Downregulation of SPINK5 promotes laryngeal cancer cell malignancy through activation of KLK6-dependent glycolysis.

BACKGROUND: Laryngeal cancer remains a significant health challenge with limited therapeutic options. Serine protease inhibitor Kazal type 5 (SPINK5) is implicated as a tumor suppressor in head and neck cancers, yet its role in laryngeal cancer progression and metabolic reprogramming remains unclear. This study aimed to define SPINK5's function and molecular mechanism in laryngeal cancer progression. METHODS: Analysis of The Cancer Genome Atlas (TCGA) data and immunohistochemistry was conducted to investigate the expression level of SPINK family members in laryngeal cancer tissues compared to adjacent non-tumorous tissues. Besides, western blotting, CCK-8, colony formation, and migration assay were used to investigate the expression of SPINK5, Glucose Transporter 1 (GLUT1), and Hexokinase II (HK-II), and growth and migration capacities of laryngeal cancer cells. While glucose uptake and lactate secretion detection were conducted to measure the glycolysis level of laryngeal cancer cells. And differences among groups were analyzed using Student's t-test or one-way analysis of variance. RESULTS: The downregulation of SPINK5 was observed in laryngeal cancer tissues compared to adjacent non-tumorous tissues. SPINK5 acted as a tumor suppressor, inhibiting laryngeal cancer cell growth and migration. Mechanistically, SPINK5 knockdown promoted glycolysis through GLUT1 and HK-II upregulation. Notably, SPINK5 could interact with kallikrein-related peptidase 6 (KLK6). SPINK5 knockdown enhanced the activity of KLK6 and the activation of the PI3K/AKT/mTOR signaling pathway in laryngeal cancer cells. Critically, silencing KLK6 reversed the oncogenic effects induced by SPINK5 knockdown, including PI3K/AKT/mTOR pathway activation, enhanced glycolysis, and accelerated cell growth and migration. CONCLUSIONS: These findings identify a novel SPINK5-KLK6-glycolysis regulatory axis driving laryngeal cancer progression. Our results highlight SPINK5 as a tumor suppressor gene for laryngeal cancer progression, providing new insights into its molecular pathogenesis.