EGF-SNX3-EGFR axis drives tumor progression and metastasis in triple-negative breast cancers

The research article “EGF-SNX3-EGFR axis drives tumor progression and metastasis in triple-negative breast cancers”, has been published in Nature Oncogene based on the study conducted at METU by the team led by METU member Prof. A. Elif Erson Bensan.

Epidermal growth factor receptor (EGFR) has critical roles in epithelial cell physiology. Over-expression and over-activation of EGFR have been implicated in diverse cancers, including triple-negative breast cancers (TNBCs), prompting anti‐EGFR therapies. Therefore, developing potent therapies and addressing the inevitable drug resistance mechanisms necessitates deciphering of EGFR related networks. Here, we describe Sorting Nexin 3 (SNX3), a member of the recycling retromer complex, as a critical player in the epidermal growth factor (EGF) stimulated EGFR network in TNBCs. We show that SNX3 is an immediate and sustained target of EGF stimulation initially at the protein level and later at the transcriptional level, causing increased SNX3 abundance. Using a proximity labeling approach, we observed increased interaction of SNX3 and EGFR upon EGF stimulation. We also detected colocalization of SNX3 with early endosomes and endocytosed EGF. Moreover, we show that EGFR protein levels are sensitive to SNX3 loss. Transient RNAi models of SNX3 downregulation have a temporary reduction in EGFR levels. In contrast, long-term silencing forces cells to recover and overexpress EGFR mRNA and protein, resulting in increased proliferation, colony formation, migration, invasion in TNBC cells, and increased tumor growth and metastasis in syngeneic models. Consistent with these results, low SNX3 and high EGFR mRNA levels correlate with poor relapse-free survival in breast cancer patients. Overall, our results suggest that SNX3 is a critical player in the EGFR network in TNBCs with implications for other cancers dependent on EGFR activity.

Cicek, E., Circir, A., Oyken, M., Akbulut Caliskan, O., Dioken, D. N., Guntekin Ergun, S., Cetin-Atalay, R., Sapmaz, A., Ovaa, H., Sahin, O.& Erson-Bensan, A. E. (2021). EGF-SNX3-EGFR axis drives tumor progression and metastasis in triple-negative breast cancers. Oncogene, 1-13.. doi: 10.1038/s41388-021-02086-9

Article access: https://www.nature.com/articles/s41388-021-02086-9

Other authors:
Cicek, E. (METU), Circir, A (METU)., Oyken, M. (METU), Akbulut Caliskan, O., Dioken, D. N. (METU), Guntekin Ergun, S. (METU), Cetin-Atalay, R. (METU), Sapmaz, A., Ovaa, H., & Sahin, O.

Acknowledgments:
We thank current and past members of the laboratory for critical reading of the manuscript and discussions. We thank METABRIC Consortium for sharing the breast cancer data. TUBITAK 116Z257 (AEEB), and 119Z672 (EC). EMBO short term fellowship (MO). National Institutes of Health Grant 2P20GM109091-06 (OS), 1R01CA251374-01A1 (OS). The Turkish Ministry of Development project #KanSil 2016K121540 (CanSyL).