A Novel Ferroptosis-Related Gene Signature to Predict Prognosis in Patients with Head and Neck Squamous Cell Carcinoma

SENP1 inhibits ferroptosis and promotes head and neck squamous cell carcinoma by regulating ACSL4 protein stability via SUMO1

Head and neck squamous cell carcinoma (HNSCC) is currently one of the most common malignancies with a poor prognosis worldwide. Meanwhile, small ubiquitin‑like modifier (SUMO) specific peptidase 1 (SENP1) was associated with ferroptosis. However, the specific functions and underlying mechanisms of action of SENP1 in ferroptosis and tumor progression of HNSCC remain to be established. The findings of the present study implicated a novel ferroptosis pathway in the initiation and progression of HNSCC, providing new functional targets to guide future therapy. In the present study, The Cancer Genome Atlas database was employed to establish a gene model related to ferroptosis and verified SENP1 as a key gene via transcriptome sequencing. Expression of SENP1 in HNSCC tissue and CAL‑27 cells was detected based on reverse transcription‑quantitative PCR and western blot analysis. Proliferation and migration abilities of cells were determined using Cell Counting Kit‑8, wound healing and Transwell experiments. Expression levels of iron, glutathione (GSH) and lipid peroxidation end‑product malondialdehyde (MDA) under conditions of silencing of SENP1 with shRNA lentivirus were assayed. Additionally, the relationship between SENP1 and long‑chain acyl‑coenzyme A synthase 4 (ACSL4) was validated with the aid of immunoblotting and co‑immunoprecipitation (co‑IP). Finally, the influence of shSENP1 on the expression of key ferroptosis proteins, glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11, was evaluated via western blotting. It was revealed that SENP1 was significantly overexpressed in HNSCC and associated with low patient survival. Silencing of SENP1 led to significant suppression of cell proliferation, migration and invasion, increase in the contents of iron ions and MDA and decline in GSH levels in HNSCC cells, thereby enhancing ferroptosis and inhibiting disease progression. Conversely, overexpression of SENP1 suppressed ferroptosis and promoted progression of HNSCC. Co‑IP and western blot analyses revealed a SUMOylation link between SENP1 and ACSL4. SENP1 reduced the stability of ACSL4 protein through deSUMOylation, leading to inhibition of ferroptosis. SENP1 silencing further inhibited the expression of the key iron death protein, GPX4, to regulate ferroptosis. Taken together, SENP1 deficiency promoted ferroptosis and inhibited tumor progression through reduction of SUMOylation of ACSL4 in HNSCC. The collective results of the present study supported the utility of SENP1 as an effective predictive biomarker for targeted treatment of HNSCC.

OTUB1's role in promoting OSCC development by stabilizing RACK1 involves cell proliferation, migration, invasion, and tumor-associated macrophage M1 polarization

Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), a deubiquitinating enzyme known to regulate the stability of downstream proteins, has been reported to regulate various cancers tumorigenesis, yet its direct effects on oral squamous cell carcinoma (OSCC) progression are unclear. Bioinformatics analysis was performed to screen for genes of interest, and in vitro and in vivo studies were carried out to investigate the function and mechanism of OTUB1 in OSCC. We found that OTUB1 was abnormally elevated in OSCC tissues and positively associated with the pathological stage and tumor stage. Knockdown of OTUB1 impaired the malignance of OSCC cells - suppressed cell proliferation, invasion, migration, and xenografted tumor growth. OTUB1 silencing also drove tumor-associated macrophage M1 polarization but suppressed M2 polarization, and the induction of M1 polarization inhibited the survival of OSCC cells. However, OTUB1 overexpression exerted the opposite effects. Furthermore, the protein network that interacted with the OTUB1 protein was constructed based on the GeneMANIA website. Receptor for activated C kinase 1 (RACK1), a facilitator of OSCC progression, was identified as a potential target of the OTUB1 protein. We revealed that OTUB1 positively regulated RACK1 expression and inhibited RACK1 ubiquitination. Additionally, RACK1 upregulation reversed the effects of OTUB1 knockdown on OSCC progression. Overall, we demonstrated that OTUB1 might regulate OSCC progression by maintaining the stability of the RACK1 protein. These findings highlight the potential roles of the OTUB1/RACK1 axis as a potential therapeutic target in OSCC.

The Role of Deubiquitinating Enzyme in Head and Neck Squamous Cell Carcinoma

Ubiquitination and deubiquitination are two popular ways for the post-translational modification of proteins. These two modifications affect intracellular localization, stability, and function of target proteins. The process of deubiquitination is involved in histone modification, cell cycle regulation, cell differentiation, apoptosis, endocytosis, autophagy, and DNA repair after damage. Moreover, it is involved in the processes of carcinogenesis and cancer development. In this review, we discuss these issues in understanding deubiquitinating enzyme (DUB) function in head and neck squamous cell carcinoma (HNSCC), and their potential therapeutic strategies for HNSCC patients are also discussed.