Expressions Of Chemokine CXCL12and Its Receptor CXCR4in Gastric Cancer And Their Signiifcance

Purpose: To investigate the expressions of chemokine CXCL12and its receptorCXCR4protein in gastric cancer and the relationship between clinicopathologicparameters and the prognosis. To study the inhibitory effect of chemokine receptorCXCR4short interference RNA(siRNA) on the invasion capability of gastric carcinomacell1ine BGC-823. Methods Part1: Immuohistochemistry was used to detect theexpressions of CXCL12and CXCR4in120samples of human gastric cancer. Thecorrelation between the expression of CXCL12CXCR4and clinicopathologicparameters of the patients with gastric cancer was analyzed respectively. We alsoanalyzed the value of CXCL12CXCR4and combined assay of the two proteins inpredicting the prognosis of patients. Part2: SiRNA specifically targeting CXCchemokine receptor CXCR4was designed, Gastric Carcinoma SGC-823cells werecultured under standard condition and the siRNA was transfected into SGC-823cellswith lipofectam line2000.Negative control and blank control were used at the sametime. The1evels of CXCR4mRNA and protein were detected by reversetranscription-poly-merase chain reaction (RT-PCR)and immunofluresene cell staining48h after transfection respectively.Transwell chamber was used to detect cell’s abilitiesof invasion and metastasis. Results Part1: CXCL12and CXCR4were detected inboth gastric carcinoma tissues and normal tissues,but the expression level of CXCL12and CXCR4were found up-regulated in gastric carcinoma tissues as compared withnormal tissues. The expression of CXCL12and CXCR4are significantly different(P<0.05).The positive expression of CXCL12was consistent with the positiveexpression of CXCR4(γ=0.439,P<0.05),and the expression levels of CXCL12and CXCR4were closely correlated with lymph node metastasis and differentiation(P<0.05),but not with age,sex,tumor size,depth of invasion, distant metastasis(P>0.05),The five-year survival rate of patients whose CXCL12and CXCR4positive expressionwas significantly lower than the patients with negative expression. Part2: CXCR4siRNA significantly inhibited the expression of CXCR4in BGC-823cell line. Thenumber of metastasis cells in BGC-823siRNA group was significantly lower than thosein negative siRNA group and control group (all p<0.05). Conclusions [1]Overexpression of CXCL12and CXCR4is correlated with the biologic behavior andprognosis of gastric carcinoma, Determination of CXCL12and CXCR4is very helpfulin predicting of metastasis and evaluating the prognosis of gastric carcinoma.[2]CXCR4siRNA can inhibit the expression of CXCR4and decrease the invasioncapability of BGC-823cells.