<p><b>OBJECTIVE</b>To investigate the function of
apoptosis in
esophageal cancer cells induced by
soybean isoflavone, and the relation between this
apoptosis and expression of bcl-2 and bax.</p><p><b>
METHODS</b>
In vitro experiments, MTT assay was used to determine the
cell growth inhibitory rate.
Transmission electron microscope and
TUNEL staining method were used to quantitatively and qualitatively detect the
apoptosis status of
esophageal cancer cell line EC-9706 before and after the
soybean isoflavone treatment. Immunohistochemical
staining and
reverse transcription-
polymerase chain reaction were used to detect the expression of
apoptosis-regulated gene bcl-2 and bax.</p><p><b>RESULTS</b>
Soybean isoflavone inhibited the
growth of
esophageal cancer cell line EC-9706 in a
dose- and
time-dependent manner.
Soybean isoflavone induced EC-9706
cells to undergo
apoptosis with typically apoptotic characteristics, including morphological changes of
chromatin condensation,
chromatin crescent formation, nucleus fragmentation and
apoptotic body formation by
transmission electron microscope and
staining positive
cells, using
TUNEL assay.
Soybean isoflavone reduced the expression of
apoptosis-regulated gene bcl-2, and improving the expression of
apoptosis-regulated
gene bax.</p><p><b>CONCLUSION</b>
Soybean isoflavone seemed to be able to induce the
apoptosis in
esophageal cancer. This type of
apoptosis might be mediated by down-expression of
apoptosis-regulated gene bcl-2 and up-expression of
apoptosis-regulated
gene bax.</p>