ASIC1a contributes to the epithelial–mesenchymal transformation of breast cancer by activating the Ca2+/β‐catenin pathway

Abstract Breast cancer is the most common cancer in the world, with metastasis being one of the leading causes of death among patients. The acidic environment of breast cancer tissue promotes tumor cell invasion and migration by inducing epithelial–mesenchymal transformation (EMT) in tumor cells, but the exact mechanisms are not yet fully understood. This study investigated the expression of acid‐sensitive ion channel 1a (ASIC1a) in breast cancer tissue samples and explored the mechanisms by which ASIC1a mediates the promotion of EMT in breast cancer cells in an acidic microenvironment through in vivo and in vitro experiments. The results showed that first, the expression of ASIC1a was significantly upregulated in breast cancer tissue and was correlated with the TNM (tumor node metastasis) staging of breast cancer. Furthermore, ASIC1a expression was higher in tumors with lymph node metastasis than in those without. Second, the acidic microenvironment promoted [Ca 2+ ]i influx via ASIC1a activation and regulated the expression of β‐catenin, Vimentin, and E‐cadherin, thus promoting EMT in breast cancer cells. Inhibition of ASIC1a activation with PcTx‐1 could suppress EMT in breast cancer cells. Finally, in vivo studies also showed that inhibition of ASIC1a could reduce breast cancer metastasis, invasion, and EMT. This study suggests that ASIC1a expression is associated with breast cancer staging and metastasis. Therefore, ASIC1a may become a new breast cancer biomarker, and the elucidation of the mechanism by which ASIC1a promotes EMT in breast cancer under acidic microenvironments provides evidence for the use of ASIC1a as a molecular target for breast cancer treatment.