Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Nov 7, 2006; 12(41): 6652-6657
Published online Nov 7, 2006. doi: 10.3748/wjg.v12.i41.6652
Effects of recombinant human canstatin protein in the treatment of pancreatic cancer
Xiao-Ping He, Zhao-Shen Li, Ren-Min Zhu, Zhen-Xing Tu, Jun Gao, Xue Pan, Yan-Fang Gong, Jing Jin, Xiao-Hua Man, Hong-Yu Wu, Ai-Fang Xu
Xiao-Ping He, Ren-Min Zhu, Department of Gastroenterology, Nanjing General Hospital, Nanjing 210002, Jiangsu Province, China
Zhao-Shen Li, Zhen-Xing Tu, Jun Gao, Xue Pan, Yan-Fang Gong, Jing Jin, Xiao-Hua Man, Hong-Yu Wu, Ai-Fang Xu, Department of Gastroenterology, the Affiliated Changhai Hospital of Second Military Medical University, Shanghai 200433, China
Supported by the Major Basic Research Programs of Shanghai Science and Technology Commission, No. 03JC14007
Correspondence to: Zhao-Shen Li, MD, Director of Gastro-enterology Department, Changhai Hospital, Shanghai 200433, China.
Telephone: +86-21-25070552
Received: July 18, 2006
Revised: August 12, 2006
Accepted: September 13, 2006
Published online: November 7, 2006

AIM: To examine the effect of canstatin, a newly discovered endogenous inhibitor of angiogenesis, in the treatment of pancreatic cancer in vivo.

METHODS: The canstatin cDNA fragment was synthesized and amplified from the total RNA extracted from human placenta tissues by RT-PCR. The resulting product was firstly cloned into pUCm-T vector, then into plasmid pET-22b (+) and transformed into E. coli BL21. Isopropyl-1-thio-b-Dgalactopyran-oside (IPTG) was used to induce the expression of canstatin protein and affinity chromatography was used to purify the protein. To determine the activity of purified recombinant human canstatin (rhCanstatin), orthotopic xenograft human pancreatic cancer models were established. Human pancreatic cancer cells (SW1990) were injected into the pancreas of BALB/c nude mice. Twenty-four nude mice with orthotopic xenograft tumor were randomly divided into 3 groups 10 d after the inoculation, and were treated with PBS 0.3 mL, or canstatin 5 mg/kg, or 10 mg/kg per day for 3 wk intraperitoneally. When the experiment was over, all tumors were resected and the effects of rhCanstatin on tumor growth, microvessel density (MVD) were analyzed.

RESULTS: After IPTG induction, SDS-PAGE showed a new monomeric 24 kDa protein band. This protein was purified through affinity chromatography and refolded through dialysis with a final concentration of 60 mg/L. In orthotopic pancreatic cancer models, the final tumor volume in groups treated with PBS, canstatin 5 mg/kg, 10 mg/kg were 355.21 ± 39.54 mm3, 112.73 ± 10.47 mm3, and 61.75 ± 6.99 mm3 respectively. The immunohistochemical examination showed that the MVD in tumors treated with canstatin was significantly less than that in other group.

CONCLUSION: These findings demonstrate that the rhCanstatin effectively retards the growth of pancreatic cancer in a dose-dependent manner through inhibiting angiogenesis and may be a promising therapeutic agent for pancreatic cancer treatment in the clinic.

Keywords: Canstatin, Angiogenesis, Pancreatic cancer, Anti-tumor agent