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Deuterium oxide (heavy water) arrests the cell cycle of PtK2 cells during interphase
D Schroeter1, J Lamprecht, R Eckhardt
1Institute of Cell and Tumor Biology, German Cancer Research Center, Heidelberg.
Abstract:
Deuterium oxide (D2O, heavy water) exerts an antiproliferative effect on a variety of cells in vitro and on some organisms. This effect is mainly ascribed to a tubulin-mediated antimitotic action. We evaluated the morphology, the mitotic activity, and the dynamics of the cell cycle of PtK2 cells grown in vitro in the presence of 75% D2O for up to eight weeks by microspectrophotometric DNA measurements as well as flow cytometric analysis and a determination of mitotic indices. Substitution of heavy water for water in the culture medium initially increased the mitotic index by a (pro-) metaphase block but after 2 to 3 days of incubation no mitotic figures were seen. Analysis of cells grown for 6 days in medium containing 75% D2O revealed accumulation of cells in S/G2-phase. Extended treatment stabilized the high level of cells in this specific phase, when compared to normal growing cells. Cells grown for 1 to 6 weeks in the presence of D2O remained non-proliferating, nevertheless, they were able to divide again after recovery in non-deuterated medium. The time needed for resumption of the mitotic activity was proportional to the duration of deuterium oxide exposure. Cells incubated for 8 weeks in 75% D2O did not recommence mitotic activity. Light and electron microscopic examination revealed characteristic morphological changes of size and ciliation in PtK2 cells subjected to prolonged deuteration.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Heavy water (D2O) halts cell proliferation by blocking mitosis, causing cells to accumulate in the S/G2 phase. While cells recover after short exposures, prolonged deuteration leads to irreversible non-proliferation and morphological changes.
Area of Science:
- Cell Biology
- Biochemistry
Background:
- Deuterium oxide (D2O, heavy water) is known to inhibit cell proliferation.
- This antiproliferative effect is primarily attributed to antimitotic action mediated by tubulin.
Purpose of the Study:
- To investigate the effects of prolonged exposure to 75% D2O on PtK2 cell morphology, mitotic activity, and cell cycle dynamics.
- To determine the reversibility of D2O-induced cell cycle arrest.
Main Methods:
- PtK2 cells were cultured in 75% D2O for up to eight weeks.
- Microspectrophotometric DNA measurements, flow cytometry, and mitotic index determinations were employed.
- Light and electron microscopy were used to assess morphological changes.
Main Results:
- Initial D2O exposure caused a metaphase block, increasing the mitotic index.
- After 2-3 days, mitotic figures disappeared, with cells accumulating in the S/G2 phase.
- Prolonged exposure (1-6 weeks) resulted in stable non-proliferation, with recovery possible after shorter durations.
- Eight weeks of D2O exposure led to irreversible cessation of mitotic activity and significant morphological alterations.
Conclusions:
- D2O induces a reversible cell cycle arrest at S/G2 phase, with reversibility dependent on exposure duration.
- Extended D2O treatment causes irreversible growth arrest and distinct morphological changes in PtK2 cells.
- Heavy water's antimitotic effects are significant and duration-dependent.