HER3 Targeting Sensitizes HNSCC to Cetuximab by Reducing HER3 Activity and HER2/HER3 Dimerization: Evidence from Cell Line and Patient-Derived Xenograft Models.
HER3 Targeting Sensitizes HNSCC to Cetuximab by Reducing HER3 Activity and HER2/HER3 Dimerization: Evidence from Cell Line and Patient-Derived Xenograft Models.
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DOI：
10.1158/1078-0432.ccr-16-0558
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发表时间：
2017-02-01
期刊：
影响因子：
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通讯作者：
Chen ZG
中科院分区：
文献类型：
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作者：
Wang D;Qian G;Zhang H;Magliocca KR;Nannapaneni S;Amin AR;Rossi M;Patel M;El-Deiry M;Wadsworth JT;Chen Z;Khuri FR;Shin DM;Saba NF;Chen ZG
Our previous work suggested that HER3 inhibition sensitizes HNSCC to EGFR inhibition with cetuximab. This study aimed to define the role of HER3 in cetuximab resistance and the anti-tumor mechanisms of EGFR/HER3 dual targeting in HNSCC. We treated cetuximab-resistant HNSCC UMSCC1-C and parental UMSCC1-P cell lines with anti-EGFR antibody cetuximab, anti-HER3 antibody MM-121, and their combination. We assessed activities of HER2, HER3 and downstream signaling pathways by Western blotting, and cell growth by sulforhodamine B (SRB) and colony formation assays. HER3-specific shRNA was used to confirm the role of HER3 in cetuximab response. The combined efficacy and alterations in biomarkers were evaluated in UMSCC1-C xenograft and patient-derived xenograft (PDX) models. Cetuximab treatment induced HER3 activation and HER2/HER3 dimerization in HNSCC cell lines. Combined treatment with cetuximab and MM-121 blocked EGFR and HER3 activities and inhibited PI3K/AKT and ERK signaling pathways and HNSCC cell growth more effectively than each antibody alone. HER3 knockdown reduced HER2 activation and re-sensitized cells to cetuximab. Cetuximab-resistant xenografts and PDX models revealed greater efficacy of dual EGFR and HER3 inhibition compared to single antibodies. In PDX tissue samples, cetuximab induced HER3 expression and MM-121 reduced AKT activity. Clinically relevant PDX models demonstrate that dual targeting of EGFR and HER3 is superior to EGFR targeting alone in HNSCC. Our study illustrates the upregulation of HER3 by cetuximab as one mechanism underlying resistance to EGFR inhibition in HNSCC, supporting further clinical investigations using multiple targeting strategies in patients who have failed cetuximab-based therapy.
