Selective Growth of Transformed Cell Lines by Rat Liver Perfusate

Perfused rat liver releases growth-promoting activity for viral, spontaneous, and chemically transformed cells. After 5 days of incubation with perfusate, cell lines 3T12-NY (a spontaneous fibroblast transformant), NQ-T-1 (a chemically transformed fibroblast line), W-8 (a chemically transformed epithelial rat liver cell line), and H-50 (an SV40-transformed hamster fibroblast line) all exhibit significant increase in cell growth above controls. Their respective normal counterparts: 3T3 Cl 42, A31-714, K-16, and HEF are not so stimulated. Within another set, the virally transformed mouse fibroblast cell line, SV3T3, exhibits a 27-fold increase in growth; however, 3T3 (mouse fibroblasts), P_y3T3 (polyomatransformed 3T3 cells), SV-FI₂-101 (a flat revertant line), and SV-P_y-3T3 (a doubly transformed line) are nonresponsive. Perfused rat liver also releases survival activity for SV-3T3 cells. The growth-stimulating activity in liver perfusate is selective for transformed cells. It is suggested that the liver may play a role in supporting neoplasia in vivo.