| Objective:1. To observe the different anti-tumor effects of Irinotecan(CPT-11), bevacizumab(Bev), Endostar(En) alone or in combination by intratumoral (i.t.) injection on nude mice colorectal cancer model.2.To observe the side effects of CPT-11, Bev, En alone or in combination by i.t. injection.3.To observe the different effects of CPT-11, Bev, En alone or in combination on tumor angiogenesis and tumor cell proliferation of nude mice subcutaneous xenograft model of colorectal cancer.Methods:Unilateral dorsum of BALB/c nude mice were injected subcutaneously with5×106HT-29tumor cells so that nude mice subcutaneous xenograft models of colorectal cancer were established.Ten days later,when the tumor Volume reached150mm3,30nude mice were randomly and equally divided into five groups:group A (control group, i.t. injection of NS), group B (CPT-11group), group C (Bev plus CPT-11group), group D (Bev plus En group), group E(Bev, En plus CPT-11group). All the drug were administrated by i.t injection,and CPT-1140mg/Kg, Bev5mg/Kg, En10mg/Kg respectively.The volume of tumor was observed every two days,which was measured as0.5×lengthxwidth2. The tumor growth rate, wet weight,tumor growth inhibition(TGI),the doubling time(DT) and specific growth rate(SGR) were compared among each group.Tumors’ organic and lymph node metastasis were examined.The side effects of drugs were evaluated from the change of blood cell count, skin ulceration and bleeding,gastrointestinal reaction,loss of weight and gastrointestinal perforation of mice. Immunohistochemical detection of expression of tumor microvessel marker CD31and tumor cell proliferation associated nuclear antigen Ki67were made in each group.Results:From the tumor growth curves we drawn, we observed that the growth rate of each treatment group from fast to slow was as follow: the group A, group D, group B, group C, and group E. Tumor volume of group D from d17to d21remained stable, while tumor volume of group E from d9to d21shrinked. The wet weight of each group from large to small were as follows:group A,1.30±0.07g; group D,0.83±0.07g; group B,0.69±0.06g; group C,0.50±0.04g; group E,0.30±0.03g, and there was significant difference between each two group.In addition,we compared the Inhibition rate (TGI), the tumor doubling time (DT),and tumor specific growth rate (SGR).Results showed that the tumor growth inhibition effects from weak to strong were the group A, group D, group B, group C, and group E. The TGI,DT and SGR value were:group A (DT7.30d, SGR9.50%/d); group D (25.50%,8.52d,8.40%/d); group B (47.57%,9.59d,7.23%/d); group C (67.79%,12.22d,5.67%/d); group E(89.03%,23.89d,2.90%/d)respectively.All the results above revealed that CPT-11, Bev, En alone or in combination by intratumoral injection all could inhibit tumor growth, particularly Bev, En plus CPT-11significantly enhanced the tumor growth inhibition effects.By anatomical examination after death, no tumor metastasis was found in liver, spleen, abdominal cavity or lung of the nude mice. The average number of metastatic lymph node of the group A is0.5,while no lymph node metastatic was found in other groups.Skin ulceration and bleeding,gastrointestinal reaction,loss of weight and gastrointestinal perforation of mice were not found in each group. There was no significant difference between each group for blood routine index. Body weight changes of group A, group B, group C, group D and group E were:+1.32±0.03g,+0.64±0.02g,+0.72±0.03g,+1.00±0.04g,+0.81±0.01g respectively. The results revealed that intratumoral injection of CPT-11, Bev, En alone or in combination were safe.The microvessel density by Weidner method of group A, group B, group C, group D and group E were52.5±2.41,50.5±2.88,36.25±2.75,23.30±2.78,21.10±2.43respectively. NS group compared with CPT-11group, P=0.204, Bev+En group compared with Bev+CPT-11+En group, P=0.164, the difference was not statistically significant, but there was significant difference between any other two groups. The results revealed that Bev enhanced the anti-angiogenesis and vascular normalization effects,while CPT-11exert little impact on tumor angiongenesis.To count Ki67positive cells every1000tumor cells as Ki67-positive rate under microscope with200magnification ratio. Results showed that the Ki67-positive rate of group A, group B, group C, group D and group E were:82.71%±5.60%,57.83%±3.92%,45.68%±3.29%,70.88%±4.03%,29.32%±2.61%respectively, and there was significant difference between each two groups. The results revealed that CPT-11could to a certain degree inhibit tumor cell proliferation,while the inhibition ability of Bev and En were inferior.However, Bev, En plus CPT-11could significantly strengthened the inhibition effects.Conclusion:1. CPT-11, Bev, En alone or in combination by intratumoral injection all could inhibit tumor growth, particularly Bev, En plus CPT-11significantly enhanced the tumor growth inhibition effects.2. Intratumoral injection of CPT-11, Bev, En alone or in combination were safe without local ulceration or bleeding, gastrointestinal reactions,gastrointestinal perforation, weight loss, reduction in white blood cell count or other adverse effects.3.The tumor growth inhibition effects of CPT-11, Bev were associated with anti-angiogenesis, vascular normalization and tumor cell proliferation inhibition, while the tumor growth inhibition enhancement of Bev, En plus CPT-11was attributed to enhancement of above effects by En. |
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