[The effect of calcyclin binding protein on gastric cancer cell proliferation].
OBJECTIVE
To study the effect of calcyclin binding protein (CacyBP) on the proliferation of gastric cancer cells.


METHODS
CacyBP siRNA expression vector was constructed and transfected into the gastric cancer cells of the line SGC7901 (SGC/CacyBP-siRNA cells). Blank vector mU6 was transfected too as control group (SGC/mU6 cells). Western blotting and semi-quantitative RT-PCR were used to detect the protein expression and mRNA expression of CacyBP in the transfected cells. Immunofluorescence staining was used to detect the intensity of green fluorescence. The cell growth was determined by MTT method. Western blotting and semi-quantitative RT-PCR were used to detect the protein expression and mRNA expression of beta-catenin, cyclooxygenase-2 (COX-2), cyclin D1, rac1, and heat shock protein (HSP) 70. The protein level of beta-catenin in the nuclei of the transfected cells was detected. Twenty-fife nude mice were randomly divided into 5 groups to be inoculated with the SGC7901 cells stably transfected with CacyBP siRNA expression vector and the size of tumor was observed 1, 2, 3, 4, and 5 weeks after the inoculation respectively. The blank vector mU6 was inoculated as control group.


RESULTS
The mRNA expression and protein expression of endogenous CacyBP in the SGC/CacyBP-siRNA cells were both markedly lower than those of the SGC/mU6 cells. Immunofluorescence staining showed weaker green fluorescence in the SGC/CacyBP-siRNA cells than the SGC/mU6 cells. MTT method showed that the growth of the SGC/CacyBP-siRNA cells was significantly faster than that of the SGC/mU6 cells (P < 0.01). Western blotting showed remarkable up-regulation of the protein expression of beta-catenin, COX-2, cyclin D1, rac1, and HSP 70 in the SGC/CacyBP-siRNA cells; and semi-quantitative RT-PCR showed remarkable up-regulation of the mRNA expression of COX-2 and cyclin D1 in the SGC/CacyBP-siRNA cells, however, the mRNA expression of HPS70, rac1, and beta-catenin showed no significant differences between these 2 groups. The size of tumor of the mice inoculated with SGC/CacyBP-siRNA cells was significantly larger than that of the mice inoculate with SGC/mU6 cells (P < 0.01). The survival times of the nude mice inoculated with SGC/CacyBP-siRNA1 and SGC/CacyBP-siRNA1 cells respectively were 60 d +/- 8 d and 50 d +/- 4 d, both significantly shorter than that of the control group (75 d +/- 9 d, both P < 0.01).


CONCLUSIONS
The down-regulation of CacyBP can promote the proliferation of gastric cancer cells and aggravate their malignant behavior.
Ning
Xiao-xuan
XX
Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
Sun
Shi-ren
SR
Li
Yuan
Y
Gong
Wei-qin
WQ
Liu
Li-Li
LL
Sun
Li
L
Liang
Jie
J
Pan
Yang-lin
YL
Cheng
Yi
Y
Wu
Kai-chun
KC
Fan
Dai-ming
DM
D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D034741:RNA, Small Interfering / Q000235:genetics*; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D014162:Transfection; D023041:Xenograft Model Antitumor Assays; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
C491778:CACYBP protein, human; D002135:Calcium-Binding Proteins; D034741:RNA, Small Interfering; D051176:beta Catenin; D019938:Cyclin D1; D051546:Cyclooxygenase 2