CTSL Promotes Autophagy in Laryngeal Cancer Through the IL6‐JAK‐STAT3 Signalling Pathway

Abstract

ABSTRACT Cathepsin L (CTSL) is an important oncogene. However, its mechanism of action in laryngeal cancer is still unclear. This study aims to explore the role of CTSL in laryngeal cancer and its clinical significance. Conducting bioinformatics analysis utilising the Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database. Performing CCK8 analysis, Western blotting, qRT‐PCR, wound healing assay and transwell invasion assay. Additionally, conducting immunoprecipitation experiments and immunohistochemical staining to investigate the impact of CTSL on cell proliferation, autophagy and related signalling pathways. We observed a significant upregulation of CTSL in laryngeal cancer tissues, and its elevated levels are indicative of poor prognosis in laryngeal cancer patients. The proliferation of laryngeal cancer cells relies on the expression of CTSL, with overexpression of this gene enhancing the proliferative capacity of these cells. Concurrently, CTSL is closely associated with the autophagic levels in laryngeal cancer cells. During the autophagic process mediated by CTSL, the IL6‐JAK‐STAT3 signalling pathway is activated, suggesting that CTSL promotes autophagy through the IL6‐JAK‐STAT3 pathway. Considering the correlation between CTSL and autophagy, we developed and validated a multi‐gene signature. The risk score derived from this signature demonstrates significant potential in predicting various aspects. We found that CTSL upregulates autophagy in laryngeal cancer cells by activating the IL6‐JAK‐STAT3 signalling pathway. By taking into account the autophagy‐regulating role of CTSL, the clinical predictive ability of CTSL in HNSC can be enhanced.