CLK2 Regulates the KEAP1/NRF2 and p53 Pathways to Suppress Ferroptosis in Colorectal Cancer

Abstract Ferroptosis, a form of regulated cell death driven by iron-dependent lipid peroxidation, plays a crucial role in colorectal cancer (CRC) progression and therapeutic response. The NRF2 pathway is one of the critical axes in ferroptosis regulation, which governs oxidative stress resistance and iron homeostasis through its downstream targets, including HMOX1, SLC7A11, and others. However, HMOX1 and SLC7A11 exhibit contrasting roles in ferroptosis, with HMOX1 promoting ferroptosis via iron accumulation and lipid peroxidation, while SLC7A11 inhibits ferroptosis by enhancing antioxidant defenses. Here, we identified CLK2 as a key regulator of the delicate balance of the opposing effects of HMOX1 and SLC7A11. CLK2 stabilized KEAP1 to suppress NRF2 activity, resulting in the downregulation of HMOX1 and SLC7A11. Simultaneously, CLK2 downregulated p53, thereby relieving p53-mediated repression of SLC7A11. The dual regulation by CLK2 disrupted the balance between HMOX1 and SLC7A11, leading to excessive activation of HMOX1 in the absence of CLK2, ultimately sensitizing CRC cells to ferroptosis. Additionally, CLK2 promoted CRC proliferation and tumorigenesis in patient-derived organoids, cell lines, and mouse models. Furthermore, combining the ferroptosis inducer Erastin with Oxaliplatin significantly enhanced anti-tumor efficacy in CLK2-deficient xenograft models. Together, this study establishes CLK2 as a critical inhibitor of ferroptosis via the KEAP1/NRF2/HMOX1 and p53/SLC7A11 axes, supporting its potential as a therapeutic target for CRC.