Exploring the role of WNK-SPAK/OSR1 kinases in cancer

Abstract

Background: With-no-lysine (WNK) kinases are crucial in regulating ion homeostasis and blood pressure. Dysregulation of WNKs contributes to cancer progression via phosphorylation of STE20/SPS1 related proline/alanine-rich kinase (SPAK) and Oxidative stress response kinase-1 (OSR1). This study aimed to explore OSR1 expression in various cell lines, assess cytotoxicity of WNK1 OSR1/SPAK-Na-K-2Cl cotransporters (NKCCs) inhibitors on normal and cancer cell lines and determine interactions between OSR1 and myelin basic protein (MBP). Methods and Materials: Throughout these experiments, MDA-MB231, MDA-MB468, MCF-7 and HEK293 cell lines were used. Western blotting assessed the activity of OSR1. MTT assay evaluated cytotoxicity of Closantel, Rafoxanide, WNK463, and Bumetanide on HEK293 and MDA-MB-231 cells. Immunoprecipitation investigated OSR1-MBP interactions. Statistical analysis was used. Results: MDA-MB-231 exhibited pOSR1 overexpression at Ser373 and Thr185, suggesting a role in cancer progression. Closantel, Rafoxanide, and WNK463 resulted in cytotoxicity of HEK293 cells (IC50=39.5352μM, 38.966μM and 32.7368μM, respectively), and Closantel and Rafoxanide caused cytotoxicity in MDA-MB-231 cells (IC50=38.739μM and 40.32μM, respectively). Bumetanide exhibited variable responses. Immunoprecipitation didn’t reveal a direct OSR1 MBP relationship. Conclusion: OSR1 overexpression may drive cancer progression, as shown in MDA-MB-231 at Ser373/Thre185 phosphosites. Closantel, Rafoxanide, and WNK463 show promise as potential anticancer agents. Further studies are needed to reveal their mechanisms and further explore OSR1's role in cancer progression.