Department of Dermatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
Clin Transl Med. 2023 Jun;13(6):e1300. doi: 10.1002/ctm2.1300.
Ferroptosis is an important iron-dependent form of cell death in hepatocellular carcinoma (HCC). Sorafenib, a potent ferroptosis inducer, is used to treat advanced HCC but its efficacy is limited by the development of drug resistance.
The effects of DUXAP8 expression on HCC progression were evaluated by TCGA database, Kaplan-Meier analysis, and in situ hybridization analysis. Sorafenib resistant HCC cell lines were modeled in vitro to study the regulation of DUXAP8 on ferroptosis in HCC induced by sorafenib. We used RNA pull-down, immunofluorescence assays, acyl-biotinyl exchange assay and mass spectrometry analysis to assess the molecular mechanism of ferroptosis regulation by DUXAP8. Syngeneic subcutaneous and orthotopic CDX models were used to assess whether DUXAP8 inhibition improves HCC in vivo.
LncRNA DUXAP8, which is highly expressed in liver cancer and associated with poor prognosis, contributes to sorafenib resistance through suppression of ferroptosis. In vitro tests revealed that DUXAP8 reduced the sensitivity of HCC to sorafenib-induced ferroptosis by acting on SLC7A11, a subunit of the amino acid antiporter system xc-. DUXAP8 facilitates SLC7A11 palmitoylation and impedes its lysosomal degradation, thereby enhancing SLC7A11 action and suppressing ferroptosis. RNA pull-down and immunofluorescence assays confirmed that DUXAP8 decreased membrane translocation and promoted sorting of de-palmitoylated SLC7A11 to lysosomes by binding of DUXAP8 to SLC7A11. In addition, mass spectrometric analysis found that the Cys414 residue of SLC7A11 might be the predominant mutant site responsible for molecular masking of SLC7A11 lysosomal sorting. Further, the antitumor effect of DUXAP8 knockdown was verified in orthotopic and subcutaneous CDX models.
Our findings suggest that a novel translational strategy combining sorafenib with DUXAP8 silencing to overcome drug resistance may improve treatment efficacy in patients with advanced HCC.
铁死亡是肝细胞癌（HCC）中一种重要的铁依赖性细胞死亡形式。索拉非尼是一种有效的铁死亡诱导剂，用于治疗晚期 HCC，但由于耐药性的发展，其疗效有限。
通过 TCGA 数据库、Kaplan-Meier 分析和原位杂交分析评估 DUXAP8 表达对 HCC 进展的影响。在体外建立索拉非尼耐药 HCC 细胞系，研究 DUXAP8 对索拉非尼诱导的 HCC 铁死亡的调节作用。我们使用 RNA 下拉、免疫荧光分析、酰基辅酶 A 交换测定和质谱分析来评估 DUXAP8 调节铁死亡的分子机制。使用同源皮下和原位 CDX 模型评估 DUXAP8 抑制是否改善 HCC 体内情况。
在肝癌中高表达且与预后不良相关的长链非编码 RNA DUXAP8 通过抑制铁死亡促进索拉非尼耐药。体外试验表明，DUXAP8 通过作用于氨基酸转运体系统 xc-的亚基 SLC7A11，降低 HCC 对索拉非尼诱导的铁死亡的敏感性。DUXAP8 促进 SLC7A11 棕榈酰化并阻碍其溶酶体降解，从而增强 SLC7A11 作用并抑制铁死亡。RNA 下拉和免疫荧光分析证实，DUXAP8 通过与 SLC7A11 结合，减少去棕榈酰化 SLC7A11 的膜易位并促进其向溶酶体的分拣。此外，质谱分析发现 SLC7A11 的 Cys414 残基可能是负责 SLC7A11 溶酶体分拣的分子掩蔽的主要突变位点。进一步，在原位和皮下 CDX 模型中验证了 DUXAP8 敲低的抗肿瘤作用。
我们的研究结果表明，结合索拉非尼和 DUXAP8 沉默的新的转化策略可能改善晚期 HCC 患者的治疗效果。
