Growth inhibition of human promonocytic leukaemic U937 cells by interferon gamma is irreversible and not cell cycle phase-specific.
Growth of human promonocytic leukaemic U937 cells was found arrested within 24 h upon exposure to interferon gamma (IFN-gamma). Removal of the interferon did not result in the resumption of growth, as is evident from the absence of doubling of viable cell count and(3)H-thymidine incorporation. 5-Bromo-2'-deoxyuridine-based flow cytometric analysis of the growth-arrested cells, 24 h subsequent to the removal of IFN-gamma, showed absence of DNA synthesis, confirming the irreversible nature of the growth inhibition. Propidium iodide-based flow cytometric analysis of the growth-arrested cells showed a distribution which is typical of a growth inhibition without resulting in the accumulation of cells in any specific phase of the cell cycle. These results indicated that IFN-gamma arrested growth of U937 cells in an irreversible and cell cycle phase-independent manner. These observations were in contrast to our earlier report on the reversible and cell cycle phase-specific growth inhibition of human amniotic (fetal epithelial) WISH cells by the interferon.
Joshi
C V
CV
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560 012, India.
Supriya
P
P
Ajitkumar
P
P
D001973:Bromodeoxyuridine; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D020298:U937 Cells / Q000166:cytology / Q000187:drug effects*
D006131:Growth Inhibitors; D007371:Interferon-gamma; D001973:Bromodeoxyuridine