AXL regulates neuregulin1 expression leading to cetuximab resistance in head and neck cancer

Abstract

Background The receptor tyrosine kinase (RTK) epidermal growth factor receptor (EGFR) is overexpressed and an important therapeutic target in Head and Neck cancer (HNC). Cetuximab is currently the only EGFR-targeting agent approved by the FDA for treatment of HNC; however, intrinsic and acquired resistance to cetuximab is a major problem in the clinic. Our lab previously reported that AXL leads to cetuximab resistance via activation of HER3. In this study, we investigate the connection between AXL, HER3, and neuregulin1 (NRG1) gene expression with a focus on understanding how their interdependent signaling promotes resistance to cetuximab in HNC. Methods Plasmid or siRNA transfections and cell-based assays were conducted to test cetuximab sensitivity. Quantitative PCR and immunoblot analysis were used to analyze gene and protein expression levels. Seven HNC patient-derived xenografts (PDXs) were evaluated for protein expression levels. Results We found that HER3 expression was necessary but not sufficient for cetuximab resistance without AXL expression. Our results demonstrated that addition of the HER3 ligand NRG1 to cetuximab-sensitive HNC cells leads to cetuximab resistance. Further, AXL-overexpressing cells regulate NRG1 at the level of transcription, thereby promoting cetuximab resistance. Immunoblot analysis revealed that NRG1 expression was relatively high in cetuximab-resistant HNC PDXs compared to cetuximab-sensitive HNC PDXs. Finally, genetic inhibition of NRG1 resensitized AXL-overexpressing cells to cetuximab. Conclusions The results of this study indicate that AXL may signal through HER3 via NRG1 to promote cetuximab resistance and that targeting of NRG1 could have significant clinical implications for HNC therapeutic approaches.

Disrupting EGFR–HER2 Transactivation by Pertuzumab in HER2-Positive Cancer: Quantitative Analysis Reveals EGFR Signal Input as Potential Predictor of Therapeutic Outcome

“…These phenomena invoke the combination of anti-EGFR/HER treatments with TAM inhibitors to replace monotherapy [ 70 , 71 , 72 , 73 , 74 , 75 ] as well as the development of pan-TAM inhibitors [ 76 , 77 ]. Clinical resistance to AXL-targeting therapies may also involve HER3 [ 78 ], but this requires further investigation [ 79 , 80 ].…”

A Receptor Tyrosine Kinase Inhibitor Sensitivity Prediction Model Identifies AXL Dependency in Leukemia

“…For example, chemotherapy-induced AXL expression was reported in AML [ 65 ], lung cancer [ 66 ], prostate cancer [ 67 ], ovarian cancer [ 68 ], and endometrial cancer [ 69 ] as conferring therapy resistance. Recently, a series of studies linked AXL to several receptor tyrosine kinase inhibitors including EGFR inhibitors in lung cancer [ 70 ], head and neck cancer [ 71 ] and colorectal cancer [ 72 ], HER2 inhibitors in breast cancer [ 73 ], and FLT3 inhibitors in AML [ 74 ]. Identification of AXL as a leading feature in the sorafenib sensitivity prediction model further emphasizes its importance in resistance to receptor tyrosine kinase inhibitors.…”

MerTK Drives Proliferation and Metastatic Potential in Triple-Negative Breast Cancer

“…Whole-cell protein lysis, protein quantification, and immunoblot analysis were performed as described previously [61,62]. Antibodies were used according to the manufacturer's instructions (Supplementary Table S1).…”