scholarly journals Continuous replication of Friend virus complex (spleen focus-forming virus-lymphatic leukemia-inducing virus) in mouse embryo fibroblasts. Retention of leukemogenicity and loss of immunosuppressive properties.

1975 ◽  
Vol 142 (4) ◽  
pp. 936-948 ◽  
Author(s):  
R J Eckner
Keyword(s):  
Mouse Embryo ◽  
Helper Virus ◽  
Productive Infection ◽  
Friend Virus ◽  
Focus Formation ◽  
Lymphatic Leukemia ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts

Exposure of NIH Swiss mouse embryo fibroblasts (MEF) to infectious Friend virus (FV) complex [containing defective spleen focus-forming virus (SFFV) and endogenous NB-tropic leukemia-inducing helper virus (LLV-F)] resulted in the productive infection of these cells by both SFFV and LLV-F. Stocks of SFFV derived after extensive growth in this Swiss MEF cell culture system are fully leukemogenic in adult mice for the induction of erythroleukemia and spleen foci. In addition, in vitro-derived LLV-F, when isolated free of SFFV, is fully leukemogenic for the induction of lymphatic leukemia when inoculated into susceptible newborn BALB/c mice. The host range of in vitro-derived FV complex (i.e., FV-TC) for focus formation in vivo is NB-tropic. Unlike in vivo-derived FV complex, FV-TC does not suppress the responsiveness of murine thymocytes to concanavalin A (Con A) in vitro. Rather, FV-TC acts as a mitogen to nonspecifically stimulate the proliferation of BALB/c thymocytes. The mitogenicity of in vitro-derived FV complex is directly associated with the presence of type-C virus particles, is a heat-labile and UV-sensitive property of the virus, and may be primarily due to LLV since equivalent amounts of LLV with or without SFFV present are equally mitogenic. One in vivo passage of FV-TC resulted in the total loss of this mitogenic property with the reappearance of full immunosuppressive properties. This result demonstrates a clear association between in vivo growth of FV and its ability to suppress mouse thymocytes, and suggests that FV complex (SFFV-LLV) is not inherently immunosuppressive for these cells. While the mechanism of this interconversion between immunostimulatory and fully suppressive virus is unknown, both virus markers appear to be dependent upon the presence of infectious FV.

Effect of Daunorubicin and Adriamycin on Nucleic ACID Synthesis of Serum Stimulated Mouse Embryo Fibroblasts

1977 ◽  
Vol 63 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Rosanna Supino ◽  
Anna M. Casazza ◽  
Aurelio Di Marco
Keyword(s):  
Dna Synthesis ◽  
Mouse Embryo ◽  
Rna Synthesis ◽  
Calf Serum ◽  
Acid Synthesis ◽  
Anthracycline Antibiotics ◽  
Simple Method ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts

This paper reports the effects of daunorubicin and adriamycin on DNA and RNA synthesis of in vitro cultured mouse embryo fibroblasts (MEF) stimulated by fetal calf serum (FCS). The addition of FCS to quiescent MEF cultures brings about a wave of RNA synthesis, followed by DNA synthesis which starts between 8 and 12 h after change of medium and proceed for up to 24 h. These cells are therefore partially synchronized. The level of DNA synthesis depends on the amount of FCS added. Daunorubicin and adriamycin are almost equally effective in inhibiting DNA synthesis, as well as cell proliferation, which takes place later. Adriamycin is more active than daunorubicin on RNA synthesis. In cultures treated for an 8 h period starting at different times after FCS addition, the highest DNA synthesis inhibition is achieved by treatment during the first 8 h, when DNA synthesis has not yet started. The cellular uptake of daunorubicin is constantly higher than that of adriamycin, in any experimental condition tested. The results show that FCS-stimulated MEF can provide a simple method for studying the effects of anthracycline antibiotics on partially synchronized cells.

scholarly journals Host Cell Specificity of Minute Virus of Mice in the Developing Mouse Embryo

2004 ◽  
Vol 78 (17) ◽  
pp. 9474-9486 ◽  
Author(s):  
Refael Itah ◽  
Jacov Tal ◽  
Claytus Davis
Keyword(s):  
Host Cell ◽  
Mouse Embryo ◽  
Cell Types ◽  
Late Gestation ◽  
Productive Infection ◽  
Minute Virus Of Mice ◽  
Minute Virus ◽  
Overlapping Sets

ABSTRACT Productive infection by the murine autonomous parvovirus minute virus of mice (MVM) depends on a dividing cell population and its differentiation state. We have extended the in vivo analysis of the MVM host cell type range into the developing embryo by in utero inoculation followed by further gestation. The fibrotropic p strain (MVMp) and the lymphotropic i strain (MVMi) did not productively infect the early mouse embryo but were able to infect overlapping sets of cell types in the mid- or late-gestation embryo. Both MVMp and MVMi infected developing bone primordia, notochord, central nervous system, and dorsal root ganglia. MVMp exhibited extensive infection in fibroblasts, in the epithelia of lung and developing nose, and, to a lesser extent, in the gut. MVMi also infected endothelium. The data indicated that the host ranges of the two MVM strains consist of overlapping sets of cell types that are broader than previously known from neonate and in vitro infection experiments. The correlation between MVM host cell types and the cell types that activate the transgenic P4 promoter is consistent with the hypothesis that activation of the incoming viral P4 promoter by the host cell is one of the host range determinants of MVM.

The reproductive potential of normal mouse embryo fibroblasts during culture in vitro

1984 ◽  
Vol 66 (1) ◽  
pp. 401-409
Author(s):  
C. Karatza ◽  
S. Shall
Keyword(s):  
Mouse Embryo ◽  
Colony Size ◽  
Reproductive Potential ◽  
Cell Strain ◽  
Growth Fraction ◽  
Growth Behaviour ◽  
Direct Estimate ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts

A direct estimate of the reproductive potential of mouse embryo fibroblasts through their entire lifespan has been made using the mini-clone technique, which permits the direct observation of the growth fraction in a bulk population by inspection of the growth behaviour of individual cells. We have measured the colony size on each island that contained one or two cells at the beginning and the fraction of islands which, starting from one or two cells failed to divide even once. We observed that even in a young culture there are individual cells that can only reproduce two or three times. With each succeeding passage the distribution of colony sizes shifts to a greater proportion of small colonies. The median colony size decreases with each passage. Furthermore, the fraction of non-dividers directly observed increases smoothly with time; the fraction of non-dividers is quite small at the first passage but increases steadily to reach 0.6 at the last passage, after about 30 generations. These smooth changes in the growth behaviour of this cell strain are accurately described by the mortalization theory of Shall and Stein, in which the single parameter gamma, describes the change in reproductive potential over the entire lifespan. The parameter gamma describes the rate at which the doubling time of the culture increases; it is the number of generations at which half of the newborn cells are themselves reproductively sterile. Our present data provide an estimate of gamma for this cell strain equal to 21.2 generations, which compares well with a previous estimate of 20.3 generations.

Effect of Syngeneic and Allogeneic Lymphocytes on L-cells and Mouse Embryo Fibroblasts in vitro

Nature ◽  
1967 ◽  
Vol 214 (5094) ◽  
pp. 1229-1230 ◽  
Author(s):  
INESSA YU. CHERNYAKHOVSKAYA ◽  
ZAIRA G. KADAGGIDZE ◽  
GEORGE J. SVET-MOLDAVSKY
Keyword(s):  
Mouse Embryo ◽  
L Cells ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts ◽  
Allogeneic Lymphocytes

scholarly journals The p53 Tumor Suppressor Protein Does Not Regulate Expression of Its Own Inhibitor, MDM2, Except under Conditions of Stress

2000 ◽  
Vol 20 (6) ◽  
pp. 2023-2030 ◽  
Author(s):  
Susan M. Mendrysa ◽  
Mary Ellen Perry
Keyword(s):  
Tumor Suppressor ◽  
Mouse Embryo ◽  
Cultured Cells ◽  
Tumor Suppressor Protein ◽  
Dependent Manner ◽  
P53 Tumor Suppressor ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts ◽  
P53 Tumor Suppressor Protein

ABSTRACT MDM2 is an important regulator of the p53 tumor suppressor protein. MDM2 inhibits p53 by binding to it, physically blocking its ability to transactivate gene expression, and stimulating its degradation. In cultured cells, mdm2 expression can be regulated by p53. Hence, mdm2 and p53 can interact to form an autoregulatory loop in which p53 activates expression of its own inhibitor. The p53/MDM2 autoregulatory loop has been elucidated within cultured cells; however, regulation of mdm2 expression by p53 has not been demonstrated within intact tissues. Here, we examine the role of p53 in regulating mdm2 expression in vivo in order to test the hypothesis that the p53/MDM2 autoregulatory loop is the mechanism by which low levels of p53 are maintained. We demonstrate that basal expression of mdm2 in murine tissues is p53 independent, even in tissues that express functional p53. Transcription ofmdm2 is induced in a p53-dependent manner following gamma irradiation, indicating that p53 regulates mdm2 expression in vivo following a stimulus. The requirement for a stimulus to activate p53-dependent regulation of mdm2 expression in vivo appeared to differ from the situation in early-passage mouse embryo fibroblasts, where mdm2 expression is enhanced by the presence of p53. Analysis of mdm2 expression in intact and dispersed embryos revealed that establishment of mouse embryo fibroblasts in culture induces p53-dependent mdm2expression, suggesting that an unknown stimulus activates p53 function in cultured cells. Together, these results indicate that p53 does not regulate expression of its own inhibitor, except in response to stimuli.

scholarly journals Properties of cell lines derived from tumors induced by Friend virus in BALB/c and BALB/c-H-2b mice.

1975 ◽  
Vol 142 (1) ◽  
pp. 212-223 ◽  
Author(s):  
H A Freedman ◽  
F Lilly
Keyword(s):  
Tumor Cells ◽  
Cell Lines ◽  
Serial Passage ◽  
Helper Virus ◽  
Friend Virus ◽  
Induced Tumors ◽  
Transplantable Tumors ◽  
D Cells

Cell lines have been established in culture from Friend virus-induced tumors of BALB/c (H-2d) and congenic BALB/c-H-2b (BALB.B) origin. Spleens from virus-infected hosts in the terminal stages of erythroleukemic disease provided tissues for the establishment of subcutaneously transplantable tumors of both strains. Subsequently cells of these tumors were introduced into culture and passed serially. Complete, infectious Friend virus (FV) has been routinely recovered from culture supernates of BALB.B tumor cells (HFL/b) throughout its 2-yr passage history. However, after only a few transfer generations in culture BALB/c tumor cells (HFL/d) became nonproducers of virus detectable in either the spleen focus assay in vivo or the XC assay in vitro. Nonproducer HFL/d cells possessed the complete genomes of the components of the FV complex, since FV could be recovered from them either by cocultivation with helper virus-infected syngeneic embryo fibroblasts or by serial passage in the ascitic form in normal, syngeneic adult hosts.

scholarly journals 5′-AMP-Activated Protein Kinase (AMPK) Is Induced by Low-Oxygen and Glucose Deprivation Conditions Found in Solid-Tumor Microenvironments

2006 ◽  
Vol 26 (14) ◽  
pp. 5336-5347 ◽  
Author(s):  
Keith R. Laderoute ◽  
Khalid Amin ◽  
Joy M. Calaoagan ◽  
Merrill Knapp ◽  
Theresamai Le ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mouse Embryo ◽  
Cellular Response ◽  
Null Mouse ◽  
Low Oxygen ◽  
Tumor Microenvironments ◽  
Mouse Embryo Fibroblasts ◽  
Embryo Fibroblasts ◽  
Amp Activated Protein Kinase

ABSTRACT Low oxygen gradients (hypoxia and anoxia) are important determinants of pathological conditions under which the tissue blood supply is deficient or defective, such as in solid tumors. We have been investigating the relationship between the activation of hypoxia-inducible factor 1 (HIF-1), the primary transcriptional regulator of the mammalian response to hypoxia, and 5′-AMP-activated protein kinase (AMPK), another regulatory system important for controlling cellular energy metabolism. In the present study, we used mouse embryo fibroblasts nullizygous for HIF-1α or AMPK expression to show that AMPK is rapidly activated in vitro by both physiological and pathophysiological low-oxygen conditions, independently of HIF-1 activity. These findings imply that HIF-1 and AMPK are components of a concerted cellular response to maintain energy homeostasis in low-oxygen or ischemic-tissue microenvironments. Finally, we used transformed derivatives of wild-type and HIF-1α- or AMPKα-null mouse embryo fibroblasts to determine whether AMPK is activated in vivo. We obtained evidence that AMPK is activated in authentic hypoxic tumor microenvironments and that this activity overlaps with regions of hypoxia detected by a chemical probe. We also showed that AMPK is important for the growth of this tumor model.

Sign in / Sign up

Export Citation Format

Share Document