Epithelial-mesenchymal transition (EMT) is considered as the key mechanism involved in cancer metastasis. Several studies showed that various cell membrane calcium channels play different roles in cancer metastasis. In the present study, the potential role of ATPase plasma membrane Ca²⁺ transporting 4 (PMCA4) in regulating EMT in gastric cancer (GC) was investigated. GC patients who underwent radical surgery were enrolled in this study. In vitro human GC cell lines MKN45 and NCI-N87 were used, and MKN45 cells were injected in nude mice to evaluate tumor development. Our results showed that low PMCA4 expression was associated with advanced TNM stage and poor prognosis in GC patients. Knockdown of PMCA4 suppressed E-cadherin, grainyhead like 2 (GRHL2) and ovo-like 1 (OVOL1) expression, up-regulated vimentin expression, increased migration and invasion ability, and promoted the resistance to cytotoxic drug. Furthermore, GC cells displayed an elongated fibroblastoid morphology when PMCA4 was knockdown. PMCA4 overexpression resulted in an up-regulated E-cadherin expression and decreased migration and invasion ability. In vivo metastasis assay showed that PMCA4 overexpression resulted in a decreased incidence of lung metastasis. PMCA4 inhibition increased ZEB1 expression and nuclear accumulation of nuclear factor of activated T-cell isoform c1 (NFATc1). EMT induced by PMCA4 inhibition could be prevented by the knockdown of NFATc1 or ZEB1. In addition, cyclosporine A prevented EMT induced by PMCA4 inhibition by suppressing the NFATc1-ZEB1 pathway. Our data identified a novel mechanism in the regulation of EMT in GC, and provided a novel target in the treatment of EMT subtype in GC.

上皮-间质转化（EMT）被认为是癌症转移的关键机制。多项研究表明，各种细胞膜钙通道在癌症转移中起着不同的作用。在本研究中，研究了ATPase质膜Ca ²⁺转运4（PMCA4）在调节胃癌（GC）EMT中的潜在作用。接受根治性手术的GC患者参加了本研究。体外使用人GC细胞系MKN45和NCI-N87，并将MKN45细胞注射到裸鼠中以评估肿瘤的发展。我们的结果表明，PMCA4低表达与GC患者TNM分期晚期和预后不良有关。敲低PMCA4抑制E-钙黏着蛋白，粒头样2（GRHL2）和卵样1（OVOL1）表达，上调波形蛋白表达，增加迁移和侵袭能力，并增强对细胞毒性药物的抗性。此外，当敲除PMCA4时，GC细胞显示出伸长的成纤维细胞形态。PMCA4过表达导致E-钙黏着蛋白表达上调并降低迁移和侵袭能力。体内转移试验显示PMCA4过表达导致肺转移的发生率降低。PMCA4抑制增加了活化T细胞同种型c1（NFATc1）的ZEB1表达和核因子的核积累。通过抑制NFATc1或ZEB1可以防止PMCA4抑制诱导的EMT。此外，环孢菌素A通过抑制NFATc1-ZEB1途径来预防PMCA4抑制诱导的EMT。我们的数据确定了GC中EMT调控的新机制，并为GC中EMT亚型的治疗提供了新的靶标。