[The role of reactive oxygen species in N-[4-hydroxyphenyl] retinamide induced apoptosis in bladder cancer cell lineT24].
OBJECTIVE
To study the mechanism of the apoptosis induced by N-[4-hydroxyphenyl] retinamide (4-HPR) in bladder cancer cell line T24, and the involvement of DNA damage and repair.


METHODS
T24 cells were treated with 4-HPR at the concentration of 2.5, 5.0 and 10.0 micromol/L, and the cell grow inhibition was measured by cell counting assay. The fluorescent intensity of reactive oxygen species (ROS) was determined by spectrofluorometer. The apoptosis was measured by flow cytometry and DNA fragment assay. The expression of XRCC1 protein and activation of caspase-3 were detected by Western blot.


RESULTS
4-HPR induced apoptosis in T24 cell. A dose-dependent increase in the percentage of apoptosis cells was observed (1.8%, 4.0% and 10.5% respectively at 2.5, 5.0, 10.0 micromol/L 4HPR). In the meantime, ROS level in the cell was increased (peaked at 3 fold). It also caused down-regulation of the expression of XRCC1, and activation of caspase-3. Vitamin C effectively inhibited ROS rise induced by 4-HPR, and also partially inhibited cell growth, apoptosis, and down-regulation of the expression of XRCC1.


CONCLUSIONS
The generation of ROS and DNA damage may be the major mechanism of the apoptosis of bladder cancer cell line T24 induced by 4-HPR.
Liu
Jia
J
Department of Molecular Cell Biology & Toxicology, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
Li
Ai-ping
AP
Li
Chun-ping
CP
Zhang
Zheng-dong
ZD
Zhou
Jian-wei
JW
D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D017313:Fenretinide / Q000494:pharmacology*; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*; D000076105:X-ray Repair Cross Complementing Protein 1
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D017382:Reactive Oxygen Species; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D017313:Fenretinide