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Updated: Aug 17, 2026
In Vivo Model for Testing Effect of Hypoxia on Tumor Metastasis
Published on: December 9, 2016
S-adenosylhomocysteine metabolism in different cell lines: effect of hypoxia and cell density
Marina Hermes1, Sandra von Hippel, Hartmut Osswald
1Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Germany.
Background/Aims:
The methylation potential (MP) is defined as the ratio of S-adenosylmethionine (AdoMet) to S-adenosylhomocysteine (AdoHcy). It was shown recently that hypoxia increases AdoMet/AdoHcy ratio in HepG2 cells (Hermes et al., Exp Cell Res 294: 325-334, 2004). In the present study, we compared AdoMet/AdoHcy ratio and energy metabolism in HepG2, HEK-293, HeLa, MCF-7 and SK-HEP-1 cell lines under normoxia and hypoxia.
Methods:
Metabolite concentrations were measured by HPLC. In addition, AdoHcy hydrolase (AdoHcyase) activity was determined photometrically.
Results:
Under normoxia HepG2 cells show the highest AdoMet/AdoHcy ratio of 53.4 +/- 3.3 followed by MCF-7 and SK-HEP-1 cells with a AdoMet/AdoHcy ratio of 14.4 +/- 1.1 and 21.1 +/- 1.3, respectively. The lowest AdoMet/AdoHcy ratios are exhibited by HeLa and HEK-293 cells (6.6 +/- 0.7 and 7.1 +/- 0.3). Hypoxia does not significantly change the MP in MCF-7 and HeLa cells, but alters the MP in HepG2, HEK-293 and SK-HEP-1 cells. These alterations are dependent on the cell density. Under normoxia HepG2 cells exhibit AdoHcyase activity of 2.5 +/- 0.2 nmol min(-1) mg(-1) protein. All other cell lines show 3-5 times lower enzyme activity. Interestingly, hypoxia affects AdoHcyase activity only in HepG2 cells.
Conclusions:
Our data clearly show that the cell lines are characterized by different MP and different behavior under hypoxia. That implies that a lower MP is not necessarily associated with impaired transmethylation activity and cellular function.
