WNK4 Enhances Anti-PD-1 Resistance and Promotes Tumor Progression in Hepatocellular Carcinoma by Reprogramming...

Hepatocellular carcinoma (HCC) is the most prevalent subtype of primary liver cancer. Immunotherapy, particularly targeting immune checkpoints such as programmed cell death protein 1 (PD-1), has shown considerable therapeutic promise. Bioinformatic analysis of Gene Expression Omnibus datasets demonstrated significant upregulation of WNK lysine deficient protein kinase 4 (WNK4) expression in HCC tissues obtained from untreated patients or anti-PD-1 non-responders, suggesting a potential role for WNK4 in HCC progression and immunotherapy resistance. Through a series of experiments, we confirmed that WNK4 promoted the proliferative and migrative abilities of HCC cells and enhanced the resistance of HCC model mice to anti-PD-1 therapy. The tumor microenvironment, particularly cancer-associated fibroblasts (CAFs), critically influences immunotherapy efficacy. The current study uncovered that WNK4 was transferred by HCC cell-derived exosomes into CAFs and promoted the cysteine metabolic reprogramming. Moreover, WNK4-mediated promotional effects of CAFs on the malignant phenotypes of HCC cells and anti-PD-1 resistance were in a cysteine-dependent manner. According to mechanism investigation, WNK4 could bind high mobility group box 1 (HMGB1) and induce its phosphorylation and cytoplasmic retention, thus reducing nuclear HMGB1-p53 interaction to enhance cystathionine gamma-lyase (CTH) expression. In summary, this study unveils a novel WNK4-HMGB1-p53 axis in CAFs that promotes HCC progression and modulates cysteine metabolism to foster immunotherapy resistance, offering potential therapeutic targets for HCC.