ESTABLISHMENT AND CHARACTERIZATION OF NEW CELL-LINES FROM HUMAN BREAST-TUMORS INITIALLY ESTABLISHED AS TUMOR XENOGRAFTS IN NMRI NUDE-MICE

Human breast cancer cell lines are required as models for use in the u nderstanding of breast carcinoma, and for improving the ability of cel l screens to detect appropriate anti-cancer agents. Four human breast cancer cell lines (MT-1, MaTu, MT-3 and MC4000) were established from human tumour xenografts grown in nude mice. All the lines were shown t o be of human origin by karyotype analysis, were epithelial in morphol ogy by both light and electron microscopy, were positive for cytokerat in 18, and were free from mycoplasma, bacterial, yeast and fungal cont amination. All of the new lines were shown to be ER and PgR negative, while using the same procedures (i.e. radioligand binding and immunohi stochemical staining) the positive control cell line MCF-7 was shown t o be positive. MaTu had been previously reported as ER and PgR positiv e in vivo and it may be that this characteristic had been lost due to in vitro selection pressures. The growth rates of all the new breast c ancer cell lines were similar and within the limits required for incor poration into a panel for screening anticancer drugs by a microtetrazo lium based, colorimetric growth inhibition assay. Three of the lines ( MT-1, MaTu and MC4000) were also able to grow into macroscopic colonie s for use in a non-agar clonogenic assay. In addition, both MT-1 and M aTu formed spheroids and were clonogenic in soft-agar. The new lines d emonstrated a wide range of sensitivities to anticancer agents commonl y used in the treatment of breast cancer, and together with their corr esponding xenografts are providing additional systems for the evaluati on of new compounds.