Background: Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is a recurrent phenomenon during clinical therapy of non-small-cell lung cancer (NSCLC). Studies have shown that HER2 is a key factor contributing to drug resistance in a variety of cancers. Furthermore, we have observed that HER2 is overexpressed in PC-9 NSCLC cells with acquired gefitinib-resistance (PC-9/GR) as compared to that in PC-9 cells.
Objective: We hypothesized that blocking both EGFR and HER2 may serve as a potential strategy for the treatment of NSCLC with acquired gefitinib-resistance.
Methods: To target both EGFR and HER2 simultaneously, we developed a bispecific antibody HECrossMAb, which was derived from a humanized Cetuximab and Trastuzumab. The binding affinity of HECrossMAb for EGFR and HER2 was measured using an enzyme-linked immunosorbent assay. The MTT assay was used to determine the effect of HECrossMAb on the proliferation of PC-9 and PC-9/GR cells in vitro. Finally, the effect of HECrossMAb on PI3K/AKT signaling and associated transcription factors was measured using western blot analysis.
Results: Our results showed that HECrossMAb exerts enhanced cytotoxicity in both PC-9 and PC-9/GR cells by inhibiting the activation of PI3K/AKT signaling and expression of relevant transcription factors such as AEG-1, c-Myc, and c-Fos.
Conclusion: Our results suggest that HECrossMAb may function as a potential therapeutic agent for treating NSCLC overexpressing EGFR and HER2.
Keywords: EGFR; HECrossMAb.; HER2; NSCLC; acquired gefitinib-resistance; bispecific antibody.
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