Preparation And Evaluation Of Recombinant Targeted Anti-tumor Immunotxoin EGF-TCSredlk

Tumor is such a kind of diseases that seriously threaten human health. To find effective anti-tumor drugs and methods is an important research project in world medicine field. There are obvious reactions of toxicity in treatment because the selectivity of existing chemotherapy and radiotherapy drugs is low and these drugs injure normal cells when they kill tumor cells. As a new generation of tumor therapy method, immunotoxin therapy is different with traditional chemotherapy. There is relatively high concentration of immunotoxin therapy drugs in tumor location and the retention time of these drugs is longer than that of chemotherapy drugs. Because the killing activity of immunotoxin drugs on tumor cells is strong and the toxicity of these drugs on normal cells is none or little, immunotoxin therapy is an important way to improve curing effect on tumor.Objective To construct the immunotoxin EGF-TCSredlk and study its cytotoxicity against human gastric carcinoma in vitro. To further observe the anti-tumor effect of recombinant toxin, we carried tumor inhibition test in vivo in naked mouse tumor model. Methods Recombinant immunotoxin EGF-TCSredlk against human gastric carcinoma cell was expressed by E. coli expression system, and the expressed product was purified by Ni-NTA affinity chromatography and determined for specific killing activity. The gastric carcinoma cell was inoculated subcutaneously on right armpit in naked mice and EGF-TCSredlk was injected intravenously (100,50,25μg/kg) to mice for therapy after6days of inocluation. There was control group and mice were killed after2days of drug withdrawal, and the tumors were weighed and the tumor inhibitory rate was calculated;Tumor tissues were examined by immunohistochemistry. Results Recombinant immunotoxin EGF-TCSredlk against gastric carcinoma cell was expressed in a form of soluble protein and purified effectively. The results of MTT showed the killing activity of expressed product to gastric carcinoma cell. The illustrated that EGF-TCSredlk could inhibit tumor growth markedly. The inhibition rate was75.5%、54.5%and35.4%for high dosage group, middle dosage group and low dosage group respectively. Variance analysis illustrated that EGF-TCSredlk could markedly inhibit the growth of naked mouse tumors,Variance analysis had significant difference(Welch=82.617,P=0.000);Immunohistochemistry experiment showed that EGF-TCSredlk could makedly inhibit tumor angiogenesis. There were no visible blood vessels in tumor tissues in high dosage group and there were fewer blood vessels in tumor tissues in middle and low dosage group than those in control group, which revealed that perhaps EGF-TCSredlk inhibited tumor growth and migration by inhibiting tumor angiogenesis. Conclusions The recombinant immunotoxin EGF-TCSredlk with killing activity to gastric carcinoma cell was successfully prepared. EGF-TCSredlk can inhibit the growth of solid tumors in tumor-bearing mice and the priliminary results suggested the potential applications of this preparation in cancer therapy.