Growth factor from tumor cells.

Suitable conditions for assay of the growth factor from Yoshida sarcoma and AH-130 tumor cells were investigated using three different cell lines: baby hamster kidney cells, human embryonic lung cells and Swiss Albino mouse 3T3 embryo fibroblast cells. The results indicated that the 3T3 cell line was more sensitive to the growth stimulating activity than the other two lines. A fraction of Yoshida sarcoma tumor cells containing the growth factor showed less growth stimulating activity than a fraction of AH-130 tumor cells prepared by the same method. Using the 3T3 cell line for assay of activity, the growth factor was partially purified from AH-130 tumor cells by ammonium sulfate fractionation, DEAE-cellulose column chromatography and gel filtration on a Sephacryl S-300 column. It appeared to be thermolabile, and its molecular weight was estimated as about 80,000 by gel filtration on Sephacryl S-300. These findings suggest that it is a high-molecular-weight substance.