Increase in homotypic aggregation of metastatic Morris hepatoma cells after fusion with membranes from non-metastatic cells.
Three types of Morris hepatoma: 7288C, 5123tc, and 9618A were assessed for their ability to grow and produce metastases in the lungs of male buffalo rats. Hepatoma 7288 formed metastatic growths more rapidly than 5123, while 9618 did not form metastatic growths in the lung at all. Cells from the same three hepatomas were then assessed for their ability to aggregate homotypically in vitro. This was used as a measure of potential for detachment from the site of primary growth in vivo, one of the critical steps in metastasis. The results were that 9618 aggregated more effectively than 5123 and 7288 did not aggregate homotypically. Thus, the ability to metastasize and the ability to aggregate homotypically were inversely related in these three tumors, with the most metastatic tumor, 7288, hardly aggregating at all. Was the ability of hepatoma 9618 to aggregate homotypically and the inability of hepatoma 7288 to do so a characteristic of the plasma membrane? Plasma membranes either from the tumor which aggregated best, 9618, or from the liver of non-tumorous neonatal buffalo rats were fused into the surface of the 7288 cells. Either fusion conferred the ability to aggregate on the previously non-aggregating metastatic hepatoma cells. In contrast, fusion of plasma membranes from hepatoma 7288 into 9618 cells failed to affect their ability to aggregate homotypically. The aggregation-conferring effect required actual fusion of the donor membrane, was dependent on the amount of membrane fused and was sensitive to treatment of the donor plasma membranes with trypsin. The results are interpreted as suggesting the presence of homotypic aggregation materials, probably proteins, in the plasma membranes of non-metastatic cells. These may be reduced or absent in the membrane of the highly metastatic hepatomas.
D000818:Animals; D002449:Cell Aggregation; D002450:Cell Communication; D002459:Cell Fusion; D002460:Cell Line; D002462:Cell Membrane / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000473:pathology*; D008175:Lung Neoplasms / Q000556:secondary*; D008297:Male; D003012:Microbial Collagenase / Q000378:metabolism; D009368:Neoplasm Transplantation; D051381:Rats; D011915:Rats, Inbred BUF
D003012:Microbial Collagenase