SLC7A11 Knockdown and Regorafenib: Ferroptosis Induction in HepG2 Cells
60th Congress of the European-Societies-of-Toxicology (EUROTOX) - Toxicology Without Borders, Vienna, Avusturya, 13 - 16 Eylül 2026, ss.112511, (Özet Bildiri)
- Yayın Türü: Bildiri / Özet Bildiri
- Basıldığı Şehir: Vienna
- Basıldığı Ülke: Avusturya
- Sayfa Sayıları: ss.112511
- İstanbul Üniversitesi Adresli: Evet
Özet
Hepatocellular carcinoma (HCC) continues to be a global health challenge due to limited treatment options. Regorafenib, a multikinase inhibitor, is a standard second-line therapy for advanced HCC; however, the precise molecular mechanisms underlying its cytotoxicity have not yet been fully elucidated [1]. This study aims to investigate whether regorafenib exerts its toxic effects by triggering ferroptosis, an iron-dependent form of regulated cell death [2], and to validate this mechanism through siRNA-mediated silencing of SLC7A11, a key negative regulator of ferroptosis [3]. HepG2 cells were treated with regorafenib for 48 hours, and experimental doses were determined as 0.75, 1.0, and 1.5 μM by assessing cell viability via MTT assay. To confirm the role of ferroptosis, SLC7A11 was silenced using siRNA (validated by qRT-PCR and Western blot) prior to drug treatment [4]. Ferroptotic markers were systematically examined: intracellular ROS, lipid peroxidation (MDA), intracellular total and ferrous iron accumulation, glutamate export, and cysteine uptake [5], as well as autophagic activity to explore the role of ferritinophagy in iron release [6]. Regorafenib treatment led to a dose-dependent decrease in cell viability and a significant increase in ROS and MDA levels, indicating that the drug triggered oxidative stress and lipid peroxidation. Regorafenib increased intracellular total and ferrous iron levels in a dose-dependent manner; this effect was significantly reduced by the SLC7A11 knockdown (silencing) process. The biochemical hallmark of ferroptosis was further evidenced by decreased cysteine levels and increased intracellular glutamate accumulation, particularly at the 1.5 μM dose in the silenced group, reflecting the inhibition of the system Xc− antiporter [5]. The increased autophagic activity in the silencing + drug group suggests that regorafenib-induced toxicity involves ferritinophagy-mediated iron mobilization [6]. Our findings demonstrate that regorafenib induces cytotoxic effects in HepG2 cells primarily by triggering the ferroptotic pathway. The potentiation of these effects following SLC7A11 silencing provides strong evidence that regorafenib-mediated cell death is driven by cysteine depletion, iron accumulation, and lipid peroxidation. Understanding this mechanism offers new insights into optimizing regorafenib-based therapies in HCC, as it identifies ferroptotic susceptibility as a crucial factor in treatment success and opens new clinical avenues for targeted combination protocols to improve patient survival.