Alkaline phosphatase activity and the regulation of growth in transformed mammalian cells (original) (raw)

The relationship between alkaline phosphatase activity and cell growth has been studied in hamster cells transformed by different carcinogens. About 90% of normal hamster embryo cells were constitutively positive for alkaline phosphatase activity (AP+). However, there were no AP+ cells in cell lines transformed after treatment with the chemical carcinogens dimethylnitrosamine or 4‐nitro‐quinoline‐N‐oxide and 0.02% and 4% AP+ cells in cell lines transformed by polyoma virus or Simian virus 40. The glucocorticoid hormone, prednisolone, induced alkaline phosphatase activity in 12% and 44% of the enzyme‐negative (AP−) cells in cell lines transformed by polyoma or Simian virus 40, but this hormone did not induce alkaline phosphatase activity in AP− cells from cell lines transformed after treatment with the chemical carcinogens. Treatment of polyoma transformed AP− cells with the mutagen N‐methyl‐N′‐nitro‐N‐nitro‐soguanidine produced AP+ cells, whereas no AP+ cells were found after mutage...