Gao Qin, Jiang YiQing, Li XiaoJie, Chen Hui, Tang Shan, Chen Han, Shi XiangXiang, Chen Yue, Fu ShaoZhi, Lin Sheng
Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou, China.
Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Affiliated Hospital of Southwest Medical University, Luzhou, China.
Front Oncol. 2021 Mar 12;11:628895. doi: 10.3389/fonc.2021.628895. eCollection 2021.
Hypoxia is a common feature of solid tumors that increases tumor invasiveness and resistance to radiotherapy (RT) and chemotherapy. Local application of anlotinib (AL) might increase the regulation of new blood vessel growth and improve tumor hypoxia in RT. Therefore, it is essential to fully understand the drug delivery system of AL. Herein, we applied hypoxia imaging using micro fluorine-18-fluoromisonidazole positron emission tomography/computed tomography (micro 18F-FMISO PET/CT) to assess responses to intratumoral injections of an AL hydrogel (AL-HA-Tyr) combined with RT in mice bearing Lewis lung carcinoma (LLC). We formed AL-HA-Tyr by encapsulating AL with hyaluronic acid-tyramine (HA-Tyr) conjugates the oxidative coupling of tyramine moieties catalyzed by HO and horseradish peroxidase. AL-HA-Tyr restrained the proliferation of human umbilical endothelial cells (HUVECs) in colony formation assays (p < 0.001). We established a subcutaneous LLC xenograft model using C57BL/6J mice that were randomly assigned to six groups that were treated with AL, HA-Tyr, AL-HA-Tyr, RT, and RT+AL-HA-Tyr, or untreated (controls). Tumor volume and weight were dynamically measured. Post treatment changes in hypoxia were assessed in some mice using micro 18F-FMISO PET/CT, and survival was assessed in others. We histopathologically examined toxicity in visceral tissues and Ki-67, VEGF-A, -H2AX, and HIF-1 expression using immunohistochemistry. Direct intratumoral injections of AL-HA-Tyr exerted anti-tumor effects and improved hypoxia like orally administered AL (p > 0.05), but reduced visceral toxicity and prolonged survival. The uptake of 18F-FMISO did not significantly differ among the AL, AL-HA-Tyr, and RT+AL-HA-Tyr treated groups. Compared with the other agents, RT+AL-HA-Tyr decreased HIF-1, Ki67, and VEGF-A expression, and increased -H2AX levels in tumor cells. Overall, compared with AL and AL-HA-Tyr, RT+AL-HA-Tyr improved tumor hypoxia, enhanced anti-tumor effects, and prolonged the survival of mice bearing LLC.
缺氧是实体瘤的一个常见特征，它会增加肿瘤的侵袭性以及对放疗（RT）和化疗的抗性。局部应用安罗替尼（AL）可能会增强对新血管生成的调控，并改善放疗中的肿瘤缺氧情况。因此，充分了解AL的给药系统至关重要。在此，我们应用微量氟-18-氟米索硝唑正电子发射断层扫描/计算机断层扫描（微量18F-FMISO PET/CT）进行缺氧成像，以评估在携带Lewis肺癌（LLC）的小鼠中，瘤内注射AL水凝胶（AL-HA-Tyr）联合放疗后的反应。我们通过用透明质酸-酪胺（HA-Tyr）共轭物包裹AL来形成AL-HA-Tyr，酪胺部分的氧化偶联由HO和辣根过氧化物酶催化。在集落形成试验中，AL-HA-Tyr抑制了人脐静脉内皮细胞（HUVECs）的增殖（p < 0.001）。我们使用C57BL/6J小鼠建立了皮下LLC异种移植模型，将其随机分为六组，分别用AL、HA-Tyr、AL-HA-Tyr、放疗以及放疗+AL-HA-Tyr进行治疗，或不进行治疗（作为对照）。动态测量肿瘤体积和重量。在部分小鼠中使用微量18F-FMISO PET/CT评估治疗后缺氧情况的变化，在其他小鼠中评估生存率。我们通过组织病理学检查内脏组织的毒性，并使用免疫组织化学检测Ki-67、VEGF-A、-H2AX和HIF-1的表达。瘤内直接注射AL-HA-Tyr发挥了抗肿瘤作用，并像口服AL一样改善了缺氧情况（p > 0.05），但降低了内脏毒性并延长了生存期。在AL、AL-HA-Tyr和放疗+AL-HA-Tyr治疗组中，18F-FMISO的摄取没有显著差异。与其他药物相比，放疗+AL-HA-Tyr降低了肿瘤细胞中HIF-1、Ki67和VEGF-A的表达，并增加了-H2AX水平。总体而言，与AL和AL-HA-Tyr相比，放疗+AL-HA-Tyr改善了肿瘤缺氧情况，增强了抗肿瘤作用，并延长了携带LLC小鼠的生存期。
