Product(s) used in this publication: Custom Peptide Synthesis
Insulin-like growthfactor I receptor (IGF-IR) is expressed on breastcancercells and involves in metastasis, survival, and proliferation. Currently, application of IGF-IR-targeting monoclonal antibodies (mAbs), alone or in combination with other drugs, is a promising strategy for breastcancer therapy. Single-chain fragment variable (scFv) antibodies have been introduced as appropriate tools for tumor-targeting purposes because of their advantages over whole antibodies. In the present study, we employed a naïve phage library and isolated scFvs against a specific epitope from extracellular domain of IGF-IR by panning process. The selected scFvs were further characterized using polyclonal and monoclonal phage ELISA, soluble monoclonal ELISA, and colony PCR and sequencing. Antiproliferative and apoptoticeffects of selected scFv antibodies on breastcancer cell lines were also evaluated by MTT and Annexin V/PI assays. The results of ELISA indicated specific reactions of the isolated scFvs against the IGF-IR peptide, and analyses of PCR product and sequencing confirmed the presence of full length VH and Vκ inserts. Treatment of MCF7 and SKBR3 cells with anti-IGF-IR scFv led to a significant growth inhibition. The results also showed that scFv treatment significantly augmented trastuzumab growth inhibitory effects on SKBR3 cells. The percentage of the apoptotic MCF7 and SKBR3 cells after 24-h treatment with scFv was 39 and 30.70 %, respectively. Twenty-four-hour treatment with scFv in combination with trastuzumab resulted in 44.75 % apoptosis of SKBR3 cells. Taken together, our results demonstrate that the targeting of IGF-IR by scFv can be an effective strategy in the treatment of breastcancer and provide further evidence for effectiveness of dual targeting of HER2 and IGF-IR in breastcancer therapy.
Breastcancer; Insulin-like growthfactor I receptor; Phage display; Single-chain fragment variable (scFv) antibodies; Trastuzumab