Invasiveness in hepatocyte and fibroblast monolayers and metastatic potential of T-cell hybridomas in mice.

Fusion of noninvasive, nonmetastatic BW5147 T-lymphoma cells with normal T-lymphocytes usually resulted in highly invasive and metastatic T-cell hybridomas, apparently due to properties derived from the normal T-cell. Occasionally hybrids arose that were non- or low invasive, probably by loss of relevant genes upon chromosome segregation, since these cells contained much less DNA than highly invasive hybrids. The metastatic potential of 20 representative T-cell hybridomas was tested by tail vein injection in syngeneic mice and cells were found to be either nonmetastatic (NM), low metastatic (LM), or high metastatic (HM).

Syngeneic in vivo passage of the murine BW 5147 lymphoma results in the expression of a stable metastatic phenotype.

BW 5147 lymphoma cells are non-invasive tumor cells which do not generate experimental metastases following i.v. inoculation.

Genetic analysis of invasion and metastasis.

Metastasis formation is a multistep process that probably requires a complex interplay of a large and heterogeneous group of genes, including genes involved in cellular resistance to immunorejection and genes controlling the invasive potential of cells. Transfection experiments have shown that oncogenes of the ras gene family as well as oncogenes of the kinase group are able to induce invasive and metastatic properties in non-transformed cells as well as in tumorigenic, but non-metastatic, cells. However, these findings are not in agreement with observations on spontaneous human tumours in which no correlation was found between activation or increased expression of ras genes and the invasive and metastatic properties of these cells.

Location of genes involved in invasion and metastasis on human chromosome 7.

We have obtained evidence for the existence of genes controlling invasion and metastasis by somatic cell fusion studies. Noninvasive, nonmetastatic mouse BW5147 T-lymphoma cells were fused with invasive human T-cells. The human cells were either activated normal peripheral blood lymphocytes or leukemic T-lymphoblasts.

Inhibition of lymphoma invasion and liver metastasis formation by pertussis toxin.

We have examined whether pertussis toxin, an agent known to inhibit entry of normal lymphocytes into tissues, affects invasion and metastasis formation by malignant lymphoma and T-cell hybridoma cells. The toxin reduced invasion in vitro in hepatocyte cultures to 20% of control values. Inhibition was maximal after pretreatment for 2 h with approximately 100 ng/ml.

Interaction of plasma membrane-associated filaments and H-2 histocompatibility antigens before and after induced patching and capping.

The interaction of H-2 antigens and plasma membrane-associated filaments was studied on dry-cleaved preparations of immunogold-labelled lymphoma cells. In prefixed cells, the plasma membrane-associated network was isotropic without any prevailing direction of the filaments, and the gold-labelled H-2 antigens were preferentially localized over or at a very short distance from membrane-associated filaments. Incubation of unfixed cells with anti-H-2 antibodies followed by fixation and incubation with anti-Ig, did not induce detectable redistribution of H-2 antigens or of the filament network.

Induction of tumoricidal activity in isolated rat liver macrophages by liposomes containing recombinant rat gamma-interferon supplemented with lipopolysaccharide or muramyldipeptide.

We examined whether the macrophages in the liver, Kupffer cells, could be activated to a tumoricidal state in a similar way as has been described for other macrophage types. Kupffer cells were isolated by centrifugal elutriation of pronase-treated rat livers. Incubation with highly purified recombinant rat gamma-interferon in combination with small amounts of lipopolysaccharide or muramyldipeptide resulted in highly cytotoxic macrophages, as measured against P815 tumor cells in an 18 h 51Cr-release assay.

Involvement of leukocyte function-associated antigen-1 (LFA-1) in the invasion of hepatocyte cultures by lymphoma and T-cell hybridoma cells.

We studied the interaction of MB6A lymphoma and TAM2D2 T cell hybridoma cells with hepatocyte cultures as an in vitro model for in vivo liver invasion by these tumor cells. A monoclonal antibody against leukocyte function-associated antigen-1 (LFA-1) inhibited adhesion of the tumor cells to the surface of hepatocytes and consequently strongly reduced invasion. This effect was specific since control antibodies, directed against Thy.

The anesthetic nitrous oxide affects dioxygen utilization by bovine heart and bean seed mitochondrial particles.

Nitrous oxide affects dioxygen utilization by both bean seed and bovine heart submitochondrial particles when either succinate or reduced cytochrome c are used as substrates. Bovine heart particles exhibit reversible, dose-dependent partial inhibition of respiratory activity when exposed to N2O. Bean seed particle respiration is stimulated by low levels of N2O, but higher concentrations are inhibitory.

Invasive and metastatic potential induced by ras-transfection into mouse BW5147 T-lymphoma cells.

Noninvasive, nonmetastatic BW5147 T-lymphoma cells were transfected with the activated human c-Ha-ras oncogene and were examined subsequently for the acquisition of invasive properties in vitro and of metastatic potential in vivo. It was found that several transfectants harboring the ras gene had become invasive in vitro, as assessed in hepatocyte cultures, and metastatic after tail vein injection into syngeneic AKR mice. The induced level of both invasive and metastatic potential appeared to depend on the level of expression of the transfected ras gene.

Cell surface sialic acid and the invasive and metastatic potential of T-cell hybridomas.

T-cell hybridomas prepared by fusion of non-invasive non-metastatic BW5147 T-lymphoma cells and activated normal T-cells were found to be highly invasive in vitro and highly metastatic in vivo upon tail vein injection. By prolonged culturing and subcloning, non-invasive, non-metastatic hybrids were selected with modal DNA/cell contents close to the diploid value of both fusion partners. Since normal activated T-cells were invasive in vitro in hepatocyte cultures, these data suggest that invasiveness of the hybrids is derived from the parental normal T-cells and is one of the properties responsible for the metastatic potential of these cells.

Invasiveness of T-cell hybridomas in vitro and their metastatic potential in vivo.

BW5147 lymphoma cells, which are noninvasive and nonmetastatic, were fused with normal T-lymphocytes. The invasiveness of the generated T-cell hybridomas was tested in hepatocyte cultures, and their metastatic potential was tested by tail vein injection. A total of 29 hybridomas generated from alloantigen-activated T-cells were all found to be invasive.

Localization of cell surface glycoproteins in membrane domains associated with the underlying filament network.

To visualize the localization of cell surface constituents in relation to the plasma membrane-associated filament network, we developed a method based on a combination of immunogold labeling and dry-cleaving. For labeling we used trinitrophenyl-derivatized ligand, anti-TNP antibodies, and protein A-coated colloidal gold. Dry-cleaving (Mesland, D.

Hepatocyte surface molecule involved in the adhesion of TA3 mammary carcinoma cells to rat hepatocyte cultures.

To identify adhesion molecules involved in the formation of liver metastases, we prepared monoclonal antibodies against rat liver plasma membranes, that inhibited the adhesion of mouse metastatic TA3 mammary carcinoma cells to rat hepatocytes in vitro. Two such antibodies (designated OPAR-1 and OPAR-2) were obtained, that inhibited by over 70%. As assessed with gel electrophoresis and immunoblotting, these antibodies bound predominantly to plasma membrane proteins with molecular weights of 125,000 and 100,000.

Generation of invasive and metastatic variants of a non-metastatic T-cell lymphoma by in vivo fusion with normal host cells.

Intravenous inoculation of the AKR mouse-strain-derived BW lymphoma into CBA recipients resulted in a case of liver metastasis; cells derived from this metastatic nodule were termed BW-Li cells. BW-Li cells, upon reinoculation, generated metastases in the spleen, liver, kidney and ovaries in 100% of CBA recipients. Furthermore, BW-Li cells, in contrast to BW cells, were found to infiltrate in vitro monolayers of hepatocytes, thus confirming their inherent invasive potential.

Adhesion of tumor cells to hepatocytes: different mechanisms for mammary carcinoma compared with lymphosarcoma cells.

Mechanisms of adhesion between tumor cells and hepatocytes, which are likely to play a role in liver metastasis formation, were studied in vitro. TA3 mammary carcinoma and MB6A lymphosarcoma cells were added to rat hepatocytes that had been cultured for 24 hours. Adhesion was quantified by counting adherent cells seen in sections of pelleted, Epon-embedded culture fragments.

Interactions between lymphoid tumor cells and isolated liver endothelial cells.

Interactions were studied between highly metastatic murine MB6A lymphosarcoma cells and rat liver endothelial cells that had been isolated by collagenase perfusion and purified by unit gravity sedimentation. Experiments were performed on the day of isolation. MB6A cells were observed to adhere to the endothelial cells.

Chromosome damage induced by artificial seed aging in barley : 3. Behavior of chromosomal aberrations during plant growth.

Barley (Hordeum vulgare L. 'Himalaya') seeds were artificially aged under two storage conditions (32 °C/12% moisture content (m.c.

Nonmetastatic tumor cells acquire metastatic properties following somatic hybridization with normal cells.

Somatic cell hybridization between nonmetastatic tumor cells and normal cells of the lymphoreticular system results in hybrid cells manifesting metastatic properties of defined target organ specificity. Thus, fusion of the nonmetastatic BALB/c originated NSI plasmacytoma with C57BL B lymphocytes resulted in hybridomas, each of which were metastatic. Of 10 hybridomas, 7 generated metastases in the spleen and liver, whereas 3 generated liver metastases.

Antigen-activated T lymphocytes infiltrate hepatocyte cultures in a manner comparable to liver-colonizing lymphosarcoma cells.

Previously we have described the infiltration of lymphosarcoma cells into hepatocyte cultures. The interaction between tumor cells and hepatocytes was comparable to that occurring during the formation of liver metastases. Presently we report that antigen-activated T lymphocytes, but not unstimulated T cells, infiltrate hepatocyte cultures in a manner comparable to the lymphosarcoma cells.

Infiltration of lymphosarcoma cells into hepatocyte cultures: inhibition by univalent antibodies against liver plasma membranes and lymphosarcoma cells.

The number of murine MB6A lymphosarcoma cells that infiltrated rat hepatocyte cultures was found to be diminished after treatment of the lymphosarcoma cells with univalent antibodies raised against these tumour cells (anti-MB6A Fab), and also after treatment of the hepatocyte cultures with univalent antibodies directed against rat liver plasma membranes (anti-LPM Fab). The inhibition of infiltration by anti-MB6A Fab and an anti-LPM Fab raised against sinusoidal face-enriched membranes could be entirely attributed to their interference with adhesion of MB6A cells to the exposed surface of the hepatocytes, because infiltration of the adherent cells was not inhibited. Anti-LPM Fab raised against contiguous face-containing LPM, on the other hand, inhibited the adhesion to the exposed surface and the subsequent infiltration of adherent cells.

Effect of tubulin-binding agents on the infiltration of tumour cells into primary hepatocyte cultures.

The influence of tubulin-binding agents on the infiltration of murine MB6A lymphosarcoma and TA3 mammary carcinoma cells into primary rat hepatocyte cultures was studied. Colchicine, nocodazole and vinblastine reduced the number of infiltrating lymphosarcoma cells, probably by interfering with the adhesion of these cells to the exposed hepatocyte surface. However, the subsequent infiltration of cells that did adhere was not affected or even slightly stimulated.