Oncological study for brain tumors by using Proton radiosurgery and enhanced drugs to oxidative stress

立体定向放射外科已被证明是外科手术和外束放疗治疗恶性脑肿瘤的有效辅助手段。质子束具有特征性的布拉格峰和急剧的衰减效应，因此质子放射外科作为恶性脑肿瘤的治疗手段是一种非常有用的方式。辐射通过在肿瘤细胞中产生氧化应激而具有细胞毒性作用。一些化疗药物也有同样的效果。另一方面，在体内存在通过氧化作用对细胞毒性进行细胞保护的清除机制。清除剂与细胞内氧化剂之间的相互作用对细胞毒性作用非常重要。本研究的目的是发展抗癌药物或根治增强药物与质子放射手术的联合治疗。(1)我们采用CT引导立体定向手术，参照Komai头固定架制作了一种简易的头固定仪，该仪器的靶差为2mm宽。(2)我们成功地可视化了辐射和CDDP在胶质母细胞瘤细胞中产生的氧化自由基。辐射和CDDP刺激细胞的存活率与刺激后早期荧光细胞与DCFHDA和活性氧反应的比例有特殊的相关性。从荧光出现到刺激后细胞死亡有一定的时间差。这些氧化应激极有可能与细胞死亡呈剂量依赖关系，并且由于细胞酶和含有DNA链损伤的代谢的催化作用，这些氧化应激诱导细胞死亡需要一定的时间。(3)正常和/或肿瘤细胞氧化应激的清除药物和/或增强药物对细胞毒性的保护并不总是表现出剂量依赖性。(4)在人脑肿瘤中，高SOD（清除率）活性的肿瘤细胞倾向于放疗和抗癌药物。但同一实验组刺激后的荧光细胞存在差异，且荧光细胞较少，死亡细胞较多。这些可能建议进一步研究DCFHDA负载细胞的数量和/或DCFHDA捕获方法。评估肿瘤细胞中的清道夫活性应该有助于选择氧化细胞毒性治疗方法，如质子放射手术和伽玛刀治疗脑肿瘤。人类脑肿瘤中免疫组织化学反应性清除物质变化的机制仍有待进一步研究。少

Stereotactic radiosurgery has proven to be a useful adjunct to surgery and external beam radiotherapy in the treatment of malignant brain tumors. Proton beams have both characteristic Bragg peak and sharp fall-off effect, therefore proton radiosurgery is a very useful modality as a therapeutic tool or malignant brain tumors. Radiation have a cytotoxic effect by oxidative stress producing in the tumor-cells by irradiation.Some chemotherapeutic drugs also have same effect.On the other hand, there is scavenge mechanism as a cell-protection for cytotoxity by the oxidative effect in vivo. Interaction between scavengers and oxidants in the cell were very important for cytotoxic effect.The aim of this study is to develop the combination therapy of anticancer drugs or radical enhancement drugs and proton radiosurgery.(1) We made a simple head-fixing instrument referring to the Komai's head-fixing frame using the CT guided stereotaxy surgery Target-error by this instrument is a 2mm width in the … More simulated proton dosimetry.(2) We could successfully visualize the oxidizing free radicals produced by radiation and CDDP in the glioblastoma cells. The surviving fraction of the cells stimulated by radiation and CDDP was specifically correlated to the ratio of the fluorescent cells reacted with DCFHDA and active oxygen in the early period after stimulation. There was a time lag from the appearance of fluorescence to cell death after stimulation. In all probability, those oxidative stresses relate dose-dependently to the cell death and those will take time to induce the cell death by the catalytic effect of the cellular enzymes and metabolisms containing DNA strand damage.(3) The scavenger-drugs and/or enhanced drugs for the oxidative stress in the normal and/or tumor cells did not always show dose-dependently the protection to the cytotoxity.(4) In human brain tumors, the tumor cells with high SOD (scavenger) activity tended to radiotherapy and anticancer drugs.However, the presence of the fluorescent cells after stimulation was different in a same experimented group and furthermore there were few fluorescent cells in comparison with the number of the dead cells. These may suggest to further investigate the number of the DCFHDA-loaded cells and/or the DCFHDA trapping method.Evaluation of scavenger activity among tumor cells should be helpful in choosing oxidative cytotoxic treatments like proton radiosurgery and gamma knife in brain tumors.The mechanism responsible for variation in immunohistochemically reactive scavenger materials in human brain tumors remains a matter for further study. Less