HSP90 regulates dCK stability and inhibits ionizing radiation-induced ferroptosis in cervical cancer cells.

Cervical squamous cell carcinoma (CESC) is one of the most common cancers in women, and radiotherapy has been used as a primary treatment. However, its efficacy is limited by intrinsic and acquired radiation resistance. Our previous study demonstrated that Deoxycytidine kinase (dCK) inhibits ionizing radiation (IR)-induced cell death, including apoptosis and mitotic catastrophe, and dCK is a HSP90-interacting protein by mass spectrometry and co-immunoprecipitation assay. In the present study, we found that dCK inhibited IR-induced ferroptosis by increasing the activity and stability of SLC7A11. Using the E3 ubiquitin ligase database (UbiBrowser), we predicted NEDD4L as a potential ubiquitin ligase of dCK, and WWP1/2 as potential ubiquitin ligases of NEDD4L, respectively. These predictions were subsequently verified through a ubiquitination IP assay. Our findings indicate that HSP90 regulates dCK stability by inhibiting NEDD4L through the recruitment of ubiquitin ligases WWP1/2. In summary, our study reveals the HSP90-WWP1/WWP2-NEDD4L-dCK-SLC7A11 axis as a critical regulator of IR-induced ferroptosis in HeLa cells. These findings provide valuable insights into potential strategies for the radiosensitization of cervical cancer.