Mechanism of ascorbic acid-induced reversion against malignant phenotype in human gastric cancer cells.
OBJECTIVE
To find out the mechanisms of redifferentiation and reversion of malignant human gastric cancer cells induced by ascorbic acid.


METHODS
Human gastric cancer cells grown in the laboratory were used. The Trypan blue dye exclusion method was used to determine the cell doubling time. The electrophoresis rate and colonogenic potential were the indices used to measure the rate of redifferentiation. The content of malondialdehyde (MDA) was measured using the thiobarbituric acid (TBA) method. The activities of superoxide dismutase (SOD), catalase (CAT) and the content of H202 were evaluated by spectrophotography.


RESULTS
Six mmol/L ascorbic acid was used as a positive control. Human gastric cancer cells were treated with 75 microm hydrogen peroxide, which alleviated many of the malignant characteristics. For example, the cell surface charge obviously decreased and the electrophoresis rate dropped from 2.21 to 1.10 microm x s(-1) x V(-1) x cm(-1). The colonogenic potential, a measure of cell differentiation, decreased 90.2%. After treatment with ascorbic acid, there was a concentration- and time-dependent increase in hydrogen peroxide (H202) and the activity of superoxide dismutase (SOD). However, the activity of catalase (CAT) resulted in a concentration- and time-dependent decrease. SOD and 3-amino-1,2,4-triazole (AT) exhibited some effects, but there were statistically significant differences between the SOD and AT group and the H202 group.


CONCLUSIONS
Ascorbic acid induces growth inhibition and redifferentiation of human gastric cancer cells through the production of hydrogen peroxide.
Sun
Ya-Xuan
YX
Life Sciences School of Lanzhou University, Lanzhou 730000, Gansu, China.
Zheng
Qiu-Sheng
QS
Li
Gang
G
Guo
De-An
DA
Wang
Zi-Ren
ZR
D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid