1242 - AKR1C3 Negatively Regulates the LGALS3/p62/NRF2 Axis to Inhibit Ferroptosis and Induce Radioresistance in Prostate Cancer
Presenter(s)
F. Lyu1, X. S. Gao1, M. Ma1, X. Ren1, J. Chen1, S. Li1, and L. Huang2; 1Department of Radiation Oncology, Peking University First Hospital, Beijing, China, 2Peking University First Hospital, Beijing, China
Purpose/Objective(s): This study aims to elucidate a novel mechanism of radioresistance in prostate cancer (PCa), wherein AKR1C3 downregulates Galectin-3 (LGALS3) to modulate the p62/KEAP1/NRF2 axis, thereby inhibiting ferroptosis. Furthermore, we explore targeting this axis as a promising strategy for radiosensitization.
Materials/Methods: A multi-level approach was employed: 1) Bioinformatics analysis: The scTenifoldKnk virtual knockout technique was applied to a PCa single-cell dataset (GSE141445) to predict key downstream molecules of AKR1C3. 2) In vitro: AKR1C3-overexpressing/knockdown and radioresistant PCa cell models were established. Radiosensitivity and ferroptosis were assessed via colony formation, CCK-8, flow cytometry (ROS/lipid ROS), TEM, and Western blot (WB) for key proteins (AKR1C3, LGALS3, p62, KEAP1, NRF2, GPX4, SLC7A11, ACSL4). Co-IP verified the LGALS3-p62 interaction. 3) In vivo: Subcutaneous xenograft and radioresistant mouse models were treated with AKR1C3 inhibitors, ferroptosis inducers (e.g., Erastin), and/or radiotherapy to evaluate tumor growth and molecular markers. 4) Clinical validation: Paired pre-/post-radiotherapy PCa tissues were analyzed by IHC, qPCR, and WB for correlation with radiosensitivity and prognosis.
Results: 1) A radioresistant PCa cell model (DU145 R84) was successfully established, showing significant AKR1C3 upregulation. 2) AKR1C3 overexpression enhanced clonogenic survival and viability, induced radioresistance, decreased intracellular ROS, increased antioxidant capacity, and reduced ?H2AX. 3) AKR1C3 activated the NRF2/ARE pathway, upregulating NRF2 and GPX4. Erastin reversed this effect, restored radiosensitivity, and induced ferroptotic morphology. 4) Single-cell analysis and validation experiments showed AKR1C3 negatively regulates LGALS3. Co-IP confirmed direct LGALS3-p62 binding. AKR1C3 knockdown increased LGALS3 and decreased NRF2 expression.
Conclusion: AKR1C3 promotes PCa radioresistance by downregulating LGALS3, which reduces LGALS3-p62 binding, facilitates p62-mediated KEAP1 autophagic degradation, stabilizes NRF2, enhances antioxidant defense, and ultimately inhibits ferroptosis. Targeting the AKR1C3/LGALS3/p62/NRF2 axis (e.g., combining AKR1C3 inhibitors with ferroptosis inducers) represents a promising strategy to overcome radioresistance.