Inhibition of Primary and Metastatic Tumor Growth in Mice by Cancer-associated Galactosyltransferase Acceptor

The antitumor activity of a glycopeptide purified from human malignant effusion, termed cancer-associated galactosyltransferase acceptor (CAGA), was assessed in BALB/c mice bearing primary and metastatic tumors. Initial studies with the fast-growing KA31 and slow-growing KB521 Kirsten sarcoma-transformed mouse fibroblast cell lines confirmed their tumorigenicity and metastatic potential. Inoculation of 1 x 105 KA31 cells s.c. resulted in palpable tumor formation in recipient animals within 14 days and death within 42 days from primary tumor growth (mean survival, 26 days; total survival, 0%). Inoculation of the slower-growing KB521 resulted in tumor formation in 85% of recipients, and tumor-bearing animals succumbed within 56 days after primary inoculation (mean survival, 48 days; total survival, 15%). Administration of CAGA by i.p. injection as a single dose or series of five daily doses (each 50 μg) inhibited primary tumor growth by 35 to 68% in animals receiving KA31 cells and by 25 to 70% in animals receiving KB521 cells. CAGA increased mean survival 50% from 26 to 38 days and total survival from 0 to 27% in animals bearing KA31 -derived primary tumors. In animals bearing KB521-derived tumors, CAGA increased mean survival from 48 to 90 days and total survival from 15 to 50%. Similarly, CAGA was also found to significantly inhibit formation of pulmonary metastases in animals after excision of primary tumors. CAGA administration reduced death from metastatic deposits by 55 to 66% in animals initially inoculated with the KA31 cell line and by 58 to 90% in animals initially bearing primary tumors derived from the KB521 line. There was a corresponding decrease in the number of metastatic deposits per lung after administration of CAGA. Thus, CAGA appears to have potential antitumor activity against tumors with a range of growth rates and appears to inhibit both primary and metastatic tumor growth.