Ubiquitin Ligase RNF149 Promotes Head and Neck Cancer Growth via Downregulation of CDKN2C

Background/Aim: Head and neck squamous cell carcinoma (HNSC) remains one of the main causes of cancer-related deaths among male patients with cancer. Although surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy are available, their success in controlling the disease remains limited. Novel targets and therapeutics for HNSC therefore await identification, which is frequently pursued using bioinformatics approaches.

Materials and Methods: Bioinformatics analyses were conducted to evaluate prognosis, differential gene expression, pathways, therapeutics, immunohistochemistry, and expression correlations. Experimental procedures included gene knockdown, proliferation assays, cell cycle analysis, drug treatment, 3D assays, proximity ligation assays, immunoprecipitation, and immunohistochemistry.

Results: In the present study, a prognostic factor for HNSC with concordant expression changes was identified. Ring finger protein 149 (RNF149) was shown to predict poor prognosis and to be upregulated during tumorigenesis. Pathway and therapeutic analyses revealed that RNF149-high HNSCs were enriched for cell cycle dysregulation, which might be counteracted by cyclin-dependent kinase inhibitors (CDKi). Cell line experiments validated that RNF149 knockdown in HNSC decreased proliferation and altered the response to CDKi in both 2D and 3D environments. Multi-omics analysis and tissue staining revealed that this ubiquitin ligase might ubiquitinate cyclin-dependent kinase inhibitor 2C (CDKN2C) in HNSC. This regulation was experimentally verified using proximity ligation assays (PLA) and immunoprecipitation. Finally, tissue array staining confirmed a negative correlation between RNF149 and CDKN2C expression in HNSC.

Conclusion: This study provides insights into RNF149-mediated proteolysis in HNSC.