Jo. Fredlund et Sm. Oredsson, ORDERED CELL-CYCLE PHASE PERTURBATIONS IN CHINESE-HAMSTER OVARY CELLSTREATED WITH AN S-ADENOSYLMETHIONINE DECARBOXYLASE INHIBITOR, European journal of biochemistry, 249(1), 1997, pp. 232-238
The polyamines putrescine, spermidine, and spermine are needed for nor
mal cell cycle progression and polyamine-depleted cells cease to proli
ferate. We have investigated cell cycle perturbations in Chinese hamst
er ovary cells seeded in the presence of 4-amidinoindan-1-one 2'-amidi
nohydrazone (CGP 48664), a potent inhibitor of S-adenosylmethionine de
carboxylase, an enzyme which is essential for the synthesis of spermid
ine and spermine. At 9 h and at 1, 2, and 3 days after seeding, cells
were labelled with the thymidine analog bromodeoxyuridine (BrdUrd) for
30 min, after which the BrdUrd-containing medium was removed and the
cells were allowed to progress through the cell cycle in BrdUrd-free m
edium before sampling (post-labelling time). Using flow cytometry, cou
pled with an indirect immunofluorenscence technique, utilizing monoclo
nal anti-BrdUrd and secondary fluorescein-isothiocyanate-conjugated an
tibodies, and the DNA stain propidium iodide, cellular BrdUrd and DNA
contents were quantified. By investigating the movement of BrdUrd-nonl
abelled G(1) cells into S phase during the post-labelling time, a meas
ure of the G(1)/S transition was obtained. The time of appearence in G
(1) of BrdUrd-labelled cells which had divided was used to monitor the
length of the G(2)+M phase. A measure of the S phase length (DNA synt
hesis time) was obtained by monitoring the progression of BrdUrd-label
led cells through S phrase. CGP 48664-induced spermine depletion signi
ficantly increased the length of the S phase already 9 h after seeding
cells in the presence of the inhibitor. No effects on the G(1)/S tran
sition or on the length of the G(2)+M phase were observed until 2 days
after seeding.