Related Experiment Video
Updated: Aug 9, 2026

Enrichment for Chemoresistant Ovarian Cancer Stem Cells from Human Cell Lines
Published on: September 10, 2014
Elevated expression of thymidylate synthase cycle genes in cisplatin-resistant human ovarian carcinoma A2780 cells
1Department of Medical Oncology, City of Hope National Medical Center, Duarte, CA 91010.
Abstract:
Activity of the thymidylate synthase cycle was compared in the human ovarian carcinoma cell line A2780 and a subline that is resistant to cisplatin by a factor of 3. Resistant cells exhibited a 3-fold increase in mRNA for both dihydrofolate reductase (5,6,7,8-tetrahydrofolate:NADP+-oxidoreductase, EC 1.5.1.3) and thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) when compared with the parent line. Resistance to cisplatin also resulted in a 2.5-fold increase in enzyme activity for dihydrofolate reductase and thymidylate synthase; however, this increase did not result from amplification of the genes for these two enzymes. These data suggest that the initial step of cisplatin resistance in A2780 cells is a consequence of enhanced expression of the thymidylate synthase cycle.
Related Concept Videos
Inhibition of Cdk Activity
Abnormal Proliferation
Treatment Resistant Cancers
Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

