与传统光热疗法（PTT，>50°C）相比，轻度PTT（≤45°C）是一种有前途的肿瘤治疗策略，且副作用较少。不幸的是，其抗肿瘤功效受到热休克蛋白（HSP）过度表达引起的耐热性的阻碍。在我们之前的研究中，我们发现蟾蜍灵（BU）是一种糖酵解抑制剂，可以消耗HSP，有望克服肿瘤细胞的耐热性。在这项研究中，开发了负载BU的多功能纳米粒子（NPs），用于增强结直肠癌（CRC）的轻度PTT。Fe3O4 NPs涂有聚多巴胺（PDA）外壳，并用聚乙二醇（PEG）和环精氨酸-甘氨酰-天冬氨酸修饰。开发了用于负载 BU (Fe3O4@PDA-PEG-cRGD/BU NPs) 的肽 (cRGD)。测量了不同条件下 Fe3O4@PDA-PEG-cRGD/BU NPs 溶液的热变化。通过测量葡萄糖摄取、细胞外乳酸和细胞内三磷酸腺苷（ATP）水平来评估糖酵解抑制。使用细胞计数试剂盒-8 测定、Calcein-AM/PI 双染色和流式细胞术在 HCT116 细胞中分析 Fe3O4@PDA-PEG-cRGD/BU NP 的细胞毒性。在HCT116荷瘤小鼠中评估Fe3O4@PDA-PEG-cRGD/BU NPs的磁共振成像（MRI）性能和抗肿瘤治疗效果。Fe3O4@PDA-PEG-cRGD/BU NPs的平均直径为260.4 ±3.5 nm，zeta电位为-23.8±1.6 mV，载药率为1.1%，具有良好的热稳定性、光热转换效率和MRI性能。此外，释放的BU不仅杀死肿瘤细胞，还通过靶向类固醇受体辅激活剂3（SRC-3）/HIF-1α途径干扰糖酵解，阻止细胞内ATP合成，对抗HSP依赖性肿瘤耐热性，最终增强肿瘤细胞的抗热性。体外和体内对轻度 PTT 的热敏感性。这项研究为增强轻度 PTT 对肿瘤的治疗效果提供了一种高效的策略。© 2024 Shang 等人。

Compared with traditional photothermal therapy (PTT, >50°C), mild PTT (≤45°C) is a promising strategy for tumor therapy with fewer adverse effects. Unfortunately, its anti-tumor efficacy is hampered by thermoresistance induced by overexpression of heat shock proteins (HSPs). In our previous study, we found bufalin (BU) is a glycolysis inhibitor that depletes HSPs, which is expected to overcome thermotolerance of tumor cells. In this study, BU-loaded multifunctional nanoparticles (NPs) were developed for enhancing the mild PTT of colorectal cancer (CRC).Fe3O4 NPs coated with the polydopamine (PDA) shell modified with polyethylene glycol (PEG) and cyclic arginine-glycyl-aspartic peptide (cRGD) for loading BU (Fe3O4@PDA-PEG-cRGD/BU NPs) were developed. The thermal variations in Fe3O4@PDA-PEG-cRGD/BU NPs solution under different conditions were measured. Glycolysis inhibition was evaluated by measuring the glucose uptake, extracellular lactate, and intracellular adenosine triphosphate (ATP) levels. The cellular cytotoxicity of Fe3O4@PDA-PEG-cRGD/BU NPs was analyzed using a cell counting kit-8 assay, Calcein-AM/PI double staining, and flow cytometry in HCT116 cells. The magnetic resonance imaging (MRI) performance and anti-tumor therapeutic efficacy of Fe3O4@PDA-PEG-cRGD/BU NPs were evaluated in HCT116-tumor bearing mice.Fe3O4@PDA-PEG-cRGD/BU NPs had an average diameter of 260.4±3.5 nm, the zeta potential of -23.8±1.6 mV, the drug loading rate of 1.1%, which had good thermal stability, photothermal conversion efficiencies and MRI performance. In addition, the released BU not only killed tumor cells but also interfered with glycolysis by targeting the steroid receptor coactivator 3 (SRC-3)/HIF-1α pathway, preventing intracellular ATP synthesis, and combating HSP-dependent tumor thermoresistance, ultimately strengthening the thermal sensitivity toward mild PTT both in vitro and in vivo.This study provides a highly effective strategy for enhancing the therapeutic effects of mild PTT toward tumors.© 2024 Shang et al.