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Objective To observe the effect of somatostatin-14 peptide (SST-14) combined with 5-fluorouracil (5- FU) by intraperitoneal injection on human gastric cancer BGC-823 xenografts in nude mice and to explore its mechanism. Methods We constructed 28 human gastric cancer cell line BGC-823 transplantation tumor models of nude mice, and ran­domly divided them into the control group, 5-Fu group, SST group and the combination group with 7 mice in each group. The combination group was treated with SST-14 and 5-FU, in which SST-14 was injected intraperitoneally 1 mg/kg for four days a week, stopped for three days； 5-FU was injected intraperitoneally 20 mg/kg one time per week. SST group was in­jected intraperitoneally with SST-14 (1 mg/kg) for four days a week, stopped for three days. 5-FU group was injected in­traperitoneally with 5-FU (20 mg/kg) one time per week. The control group was given the same volume of sterile saline. Each group was treated for 21 d. The nude mice were killed by cervical dislocation at 24 h after the last medication. The tumor tissue was stripped completely. The tumor volume was measured and the tumor inhibition rate was calculated. TUNEL method was used to detect the apoptosis rate in the tumor tissues. The expression of Bcl-2 and Bax in tumor tissues was de­tected by immunohistochemical SP method, and pERK and ERK was detected by Western blotting. Results The tumor volume of 5-FU group, SST group and the combination group was less than that of the control group after treatment, and the tumor volume of the combination group was less than that of 5-FU group and SST group ( all P < 0. 05 ) . The inhibition rate of tumor volume was 26. 243% in the 5-Fu group, 25.447% in the SST group, and 44. 433% in the combination group. The apoptosis rate in the 5-FU group, SST group and the combination group was higher than that of the control group, and the apoptosis rate in the combination group was higher than that in the 5-FU group and SST group (all P <0. 05). Com­pared with the control group, Bel-2 protein expression and Bcl-2/Bax in transplanted tumor tissues decreased, Bax protein expression increased in the 5-FU group, SST group and the combination group (all P <0.05). Compared with 5-FU group and SST group, the relative expression level of Bel-2 protein and Bcl-2/Bax decreased, but the relative expression level of Bax protein increased in the combination group (all P <0.05). The expression of pERK protein of the SST group and the combination group was lower than that of the control group (P <0. 05). Conclusions SST-14 combined with 5-FU by in- traperitoneal injection can inhibit the growth of human gastric cancer BGC-823 xenografts in nude mice, promote apoptosis of gastric cancer cells, and the effect is better than that of SST-14 or 5-FU alone. The mechanism may be related to the down-regulation of pERK expression in gastric cancer cells by SST-14. [ABSTRACT FROM AUTHOR]

Objective: To investigate the inhibitory effects of DC load α-galactosylceramide as the stimulus of natural killer T cells(NKT) on liver cancer of mice. Methods: Mouse model of the solid tumor of liver cancer were established. Then the mice were randomly divided into three groups(n=10 each): Normal saline control group, dendritic cells(DC) group and DC load α-Galcer group. For the latter two groups, 4 ×106/m L dentritic cells, DC cells loaded with α-Galcer were respectively injected into the mice through the tail vein,while the mice in the NS control group were administrated with the same volume of NS. The administration was carried out every other day, totally 3 times. Peripheral blood and spleen was detached 2 weeks after injection in each group. The number of CD4+, CD8+T cells in peripheral blood of mice was counted by flow cytometry(FCM), The expression of Bax in transplanted tumor was detected by immunohistochemistry and Western blot. Results: The number of CD4+and CD8+T cells was higher in the DC load α-Galcer group than that of DC group and control group(P<0.05), while it was higher in DC group than that of the control group, but no obvious difference(P>0.05). The average tumor weight of DC load α-Galcer group was significantly decreased than that of DC group and the control group(P<0.05). There was no significant change in the average tumor weight between the DC group and control group(P>0.05). The number of Bax-positive cells in DC load α-Gal Cer group was significantly decreased compared with that of DC group and control group(P<0.05)by Western blot detection, while no significant change was detectable in the number of Bax-positive cells between DC group and control group. Conclusions: DC load α-Galcer can activate NKT cells, and also can activate the peripheral blood anti-tumor immune cells to inhibit the growth of Heps tumor in mice. [ABSTRACT FROM AUTHOR]