PRODUCTION OF GROWTH-INHIBITORY ACTIVITY IN SERUM-FREE MEDIUM BY HUMAN MONOCYTIC LEUKEMIA-CELLS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (8) , 3668-3673
Abstract
Serum-free medium conditioned by activated cells of the acute monocytic leukemia line, THP-1, was examined for growth-inhibitory activity with several established human cell lines. Free-floating clusters of THP-1 cells were activated into adherent nonproliferating cells by a 24 h exposure to 10-7 M mezerein in Roswell Park Memorial Institute 1640 medium containing 1% fetal bovine serum. Adherent cells were incubated for an additional 24 h in serum-free medium containing insulin (5 .mu.g/ml). Dose-response studies revealed that a cervical carcinoma (HeLa), a melanoma (A375Ag5), and several mammary carcinoma cell lines (MCF-7, BT474, MDA-MB415 and T47D) were growth inhibited by this conditioned medium. From the results of thymidine release assays and from experiments on reversibility, inhibition was concluded to be a cytostatic and not a cytolytic response. In contrast, THP-1 conditioned medium stimulated the growth of 2 mammary lines (ZR75-1 and HBL-100), a lung type II carcinoma (549), and a colon adenocarcinoma (SW48). Preliminary characterization showed that the inhibitory activity was stable to acid and urea treatment but was destroyed by trypsin and sodium dodecyl sulfate. Molecular sieve chromatography of acetic acid-extracted material separated the inhibitory and stimulatory components.