Expression And Significance Of GRP78 In Gastric Cancer

[purpose]The mechanism and clinical pathological significance of GRP78 were investigated. The relationship was analyzed between expression of GRP78 and metastasis in gastric cancer.[Methods] The expression level of GRP78 protein was detected with immunohistochemical technology in 48 samples of gastric cancer at different clinical stage and 28 samples normal gastric mucosa tissues adjacent to carcinoma, and the relationship between GRP78 expression and metastasis, clinical stage, pathological classification of gastric cancer was analyzed to determine its clinical pathological significance. Then si RNA targeting GRP78 was built and transfected into SGC-7901 gastric cancer cell lines in which GRP78 was high expression. After reducing GRP78 expression in SGC-7901 gastric cancer cell, changes in cell proliferation, invasion capability and gene expression related to it were observed by MTT, trans-well and Western- blot, respectively.[Results] The expression of GRP78 protein in gastric cancer tissue was significantly higher than that in normal gastric mucosa tissues(P < 0.05). GRP78 was mainly distributed in cytoplasm showed by immunohistochemistry. The positive rates of GRP78 in 28 cases ofnormal gastric tissues,28 cases of well or moderately-differentiated and 20 cases of poorly-differentiated gastric cancer tissues are 10.7%( 3/28), 59.4%( 19/32) and 93.8%(15/16), respectively.The positive rate of GRP78 in gastric carcinoma tissues with diameter ≥5 cm, at Ⅲ, period Ⅳin TNM staging, with recurrence or death during follow-up period, was higher than that with diameter < 5 cm, atⅠ,Ⅱperiod, with relapse-free in five years, respectively. The positive rate of GRP78 in gastric carcinoma tissues with lymphatic metastasis was 96.2%(25/26),which was much higher than that of gastric cancer without lymphatic metastasis(40.9%, 9/22)(P < 0.05). The results of q RT-PCR and Western- blot showed that si RNA targeting GRP78 had succeed in inhibiting its protein expression in SGC-7901 cells in which GRP78 is high expression. Cell proliferation and invasive ability were suppressed showed by MTT and Trans-well experiment and the expression of Akt and NF-κB had no obvious changes which were detected by Western- blot after reducing the expression of GRP78 in SGC-7901 cells.[Conclusion] 1、GRP78 protein expression level in gastric cancer tissue is closely related with tumor size, differentiation degree, lymph node metastasis, clinical stage and prognosis of gastric cancer.2、The reduction of GRP78 protein expression can inhibit proliferation and invasion ability of SGC-7901 gastric cancer cells.