Inhibitory effects of human epidermal growth factor receptor-2-single-chain antibody on human epidermal growth factor receptor-2 positive tumors

Abstract

Objective To study the inhibitory effect of single-chain antibody (scFv) against human epidermal growth factor receptor-2 (Her-2) on tumor cell T6-17 proliferation. To investigate the potential of Her-2-scFv protein targeted therapy of Her-2 positive tumors. Methods In our study, Her-2-scFv gene fragment was amplified from plasmid pUC57-Her-2-scFv by polymerase chain reaction (PCR). Then Her-2-scFv gene fragment was cloned into the prokaryotic expression vector pET28a though double enzyme, and get the recombinant plasmid pET28a-Her-2-scFv. Plasmid pET28a-Her-2-scFv was transformed into Rosetta of E. coli. Her-2-scFv protein successful expression was detected by Western blotting. Her-2 positive tumor cell T6-17 proliferation inhibition were tested by methyl thiazol tetrazolium (MTT) assay. The tumor volume was measured by animal model of gastric cancer in vivo test. Results Her-2-scFv gene fragments were received by PCR successfully. Location of Her-2-scFv gene and its sequence in recombinant plasmid pET28a-Her-2-scFv is in a right direction by gene sequencing. MTT assay showed that the growth inhibition ratio of Her-2-positive tumor cell T6-17 in Her-2-scFv group was 33.52%, trastuzumab treatment group was 34.79%, with no statistic significance between them (P=0.429). Compared with the negative control group (PBS group), the differences were statistically significant (P=0.000). In vivo experiments: The inhibiting tumor rates of 100 ng/kg group, 250 ng/kg group, 500 ng/kg group were 33.7%, 27.2%, 63.3%, separately. Compared with the control group, the difference were statistically significant (P=0.027, 0.035, 0.000). In Hessaitin group, the inhibition rate was 70.2%, compared with 500 ng/kg group, there was no statistically significant difference (P=0.643). Conclusion Her-2-scFv protein can inhibit the proliferation of T6-17 positive tumor cells in vitro and in vivo. Key words: Human epidermal growth factor receptor-2; Single-chain antibody; Tumor cell T6-17