Malignancies of metastatic murine lymphosarcoma cell lines and clones correlate with decreased cell surface display of RNA tumor virus envelope glycoprotein gp70.

Variant sublines of the murine lymphosarcoma RAW117 have been derived by sequential cycles of intravenous inoculation of cells and harvesting of solid liver tumors in syngeneic BALB/c mice [Brunson K. W. & Nicolson, G. L. (1978) J. Natl. Cancer Inst. 61, 1499-1503] and also by sequential removal of lectin-reactive cells via repeated adsorption on immobilized-lectins [Reading, C. L. Belloni, P. N. & Nicolson, G. L. (1980) J. Natl. Cancer Inst. 64, 1241-1249]. These cell sublines and their clones were analyzed for abilities to form gross liver tumor metastases after injection intravenously or subcutaneously into syngeneic mice, and this response was related to certain cell surface properties including quantities of viral antigens and lectin-binding sites, exposure of specific cell surface proteins, and quantities of cell surface glycoproteins visualized in gels with 125I-labeled lectins or antibodies. Consistent differences were obtained between RAW117 sublines of low and high malignancy with respect to the amounts or exposures of cell surface glycoprotein components of Mr approximately 70,000 or 69,000 and 71,000, depending on the gel system. Competition radioimmunoassays for RNA tumor virus antigens in the RAW117 lines and clones indicated the presence of Moloney murine leukemic virus antigens gp70, p30, and p12. Enhanced malignancy and metastasis to liver was accompanied by decreases in the cellular contents of viral antigens and loss of gp70 cell surface exposure. Analysis of several clones obtained from sublines selected in vivo and in vitro for high or low malignancy confirmed the inverse relationship between metastasis and expression of gp70 in this system.