The Combination of Afatinib with Dasatinib or Miransertib Results in Synergistic Growth Inhibition of Stomach Cancer Cells

Background:Of various human epidermal growth factor receptor (HER) inhibitors, only the anti-HER2 monoclonal antibody (mAb) Herceptin/trastuzumab and the antibody-drug conjugate trastuzumab deruxtecan (T-Dxd) has been approved for the treatment of patients with stomach cancer. However, the duration of response may be short in many patients, with tumor heterogeneity being one contributing factor.Methods:We investigated the effect of various types of targeted agents on growth in vitro and migration of a panel of human stomach cancer cells (HSCCLs) and the impact of cell proliferation rate on the anti-tumor activities of these agents. We also investigated the association between the cell surface expression of the HER family members, hepatocyte growth factor receptor (c-Met), anaplastic lymphoma kinase (ALK)7 and cancer stem cell markers CD44 and CD133, and the response to the targeted agents.Results:Of the 18 agents examined, the cyclin dependent kinase (CDK) 1/2/5/9 inhibitor dinaciclib was the most effective and inhibited the growth of all human HSCCLs at 50% inhibitory concentration (IC50) values between 9 nM to 23 nM. Of various HER inhibitors, the irreversible pan-HER family inhibitors (e.g., afatinib) were more effective than the reversible dual epidermal growth factor receptor (EGFR)/HER2 tyrosine kinase inhibitor (TKI) lapatinib and the EGFR-specific TKI erlotinib in inhibiting the growth of HSCCLs. Of agents targeting different downstream cell signaling molecules, dasatinib targeting Ab1/Src/C-Kit, trametinib targeting MERK1/2 and miransertib targeting AKT1/2/3 inhibited growth of majority of HSCCLs, with the IC50 values ranging from 2 nM to 7 µM. Many of these agents were more effective in inhibiting the growth of HSCCLs when they were proliferating at a slower rate. Treatment with neratinib, afatinib, dinaciclib, dasatinib, stattic, miransertib and paclitaxel significantly inhibited migration of stomach cancer cells. Interestingly, treatment with a combination of afatinib and dasatinib or afatinib and miransertib resulted in synergistic and additive growth inhibition of stomach cancer cells.Conclusions:These results suggest that treatment with a combination of these agents may be of therapeutic value in stomach cancer and warrants further investigations.