Effect of morphine on growth of subcutaneous tumor of human gastric cancer cells in nude mice

Abstract

Objective To evaluate the effect of morphine on the growth of subcutaneous tumor of human gastric cancer cells in nude mice. Methods Thirty SPF male BALB/C nude mice, aged 4-5 weeks, weighing 15-20 g, in which the model of subcutaneous tumor of human gastric cancer cell line MGC-803 was established, were randomly divided into 3 groups (n=10 each)using a random number table: control group (group C), normal saline group (group N), and morphine group (group M). The mice in group C received no treatment.Morphine 20 mg/kg was intraperitoneally injected once a day for 14 consecutive days in group M, while normal saline 1.5 ml/kg was given instead of morphine in group N. The caliper was used to measure the tumor size every 2 days starting from 3 days after beginning of administration, and the relative tumor volume was calculated.The nude mice were sacrificed on 15th day, and the tumor tissues were obtained for determination of nuclear factor-kappa B activity and Bcl-2 and Bax protein and mRNA expression by real-time reverse transcriptase polymerase chain reaction and Western blot. Results Compared with group C, the relative tumor volume was significantly decreased, the activity of nuclear factor-kappa B in tumor tissues was significantly decreased, the expression of Bcl-2 protein and mRNA was significantly down-regulated, and the expression of Bax protein and mRNA was significantly up-regulated at each time point in group M (P 0.05). Conclusion Morphine can inhibit the growth of subcutaneous tumor of human gastric cancer cells in nude mice, and the mechanism is associated with promotion of apoptosis in tumor cells. Key words: Morphine; Stomach neoplasms; Growth