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Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 15, 2004; 10(14): 2140-2144
Published online Jul 15, 2004. doi: 10.3748/wjg.v10.i14.2140
Inhibition of growth and metastasis of human gastric cancer implanted in nude mice by d-limonene
Xiao-Guang Lu, Li-Bin Zhan, Bing-An Feng, Ming-Yang Qu, Li-Hua Yu, Ji-Hong Xie
Xiao-Guang Lu, Department of General Surgery, The Fourth Affiliated Hospital of Dalian Medical University, Dalian 116001, Liaoning Province, China
Li-Bin Zhan, Bing-An Feng, Ming-Yang Qu, Li-Hua Yu, Dalian Medical University Molecular Biological Laboratory for Chinese Traditional Medicine, Dalian 116027, Liaoning Province, China
Ji-Hong Xie, Dalian Medical Science Instituteg, Dalian 116001, Liaoning Province, China
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Xiao-Guang Lu, M.D. Department of General Surgery, Fourth Hospital of Dalian Medical University, Dalian 116001, Liaoning Province, China.
Telephone: +86-411-3039179 Fax: +86-411-4721582
Received: February 2, 2004
Revised: February 11, 2004
Accepted: February 21, 2004
Published online: July 15, 2004

AIM: To investigate the effects and mechanism of d-limonene on the growth and metastasis of gastric cancer in vivo.

METHODS: Metastatic model simulating human gastric cancer was established by orthotopic implantation of histologically intact human tumor tissue into gastric wall of nude mice. One percent d-limonene was orally administered at dose of 15 ml/kg every other day for seven weeks. Eight weeks after implantation, tumor weight, inhibition rate, apoptotic index (AI), microvessel density (MVD), vascular endothelial growth factor (VEGF), variation of ultrastructure, and the presence of metastasis were evaluated, respectively, after the mice were sacrificed.

RESULTS: The tumor weight was significantly reduced in 5-FU group (2.55 ± 0.28 g), d-limonene group (1.49 ± 0.09 g) and combined treatment group (1.48 ± 0.21 g) compared with the control group(2.73 ± 0.23 g, P < 0.05). In 5-FU group, d-limonene group, combined treatment group, the inhibition rates were 2.60%, 47.58% and 46.84% and 0, respectively; AI was (3.31 ± 0.33)%, (8.26 ± 1.21)%, (20.99 ± 1.84)% and (19.34 ± 2.19)%, respectively; MVD was (8.64 ± 2.81), (16.77 ± 1.39), (5.32 ± 4.26) and (5.86 ± 2.27), respectively; VEGF expression was (45.77 ± 4.79), (41.34 ± 5.41), (29.71 ± 8.92) and (28.24 ± 8.55), respectively. The incidences of peritoneal metastasis also decreased significantly in 5-FU group(77.8%), d-limonene group (20.0%) and combined group (22.2%) compared with control group (100%) versus 62.5%, 30% and 22.2%) (P < 0.05). Liver metastasis was also inhibited and the incidences decreased significantly in 5-FU group, d-limonene group and combined group than that in control group (87.5% vs 55.5%, 20.0% and 22.2% respectively) (P < 0.05). The incidence of ascites in control group, 5-FU group, d-limonene group and combined group was 25.0%, 22.2%, 0, 0, respectively and 12.5%, 11.1% 0, 0, with respect to the metastasis rate to other organs.

CONCLUSION: d-limonene has antiangiogenic and proapoptotic effects on gastric cancer, thereby inhibits tumor growth and metastasis. Combination of d-limonene with cytotoxic agents may be more effective.

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