GABA-GABRA5 Axis confers cervical cancer lymph node metastasis

Lymph node metastasis is a major determinant of poor prognosis in cervical cancer, yet the mechanisms underlying the strong and highly directed lymphatic dissemination of tumor cells remain incompletely understood. Increasing evidence suggests that non-neuronal neurotransmitter signaling may participate in tumor progression, but its role in lymphatic metastasis has not been clearly defined. Transcriptomic analyses were performed to identify neurotransmitter-related genes associated with lymph node metastasis in cervical cancer. Clinical relevance was evaluated using patient specimens and survival analyses. Functional roles of gamma-aminobutyric acid receptor subunit alpha 5 were investigated using in vitro assays and in vivo lymph node metastasis models. Intracellular calcium levels and downstream signaling pathways were assessed by fluorescence imaging and immunoblotting. Multiplex immunofluorescence was used to determine the distribution and cellular source of gamma-aminobutyric acid in human and mouse lymph nodes. Pharmacological inhibition experiments were conducted to evaluate therapeutic potential. Statistical significance was assessed using Student’s t test, one-way analysis of variance, or log-rank tests, as appropriate. Gamma-aminobutyric acid receptor subunit alpha 5 was markedly upregulated in cervical cancer patients with lymph node metastasis and was associated with unfavorable survival outcomes. Functional studies demonstrated that its overexpression promoted epithelial-mesenchymal transition and lymphatic dissemination through calcium-dependent activation of AKT signaling, particularly in a gamma-aminobutyric acid-enriched environment. Notably, lymph nodes contained substantially higher levels of gamma-aminobutyric acid than primary tumors, forming a stable metabolic gradient. This gamma-aminobutyric acid was predominantly derived from B cells and directed the chemotactic invasion and homing of receptor-high tumor cells. Pharmacological blockade of gamma-aminobutyric acid receptor subunit alpha 5 significantly suppressed epithelial-mesenchymal transition and reduced lymph node metastasis in vivo. These findings identify a previously unrecognized gamma-aminobutyric acid-mediated mechanism of lymph node metastasis in cervical cancer and establish “metabolite-guided homing” as a distinct mode of metastatic dissemination. Targeting gamma-aminobutyric acid receptor subunit alpha 5 may represent a promising strategy for metastatic risk stratification and therapeutic intervention. Not applicable.