Evodiamine Resensitizes Cisplatin Resistance by Targeting SOX9-β-Catenin Axis in Non-Small Cell Lung Cancer

Abstract

Natural dietary alkaloid evodiamine has demonstrated anticancer properties. Here, the mechanistic role of evodiamine in cell proliferation and migration in non-small cell lung cancer (NSCLC) was investigated. In A549 and NCI-H522 cells, evodiamine reduces cell viability by inducing apoptotic cell death. It induces cell death by elevating reactive oxygen species (ROS) levels resulted in the depletion of mitochondrial membrane potential. In contrast, the pre-treatment of ROS scavenger, N-acetyl cysteine, attenuates cell death effect of evodiamine. Furthermore, it caused DNA damage and arrested the cell cycle in A549 and NCI-H522 cells at the G2/M phase. Evodiamine also suppressed tumorigenicity significantly by inhibiting tumorsphere formation. However, treatment of evodiamine regulated the expression of cancer stem cell markers CD44 and CD133 and epithelial to mesenchymal transition (EMT) markers E-cadherin, ZO-1, N-cadherin, and Vimentin. Additionally, current study has revealed that evodiamine targets the SOX9–β-catenin axis by reducing SOX9 and β-catenin expression. SOX9 has been also linked to drug resistance in a variety of cancers. Therefore, the role of SOX9 and its regulatory component β-catenin in cisplatin-resistant NSCLC was investigated. SOX9 and β-catenin expression was found to be higher in cisplatin-resistant A549 (A549CR) and NCI-H522 (NCI-H522CR) than in parental A549 and NCI-H522. SOX9 knockdown decreased cell proliferation, colony formation and cell migration in A549CR and NCI-H522CR. As expected, apoptotic cell death was significantly increased in siSOX9 transfected A549CR and NCI-H522CR cells treated with cisplatin compared to control cells. Additionally, silencing of SOX9 reverses resistance to cisplatin by regulating β-catenin. Existing NSCLC patients treated with cisplatin shows resistance. As a result, a new agent capable of sensitizing cisplatin-resistant NSCLC cells to cisplatin is desperately needed. Previously it was demonstrated that evodiamine can limit the growth of NSCLC. Therefore, this study examines the mechanism behind evodiamine's ability to reverse resistance to cisplatin. Results show that evodiamine promotes cisplatin induced cytotoxicity by boosting intracellular ROS production in A549CR and NCI-H522CR cells. Mechanistically, it was found that evodiamine resensitizes cisplatin-resistant NSCLC cells by inhibiting EMT markers and SOX9 and β-catenin expression. Combination of evodiamine and cisplatin may be a therapeutic regimen for overcoming cisplatin resistance in NSCLC.