Related Experiment Videos
Inhibition of DNA methylation in malignant MOLT F4 lymphoblasts by 6-mercaptopurine
L H Lambooy1, P A Leegwater, L P van den Heuvel
1Center for Pediatric Oncology SE Netherlands, Department of Pediatrics, St. Radboud University Hospital of Nijmegen, The Netherlands.
Abstract:
Treatment of MOLT F4 lymphoblasts with 6-mercaptopurine (6-MP) resulted in a decrease of ATP and a depletion of S-adenosylmethionine (AdoMet). To investigate whether this might affect the methylation of DNA, we treated MOLT F4 lymphoblasts with increasing concentrations of 6-MP, followed by labeling with [methyl-14C]methionine and [methyl-3H]thymidine. After DNA isolation, we measured the incorporated radioactivity and determined the 14C/3H ratio as a measure for the methylation of newly formed DNA. The 14C/3H ratio was decreased by 17% with 1 mumol/L 6-MP; treatment with increasing concentrations of 6-MP up to 10 mumol/L showed a further decrease to 70%, in comparison with untreated cells. To demonstrate that the methylation of deoxycytidine residues in DNA was reduced, we quantified hydrolyzed DNA by HPLC. The 14C/3H ratio showed a decrease with increasing 6-MP concentrations, indicating that treatment with 6-MP resulted in hypomethylation of DNA.
Insights
6-mercaptopurine (6-MP) treatment reduces DNA methylation in lymphoblasts. This study shows 6-MP causes hypomethylation, impacting DNA integrity and potentially cancer therapy.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- 6-mercaptopurine (6-MP) is a chemotherapy drug.
- 6-MP depletes S-adenosylmethionine (AdoMet), a key methyl donor.
- The effect of 6-MP on DNA methylation is not fully understood.
Purpose of the Study:
- To investigate the impact of 6-MP on DNA methylation levels.
- To determine if 6-MP causes hypomethylation in lymphoblasts.
Main Methods:
- MOLT F4 lymphoblasts were treated with varying concentrations of 6-MP.
- Cells were labeled with [methyl-14C]methionine and [methyl-3H]thymidine.
- DNA was isolated, and radioactivity was measured to determine the 14C/3H ratio.
- Hydrolyzed DNA was quantified by HPLC to assess deoxycytidine methylation.
Main Results:
- 6-MP treatment decreased the 14C/3H ratio in a dose-dependent manner.
- A 17% decrease was observed at 1 mumol/L 6-MP, reaching a 70% decrease at 10 mumol/L.
- HPLC analysis confirmed reduced methylation of deoxycytidine residues in DNA.
Conclusions:
- 6-MP treatment leads to significant hypomethylation of DNA in MOLT F4 lymphoblasts.
- This hypomethylation effect may have implications for the efficacy and side effects of 6-MP therapy.
- Further research is warranted to explore the downstream consequences of 6-MP-induced DNA hypomethylation.