Macrophage-like transformation of leukemia cells in vitro liquid culture and its biological significance
Sakai, C.
Nihon Ketsueki Gakkai Zasshi Journal of Japan Haematological Society 48(7): 1493-1507
1985
ISSN/ISBN: 0001-5806 PMID: 4090929 Document Number: 244564
Leukemia cells of three human leukemia cell lines (K562, KU812, KY821) and the fresh leukemia cells from 46 patients with various types of leukemia were incubated with or without 12-O-tetradecanoylphorbol 13-acetate (TPA) in vitro liquid culture for 5 days. Strong adherent ability was induced by TPA in KU812 and KY821 but not in K562. The adherent cells of both KU812 and KY821 were macrophage-like cells. The number of patients whose leukemia cells showed strong adherent ability in culture with and without TPA was 24(52%) and 16(35%) respectively. It was noteworthy that strong adherence was seen in 3 of 10 cases of ALL. Although the morphology of the adherent cells varied slightly from case to case, the cells of all cases but one were macrophage-like. In one case of CML in basophilic blast crisis, the majority of adherent cells were basophils. Mitoses were not seen in any adherent cells. Many Auer-rods were seen in the adherent cells derived from Auer-rod positive leukemia. Almost all adherent cells derived from ALL showed only butyrate esterase activity. Both butyrate esterase and chloroacetate esterase activity was seen in the adherent cells of AML and AMMoL. Predominant chloroacetate esterase activity was seen in the adherent cells of APL. Because macrophage-like transformation of leukemia cells in vitro is seen not only in myeloid leukemias but also in lymphoid leukemias, this phenomenon must be nonspecific and is probably a kind of atavism that a leukemia cell reverts to an ancestral macrophage from which every hematopoietic cells had evolved. From another point of view, this phenomenon may be an environmental adaptation of leukemia cells in order to survive in vitro.