Characterizing the role of NOTCH1 for the Squamous-Cell-Carcinoma of the Head-and-Neck

Introduction In search of a valid prognostic marker for HNSCC, NOTCH1 came up as the second most common mutated gene in whole-exome sequencing of HNSCC specimen. The aim of this project is to get further insight into the underlying functional mechanisms of NOTCH1 in HNSCC, potentially establishing NOTCH1 as a prognostic marker or therapeutic target for HNSCC.

Methods NOTCH1 was knocked down via RNA interference in 3 HPV-positive and 3 HPV-negative cell lines and the impact was evaluated in various functional assays. Additionally, cells were treated with DAPT or DLL4, an inhibitor or stimulator of NOTCH1-receptor, respectively. Mediators of the signaling pathway were assessed by Western blot. Afterwards the expression of NOTCH1, CD3 and CD8 was examined by immunohistochemistry in 74 oropharyngeal squamous cell cancer FFPE tissue samples.

Conclusions Knockdown of NOTCH1 resulted in a significant decrease in migration, proliferation and invasion, whereas the NOTCH1 ligand DLL4 could increase proliferation and invasion of HNSCC cells. These findings were independent from HPV status. Western blotting of the Knockdown revealed a reduction of AKT, EGFR and MEK. In our IHC cohort, NOTCH1 was upregulated in OPSCC and a high expression was associated with advanced T stage.

Conclusions NOTCH1 is involved in migration, invasion and proliferation of HNSCC cell lines. These findings are consistent with in vivo correlation of the increased NOTCH1 expression and advanced T stage in OPSCC. Overall, NOTCH1 seems to have a bimodal role as an oncogene and tumor suppressor in HNSCC.

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Publication History

Article published online:
10 June 2020