Differential growth control of normal, preneoplastic and neoplastic Syrian hamster embryo cells in serum-free media

The objective of this work was to develop a serum-free mediumthat supported the growth of secondary Syrian hamster embryo(SHE) cells suitable for use in the morphological transformationassay (MTA). The current assay employs high levels of fetalbovine serum, each lot of which must be selected for its efficacyin the assay. To circumvent the problems associated with theuse of serum, two serum-free media (CGM–4 and CGM–9)were developed. The approach used was to replace serum withmore defined hormones and growth factors. DME/F12 with low NaHCO₃(pH 6.7) was chosen as a basal nutrient medium since this pHhas been reported to give enhanced transformation. Both serum-freemedia supported the clonal high density growth of normal secondarySHE cells. These media were also found to support the growthof several established SHE cell lines exhibiting successivestages of neoplastic progression. However, significant differentialresponses of the individual cell lines to CGM-4 and CGM-9 wereobserved, whereas, in serum-supplemented medium all three linesresponded similarly. These results raise the hope that CGM-4and CGM-9 will be useful for studies of altered autocrine functionduring transformation and progression as well as for use inthe transformation assay itself.