Growth of a human mammary tumour cell line in a serum-free medium

Abstract

The MCF-7 line of human mammary carcinoma cells is a well characterised line¹ which has retained a number of the properties expressed by breast epithelium in vivo, making it a good model for the in vitro study of normal and neoplastic mammary cells. MCF-7 cells have been reported to possess receptors for oestrogen, androgen, progesterone, glucocorticoid², insulin³ and L-3, 3′, 5-triiodothyronine (T₃)⁴. These cells also show responses to prolactin⁵, and dome formation¹. This line, like most cells in culture, requires the addition of a serum supplement to the medium for growth. The complex and undefined nature of serum adds a complicating aspect to the design and interpretation of any experiments aimed at understanding the interactions of hormones or drugs with mammary epithelium. Our laboratory has shown that it is possible to replace the serum requirement for a number of cell lines with mixtures of hormones and purified serum factors^6–8. We now report that MCF-7 cells may be grown, without a lag or adaptation phase, in a serum-free medium supplemented with physiological levels of insulin, transferrin, epidermal growth factor (EGF), prostaglandin F_2α (PGF_2α) and cold-insoluble globulin (CIg). This medium will support a growth rate identical to that of cells in medium supplemented with an optimal concentration of fetal calf serum. The further addition of the α-1 serum protein first purified by Holmes⁹ results in a morphology identical to that of cells in 10% serum. Turkington has previously shown EGF effects on mouse mammary expiant cultures¹⁰, and mouse EGF has been reported to be stimulatory for human mammary tumour cells . Insulin and transferrin have been shown to be required for the continuous serum-free growth of the ZR-75-1 human mammary tumour cell line¹². We believe that this is the first report of the effects of transferrin, PGF_2α, Clg, EGF or the α-1 protein on the MCF-7 line.