Elevated VAMP8 Expression Promotes Cervical Cancer Progression by Enhancing Autophagy via HIF-1 Pathway

Background: Cervical cancer, prevalent in low- and middle-income countries, is primarily caused by high-risk HPV16. Vesicle-Associated Membrane Protein 8 (VAMP8), involved in vesicle trafficking and autophagy, may influence HPV16-related cervical cancer progression. Methods: VAMP8 expression was evaluated in cervical tissue specimens from patients with HPV16-positive lesions (including low- and high-grade squamous intraepithelial lesions and cancer) and HPV-negative normal controls using proteomics, qPCR, and immunohistochemistry. A Cox proportional hazards model for prognosis was developed using immunohistochemical data from a cohort of cervical cancer patients. The clinical significance of VAMP8 was further assessed using RNA-seq and clinical data from The Cancer Genome Atlas-Cervical Cancer (TCGA-CESC) cohort. The effects of VAMP8 on autophagy and tumor progression were examined in HPV16 E6/E7-immortalized cervical epithelial cells (Ect1/E6E7) and cervical cancer cell lines (SiHa, HeLa, C-33A) in vitro, and in a SiHa xenograft model in vivo. Transcriptomic analysis of Ect1/E6E7 and SiHa cells identified VAMP8-regulated pathways. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays in SiHa cells were used to confirm the regulation of the HIF-1 pathway. Results: VAMP8 was upregulated in HPV16-positive samples, particularly in low-grade squamous intraepithelial lesions (LSIL). Elevated VAMP8 correlated with poor survival outcomes and advanced tumor stages. VAMP8 enhanced autophagy and reduced proliferation and invasiveness in HPV16-positive cervical cells but increased in established cancer cell lines. In vivo, VAMP8 overexpression promoted tumor growth and autophagy. The HIF-1 pathway emerged as a key regulatory axis of VAMP8, enhancing hypoxic responses and angiogenesis. Conclusion: Elevated VAMP8 in HPV16-associated cervical cancer promotes tumor progression by enhancing autophagy via the HIF-1 pathway, suggesting its potential as a diagnostic and prognostic biomarker.