Showing papers by "Garth L. Nicolson published in 1981"

Effects of tunicamycin on B16 metastatic melanoma cell surface glycoproteins and blood-borne arrest and survival properties.

Abstract: The role of cell surface glycoproteins in determining in vivo blood-borne arrest and survival characteristics of murine melanoma sublines of low (B16-F1) or high (B16-F10) potential to form experimental lung metastases after injection iv was assessed after inhibiting tumor cell protein glycosylation with tunicamycin Incubation of B16-F1 or B16-F10 cells with 05 micrograms (or above) tunicamycin per ml for 12 to 36 hr inhibited significantly lung tumor colony formation Examination of B16 cells in the presence of 05 micrograms drug per ml indicated that complex oligosaccharide synthesis was inhibited greater than 90%, while protein synthesis remained at about 50% of the control levels Tunicamycin induced morphological changes in B16-F1 and B16-F10 cells such as cellular rounding Cell growth was also inhibited by tunicamycin These effects were reversible, and B16 cells recovered their normal morphologies and growth rates within 24 hr after removal of the drug Exposed cell surface protein analyzed by lactoperoxidase-catalyzed 125I iodination-sodium dodecyl sulfate-polyacrylamide gel electrophoresis-autoradiography showed few changes after tunicamycin treatment; however, sialogalactoproteins (detected by the binding of 125I-labeled R communis agglutinin I to polyacrylamide gels containing desialized B16 cell surface components) were reduced dramatically by the drug The adhesive properties of untreated and tunicamycin-treated B16 cells were assessed by the binding of 51Cr-labeled B16 cells to endothelial cell monolayers Tunicamycin-treated B16-F1 and B16-F10 cells adhered at lower rates to endothelial cells such that after 24 to 36 hr of drug (05 micrograms/ml) treatment adhesion was almost completely blocked, suggesting that tunicamycin-induced cell surface glycoprotein changes in B16 melanoma cells may interfere with tumor cell-host cell interactions that lead to arrest and survival of blood-borne malignant cells

Distribution of fibronectin on clonal cell lines of a rat mammary adenocarcinoma growing in vitro and in vivo at primary and metastatic sites.

Abstract: With the use of a rat 13762 mammary adenocarcinoma tumor, we have examined the relationship between cellular fibronectin (FN) expression and ability to metastasize spontaneously to regional lymphatic and distant blood-borne sites. This model is based on the isolation and establishment of cell clones from primary parental tumor and from spontaneous metastases that show differing metastatic potentials when implanted s.c. into the mammary fat pads of syngeneic female Fischer 344/CRBL rats. Cellular FN expression was determined in tissue culture as well as at primary and secondary tumor sites, utilizing: (a) indirect immunofluorescence microscopy with a specific anti-rat FN antibody (in vitro and in vivo grown cells); (b) competition radioimmunoassay for cell-released FN (in vitro grown cells); and (c) surface labeling by radioiodination-sodium dodecyl sulfate-polyacrylamide gel electrophoresis-autoradiography for cell surface-bound FN (in vitro grown cells). Tissue culture-grown parental tumor clones displayed FN at their cell surfaces. At confluency, they expressed higher quantities of FN at their peripheries and in fibrillar structures between adjacent cells and released greater amounts of this glycoprotein. Lung metastases-derived tumor clones released negligible amounts of FN by radioimmunoassay and failed to express detectable amounts of FN by indirect immunofluorescence and cell surface-labeling techniques. However, when parental tumor- and metastasis-derived clones of widely different metastatic potentials were carefully examined for FN expression and release, there was no obvious relationship between metastasis and FN expression or release in culture or display in tumors at primary or secondary sites. The results suggest that expression or release of FN per se is not a determinant of metastasis, although it may be a factor in certain steps of the metastatic sequence.

In vivo and in vitro production and detection of monoclonal antibodies to surface components on metastatic variants of murine tumor cells.

Abstract: Mouse-mouse and rat-mouse hybridoma cell lines secreting complement-dependent cytotoxic or cell-binding monoclonal antibodies have been produced against cell surface components of two murine metastatic tumor systems: B16 melanoma and RAW117 lymphosarcoma. We have used both in vivo and in vitro spleen cell culture methods for immunization and have made a number of methodologic alterations to increase the yield and survival of hybridomas including media osmolality, pH, serum type, macrophage feeder layers and supplemented amino acids, vitamins and metabolites. Using complement-dependent cytotoxicity or lectin immobilization of tumor cells to polystyrene via a water-soluble carbodiimide for an enzyme-linked immunosorbant assay we were able to rapidly screen hybridoma cultures for specific antibody secretion.