Human breast epithelial cell type with stem cell and luminal epithelial

Abstract

Described is a substantially purified human breast epithelial cell (Type I HBEC) displaying the following characteristics: variable cell shape; smooth cell colony boundary; deficiency in gap junctional intercellular communication; positive expression of epithelial membrane antigen and keratin 18; negative expression of keratin 14, .alpha.6 integrin and gap junction genes for connexins (Cx26, Cx32 and Cx43); growth promotion by fetal bovine serum; induction by cholera toxin to differentiate into Type II HBEC (prior art); and acquisition of anchorage independent growth by Semian virus 40 transfection. Also described is a method of obtaining the above-identified epithelial cells comprising the steps of: a) development of a mixture of human breast epithelial cells from reduction mammoplasty tissues using the MSU-1 medium; b) eliminating stromal fibroblasts by a trypsin (0.002%) and ethylenediamine tetraacetic acid (0.02%) solution; c) separating Type I HBEC from Type II HBEC which attach on culture dishes earlier by collecting Type I HBEC that remain in suspension after trypsinization and prolonged incubation; d) the continuing culture of these cells in MSU-1 medium supplemented with fetal bovine serum, which inhibits the growth of Type II HBEC while promoting the growth of Type I HBEC, gives rise to Type I HBEC. Described also is a new defined medium (the MSU-1 medium) which supports the growth of both Type I and Type II human breast epithelial cells.