Polyamine profiles and growth properties of ornithine decarboxylase overexpressing MCF-7 breast cancer cells in culture.
To determine the direct influence of the polyamine (PA) pathway on breast cancer phenotype, we employed a transfection approach to induce overexpression of the PA biosynthetic enzyme ornithine decarboxylase (ODC) in the hormone-responsive MCF-7 breast cancer cell line. Using a modified calcium phosphate method and an ODC cDNA coding for a truncated and more stable enzyme, we were able to achieve a moderate to marked degree of ODC overexpression (up to 150-fold) in a transient transfection system. ODC-overexpressing MCF-7 cells exhibited a selective increase in cellular putrescine content, while the levels of spermidine and spermine remained unaffected. Under defined culture conditions, overexpression of ODC resulted in a consistent but modest increase in [3H]thymidine incorporation into DNA which was similar in the presence and absence of 17-beta-estradiol, TGF-alpha, and IGF-I. In the presence of serum, the effect of ODC overexpression on basal [3H]-thymidine incorporation into DNA was inconsistent, possibly as a result of subtle differences in culture conditions. Overall, our results support the hypothesis that activation of the PA biosynthetic pathway may confer a growth advantage to breast cancer cells.
Manni
A
A
Department of Medicine, Pennsylvania State University College of Medicine, Hershey 17033, USA.
Wechter
R
R
Grove
R
R
Wei
L
L
Martel
J
J
Demers
L
L
D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D002455:Cell Division; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D011073:Polyamines / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D011073:Polyamines; D009955:Ornithine Decarboxylase