Naito Eriko, Igawa Kazuyo, Takada Sho, Haga Kenta, Yortchan Witsanu, Suebsamarn Orakarn, Kobayashi Ryota, Yamazaki Manabu, Tanuma Jun-Ichi, Hamano Tsuyoshi, Shimokawa Takashi, Tomihara Kei, Izumi Kenji
Division of Biomimetics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-Ku, Niigata, 951-8514, Japan.
Division of Oral and Maxillofacial Surgery, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-Ku, Niigata, 951-8514, Japan.
In Vitro Cell Dev Biol Anim. 2024 Dec;60(10):1184-1199. doi: 10.1007/s11626-024-00958-4. Epub 2024 Aug 7.
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.
鉴于无法重现口腔癌的原始肿瘤微环境，利用单层培养和异位肿瘤动物模型预测放疗效果具有挑战性。碳离子辐射（CIR）具有布拉格峰的独特特性，对肿瘤具有治疗作用，并可预防周围正常组织的不良事件。然而，其潜在机制仍不清楚。在由HSC-3和HSC-4细胞组成的正常口腔黏膜（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。对NOMM、OCM3和OCM4模型给予单次10或20 Gy剂量的CIR。在CIR后检查组织病理学和组织形态计量学分析以及Ki-67、γH2AX和TUNEL的标记指数。测量高迁移率族蛋白B1（HMGB1）的浓度。CIR后NOMM出现上皮变薄，这可能是由于Ki-67标记的基底细胞数量减少所致。CIR后癌症模型中癌细胞厚度与下层基质的相对比例降低。这一发现似乎得到了三个标记指数变化的支持，表明CIR诱导癌细胞死亡，主要通过凋亡。此外，在接受不同剂量和CIR后不同孵育时间的OCM4中，这三个指数和HMGB1释放水平有显著差异，而OCM3模型则没有，表明OCM4对放疗更敏感。这三种3D体外模型可能是阐明放射生物学的一种可行且新颖的工具。
