Coupling of Cell Surface Biotinylation and SILAC-Based Quantitative Proteomics Identified Myoferlin as a Potential Therapeutic Target for Nasopharyngeal Carcinoma Metastasis.

Maoyu Li,Yongheng Chen,Xujun Liang,Meiying Shao,Fang Peng,Zhuchu Chen,Guoqiang Wang

doi:10.3389/fcell.2021.621810

Abstract

Distant metastasis is a major cause of treatment failure in nasopharyngeal carcinoma (NPC) patients. Cell surface proteins represent attractive targets for cancer diagnosis or therapy. However, the cell surface proteins associated with NPC metastasis are poorly understood. To identify potential therapeutic targets for NPC metastasis, we isolated cell surface proteins from two isogenic NPC cell lines, 6-10B (low metastatic) and 5-8F (highly metastatic), through cell surface biotinylation. Stable isotope labeling by amino acids in cell culture (SILAC) based proteomics was applied to comprehensively characterize the cell surface proteins related with the metastatic phenotype. We identified 294 differentially expressed cell surface proteins, including the most upregulated protein myoferlin (MYOF), two receptor tyrosine kinases(RTKs) epidermal growth factor receptor (EGFR) and ephrin type-A receptor 2 (EPHA2) and several integrin family molecules. These differentially expressed proteins are enriched in multiple biological pathways such as the FAK-PI3K-mTOR pathway, focal adhesions, and integrin-mediated cell adhesion. The knockdown of MYOF effectively suppresses the proliferation, migration and invasion of NPC cells. Immunohistochemistry analysis also showed that MYOF is associated with NPC metastasis. We experimentally confirmed, for the first time, that MYOF can interact with EGFR and EPHA2. Moreover, MYOF knockdown could influence not only EGFR activity and its downstream epithelial–mesenchymal transition (EMT), but also EPHA2 ligand-independent activity. These findings suggest that MYOF might be an attractive potential therapeutic target that has double effects of simultaneously influencing EGFR and EPHA2 signaling pathway. In conclusion, this is the first study to profile the cell surface proteins associated with NPC metastasis and provide valuable resource for future researches.

Highlights

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy common in Southern China and Southeast Asia
We found that MYOF impairs epidermal growth factor receptor (EGFR) activation and its downstream epithelial– mesenchymal transition (EMT) process, and ephrin type-A receptor 2 (EPHA2) ligandindependent activation
In order to clarify the potential mechanism behind the knockdown of MYOF suppressing the malignant phenotype, we investigated whether MYOF knockdown can influence EGFR or EPHA2 activity in nasopharyngeal carcinoma (NPC) cells

Summary

Introduction

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy common in Southern China and Southeast Asia. NPC is prone to early metastasis, but patients are asymptomatic at the early stage (Chua et al, 2016). Most NPC patients (60–70% cases) are diagnosed at an advanced stage (Mao et al, 2009). Radiotherapy and chemo-radiotherapy are the routine treatment strategies for patients with non-metastatic or locally advanced NPC. It has been reported that for approximately 2530% of patients therapy still fails, with local recurrence and/or distant metastases, and the prognosis for patients with metastatic disease is poor (Lai et al, 2011). NPC metastasis and recurrence are the main bottleneck for treatment. The demand for new therapeutic strategies for advanced NPC, to further improve treatment outcome is urgent

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Conclusion