3157 - Overcoming Radioresistance in Hepatocellular Carcinoma through Ferroptosis Modulation and Exosomal Biomarkers
Presenter(s)
P. H. Wu1,2, W. M. Chang3, J. F. Chiou4, I. C. Lai5, W. Y. Kao3, C. C. Kuo6, W. J. Wang7, and H. L. Lee8; 1Taipei Medical University, Taipei City, Taiwan, 2TMU Proton Center, Taipei City, Taiwan, 3Taipei Medical University, Taipei City, Taipei City, Taiwan, 4Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 5Department of Heavy Particles & Radiation Oncology, Taipei Veterans General Hospital, Taipei, Taiwan, 6Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan, 7Department of Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan, 8Taipei Medical University Hospital, Taipei City, Taipei City, Taiwan
Purpose/Objective(s): Hepatocellular carcinoma (HCC) is among the most lethal malignancies worldwide. With the rise of advanced proton therapy, more HCC patients receive curative radiotherapy, improving local control. However, acquired radioresistance remains a major challenge, leading to treatment failure. The molecular basis of this resistance is not fully understood, requiring further investigation to identify therapeutic targets. This study established a radioresistant HCC cell line to explore resistance-associated molecular changes, with a focus on iron metabolism and ferroptosis. We also examined curcumin’s potential to sensitize resistant cells to radiotherapy and assessed exosomal microRNAs (miRNAs) as potential biomarkers for predicting radioresistance.
Materials/Methods: A radioresistant HepG2 derivative (HepG2-RR) was developed via repeated fractionated radiation exposure. Resistance was validated through dose-response survival curves. Transcriptome analysis compared gene expression between HepG2-RR and parental HepG2 cells. Key genes were confirmed by qRT-PCR and Western blot. Ferroptotic sensitivity was assessed via cell viability, lipid peroxidation, and ROS levels following curcumin treatment. Exosomal RNA sequencing identified differentially expressed miRNAs in HepG2-RR cells. Functional enrichment analysis explored their roles in radioresistance.
Results: HepG2-RR cells showed significantly higher survival fractions after radiation than parental cells, confirming acquired resistance. Transcriptomic analysis revealed upregulation of iron metabolism genes FTH1, FTL, and HAMP, indicating altered iron homeostasis. Biochemical assays confirmed increased intracellular iron storage and reduced ferroptotic susceptibility. Notably, curcumin treatment restored ferroptosis sensitivity in HepG2-RR cells, increasing lipid peroxidation, ROS levels, and reducing viability in a dose-dependent manner. Ferroptosis induction was associated with ferritin downregulation and modulation of key regulators GPX4 and ACSL4.
Exosomal miRNA profiling identified miR-378 family upregulation in HepG2-RR exosomes. Functional analysis linked miR-378 to oxidative stress and iron metabolism, suggesting its role in radioresistance. Differential miR-378 expression highlights its potential as a non-invasive biomarker for HCC radioresistance.Conclusion: This study reveals the role of iron metabolism and ferroptosis in HCC radioresistance. HepG2-RR cells exhibit altered iron homeostasis, reducing ferroptosis susceptibility. Curcumin effectively restores ferroptotic sensitivity, presenting a potential adjuvant strategy to overcome radioresistance. Exosomal miR-378 may serve as a predictive biomarker for HCC radiotherapy resistance. Further studies should validate these findings and explore additional ferroptosis-targeting therapies.