Paradoxical antiproliferative effect by a murine mammary tumor-derived epithelial cell line

[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-234epderived 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.This work was supported by Cancer Research Foundation (Fundación de Investigación del Cáncer, FUNDIC), Buenos Aires, Argentina.Peer reviewe

Paradoxical antiproliferative effect by a murine mammary tumor-derived epithelial cell line

<p>Abstract</p> <p>Background</p> <p>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 <it>in vitro </it>and <it>in vivo </it>effect of cellular soluble factors produced by the epithelial cell line on tumor cells.</p> <p>Methods</p> <p>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 <it>in vitro </it>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 <it>in vivo </it>anti-tumor activity of LM-234ep conditioned media was evaluated in subcutaneous tumors formed in <it>nude </it>mice by B16-F10 and HeLa cells.</p> <p>Results</p> <p>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 <it>in vitro </it>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 <it>in vitro </it>growth of LM-234mf, B16-F10, and HeLa cells, inducing cell cycle arrest in G₀/G₁phase. The administration of LM-234ep conditioned medium inhibited the growth of B16-F10 and HeLa tumors in <it>nude </it>mice.</p> <p>Conclusion</p> <p>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.</p

The retention of maize dwarf mosaic virus by the greenbug, schizaphis graminum rondani and its implications for transmission mechanisms

Typescript (photocopy).For over five decades it was thought that aphids transmitted nonpersistent phytopathogenic viruses in what has been termed a "stylet-borne" manner. More recently, it has been proposed that aphids transmit virus as a result of "ingestion and egestion" of virus-containing plant sap. In the former case, virus is acquired and carried as a contaminant in the distal portion of the stylets. Ingestion-egestion, on the other hand, provides that virus is carried up to the maxillary food canal of the alimentary canal and perhaps beyond the pharyngeal gustatory organ. In the latter case there is greater opportunity for interaction between virus and both living and nonliving surfaces within the aphid. When the rate of loss of infectivity of MDMV (maize dwarf mosaic virus) was studied, early results suggested that both ingestion-egestion and stylet-borne contamination were operative mechanisms, the degree to which one predominates depending on the length of the acquisition period. Short acquisition times would result in aphids transmitting virus primarily because of stylet-borne contamination, whereas long acquisition times should result in primarily ingestion-egestion of virus-containing plant sap. Results indicate that the rate of loss of infectivity is independent of acquisition access time. There is a maximal amount of virus that can be acquired by aphids. The hypothesis that a dual-mechanistic approach can explain nonpersistent transmission is not supported. Nonlinear regression analyses can provide good predictions of transmission efficiency after extended retention time intervals. Possible implications of these findings are discussed

Communication for results A Guide for Busines And The Professions

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Potenciación de la resistencia mixta en futbolistas a través de ejercicios físicos en el club deportivo especializado formativo Sportivo Loja

La Combinación entre la resistencia anaeróbica y aeróbica en conocida desde el punto de vista técnico como resistencia mixta. Dicho tipo de resistencia es una de las direcciones determinantes del entrenamiento de muchos deportes, siendo una capacidad física fundamental en el fútbol dado las características del deporte. En dicho sentido, potenciar la resistencia mixta implica mejorar indicadores de rendimiento en el deporte investigado. En tal sentido, el propósito de la investigación es implementar diversos ejercicios especializados para potenciar la resistencia mixta en futbolistas del Club Deportivo Especializado Formativo “Sportivo Loja”. La investigación es cuantitativa con enfoque mixto, dado la aplicación de investigaciones descriptivas, longitudinal, correlacional y analítica. Se estudia a 20 jugadores del club mencionado, entre un rango etario de 16 a 19 años de edad, estudiando a 10 entrenadores especialistas, valorando algunos aspectos esenciales antes y después de implementar la propuesta de intervención. Partiendo de los diagnósticos preliminares establecidos, se diseñó una estrategia con 8 ejercicios físicos especializados y sus respectivas variantes, implementándose en un macrociclo de entrenamiento. Se demuestra una potenciación significativa de la resistencia mixta en los futbolistas, luego de aplicar en su segundo momento el test de Course Navette (p=0,000), presentándose 19 rangos positivos de 20 posible

Paradoxical antiproliferative effect by a murine mammary tumor-derived epithelial cell line

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