Importance of polyamines in cell cycle kinetics as studied in a transgenic system.
Polyamines are organic cations, which are considered essential for normal cell cycle progression. This view is based on results from numerous studies using a variety of enzyme inhibitors or polyamine analogues interfering with either the metabolism or the physiological functions of the polyamines. However, the presence of non-specific effects may be hard to rule out in such studies. In the present study, we have for the first time used a transgenic cell system to analyze the importance of polyamines in cell growth. We have earlier shown that expression of trypanosomal ODC in an ODC-deficient variant of CHO cells (C55.7) supported growth of these otherwise polyamine auxotrophic cells. However, one of the transgenic cell lines grew much slower than the others. As shown in the present study, the level of ODC activity was much lower in these cells, and that was reflected in a reduction of cellular polyamine levels. Analysis of cell cycle kinetics revealed that reduction of growth was correlated to prolongation of the G1, S, and G2+M phases in the cells. Providing exogenous putrescine to the cells resulted in a normalization of polyamine levels as well as cell cycle kinetics indicating a causal relationship.
Nasizadeh
Sima
S
Department of Physiological Sciences, Lund University, BMC F-13, S-221 84 Lund, Sweden.
Myhre
Louise
L
Thiman
Lena
L
Alm
Kersti
K
Oredsson
Stina
S
Persson
Lo
L
D000818:Animals; D016466:CHO Cells; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D016193:G1 Phase / Q000187:drug effects / Q000502:physiology; D016195:G2 Phase / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D009955:Ornithine Decarboxylase / Q000378:metabolism* / Q000494:pharmacology; D011073:Polyamines / Q000378:metabolism* / Q000494:pharmacology; D011700:Putrescine / Q000378:metabolism / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014162:Transfection; D019076:Transgenes / Q000502:physiology
D018797:Cell Cycle Proteins; D011073:Polyamines; D004247:DNA; D009955:Ornithine Decarboxylase; D011700:Putrescine