Differences in cell surface carbohydrates, and in laminin and fibronectin synthesis, between adherent and non-adherent Ehrlich ascites tumor cells.

Differences in cell surface carbohydrates and in laminin and fibronectin synthesis between 2 Ehrlich ascites tumor (EAT) cell lines, the adherent and non-adherent EAT cells, have been studied. The adherent EAT (a-EAT) cells grow in monolayer in vitro in the presence of fetal bovine serum. The classical, or non-adherent EAT (na-EAT), cells grow in suspension in ascites form in the peritoneal cavity of mice, and they do not adhere when cultured in vitro. Both EAT cell lines express surface glycoproteins reactive with Maackia amurensis lectin (MAL) and Griffonia simplicifolia isolectin GS I-B4. However, only a-EAT cells react with elderberry (Sambucus nigra) bark lectin (SNA), suggesting that there are some differences in the sialylation of cell surface carbohydrate moieties between these 2 EAT cell lines. Removal of cell surface sialic acid by treating a-EAT cells with Vibrio cholerae neuraminidase did not abolish the ability of these cells to adhere to laminin- or fibronectin-coated plates, indicating that the sialic acid of the cell surface glycoproteins is not essential for their adhesion to these extracellular matrices. Therefore, the difference in sialylation of cell surface glycoproteins is not responsible for the difference in cell adhesion between these 2 lines of EAT cells. Both EAT cell lines express detectable amounts of laminin but not fibronectin on their surfaces; they both secrete fibronectin and entactin into the medium. The na-EAT cells (but not the a-EAT cells) also secrete laminin A chain into the culture medium; however, no B chain was detected in the culture medium of either cell line. The laminin isolated from the cell surface of na-EAT cells reacts with GS I and MAL lectins, but not with SNA, whereas the laminin isolated from a-EAT cells reacts with SNA, as well as GS I and MAL.