Apoptosis of human primary gastric carcinoma cells induced by genistein.
OBJECTIVE
To investigate the apoptosis in primary gastric cancer cells induced by genistein, and the relationship between this apoptosis and expression of bcl-2 and bax.


METHODS
MTT assay was used to determine the cell growth inhibitory rate in vitro. Transmission electron microscope and TUNEL staining were used to quantitatively and qualitatively detect the apoptosis of primary gastric cancer cells before and after genistein treatment. Immunohistochemical staining and RT-PCR were used to detect the expression of apoptosis-associated genes bcl-2 and bax.


RESULTS
Genistein inhibited the growth of primary gastric cancer cells in dose-and time-dependent manner. Genistein induced primary gastric cancer cells to undergo apoptosis with typically apoptotic characteristics. TUNEL assay showed that after the treatment of primary gastric cancer cells with genistein for 24 to 96 h, the apoptotic rates of primary gastric cancer cells increased time-dependently. Immunohistochemical staining showed that after the treatment of primary gastric cancer cells with genistein for 24 to 96 h, the positivity rates of Bcl-2 proteins were apparently reduced with time and the positivity rates of Bax proteins were apparently increased with time. After exposed to genistein at 20 micromol/L for 24, 48, 72 and 96 respectively, the density of bcl-2 mRNA decreased progressively and the density of bax mRNA increased progressively with elongation of time.


CONCLUSIONS
Genistein is able to induce the apoptosis in primary gastric cancer cells. This apoptosis may be mediated by down-regulating the apoptosis- associated bcl-2 gene and up-regulating the expression of apoptosis-associated bax gene.
Zhou
Hai-Bo
HB
Department of Gastroenterology, Second Affiliated Hospital of Zhejiang University, Hangzhou 310009, Zhejiang Province, China. zhouhaibohz@163.com
Chen
Juan-Juan
JJ
Wang
Wen-Xia
WX
Cai
Jian-Ting
JT
Du
Qin
Q
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D020287:In Situ Nick-End Labeling; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms; D013778:Tetrazolium Salts; D013844:Thiazoles; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051028:bcl-2-Associated X Protein
D000970:Antineoplastic Agents; C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D013778:Tetrazolium Salts; D013844:Thiazoles; D051028:bcl-2-Associated X Protein; D019833:Genistein; C022616:thiazolyl blue