[Apoptosis of human gastric cancer cell induced by photochemical riboflavin].
OBJECTIVE
Photochemical riboflavin, the production of reactive oxygen species (ROS), has been reported having cytotoxity on some cancer cells. The aim of this study was to investigate the effect of photochemical riboflavin on inducing apoptosis in human gastric cancer cell line MGC80-3.


METHODS
Trypan blue exclusion method, Giemsa staining, DNA electrophoresis, DNA quantification, Western blot analysis, and flow cytometry were conducted to determine the effect of photochemical riboflavin on cell survival, morphology, DNA fragmentation, gene expression, and cell cycle arresting.


RESULTS
The cell viability dropped down according to the riboflavin concentration and treating time. Exposure of the cells in 20 micromol/L riboflavin for 24 hours resulted in typical apoptotic morphology and G(2)/M arresting. As MGC80-3 cells were separately treated with 10, 20, 30, and 40 micromol/L photochemical riboflavin, DNA electrophoresis showed that the ladder bands, a typical feature of apoptotic cell, appeared in the groups treated by over 20 micromol/L photochemical riboflavin. The efficiency rates of DNA fragmentation were 35.4%, 54.1%, 70.6%, and 86.8%, respectively. Western blot analysis showed that the expression of apoptosis related proteins p53, C-myc, and Bax were up-regulated whereas the expression of Bcl-2 was down-regulated.


CONCLUSIONS
These results indicate that photochemical riboflavin has high efficiency of inducing cell apoptosis on MGC 80-3 cells in vitro and there is a correlation between apoptosis and G(2)/M arresting.
Li
Jin-Quan
JQ
Department of Biology, Life Science School of Xiamen University, Xiamen, Fujian, 361005, P.R.China. jinquanli@hotmail.com
Chen
Rui-Chuan
RC
Cai
Ke-Xia
KX
Ye
Zhi-Yun
ZY
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D017319:Photosensitizing Agents / Q000494:pharmacology; D012256:Riboflavin / Q000494:pharmacology*; D013274:Stomach Neoplasms / Q000473:pathology*; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D017319:Photosensitizing Agents; D012256:Riboflavin