Li Yu-Mei, Zhao Qing-Li, Ogawa Ryohei, Mizukami Tatsuji, Song Yu, Cui Zheng-Guo, Saitoh Jun-Ichi, Noguchi Kyo
Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, University of Toyama.
Department of Environmental Health, University of Fukui School of Medical Sciences.
Environ Health Prev Med. 2025;30:67. doi: 10.1265/ehpm.25-00204.
Hyperthermia (HT), while a cancer treatment approach, isn't always effective alone. Therefore, identifying hyperthermia enhancers is crucial. We demonstrated that Mito-TEMPO ([2-[(1-Hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) amino]-2-oxoethyl]-triphenylphosphanium, MT) acts as a potent thermosensitizer, promoting cell death in human cervical cancer (HeLa) cells.
Cells were pretreated with 0.4 mM MT for 5 minutes, followed by exposure to hyperthermia (42 °C for 60 minutes). The impacts of MT/HT on cell viability, proliferation, apoptosis, endoplasmic reticulum (ER) stress, apoptosis-related proteins and autophagy, autophagy-related proteins expression were measured. The relationships between autophagy and apoptosis were further investigated using the specific autophagy inhibitor chloroquine (CQ) and the autophagy inducer rapamycin (Rapa).
The combined treatment reduced the mitochondrial membrane potential (MMP) and increased ROS production. It also upregulated the pro-apoptotic protein Bax and downregulated anti-apoptotic proteins such as Bcl-2 and MCL-1. As a result, Caspase-3 was activated. Additionally, the combined treatment upregulated the expression of p-PERK/PERK, ATF-4, CHOP proteins. Moreover, the combined treatment also increased the expression of LC3 II and p62, decreased expression of LAMP 1 and Cathepsin D and increased lysosomal pH, indicating coordinated changes in autophagy regulation. Notably, intensification of apoptosis induced by the combined treatment was observed with CQ, whereas attenuation was seen with Rapa.
MT effectively enhanced HT-induced apoptosis in HeLa cells. Elevated ER stress and interruption of autophagy flux are the possible underlying molecular mechanisms for this phenomenon. These findings suggested MT can act as a potential thermosensitizer, highlighting its versatility in cancer treatment strategies.
热疗（HT）作为一种癌症治疗方法，单独使用时并不总是有效。因此，识别热疗增强剂至关重要。我们证明了线粒体靶向抗氧化剂Mito-TEMPO（[2-[(1-羟基-2,2,6,6-四甲基哌啶-4-基)氨基]-2-氧代乙基]-三苯基鏻，MT）作为一种有效的热敏剂，可促进人宫颈癌（HeLa）细胞的死亡。
细胞先用0.4 mM MT预处理5分钟，然后暴露于热疗（42°C，60分钟）。测量MT/HT对细胞活力、增殖、凋亡、内质网（ER）应激、凋亡相关蛋白和自噬、自噬相关蛋白表达的影响。使用特异性自噬抑制剂氯喹（CQ）和自噬诱导剂雷帕霉素（Rapa）进一步研究自噬与凋亡之间的关系。
联合治疗降低了线粒体膜电位（MMP）并增加了活性氧（ROS）的产生。它还上调了促凋亡蛋白Bax的表达，下调了抗凋亡蛋白如Bcl-2和MCL-1的表达。结果，半胱天冬酶-3被激活。此外，联合治疗上调了p-PERK/PERK、ATF-4、CHOP蛋白的表达。此外，联合治疗还增加了LC3 II和p62的表达，降低了LAMP 1和组织蛋白酶D的表达，并增加了溶酶体pH值，表明自噬调节发生了协同变化。值得注意的是，CQ可增强联合治疗诱导的凋亡，而Rapa则可减弱这种凋亡。
MT有效地增强了HT诱导的HeLa细胞凋亡。内质网应激升高和自噬流中断是这一现象可能的潜在分子机制。这些发现表明MT可作为一种潜在的热敏剂，突出了其在癌症治疗策略中的多功能性。
