Studies of the differentiation properties of camptothecin in the human leukaemic cells K562.
Camptothecin, a specific inhibitor of topoisomerase I, caused erythroid differentiation of the human leukaemia cell-line K562, as assessed by benzidine staining at 70 h recovery following a 60 min treatment of the cells. Differentiation was confirmed by increased levels of epsilon-globin and gamma-globin mRNA in the treated cells and was accompanied by down-regulation of c-myb mRNA. Synchronisation of K562 cells by non-cytotoxic doses of methotrexate increased the differentiation induced by camptothecin, without affecting the camptothecin-induced inhibition of cellular proliferation. Camptothecin induction of differentiation and inhibition of proliferation may occur by independent mechanisms.
McSheehy
P M
PM
Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, London, U.K.
Gervasoni
M
M
Lampasona
V
V
Erba
E
E
D'Incalci
M
M
D002166:Camptothecin / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D005914:Globins / Q000032:analysis; D006801:Humans; D007938:Leukemia / Q000473:pathology*; D008215:Lymphocytes, Null / Q000737:chemistry; D008727:Methotrexate / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis; D059004:Topoisomerase I Inhibitors; D014407:Tumor Cells, Cultured / Q000187:drug effects
D012333:RNA, Messenger; D059004:Topoisomerase I Inhibitors; D005914:Globins; D002166:Camptothecin; D008727:Methotrexate