Ascorbic acid-dehydroascorbate induces cell cycle arrest at G2/M DNA damage checkpoint during oxidative stress

Area of Science:

• Cell Biology
• Oxidative Stress Research
• Biochemistry

Background:

• Reactive oxygen species (ROS) cause cellular damage and mediate signaling.
• The link between cellular redox status and cell cycle progression remains unclear.
• Ascorbic acid (AA) previously showed protective effects against oxidative stress in AS52 cells when administered pre-stress.

Purpose of the Study:

• To elucidate the mechanism of AA's protective effect against oxidative stress.
• To determine the impact of AA on cell cycle progression during oxidative stress.
• To investigate the role of AA's oxidized form, dehydroascorbate (DHA), in cell cycle regulation.

Main Methods:

• Utilized Chinese hamster ovary (CHO) cell line AS52.
• Employed flow cytometry to analyze cell cycle progression.
• Applied radical generating systems (RGS) to induce oxidative stress.
• Manipulated conditions to control dehydroascorbate (DHA) reduction.

Main Results:

• Pre-treatment with AA enhanced G2/M DNA damage checkpoint arrest in cells exposed to RGS.
• AA alone, without oxidative stress, did not affect cell cycle progression.
• Arrest at the G2/M checkpoint was also observed when DHA reduction was inhibited.
• DHA was found to delay cyclin B-cdc2 activation, contributing to G2/M arrest.

Conclusions:

• Ascorbic acid (AA) acts as an antioxidant during oxidative stress.
• Dehydroascorbate (DHA) plays a role in transient G2/M checkpoint arrest.
• A unique redox mechanism regulates cell cycle progression.
• AA offers novel protection against oxidative stress-induced cellular damage via cell cycle modulation.