N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification that regulates in various important biological processes. However, its role in human cancer, especially lymph node metastasis, remains largely unknown. Here, we demonstrated N-Acetyltransferase 10 (NAT10), as the only known “writer” of ac4C mRNA modification, was highly expressed in head and neck squamous cell carcinoma (HNSCC) patients with lymph node metastasis. High NAT10 levels in the lymph nodes of patients with HNSCC patients are a predictor of poor overall survival. Moreover, we found that high expression of NAT10 was positively upregulated by Nuclear Respiratory Factor 1 (NRF1) transcription factor. Gain- and loss-of-function experiments displayed that NAT10 promoted cell metastasis in mice. Mechanistically, NAT10 induced ac4C modification of Glycosylated Lysosomal Membrane Protein (GLMP) and stabilized its mRNA, which triggered the activation of the MAPK/ERK signaling pathway. Finally, the NAT10-specific inhibitor, remodelin, could inhibit HNSCC tumorigenesis in a 4-Nitroquinoline 1-oxide (4NQO)-induced murine tumor model and remodel the tumor microenvironment, including angiogenesis, CD8⁺ T cells and Treg recruitment. These results demonstrate that NAT10 promotes lymph node metastasis in HNSCC via ac4C-dependent stabilization of the GLMP transcript, providing a potential epitranscriptomic-targeted therapeutic strategy for HNSCC.

The mucosal epithelium of the head and neck region (including the oral cavity, nasal cavity, pharynx, nasopharynx, and larynx) is the primary site exposed to tobacco smoke, and its presence of nicotinic acetylcholine receptors (nAChRs) has been observed in the mucosal epithelial cells of this area. It remains unclear whether HNSC cells can migrate and invade through nAChR signaling. A model of HNSC cells exposed to nicotine is established. Cell proliferation following nicotine exposure is assessed using the CCK-8 assay, while migration and invasion are evaluated through wound healing and Transwell assays. The effects of CHRNA5 knockdown and overexpression are also investigated. Immunofluorescence staining is used to analyze CHRNA5 expression and localization, and clonogenic assays are performed to measure colony proliferation after CHRNA5 knockdown and overexpression. The interaction between CHRNA5 and CES1 is examined using molecular docking, co-immunoprecipitation, and immunofluorescence. Differentially expressed genes are subjected to pathway enrichment analysis, and MEK/ERK protein expression and phosphorylation are validated via western blot. Tumor formation assays are performed in nude mice using sh-CHRNA5 Cal27 cells, followed by western blot and immunohistochemical staining. Additionally, laryngeal and hypopharyngeal cancer tissues are analyzed through immunohistochemistry. Nicotine significantly enhanced the proliferation, migration, and invasion capabilities of head and neck tumor cells, including Cal27, Fadu, HN6, and Tu686 cells, through the expression of CHRNA5. Knockdown of CHRNA5 can reduce cell migration, invasion, and proliferation, whereas nicotine exposure can reverse this trend. Additionally, the mRNA and protein expression of CES1 decreases with the knockdown of CHRNA5, indicating a regulatory relationship between the two. Transcriptomics revealed that the knockdown of CHRNA5 is associated with the MEK/ERK signaling pathway. Further cellular- and tissue-level evidence confirmed that the levels of p-MEK/MEK, p-ERK/ERK, and CES1 decreased following knockdown of CHRNA5, a trend that nicotine can reverse. Nicotine promotes the proliferation, migration, and invasion of HNSC by upregulating CHRNA5 expression. Knockdown of CHRNA5 reduces these effects, which can be reversed by nicotine. Nicotine exposure activates CHRNA5, regulating CES1 expression via the MEK/ERK pathway, contributing to the recurrence and metastasis of head and neck squamous carcinoma.

Recurrent laryngeal nerve (RLN) injury remains a challenge due to the lack of effective treatments. In this study, we established a new drug delivery system consisting of a tube of Heal-All Oral Cavity Repair Membrane loaded with laminin and neurotrophic factors and tested its ability to promote functional recovery following RLN injury. We created recombinant fusion proteins consisting of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) fused to laminin-binding domains (LBDs) in order to prevent neurotrophin diffusion. LBD-BDNF, LBD-GDNF, and laminin were injected into a collagen tube that was fitted to the ends of the transected RLN in rats. Functional recovery was assessed 4, 8, and 12 weeks after injury. Although vocal fold movement was not restored until 12 weeks after injury, animals treated with the collagen tube loaded with laminin, LBD-BDNF and LBD-GDNF showed improved recovery in vocalisation, arytenoid cartilage angles, compound muscle action potentials and regenerated fibre area compared to animals treated by autologous nerve grafting (p < 0.05). These results demonstrate the drug delivery system induced nerve regeneration following RLN transection that was superior to that induced by autologus nerve grafting. It may have potential applications in nerve regeneration of RLN transection injury.

Previous reports suggest a strong association between human papillomavirus (HPV) and the etiology of laryngeal squamous cell carcinoma (LSCC). However, clinical data regarding the HPV infection rate among LSCC patients remain largely inconsistent. In total, 674 LSCC patients from three major hospitals in Shanghai were enrolled in this study. We determined the patients' HPV infection status using immunohistochemistry and the GenoArray HPV genotyping assay and calculated their long-term survival rate using the Kaplan-Meier method. The total P16-positive rate according to immunostaining results was 7.57% (51/674). None of the P16-negative patients were HPV-positive according to the HPV genotyping test. The rate of HPV infection among patients with LSCC was 4.9% (33/674). HPV infection was more common among nonsmokers (P<0.05), nondrinkers (P<0.05), and patients with supraglottic LSCC (P<0.05). Of the 33 HPV-positive patients, 28 (84.8%) were infected with HPV-16, 2 with HPV-18, 1 with HPV-31, 1 with HPV-33 and 1 with HPV-45. The 3-year overall survival rate and progression-free survival rate were higher in HPV-positive than HPV-negative patients, but the difference was not statistically significant (76.3% vs. 70.7%, P = 0.30 and 65.1% vs. 58.3%, P = 0.37, respectively). HPV was not a main causal factor in LSCC carcinogenesis in this Chinese population. HPV infection did not alter patients' overall survival or progression-free survival rates in this study.