Transformation of hamster embryo cells by 7-methyl benz(a)anthracene in vitro: Tumorigenicity, chromosome pattern and spheroid formation

Growth in serum‐free medium of NIH3T3 cells transformed by the EJ‐H‐ras oncogene: Evidence for multiple autocrine growth factors

“…Molecular-weight studies. The results of these studies were reminiscent of those obtained earlier in the study of mitogenic factors secreted by BA10-IR cells and non-transformed hamster embryo fibroblasts (Li Wen Xin et al, 1987). Indeed, on a Sephacryl300 column, under neutral conditions, the activities in the cell-conditioned media stimulating the formation of A1 colonies by T R cells, in S-medium, eluted mainly in one or a few high-molecular-weight peaks, between 200 and 1,000 kDa, which could be aggregates of smaller components.…”

“…in the form of Premix (Collaborative Research, Waltham, MA); (iii) D H M without additives. Cell-conditioned Smedia of transformed and non-trans-Rcccived: February 29.1992 and in revised form March 23,1992, formed cells were obtained from confluent cultures incubated for 2 days in these media, as previously described (Li Wen Xin et al, 1987). When cells were plated in S+ medium, then switched to S-medium, they were rinsed twice for 1 hr with PBS before switching.…”

“…The capacity of TR cells, or non-transformed NIH3T3 cells, to form A1 colonies, was tested by seeding lo3 to lo5 trypsinized cells, in semi-solid S+ or S-media, in the 16-mm-diameter wells of 24-well Linbro plates, as previously described (Li Wen Xin et al, 1987), except that Sea Plaque agarose (Marine Colloids, FMC, Rockland, ME: 0.4% in the cell-containing overlayer, and 0.6% in the underlayer) was substituted for agar. Colonies over 30 and 100 cells (i.e.…”

“…The earlier study of the factors stimulating A1 growth of BA10-IR cells, secreted by these cells and by non-transformed hamster embryo fibroblasts, had shown that they were acidsensitive after partial purification, and present as high-and low-molecular-weight components, in gel filtration experiments (Li Wen Xin et al, 1987). Other studies with fibroblastic rodent cells transformed by ras oncogenes suggested that their capacity to grow in Smedia could be due to the secretion of autocrine factors related to known growth factors, such as TGF-(Y or PDGF (see opening paragraphs).…”

“…Thus, both T R and NIH3T3 cells appear to secrete a low amount of 10 20 Fractions FIGURE 3 -Biological activity of Biogel P60 column fractions of concentrated S-medium of NIH3T3 cells, obtained under neutral conditions. The fractions were eluted with Hanks' saline solution, as previously described (Li Wen Xin et al, 1987), and 0.1 ml of each fraction was assayed, in duplicate wells, for its capacity to stimulate the formation of A1 colonies by lo4 TR cells in S-DHM plus Premix. 0 Colonies > 30 cells; 0 Colonies > 100 cells.…”