A novel nanobody as therapeutics target for EGFR-positive colorectal cancer therapy: exploring the effects of the nanobody on SW480 cells using proteomics approach

Abstract

Background: The epidermal growth factor receptor (EGFR) overexpression is found in metastatic colorectal cancer (mCRC). Targeted molecular therapies such as monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKI) are becoming more precise, targeting specifically for cancer therapeutics. However, there are adverse effects of currently available anti-EGFR drugs, including drug-resistant and side effects. Nanobodies can overcome these limitations. Our previous study has found that cell-penetrable nanobodies targeted at EGFR-tyrosine kinase were significantly reduced EGFR-positive lung cancer cells viability and proliferation. The aim of the present study was to determine the effect of cell-penetrable nanobody (R9VH36) on cell viability and proteomic profile in EGFR-positive human colorectal cancer cell lines. Methods: The human colorectal carcinoma cell line (SW480) was treated with R9VH36, compared with gefitinib. Cell viability was monitored using the MTT cell viability assay. The proteomic profiling was analyzed by LC–MS/MS. Results: The half-maximal inhibitory concentration (IC50) values determined for R9VH36 and gefitinib against SW480 were 527 ± 0.03 nM and 13.31 ± 0.02 μM, respectively. Moreover, both the gefitinib-treated group and nanobody-treated group had completely different proteome profiles. A total 6626 differentially expressed proteins were identified. PCA analysis revealed different proteome profiling in R9VH36 experiment. There were 8 proteins in R9VH36 that significantly exhibited opposite expression directions when compared to gefitinib. These proteins are involved in DNA-damage checkpoint processes. Conclusion: The proteomics explored those 6,626 proteins had different expressions between R9VH36 and gefitinib. There were 8 proteins in R9VH36 exhibited opposite expression direction when comparing to gefitinib. Our findings suggest that R9VH36 has the potential to be an alternative remedy for treating EGFR-positive colon cancer.