Abstract：
Given that the original tumor microenvironment of oral cancer cannot be reproduced, predicting the therapeutic effects of irradiation using monolayer cultures and animal models of ectopic tumors is challenging. Unique properties of carbon-ion irradiation (CIR) characterized by the Bragg peak exert therapeutic effects on tumors and prevent adverse events in surrounding normal tissues. However, the underlying mechanism remains unclear. The biological effects of CIR were evaluated on three-dimensional (3D) in vitro models of normal oral mucosa (NOMM) and oral cancer (OCM3 and OCM4) consisting of HSC-3 and HSC-4 cells. A single 10- or 20-Gy dose of CIR was delivered to NOMM, OCM3, and OCM4 models. Histopathological and histomorphometric analyses and labeling indices for Ki-67, γH2AX, and TUNEL were examined after CIR. The concentrations of high mobility group box 1 (HMGB1) were measured. NOMM exhibited epithelial thinning after CIR, which could be caused by the decreased presence of Ki-67-labeled basal cells. The relative proportion of the thickness of cancer cells to the underlying stroma in cancer models decreased after CIR. This finding appeared to be supported by changes in the three labeling indices, indicating CIR-induced cancer cell death, mostly via apoptosis. Furthermore, the three indices and the HMGB1 release levels significantly differed among the OCM4 that received different doses and with different incubation times after CIR while those of the OCM3 models did not, suggesting more radiosensitivity in the OCM4. The three 3D in vitro models can be a feasible and novel tool to elucidate radiation biology.
摘要：
鉴于口腔癌的原始肿瘤微环境无法再现，使用单层培养物和异位肿瘤的动物模型预测照射的治疗效果是具有挑战性的。以布拉格峰为特征的碳离子辐照（CIR）的独特特性对肿瘤发挥治疗作用，并防止周围正常组织的不良事件。然而,潜在机制尚不清楚.在由HSC-3和HSC-4细胞组成的正常口腔粘膜（NOMM）和口腔癌（OCM3和OCM4）的三维（3D）体外模型上评估了CIR的生物学效应。向NOMM输送单次10或20Gy剂量的CIR，OCM3和OCM4型号。Ki-67、γH2AX、和TUNEL在CIR后进行了检查测量高迁移率基团盒1(HMGB1)的浓度。NOMM在CIR后表现出上皮变薄，这可能是由于Ki-67标记的基底细胞的存在减少所致。CI后，癌症模型中癌细胞厚度与潜在基质的相对比例降低。这一发现似乎得到了三个标签指数变化的支持，表明CIR诱导的癌细胞死亡，主要通过凋亡。此外，在CIR后接受不同剂量和不同孵育时间的OCM4之间，这三个指标和HMGB1释放水平显着不同，而OCM3模型则没有，表明OCM4的放射敏感性更高。三个3D体外模型可以是阐明辐射生物学的可行且新颖的工具。
