[Effect of chemokine stromal cell derived factor-1 and its receptor CXCR4 on the peritoneal carcinometastasis of gastric cancer].

OBJECTIVE: To investigate the effect of chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 on the peritoneal carcinometastasis of gastric cancer.

METHODS: Human gastric cancer cells of the lie NUGC4 and mesothelial cells of the line HMrSV were cultured. RT-PCR was used to detect the expression of CXCR4 and SDF-1 mRNA in the NUGC4 and HMrSV cells. The proliferation of NUGC4 cells was detected by MTT method. In mesothelial cell adhesion teat NUGC4 cells were cultured with confluent HMrSV mesothelial cells in 24-well plate and then divided into 3 groups: chemokine group, added with SDF-1, antibody blocking group, in which the NUGC4 cells were pre-incubated with CXCR4 monoclonal antibody for 2 h and then SDF-1 was added, and control group added with only culture fluid. Microscopy was used to calculate the number of gastric cancer cells adhered with mesothelial cells. In the mesothelial cell migration test HMrSV cells were put in the upper chamber of a Transwell chamber so as to cover the infiltration membrane. This Transwell chamber was put into a culture plate, NUGC4 cells, divided into 3 groups as mentioned above were put into the upper chamber, 24 h later HE staining and microscopy were performed to calculate the number of the NUGC4 cells that penetrated the membrane. BALB/c nu/nu female nude mice underwent intraperitoneal injection of NUGC4 cells, and then with PBS or AMD3100, small molecular specific antagonist, one day after the cancer cell injection once a day for 2 weeks. Then the mice were killed to observe the intraperitoneal tumorigenesis.

RESULTS: CXCR4 mRNA was highly expressed in the NUGC4 cells but only very weekly expressed in the HMrSV cells. SDF-1 mRNA expression was seen in the HMrSV cells but in the NUGC4 cells. Anti-CXCR4 monoclonal antibody (McAb) inhibited the proliferation of NUGC4 cells significantly (P < 0.05). In mesothelial cell adhesion test, the number of the NUGC4 cells adhered with HMrSV cells after SDF-1 stimulation was 84.4 +/- 21.2, significantly higher than that of the control group (43.6 +/- 12.4, P < 0.05). The number of migrating NUGC4 cells in the chemokine group was 170.8 +/- 24.2, significantly higher than hat of the control group (102.8 +/- 18.2, P < 0.05); and the number of migrating NUGC4 cells in the antibody blocking group was 114.7 +/- 20.3, significantly lower than that of the chemokine group (P < 0.05). The survival time of the mice injected with both NUGC4 cells and AMD3100 was (43.8 +/- 2.8) days, significantly longer than that of the control group [(28.2 +/- 2.5) days, P < 0.01]. The tumor number of the AMD3100 group was (64.6 +/- 8.2), significantly lower than that of the control group [(103 +/- 12.4), P < 0.01].

CONCLUSION: SDF-1 and its receptor CXCR4 play an important role in the development of peritoneal carcinometastasis from gastric cancer. Interfering with the SDF-1/CXCR4 biological axis may become a potential strategy in the prevention and treatment of peritoneal carcinometastasis from gastric cancer.