COMPARATIVE STUDIES IN ROUS SARCOMA WITH VIRUS, TUMOR CELLS, AND CHICK EMBRYO CELLS TRANSFORMED IN VITRO BY VIRUS : I. PRODUCTION OF MUCOPOLYSACCHARIDES

COMPARATIVE STUDIES IN ROUS SARCOMA WITH VIRUS, TUMOR CELLS AND CHICK EMBRYO CELLS TRANSFORMED IN VITRO BY VIRUS : III. MALIGNANCY IN VIVO OF CELLS TRANSFORMED IN VITRO BY VIRUS

Chick embryo fibroblasts infected with Rous sarcoma virus in vitro are rendered malignant for such cells produce typical Rous sarcomas when injected into susceptible chicks since the tumors produced predominantly retain the sex chromatin patterns of the donor cells when such cells are injected into a recipient of the opposite sex. However, examination of the sex chromatin of cells at the periphery of the tumor shows presence of recipient cells though the bulk of the tumor is clearly of donor cell origin. Such tumors grow and cause death of the recipient. Injection of RSV induces tumors of the sex of the recipient as also does the injection of transformed cells rendered incapable of multiplication by x-rays. Following their injection into susceptible chicks, the cells transformed in vitro by virus behave in the same manner as tumor cells obtained from tumors induced by virus in vivo and cultivated in the same conditions in vitro. When such tumors induced by transformed cells are serially transferred in recipients of the opposite sex, they gradually convert to the sex of the recipient indicating that the tumors are not indefinitely transplantable. These chick embryo fibroblasts transformed in vitro show the same neo-plastic properties as tumor cells when they are introduced into the cheek pouch of the hamster or the eye of the guinea pig.

Hyaluronan activates cell motility of v-Src-transformed cells via Ras-mitogen-activated protein kinase and phosphoinositide 3-kinase-Akt in a tumor-specific manner

We investigated the production of hyaluronan (HA) and its effect on cell motility in cells expressing the v-src mutants. Transformation of 3Y1 by v-src virtually activated HA secretion, whereas G2A v-src, a nonmyristoylated form of v-src defective in cell transformation, had no effect. In cells expressing the temperature-sensitive mutant of v-Src, HA secretion was temperature dependent. In addition, HA as small as 1 nM, on the other side, activated cell motility in a tumor-specific manner. HA treatment strongly activated the motility of v-Src-transformed 3Y1, whereas it showed no effect on 3Y1- and 3Y1-expressing G2A v-src. HA-dependent cell locomotion was strongly blocked by either expression of dominant-negative Ras or treatment with a Ras farnesyltransferase inhibitor. Similarly, both the MEK1 inhibitor and the kinase inhibitor clearly inhibited HA-dependent cell locomotion. In contrast, cells transformed with an active MEK1 did not respond to the HA. Finally, an anti-CD44-neutralizing antibody could block the activation of cell motility by HA as well as the HA-dependent phosphorylation of mitogen-activated protein kinase and Akt. Taken together, these results suggest that simultaneous activation of the Ras-mitogen-activated protein kinase pathway and the phosphoinositide 3-kinase pathway by the HA-CD44 interaction is required for the activation of HA-dependent cell locomotion in v-Src-transformed cells.

Comparative studies in Rous sarcoma with virus, tumor cells, and chick embryo cells transformed in vitro by virus. II. Response of normal and immunized chicks

Chick embryo fibroblasts infected in vitro with Rous sarcoma virus have properties similar to tumor cells when injected into virus-immune chickens. When such virus-transformed fibroblasts are injected into normal chickens, they apparently participate in the production of tumors independent of their release of virus and are thus apparently malignant in vivo.

Synthesis of glycoconjugates in mouse primordial germ cells

The synthesis of protein-bound carbohydrates has been studied in primordial germ cells (PGCs) and in somatic cells of 12.5 to 13.5-days-postcoitum (dpc) fetal mouse gonads. Both cell types were shown to synthesize asparagine-linked glycopeptides and glycosaminoglycans (GAGs). In addition, PGCs also synthesize lactosaminoglycans (LAGs) although in different proportions in female and male germ cells. Female PGCs, which at 13.5 dpc are entering meiosis, synthesize mainly LAGs, and minor amounts of hyaluronic acid (HA) and chondroitin sulfate (CS). Male germ cells, on the other hand, synthesize mainly CS. Furthermore, somatic cells of fetal gonads synthesize HA as the major class of GAGs. It is suggested that the activation of LAG synthesis in developing germ cells might be related to the beginning of meiosis. Moreover, we propose that HA synthesis might be developmentally regulated in somatic cells of the gonad, in order to regulate the establishment of specific interactions with germ cells.

Poor prognosis for mucin-producing Wilms' tumor

This report describes two cousins with Wilms' tumor and mucin detected in the sera with rapidly fatal courses. A review of the literature reveals five additional reported cases of Wilms' tumor where mucin was observed in the sera. The patients in this report are similar to those previously reported in that all had metastatic disease at diagnosis, and four of five died within one year of diagnosis. Both the extent of disease at diagnosis at the poor response to therapy in these two cases, and those from the literature suggest that evidence of mucin production may indicate poor prognosis in Wilms' tumor. In addition, evidence is reviewed that mucin itself may contribute to a rapid tumor growth and metastases. The genetics of Wilms' tumor and familial nature of these cases is also discussed.

Distribution of glycoconjugates in mouse fibroblasts with varying degrees of tumorigenicity

Analysis of glucosamine labeled glycoconjugates in cultured cells has been made comparing 2 clones and the parent embryonic mouse cell line. Hyaluronic acid, heparan sulphate, and chondrotin sulphate as well as a complex mixture of glycopeptides were found in the medium, the trypsinate, and the trypsinized cells, although the distribution was not uniform. The 3 cell lines had very similar in vitro growth properties, including their plating efficiency in viscous medium. However, the tumorigenicity of the cells, determined syngeneic mice, was found to differ. All 3 cell lines were found to have similar glycoconjugate distributions, although a slight relative increase in labeled hyaluronic acid was found in the more tumorigenic mass cell line than either of the clones. The possible significance of this increase is discussed.

Virus-induced transformation without cell division

Interference with the cell cycle by vinblastine sulfate immediately after cells were infected with Rous sarcoma virus had little effect on the a development of two metabolic changes that occur in transformed cells. These results, along with an earlier demonstration of morphological changes developing in infected nondividing cells, demonstrate that the phenotypic development of the malignant state can occur without the intervention of cell divisions after infection by Rous sarcoma virus.

Temperature-dependent transformation of cells infected with a mutant of Bryan Rous sarcoma virus

Chick embryo cells infected with a mutant (Ta) of the Bryan high-titer strain of Rous sarcoma virus (RSV-BH) are morphologically transformed at 36 C but appear similar to uninfected cells at 41 C. When cells infected with RSV-BH-Ta are switched from 41 to 36 C, morphological changes characteristic of transformation are observable within 10 min. The transformation is reversible; cells shifted from 36 to 41 C have been observed to lose their transformed morphology within 1 hr. The transformation after a shift in temperature is unaffected by inhibition of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), or protein synthesis, demonstrating that the proteins involved in the morphological change are already present. Transformed cells infected with RSV-BH or RSV-BH-Ta take up hexose and synthesize hyaluronic acid at higher rates than uninfected cells or RSV-BH-Ta-infected cells grown at 41 C. However, inhibition of either protein or RNA synthesis, but not DNA synthesis, prevented the induction of increased hexose uptake and hyaluronic acid synthesis after a shift of RSV-BH-Ta-infected cells from 41 to 36 C. Therefore, these biochemical changes are secondary to a more basic change responsible for morphological transformation.

Cell aggregation: role of acid mucopolysaccharides

Factors that induce cell aggregation are released by several types of chick embryo and mammalian cell cultures. These aggregation factors are also present in some serums. The factors in each of the preparations tested were inactivated by treatment with bovine testicular hyaluronidase. Conversely, hyaluronic acid promoted aggregation of only those cells that were aggregated by media containing the factors. These factors appear to be acid mucopolysaccharides, with hyaluronic acid being a major component.

Ultrastructure of the surfaces of cells infected with avian leukosis-sarcoma viruses

When stained with ruthenium red (RR), chick embryo cells infected with various strains of Rous sarcoma virus (RSV) and with avian leukosis viruses RAV-1 and RAV-3 showed an increase in the layer of acid mucopolysaccharides (AMPS) at their surfaces as compared with uninfected cells. This increase was most prominent in cells infected with the Fujinami strain of RSV. The layer was resistant to digestion with neuraminidase or trypsin but was readily removed by exposure to hyaluronidase. The thickness of this AMPS layer was not correlated with the varying degree of loss of contact inhibition exhibited by cells infected with the different strains of virus. The staining of the cell envelope with a solution of phosphotungstic and chromic acids (PTA-CR) suggested the presence of glycoproteins. The outer surface of the virions showed the same staining as the cell surface with RR and PTA-CR, and the budding virus particle was seen to incorporate the RR layer of the cell into its structure. The RR layers of cells and virions appeared to fuse, as did those between virus particles, suggesting that these layers play a role in the aggregation of virus particles and in their adherence to the surface of the cell.

Studies on cytotropism in animal viruses. 3. Growth of influenza virus in epithelial-like and fibroblastic cells derived from chick embryo lung

Stewart, Robert B. (University of Rochester, Rochester, N.Y.), and Paul H. Frickey. Studies on cytotropism in animal viruses. III. Growth of influenza virus in epithelial-like and fibroblastic cells derived from chick embryo lung. J. Bacteriol. 92:972-977. 1966.-Growth of the PR8 strain of influenza virus was studied in epithelial-like and fibroblastic cell cultures derived from chick embryo lungs. The cells were found to differ in morphology, staining characteristics, and in their ability to support production of infectious influenza virus. Fibroblastic cells were characterized by their spindle shape, content of a mucopolysaccharide, their relative inability to synthesize infectious influenza virus, and production of a cell-associated noninfectious hemagglutinin. Epithelial-like cells were characterized by their polygonal shape, absence of mucopolysaccharide, and ability to synthesize infectious influenza virus.

CANINE NEOPLASIA. A PROTOTYPE FOR HUMAN CANCER STUDY

The authors review current knowledge of spontaneous neoplasms in the dog. The prevalence of certain types of canine tumour has been studied, and comparisons have been made with the occurrence of similar neoplasms in man. Where there are appropriate analogies between the two species, the dog with spontaneous tumours can be used for studies that are not practicable in man.Nutritional and morphological studies have been done on cells cultured from canine tumours. Some consistency has been demonstrated in the morphology of cultures of different tumours of the same type. Nutritional studies with the transmissible venereal sarcoma of the dog have shown the cells to be subject to a growth-repressing effect by SH-containing amino-acids.Attempts to transmit tumours to other dogs or other species have generally been unsuccessful. A transplantable tumour developed in a mouse injected with non-cellular material from a canine thyroid carcinoma, but it is not certain that the tumour was induced. Cell-culture studies have shown that some tumours yield a factor that is cytopathogenic for normal cells, but none has been shown capable of inducing neoplasms in vivo.