SEM study of the attachment of mouse ascitic hepatoma cells to various substrata.

Attachment of the cells of mouse ascitic hepatoma to various substrata was examined with the aid of SEM. Ascitic cells did not attach themselves in vitro to the mesothelium-covered surface of peritoneum. However, these cells were attached to the surface of peritoneum from which mesothelial layer had been removed. In the course of growth of ascitic tumor in vivo attached ascitic cells on the peritoneal surface were seen only in the areas of stomata but not in the mesothelium-covered areas. Ascitic cells taken from the peritoneal fluid adhered poorly to the glass surface in culture. However, adhesiveness of these cells to the glass and their ability to spread on the glass surface increased considerably after cultivation in vitro. This alteration of adhesiveness was completely reversible: the cultured cells transplanted intraperitoneally restored their poor adhesive properties. It is suggested that non-adhesiveness of mesothelial surface is the main factor preserving suspended state of intraperitoneally growing ascitic cells. Depending on the environment, ascitic cells may undergo reversible changes of adhesiveness.