Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany.
Strahlenther Onkol. 2010 Nov;186(11):587-99. doi: 10.1007/s00066-010-2154-x. Epub 2010 Nov 8.
The malignancy of tumor cells can be attenuated by interfering with cell death pathways. Since hyperthermia (HT) is a very potent radiosensitizer, the influence of HT (41.5 °C for 1 hour) alone and in combination with ionising irradiation (X-ray; 5 Gy or 10 Gy) on the form of cell death as well as on the expression of proteins known to be major components in tumor cells' apoptotic and necrotic pathways were examined in colorectal tumor cells.
The expression of proteins was analysed by western blot and the relative activity of caspases-3/7 by fluorescence- based assay. Colony formation was analysed using the clonogenic assay and cell death was determined with annexin V-FITC/propidium iodide staining.
Combining X-ray with HT led to similar activation of caspase-3/7 and p53 expression in comparison to irradiation only while the amount of the pro-apoptotic proteins PUMA and Bax was increased in HCT15 and SW480 cells. HT alone or combinations with X-ray further resulted in a temporarily increased level of the anti-apoptotic protein Bcl-2. Irradiation plus HT further led to an up-regulation of IRF-5. The levels of RIP-1, a marker for programmed necrosis, increased in tumor cells which were treated with HT and/or X-ray. Combining 5 Gy irradiation with HT compared to irradiation resulted in a significantly increased number of necrotic tumor cells and in decreased colony formation.
The combined treatment of colorectal tumor cells with X-ray and HT activates distinct tumor cell pathways and fosters the early appearance of a necrotic tumor cell phenotype.
通过干扰细胞死亡途径，可以减弱肿瘤细胞的恶性程度。由于热疗（HT）是一种非常有效的放射增敏剂，因此研究了 HT（41.5°C 加热 1 小时）单独作用以及与电离辐射（X 射线；5Gy 或 10Gy）联合作用对细胞死亡方式以及对肿瘤细胞凋亡和坏死途径中主要蛋白表达的影响。
通过 Western blot 分析蛋白表达，通过荧光法测定相对 caspase-3/7 活性。通过集落形成分析测定克隆形成，通过 Annexin V-FITC/碘化丙啶染色测定细胞死亡。
与单独照射相比，X 射线与 HT 联合使用可导致 caspase-3/7 和 p53 表达的相似激活，而在 HCT15 和 SW480 细胞中促凋亡蛋白 PUMA 和 Bax 的量增加。HT 单独或与 X 射线联合使用还导致抗凋亡蛋白 Bcl-2 的水平暂时增加。照射加 HT 还导致 IRF-5 的上调。在接受 HT 和/或 X 射线治疗的肿瘤细胞中，程序性坏死的标志物 RIP-1 的水平增加。与照射相比，将 5Gy 照射与 HT 联合使用可导致更多的肿瘤细胞坏死，并减少集落形成。
X 射线和 HT 联合治疗结直肠肿瘤细胞可激活不同的肿瘤细胞途径，并促进早期出现坏死的肿瘤细胞表型。
