Ganglioside profiles of metastases and of metastasizing and nonmetastasizing rat primary mammary carcinomas.

The possible relationship between ganglioside levels and ganglioside profiles in malignant tumors and the formation of metastasis was investigated by the analysis of gangliosides in metastasizing SMT-2A and nonmetastasizing MT-W9a mammary carcinomas as well as in metastases formed from SMT-2A tumors. The extracted lipid of SMT-2A tumors contained 3.3-fold more lipid-bound sialic acid than did that of MT-W9a tumors. THe differences were also substantial in the ganglioside profiles in these 2 tumors. Plasma membranes isolated from SMT-2A tumors also contained 1.8-fold more lipid-bound sialic acid than did plasma membranes from MT-W9a tumors. Ganglioside profiles in two types of SMT-2A secondary tumors were investigated. The lipid-bound sialic acid content was 1.5-fold higher in tumor nodules in the lung and 1.9-fold higher in axillary lymph node tumors than it was in primary SMT-2A tumors. The ganglioside pattern in these 2 secondary tumors generally reflected that found in SMT-2A: high levels of gangliosides containing three or four sialic acid molecules. The lung nodule retained its specificity with respect to lipid-bound sialic acid content and ganglioside pattern after the lung nodule was sequentially transplanted three times to the site of the original SMT-2A tumor growth.