Background/Objectives: Ferroptosis is an iron-dependent form of regulated cell death driven by lipid peroxidation and holds promise as a therapeutic strategy against cancers with elevated iron metabolism. However, many tumors evade ferroptosis through the upregulation of specialized antioxidant defense mechanisms. Here, we investigated ferroptosis susceptibility and resistance mechanisms in TSC models and in ovarian and breast cancer cell lines, aiming to identify potential therapeutic targets.Methods: Ferroptosis sensitivity was assessed using RSL3 and erastin. We explored the contribution of ferroptosis defense pathways using inhibitors of NRF2 (ML385) and FSP1 (iFSP1). RNA sequencing was performed to evaluate the expression of ferroptosis resistance genes and to explore NRF2-regulated transcriptional programs.Results:TSC2-deficient cells were resistant to RSL3- and erastin-induced ferroptosis. This resistance correlated with upregulation of ferroptosis defense genes, including NRF2 and its downstream targets. Pharmacological inhibition of NRF2 resensitizedTSC2-deficient cells to ferroptosis, confirming a protective role for NRF2. However, FSP1 inhibition did not restore ferroptosis sensitivity inTSC2-deficient angiomyolipoma cells. In contrast, FSP1 knockdown significantly enhanced ferroptosis sensitivity in ovarian (PEO1, PEO4, OVCAR3) and breast (MDA-MB-436) cancer cells. Notably, in MDA-MB-436 cells, FSP1 knockdown was more effective than NRF2 inhibition to enhance ferroptosis sensitivity. FSP1 expression was not regulated by NRF2, suggesting that NRF2-targeted therapies alone may be insufficient to overcome ferroptosis resistance in certain cancer contexts.Conclusions:TSC2-deficient cells resist ferroptosis via an adaptive antioxidant response that protects against elevated iron-mediated lipid peroxidation. Our findings identify NRF2 and FSP1 as key, but mechanistically distinct, regulators of ferroptosis resistance. The differential efficacy of targeting these pathways across cancer types highlights the potential need for patient stratification. Dual targeting of NRF2 and FSP1 may offer an effective therapeutic strategy for iron-dependent, ferroptosis-resistant cancers.
背景/目的：铁死亡是一种由脂质过氧化驱动的铁依赖性调节性细胞死亡形式，有望成为针对铁代谢升高癌症的治疗策略。然而，许多肿瘤通过上调特异性抗氧化防御机制来逃避铁死亡。本研究旨在探讨结节性硬化症（TSC）模型以及卵巢癌和乳腺癌细胞系中的铁死亡易感性及耐药机制，以确定潜在的治疗靶点。 方法：使用RSL3和erastin评估铁死亡敏感性。通过NRF2抑制剂（ML385）和FSP1抑制剂（iFSP1）探究铁死亡防御通路的作用。采用RNA测序技术评估铁死亡耐药基因的表达，并探索NRF2调控的转录程序。 结果：TSC2缺陷细胞对RSL3和erastin诱导的铁死亡具有耐药性。这种耐药性与铁死亡防御基因（包括NRF2及其下游靶基因）的上调相关。NRF2的药理学抑制使TSC2缺陷细胞重新对铁死亡敏感，证实了NRF2的保护作用。然而，FSP1抑制并未恢复TSC2缺陷型血管平滑肌脂肪瘤细胞的铁死亡敏感性。相比之下，在卵巢癌细胞（PEO1、PEO4、OVCAR3）和乳腺癌细胞（MDA-MB-436）中，FSP1敲除显著增强了铁死亡敏感性。值得注意的是，在MDA-MB-436细胞中，FSP1敲除在增强铁死亡敏感性方面比NRF2抑制更有效。FSP1表达不受NRF2调控，这表明仅针对NRF2的治疗可能不足以克服某些癌症中的铁死亡耐药。 结论：TSC2缺陷细胞通过适应性抗氧化反应抵抗铁死亡，该反应可抵御铁介导的脂质过氧化升高。我们的研究确定NRF2和FSP1是铁死亡耐药的关键但机制不同的调节因子。针对这些通路在不同癌症类型中的疗效差异凸显了患者分层的潜在必要性。同时靶向NRF2和FSP1可能为铁依赖性、铁死亡耐药的癌症提供有效的治疗策略。
Targeting NRF2 and FSP1 to Overcome Ferroptosis Resistance inTSC2-Deficient and Cancer Cells
肿瘤(癌症)患者之家