OBJECTIVETo investigate the inhibitory effect of arsenic trioxide, aspirin and their combination on the growth of human gastric adenocarcinoma SGC-7901 graft in nude mice.

METHODSThirty-one model nude mice with transplanted tumor of human gastric adenocarcinoma SGC-7901 were established successfully by fixing tumor tissue under the left axillary subcutaneously. They were randomly divided into 4 groups and treated respectively with normal saline (control group, n = 7), aspirin (Asp group, n = 8), arsenic trioxide (AT group, n = 8), and AT +Asp (combined treated group, n = 8), medicated by intraperitoneal injection for 14 successive days. All mice were sacrificed 48 h after the final medication, the transplanted tumor mass volume and weight were measured to calculate the tumor inhibition rate, and changes of tumors and tissues of heart, liver, and kidney, etc were observed. Moreover, expressions of proliferation associated protein Ki67 and apoptosis inhibitory protein Bcl-2 were detected by immunohistochemical SP method, and expression of apoptosis associated protein Bax was detected by Western blotting.

RESULTSAfter terminating the medication, in the combined treated group the tumor volume and weight were significantly lower than those in the control group (P < 0.05) and the tumor weight was lower than that in the AT and Asp groups (both P < 0.05). The volume inhibition rate was 59.12% in the AT group, 47.60% in the Asp group, and 76.70% in the combined treated group, and the weight inhibition rate in them 35.60%, 45.44% and 63.90%, respectively. Immunochemical staining showed that as compared with the control group, expressions of Ki67 and Bcl-2 were down-regulated in all the three treated groups to some extent (all P < 0.05), and significant difference was also shown in comparison of the two indices between the combined treated group with the other two treated groups (P < 0.05). The expression of Bax was higher in the combined treated group than in other groups (all P < 0.05).

CONCLUSIONCombined use of AT and Asp has certain cooperative effect in inhibiting the growth of gastric carcinoma cells without obvious toxic-side effects.