The oligometastatic setting in HNSCC: A critical review by the Rete Oncologica Piemonte e Valle d'Aosta multidisciplinary team

Cavernous sinus metastasis in head and neck cancer: Focus on oral squamous cell cancer

Intracranial metastatic disease is rarely found in head and neck cancer (HNC), in particular, cavernous sinus (CS) involvement is difficult to recognize, because of its rarity, not specific symptoms associated and challenging imaging features. We report our experience in 4 cases, reviewing also the English literature. We analysed data from 21 patients showing that CS metastasis is a dramatic event, with rapid onset, usually starting with neurological manifestations (ophthalmoplegia, headache and trigeminal dysesthesia) and almost unavoidable outcome (DOD in 18/21 patients). Furthermore, we assessed that the diagnostic confirmation could be difficult to perform because of the need for multiple exams and time consuming procedures. Unfortunately, usual antineoplastic therapies seem to be not effective in prolonging survival, also because patients are already weakened by primary tumour treatments. The only option that seems useful in improving outcomes is immunotherapy.

De novo metastatic head and neck squamous cell carcinoma: Why does locoregional control "always" matter?

De novo metastatic Head and Neck Squamous Cell Carcinoma (HNSCC) constitutes 10% of recurrent/metastatic (RM) cases. Radiotherapy (RT) has a crucial role in the treatment of locally advanced HNSCC, however its application on RM diseases is still limited. The advent of immune checkpoint inhibitors (ICIs) improves the survival of RM HNSCC, however median overall survival is still limited. Integration of locoregional RT with ICIs in de novo metastatic HNSCC represents a promising treatment option. This perspective aims to explore the role of the combination of locoregional and systemic treatment in improving outcomes for synchronous de novo metastatic HNSCC patients and highlights the principal crucial point in decision making.

DTL promotes head and neck squamous cell carcinoma progression by mediating the degradation of ARGLU1 to regulate the Notch signaling pathway

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with a high incidence in squamous epithelium. The E3 ubiquitin ligase DTL is a component of the CRL4A complex and is widely involved in tumor progression. We aimed to analyze the role of DTL in HNSCC and to explore its mechanism of action. Through clinical analysis, we found that DTL is upregulated in HNSCC tissues and is associated with the tumor microenvironment and poor survival in patients. Through gain-of-function and loss-of-function assays, we showed that DTL promotes cell proliferation and migration in vitro and tumor growth in vivo. Mass spectrometry analysis and immunoprecipitation assays showed that DTL interacts with ARGLU1 to promote K11-linked ubiquitination-mediated degradation of ARGLU1, thereby promoting the activation of the CSL-dependent Notch signaling pathway. Furthermore, siARGLU1 blocks the inhibitory effects of DTL knockdown on HNSCC cells. In this study, we showed that DTL promotes HNSCC progression through K11-linked ubiquitination of ARGLU1 to activate the CSL-dependent Notch pathway. These findings identify a promising therapeutic target for HNSCC.

Combination of downregulating FEN1 and PD-1 blockade enhances antitumor activity of CD8+ T cells against HNSCC cells in vitro

BACKGROUND

Programmed cell death ligand 1 (PD-L1) and human leukocyte antigen/major histocompatibility complex (HLA/MHC) are two main kinds of immunophenotypes affecting the susceptibility to anti-PD therapy. Our previous study found that down-regulation of flap endonuclease-1 (FEN1) could not only inhibit PD-L1 expression, but also upregulate HLA expression in head and neck squamous cell carcinoma (HNSCC). We aimed to clarify whether downregulating FEN1 cloud enhance the response to PD-1 blockade, and possible mechanisms in HNSCC in vitro.

METHODS

Differential expression of FEN1 in HNSCC tumor and normal tissues were explored in the TIMER and TISIDB datasets. A HNSCC cells/CD8+ T cells co-culture model was established. HNSCC cell cycle and apoptosis were recorded by flow cytometry. Immune activity markers of granzyme A, granzyme B, and PRF1 expressed in the CD8+ T cells, and IFN-γ, IL-2, and TNF-α secreted in the supernatants were detected by western blot, ELISA, respectively.

RESULTS

FEN1 was highly expressed in HNSCC and associated with low immune infiltration. Downregulating FEN1 could induce HLA class I expression, and inhibit PD-L1 expression in HNSCC cells. Functionally, FEN1 knockdown enhanced the response to αPD-1 mAb by mediating G2/M phase arrest, apoptosis of HNSCC cells. Mechanistically, targeting FEN1 synergized with αPD-1 mAb could reinforce the antitumor response of CD8+ T cells against HNSCC cells, as indicated by increasing granzyme A, granzyme B, and PRF1 expressions, and promoting IFN-γ, IL-2, and TNF-α secretions.

CONCLUSION

These findings might offer a potential combined strategy for patients resistant to anti-PD therapy via combining FEN1 knockdown and PD-1 blockade.