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Regulatory volume decrease is actively modulated during the cell cycle
Liwei Wang1, Lixin Chen, Linyan Zhu
1School of Biosciences, Cardiff University, Cardiff, United Kingdom.
Abstract:
Nasopharyngeal carcinoma cells, CNE-2Z, when swollen by 47% hypotonic solution, exhibited a regulatory volume decrease (RVD). The RVD was inhibited by extracellular applications of the chloride channel blockers tamoxifen (30 microM; 61% inhibition), 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, 100 microM; 60% inhibition), and ATP (10 mM; 91% inhibition). The level and time constant of RVD varied greatly between cells. Most cells conducted an incomplete RVD, but a few had the ability to recover their volume completely. There was no obvious correlation between cell volume and RVD capacity. Flow cytometric analysis showed that highly synchronous cells were obtained by the mitotic shake-off technique and that the cells progressed through the cell cycle synchronously when incubated in culture medium. Combined application of DNA synthesis inhibitors, thymidine and hydroxyurea arrested cells at the G1/S boundary and 87% of the cells reached S phase 4 h after being released. RVD capacity changed significantly during the cell cycle progression in cells synchronized by shake-off technique. RVD capacity being at its highest in G1 phase and lowest in S phase. The RVD capacity in G1 (shake-off cells sampled after 4 h of incubation), S (obtained by chemical arrest), and M cells (selected under microscope) was 73, 33, and 58%, respectively, and the time constants were 435, 769, and 2,000 sec, respectively. We conclude that RVD capacity is actively modulated in the cell cycle and RVD may play an important role in cell cycle progress.
Insights
Nasopharyngeal carcinoma cells show regulatory volume decrease (RVD) which is inhibited by chloride channel blockers and ATP. RVD capacity varies during the cell cycle, being highest in G1 phase and lowest in S phase.
Area of Science:
- Cell Biology
- Physiology
Background:
- Nasopharyngeal carcinoma (NPC) is a malignancy with complex cellular behaviors.
- Regulatory Volume Decrease (RVD) is a cellular process crucial for maintaining cell volume homeostasis.
Purpose of the Study:
- To investigate the characteristics of RVD in CNE-2Z nasopharyngeal carcinoma cells.
- To determine the influence of the cell cycle on RVD capacity.
Main Methods:
- CNE-2Z cells were subjected to hypotonic swelling to induce RVD.
- Chloride channel blockers (tamoxifen, NPPB) and ATP were used to assess RVD inhibition.
- Flow cytometry and mitotic shake-off were employed for cell cycle synchronization.
- RVD capacity was measured across different cell cycle phases (G1, S, M).
Main Results:
- Hypotonic swelling induced RVD in CNE-2Z cells, which was significantly inhibited by tamoxifen, NPPB, and ATP.
- RVD capacity exhibited cell cycle-dependent modulation, with the highest capacity in G1 phase (73%) and the lowest in S phase (33%).
- RVD capacity was also substantial in M phase (58%), but with longer time constants.
Conclusions:
- RVD capacity is actively regulated during the cell cycle in nasopharyngeal carcinoma cells.
- The findings suggest a potential role for RVD in facilitating cell cycle progression.