Dongsheng Wang1, Yue Lu2, Sreenivas Nannapaneni1, Christopher C Griffith3, Conor Steuer1, Guoqing Qian1, Xu Wang1, Zhengjia Chen4, Mihir Patel5, Mark El-Deiry5, Dong M Shin1, Xia He6, Zhuo G Chen7, Nabil F Saba8. 1. Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University School of Medicine, United States. 2. Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University School of Medicine, United States; Department of Radiotherapy, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research and the affiliated Cancer Hospital of Nanjing Medical University, China. 3. Department of Pathology, Emory University, United States. 4. Department of Biostatistics and Bioinformatics, Emory University School of Public Health, United States. 5. Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States. 6. Department of Radiotherapy, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research and the affiliated Cancer Hospital of Nanjing Medical University, China. 7. Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University School of Medicine, United States. Electronic address: gzchen@emory.edu. 8. Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University School of Medicine, United States. Electronic address: nfsaba@emory.edu.
Abstract
OBJECTIVE: We aimed to develop novel combinations of inhibitors targeting EGFR family members and c-Met for the treatment of recurrent SCCHN. MATERIALS AND METHODS: Three different c-Met inhibitors in combination with a pan-HER inhibitor (crizotinib/afatinib, tivantinib/afatinib and cabozantinib/afatinib) were investigated for their anti-tumor effects on SCCHN cell lines in vitro. In vivo activity of the combinations was tested in SCCHN cell line xenografts and patient-derived xenograft (PDX) animal models generated from patients with recurrent SCCHN. RESULTS: Western blot assay indicated that activation of EGFR, HER2, HER3, and c-Met was blocked by all three combinations and the downstream PI3K/AKT and ERK signaling pathways were inhibited. Sulforhodamine B colorimetric assay revealed SCCHN cell growth was more effectively inhibited by the combinations than by single agents, particularly in cell lines with high c-Met expression. Furthermore, the combinations were more potent in inducing apoptosis than each of the single agents. In the PDX models, the combination treatments exhibited significantly better efficacy in tumor growth inhibition compared to the respective single agents. CONCLUSION: In conclusion, we demonstrated that the simultaneous targeting of EGFR, HER2, and c-Met is more effective than the individual inhibition of these targets in vitro and in SCCHN cell line xenograft and PDX models. Our findings pave the way for further clinical investigation of such combinations in SCCHN.
OBJECTIVE: We aimed to develop novel combinations of inhibitors targeting EGFR family members and c-Met for the treatment of recurrent SCCHN. MATERIALS AND METHODS: Three different c-Met inhibitors in combination with a pan-HER inhibitor (crizotinib/afatinib, tivantinib/afatinib and cabozantinib/afatinib) were investigated for their anti-tumor effects on SCCHN cell lines in vitro. In vivo activity of the combinations was tested in SCCHN cell line xenografts and patient-derived xenograft (PDX) animal models generated from patients with recurrent SCCHN. RESULTS: Western blot assay indicated that activation of EGFR, HER2, HER3, and c-Met was blocked by all three combinations and the downstream PI3K/AKT and ERK signaling pathways were inhibited. Sulforhodamine B colorimetric assay revealed SCCHN cell growth was more effectively inhibited by the combinations than by single agents, particularly in cell lines with high c-Met expression. Furthermore, the combinations were more potent in inducing apoptosis than each of the single agents. In the PDX models, the combination treatments exhibited significantly better efficacy in tumor growth inhibition compared to the respective single agents. CONCLUSION: In conclusion, we demonstrated that the simultaneous targeting of EGFR, HER2, and c-Met is more effective than the individual inhibition of these targets in vitro and in SCCHN cell line xenograft and PDX models. Our findings pave the way for further clinical investigation of such combinations in SCCHN.