Friend erythroleukemia cells induce angiogenesis in chick embryo chorioallantoic membrane and in human umbilical vein endothelial cells

The effects of Friend erythroleukemia cells on angiogenesis were studied in chick embryo chorioallantoic membrane assay and in human umbilical vein endothelial cells. In chorioallantoic membrane assay, the conditioned medium of Friend cells stimulated in vivo angiogenesis to an extent comparable to that observed with Prostaglandin El, used as positive control. Prostaglandin El added to conditioned medium of Friend cells did not further increase angiogenesis. Conditioned medium of Friend erythroleukemia cells also stimulated proliferation of human umbilical vein endothelial cells to an extent comparable to that observed with fetal bovine serum, used as positive control. Conditioned medium and fetal bovine serum together did not affect human umbilical vein endothelial cells proliferation, as compared to that observed when tested separately. These results seem to indicate that Friend erythroleukemia cells produce and secrete factors stimulating angiogenesis. These findings extend and confirm the hypothesis that successful angiogenesis is necessary for development of leukemias.

Differentiation and malignant suppression induced by mouse erythroid differentiation and denucleation factor on mouse erythroleukemia cells / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the roles of mouse erythroid differentiation and denucleation factor (MEDDF), a novel factor cloned in our laboratory recently, in erythroid terminal differentiation.</p><p><b>METHODS</b>Mouse erythroleukemia (MEL) cells were transfected with eukaryotic expression plasmid pcDNA-MEDDF. Then we investigated the changes on characteristics of cell growth by analyzing cells growth rate, mitotic index and colony-forming rate in semi-solid medium. The expressions of c-myc and beta-globin genes were analysed by semi-quantitative RT-PCR.</p><p><b>RESULTS</b>MEL cells transfected with pcDNA-MEDDF showed significant lower growth rate, mitotic index, and colony-forming rate in semi-solid medium (P<0.01). The percentage of benzidine-positive cells was 32.8% after transfection. The expression of beta-globin in cells transfected with pcDNA-MEDDF was 3.43 times higher than that of control (MEL transfected with blank vector, pcDNA3.1), and the expression of c-myc decreased by 66.3%.</p><p><b>CONCLUSIONS</b>MEDDF can induce differentiation of MEL cell and suppress its malignancy.</p>

ß-Lapachona: una naftoquinona con actividad antitumoral in vivo / ß-Lapachone: a naphthoquinone with antitumor activity in vivo

ß-Lapachona prolonga la sobrevida de ratones con leucemia inducida por el virus de Friend y de pollos con sarcoma inducido por el virus de Rous y recientemente ha demostrado inhibir la proliferación in vitro de varias líneas tumorales humanas. La estructura química de esta droga y presumiblemente su modo de acción, son muy diferentes de la estructura y modo de acción de las drogas antitumorales comúnmente utilizadas en la terapia. Por tal motivo, y con el propósito de ampliar el conocimiento sobre nuevas drogas antineoplásicas intentamos determinar, en este trabajo, si ß-lapachona era capaz de inhibir in vivo el desarrollo de un tumor de ratón no inducido por virus que ha demostrado ser refractario al tratamiento con drogas antineoplásicas convencionales. Se mostró que la administración oral y diaria de ß-lapachona redujo la toma tumoral y prolongó la sobrevida en aquellos ratones donde el tumor LB había crecido. El mayor efecto se produjo cuando la droga fue administrada en la concentración de 125 mg/Kg/día simultáneamente con un inóculo tumoral de 10n ó 10 elevado a la 4, células LB. El efecto sobre un inóculo mayor (10 elevado a la 5, células) o sobre un tumor vascularizado y en activo crecimiento fue más tenue aunque igualmente perceptible. Estos resultados son, en principio, promisorios, pero más experimentos, con diferentes concentraciones de la droga y con diferentes modelos tumorales serán necesarios para determinar adecuadamente el valor terapéutico de ß-lapachona sobre tumores murinos.