High ASIC3 Expression Correlates with Poor Prognosis in Lung Cancer Patients and Mediates Hypercapnic...

IntroductionEpithelial-mesenchymal transition (EMT) is a key driver of tumor invasion and metastasis, which is closely associated with poor prognosis in patients with surgically resected lung cancer. Hypercapnic acidosis (HCA) is a common comorbidity in various lung diseases; however, its specific role in regulating EMT in lung cancer remains unclear. Acid-sensing ion channel (ASIC) genes have been implicated in tumor progression, but their expression patterns and prognostic value in lung cancer, as well as their involvement in HCA-mediated EMT regulation, require further investigation.MethodsThe expression levels of ASIC genes and their prognostic significance were analyzed in lung adenocarcinoma and lung squamous cell carcinoma using the Gene Expression Profiling Interactive Analysis (GEPIA) database. A549 lung cancer cells were exposed to HCA conditions (10% CO₂, pH 6.69 ± 0.02) for five days to induce EMT phenotypes. Cell proliferation, migration, and invasion capacities were evaluated using corresponding functional assays. The expression levels of EMT-related markers (E-cadherin and vimentin) and ASIC3 were quantified by immunohistochemical staining, western blot analysis, and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). Additionally, amiloride was used to inhibit ASIC3 expression to verify its regulatory role in HCA-induced EMT.ResultsBioinformatics analysis showed that overexpression of ASIC3 mRNA was significantly correlated with reduced overall survival in lung cancer patients (P < .05). In vitro experiments demonstrated that HCA exposure significantly upregulated ASIC3 expression (P < .01) and promoted EMT in A549 cells, as evidenced by downregulated E-cadherin expression and upregulated vimentin expression. Moreover, HCA significantly enhanced the migration and invasion abilities of A549 cells (P < .01). Importantly, inhibition of ASIC3 expression by amiloride reversed all these HCA-induced effects, including the alterations in EMT markers and the enhancement of cell migratory/invasive capacities.ConclusionThe HCA microenvironment induces EMT in A549 lung cancer cells through the activation of ASIC3. These findings suggest that ASIC3 may serve as a potential therapeutic target for the treatment of lung cancer, which could help improve clinical outcomes by inhibiting tumor invasion and metastasis mediated by EMT.