Enhanced glucocorticoid responses in a human leukemic cell line, CEM-C7, cultured in a serum-free mediu

CEM-C7, a human leukemic T-lymphocyte cell line previously cultured in a serum supplemented medium, has been adapted to a serum-free medium. The best serum-free medium of several tested was RPMI-1640 supplemented with 5 ug/mL human transferrin, 5 ug/mL bovine insulin and 5 ng/mL sodium selenite. This formulation was assayed for cell growth with and without the addition of bovine serum albumin (BSA). Cell proliferation of CEM-C7 cells cultured in both serum-free and serum supplemented media has been sustained for three months with doubling times of approximately 25 hours while maintaining their viability at 90% $pm$ 3.3. When grown in serum-free medium, CEM-C7 cells exhibit increased steroid responsiveness as evidenced by increased glucocorticoid receptor (GR) binding sites, increased induction of glutamine synthetase, and cell lysis at lower concentrations of steroid. These results suggest that substances in serum influence steroid effects on these cells and that the molecular details of glucocorticoid hormone action may be pursued more precisely in a clearly defined culture medium.