ABSTRACT
Objective:
To investigate the effect of GTPBP4 silencing by
RNA interference on the
radiosensitivity of esphageal
cancer EC9706
cells line.
Methods:
The expression data of GTPBP4 in
esophageal cancer tissues was obtained from public
Gene Expression Omnibus (GEO) database. Recombinant
plasmid-mediated
RNA interference (
RNAi) was employed to transfect the
esophageal cancer EC9706
cell to evaluate the influence of GTPBP4 silencing on the proliferation,
apoptosis and
radiosensitivity of esphageal
cancer EC9706
cells. The expression levels of GTPBP4
mRNA and
protein and
apoptosis-associated
proteins of Bax, cleaved
caspase-9, cleaved
caspase-3 and Bcl-2 were determined by qRT-
PCR and
Western blot. The
cell proliferation was determined by MTT assay. The changes in
cell apoptosis were detected
AnnexinⅤ-
FITC/PI double
staining flow cytometry. The variations in
radiosensitivity after
radiation exposure were assessed by
clone formation assay.
Results:
The expression level of GTPBP4 in the
esophageal cancer tissues was significantly higher than that in the normal adjacent esophageal
tissues ( P<0.001). qRT-
PCR and
Western blot demonstrated that the expression levels of GTPBP4
mRNA and
protein in the GTPBP4-
siRNA group were significantly lower than those in the blank and negative
control groups (both P<0.001), suggesting that the
plasmid was successfully transfected into the EC9706
cells. MTT assay indicated that the EC9706
cell proliferation rate was significantly inhibited ( P<0.001).
Flow cytometry found that the
apoptosis rate was significantly increased in the GTPBP4-
siRNA group ( P<0.001). After GTPBP4
gene interference combined with
radiotherapy, the
cell sensitivity enhancement ratio was 1.716. The
apoptosis rate of EC9706
cells was significantly increased in the GTPBP4-
siRNA group ( P<0.001). The expression levels of
apoptosis-associated
proteins including cleaved
caspase-9, cleaved
caspase-3 and Bax were significantly up-regulated, whereas that of Bcl-2 was significantly down-regulated in the EC9706
cells in the GTPBP4-
siRNA group ( P<0.001, P=0.001, P=0.001 and P=0.005).
Conclusions:
GTPBP4
gene is highly expressed in
human esophageal cancer tissues.
RNAi technology can effectively inhibit the expression of GTPBP4
gene in the EC9706
cells, thereby suppressing
cell proliferation, inducing
cell apoptosis and enhancing the
radiosensitivity of
cells.