural and inducible T regulatory cells of peripheral blood achieved during tumor growth was significantly downregulated by cyclophosphamide. On the contrary, natural killer T I cells were not modulated by the treatment. Conclusion: The antimetastatic effect of a single low dose of Cy would be due, at least in part, to downregulation of natural and inducible T regulatory cells.