[Inhibition of growth and metastases of human colon cancer xenograft in nude mice by angiogenesis inhibitor endostatin].

BACKGROUND & OBJECTIVE: Tumor angiogenesis is essential for growth and metastases of colon cancer. Angiogenesis inhibitors can induce apoptosis in colon cancer by inhibiting tumor angiogenesis and has strong inhibitory effect both on tumor growth and metastases of human colon cancer. Anti-angiogenic cancer therapy is important for selecting the timing and method of operation and program of complex treatment and enhancing the five-year survival rate of patients with colon cancer. In this study, we aimed to investigate the effects of angiogenesis inhibitor endostatin on the growth and metastases of colon cancer in vivo. METHODS: Metastatic model simulating human colon cancer was established by orthotopic implantation of histologically intact human tumor tissue into colon wall of nude mice. Endostatin was administered s.c. at dose of 0 mg/kg, 5 mg/kg, 10 mg/kg and 20 mg/kg, every day for six weeks. Seven weeks after implantation, the tumor weight and inhibition rates and intratumoral microvessel density (MVD) and apoptotic index (AI) and the presence of metastases are evaluated respectively after the mice were sacrificed. RESULTS: In compared with the untreated controls, growth of the orthotopically implanted tumor was significantly reduced in weight in mice treated with endostatin with an inhibition rate of 0%, 67.9%, 84.0%, and 90.1% at the dosage of 0 mg/kg, 5 mg/kg, 10 mg/kg, and 20 mg/kg, respectively. The MVD also decreased significantly in the treated mice [(12.8 +/- 4.1) versus (5.9 +/- 2.5), (2.2 +/- 1.4) and (0.74 +/- 0.3)]. The AI increased significantly in the treated mice [(3.87 +/- 2.61)%, versus (6.89 +/- 5.18%), (13.24 +/- 4.76)% and (20.97 +/- 9.04)%]. The incidences of peritoneal metastases were also significantly inhibited in the treated mice (90.0% versus 36.4%, 25.0%, and 0%). The incidences of liver metastases were also significantly inhibited in the treated mice (80.0% versus 27.3%, 16.7% and 0%). Tumor metastases to the liver and peritoneaum were also significantly inhibited in a dose-dependent manner (P < 0.05). CONCLUSIONS: Angiogenesis inhibitor endostatin can induce apoptosis in colon cancer by inhibiting tumor angiogenesis and has strong inhibitory effect both on tumor growth and metastases of human colon cancer xenograft in nude mice.

[Inhibition of growth and metastasis of human gastric cancer implanted in nude mice by the angiogenesis inhibitor endostatin].

OBJECTIVE: To study the effects of angiogenesis inhibitor endostatin 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. Endostatin was administered sc at dose of 0 mg/kg, 2.5 mg/kg, 10.0 mg/kg and 20.0 mg/kg every other day for seven weeks. Eight weeks after implantation, the tumor size and inhibition rates and intratumoral microvessel density (MVD) and apoptotic index (AI) and the presence of metastasis are evaluated respectively after the mice were sacrificed. RESULTS: Compared with the untreated controls, growth of the orthotopically implanted tumor was significantly reduced in size in mice treated with endostatin with an inhibition rate 0, 62.7%, 95.8% and 99.9% at the dosage of 0 mg/kg, 2.5 mg/kg, 10.0 mg/kg, and 20.0 mg/kg, respectively. The MVD was also decreased significantly in the treated mice [(13.7 +/- 3.90) versus (5.73 +/- 2.36), (2.17 +/- 1.28) and (0.66 +/- 0.25)]. The AI was increased significantly in the treated mice [(3.91 +/- 2.58)%, versus (6.76 +/- 5.03)%, (18.92 +/- 6.75)% and (28.57 +/- 10.34)%]. The incidences of peritoneal metastases was also significantly inhibited in the treated mice (87.1% versus 54.5%, 16.7% and 0). The incidences of liver metastases was also significantly inhibited in the treated mice (83.9% versus 27.3%, 8.3% and 0). The growth and metastasis of human gastric cancer implanted in nude mice were significantly inhibited in a dose-dependent manner (P < 0.05). CONCLUSIONS: Angiogenesis inhibitor endostatin can induce apoptosis in gastric cancer by inhibiting tumor angiogenesis and has strong inhibitory effect both on tumor growth and metastasis of human gastric cancer implanted in nude mice.