State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China.
Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China.
Drug Resist Updat. 2024 Nov;77:101126. doi: 10.1016/j.drup.2024.101126. Epub 2024 Aug 6.
With the wide application of trastuzumab deruxtecan (T-DXd), the survival of HER2-low breast cancer patients is dramatically improved. However, resistance to T-DXd still exists in a subset of patients, and the molecular mechanism remains unclear.
An in vivo shRNA lentiviral library functional screening was performed to identify potential circular RNA (crRNA) that mediates T-DXd resistance. RNA pull-down, mass spectrometry, RNA immunoprecipitation, and co-immunoprecipitation assays were conducted to investigate the molecular mechanism. Ferroptosis was detected using C11-BODIPY, Liperfluo, FerroOrange staining, glutathione quantification, malondialdehyde quantification, and transmission electron microscopy. Molecular docking, virtual screening, and patient-derived xenograft (PDX) models were used to validate therapeutic agents.
VDAC3-derived crRNA (crVDAC3) ranked first in functional shRNA library screening. Knockdown of crVDAC3 increased the sensitivity of HER2-low breast cancer cells to T-DXd treatment. Further mechanistic research revealed that crVDAC3 specifically binds to HSPB1 protein and inhibits its ubiquitination degradation, leading to intracellular accumulation and increased levels of HSPB1 protein. Notably, suppression of crVDAC3 dramatically increases excessive ROS levels and labile iron pool accumulation. Inhibition of crVDAC3 induces ferroptosis in breast cancer cells by reducing HSPB1 expression, thereby mediating T-DXd resistance. Through virtual screening and experimental validation, we identified that paritaprevir could effectively bind to crVDAC3 and prevent its interaction with HSPB1 protein, thereby increasing ubiquitination degradation of HSPB1 protein to overcome T-DXd resistance. Finally, we validated the enhanced therapeutic efficacy of T-DXd by paritaprevir in a HER2-low PDX model.
This finding reveals the molecular mechanisms underlying T-DXd resistance in HER2-low breast cancer. Our study provides a new strategy to overcome T-DXd resistance by inhibiting the interaction between crVDAC3 and HSPB1 protein.
随着曲妥珠单抗-德鲁替康（T-DXd）的广泛应用，HER2 低表达乳腺癌患者的生存率得到了显著提高。然而，在一部分患者中仍然存在对 T-DXd 的耐药性，其分子机制尚不清楚。
采用体内 shRNA 慢病毒文库功能筛选，鉴定介导 T-DXd 耐药的潜在环状 RNA（circRNA）。通过 RNA 下拉实验、质谱分析、RNA 免疫沉淀和共免疫沉淀实验来探究分子机制。通过 C11-BODIPY、Liperfluo、 FerroOrange 染色、谷胱甘肽定量、丙二醛定量和透射电子显微镜检测铁死亡。采用分子对接、虚拟筛选和患者来源的异种移植（PDX）模型来验证治疗药物。
在功能 shRNA 文库筛选中，VDAC3 衍生的 circRNA（crVDAC3）排名第一。敲低 crVDAC3 增加了 HER2 低表达乳腺癌细胞对 T-DXd 治疗的敏感性。进一步的机制研究表明，crVDAC3 特异性结合 HSPB1 蛋白并抑制其泛素化降解，导致 HSPB1 蛋白在细胞内积累和水平升高。值得注意的是，抑制 crVDAC3 可显著增加过量的 ROS 水平和不稳定铁池的积累。通过降低 HSPB1 表达，抑制 crVDAC3 在乳腺癌细胞中诱导铁死亡，从而介导 T-DXd 耐药。通过虚拟筛选和实验验证，我们发现帕立肽能有效地与 crVDAC3 结合并阻止其与 HSPB1 蛋白相互作用，从而增加 HSPB1 蛋白的泛素化降解，克服 T-DXd 耐药性。最后，我们在 HER2 低 PDX 模型中验证了帕立肽增强 T-DXd 的治疗效果。
本研究揭示了 HER2 低表达乳腺癌中 T-DXd 耐药的分子机制。我们的研究为通过抑制 crVDAC3 和 HSPB1 蛋白之间的相互作用来克服 T-DXd 耐药性提供了一种新策略。
