Radiation-induced division delay in 9L spheroid versus monolayer cells

Area of Science:

• Cell Biology
• Radiation Oncology
• Cancer Research

Background:

• Cell-cell contact influences cellular responses to radiation.
• Understanding division delay is crucial for radiotherapy efficacy.

Purpose of the Study:

• To compare radiation-induced division delay in 9L rat gliosarcoma cells grown as spheroids versus monolayers.
• To investigate the impact of three-dimensional (3D) cell growth on radiation response.

Main Methods:

• Utilized the percentage labeled mitoses technique.
• Measured division delay by comparing the time to reach the first peak of labeled mitoses in control and irradiated cultures.
• Exposed cells to five different X-ray doses.

Main Results:

• Spheroid cells exhibited significantly longer radiation-induced division delays than monolayer cells.
• Dose-response slopes were 32 min/Gy for spheroids and 13 min/Gy for monolayers.
• Division delay was consistent across small (150 micron) and large (800 micron) spheroids.

Conclusions:

• Three-dimensional growth and cell-cell contact in spheroids enhance radiation-induced division delay in 9L gliosarcoma cells.
• This finding parallels the observed enhanced radiation survival in spheroids, suggesting a contact-mediated effect.
• Cellular contact in 3D environments may modulate cell cycle progression following radiation exposure.