A growth-promoting ribosome extract (GPRE) from mouse L-929 cells stimulates growth of the HL-60 human promyelocytic leukemia cell line.
An extract termed growth-promoting ribosome extract (GPRE), isolated from mouse L-929 cells stimulates growth of HL-60 human promyelocytic leukemia cells. The stimulation first becomes apparent at 72 h when the cells start to enter the quiescent state. The inhibition of protein synthesis by the addition of cycloheximide to L-929 cells before ribosomal extracts were prepared did not alter the stimulatory effect of GPRE. When GPRE was added together with 20% fetal calf serum to cultures of quiescent HL-60 cells, growth was stimulated to the extent that the generation time was reduced by approximately 9 h to 32.4 h. GPRE alone was unable to stimulate the quiescent cells. The growth stimulatory effect was not restricted to one cell generation but was a characteristic of at least the following two cell cycles. GPRE extract from L-cells synchronized by centrifugal elutriation was most efficient when isolated from cells in early G1 phase, while extract from S phase cells had virtually no effect. It is tentatively suggested that the factor belongs to the competence/progression group of growth factors.
Olsen
L C
LC
Department of Biochemistry, University of Bergen, Norway.
Pryme
I F
IF
Bassøe
C F
CF
D000818:Animals; D002453:Cell Cycle; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D006133:Growth Substances / Q000302:isolation & purification*; D006801:Humans; D007700:Kinetics; D007739:L Cells / Q000166:cytology / Q000502:physiology; D015473:Leukemia, Promyelocytic, Acute; D051379:Mice; D014407:Tumor Cells, Cultured / Q000166:cytology* / Q000187:drug effects
D006133:Growth Substances