Pyrotinib inhibits the tumorigenicity of HER2-positive non-small cell lung cancer by inducing ARIH1/ubiquitin/lysosome-dependent degradation of HER2.

PURPOSE: Non-small cell lung cancer (NSCLC), accounting for the majority of lung cancer, is the leading cause of cancer death worldwide, and molecular targeted drugs promote greatly advance in the treatment of this disease. Overexpression of human epidermal growth factor receptor 2 (HER2) occurs in 1-5% of NSCLC cases, correlating with poorer outcomes and lack of approved targeted drugs. Pyrotinib is an irreversible HER2 receptor tyrosine kinase inhibitor developed for the treatment of HER2-positive advanced solid tumors; however, the comprehensive exploration of Pyrotinib's anti-tumor mechanism in HER2-positive NSCLC cells needs further explored. METHODS: Using HER2-high copy number NSCLC cancer cell lines, primary cells and subcutaneous tumor models in nude mice, we systematically evaluated pyrotinib’s anti-tumor activity through viability assays, Colony formation assay, and apoptosis analysis. Mechanistic studies included co-immunoprecipitation, Quantitative reverse transcription-PCR, ubiquitination assays, and Liquid Chromatography-Tandem Mass Spectrometry analysis. RESULTS: This study revealed that Pyrotinib suppressed the tumorigenicity of HER2-positive NSCLC cells (H2170 and Calu-3 cell lines) by promoting HER2 degradation, inhibiting HER2 downstream signalings, inducing cell apoptosis, and ultimately triggering cell death. However, however, this drug presented low cytotoxic effects on H1299 (low-HER2 cell line) and BEAS-2B (human lung epithelial cell line) cells. Mechanistic analyses revealed that Pyrotinib facilitated HER2 degradation by inducing ubiquitination of HER2, enhancing interaction between ARIH1 and HER2, and subsequent triggering lysosomal degradation of HER2. Furthermore, Pyrotinib suppressed tumor growth of HER2-positive NSCLC xenografts, in an ARIH1-dependent manner. CONCLUSION: Pyrotinib enhances the binding of the E3 ubiquitin ligase ARIH1 to HER2, promoting HER2 ubiquitination and endocytosis, which leads to degradation via the lysosomal pathway. Our data explain why Pyrotinib has shown good efficacy in clinical trials and provide new insights into the application of Pyrotinib in HER2-positive non-small cell lung cancer. CLINICAL TRIAL NUMBER: Not applicable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13402-025-01107-z.