Celecoxib and radioresistant glioblastoma-derived CD133+ cells: improvement in radiotherapeutic effects Laboratory investigation
Celecoxib and radioresistant glioblastoma-derived CD133+ cells: improvement in radiotherapeutic effects Laboratory investigation
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DOI：
10.3171/2009.11.jns091396
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发表时间：
2011-03-01
影响因子：
4.1
通讯作者：
Sytwu, Huey-Kang
中科院分区：
文献类型：
--
作者：
Ma, Hsin-I;Chiou, Shih-Hwa;Sytwu, Huey-Kang
物体。胶质母细胞瘤是最常见的脑部原发肿瘤，即使接受积极的切除和放化疗，预后也很差。最近的研究表明，CD133(+)细胞在胶质母细胞瘤的耐药性和复发中起关键作用。环氧合酶-2(COX-2)可将花生四烯酸转化为前列腺素，在包括CD133(+)胶质母细胞瘤在内的多种肿瘤中均有过度表达。COX-2衍生的前列腺素在肿瘤发展过程中促进新生血管的形成，而传统的放射治疗增加了CD133(+)细胞的比例，而不是消除它们。本研究的目的是探讨选择性COX-2抑制剂塞来昔布对CD133(+)胶质母细胞瘤放射治疗效果的影响。从胶质母细胞瘤标本中分离CD133阳性细胞，用流式细胞仪进行鉴定，然后用塞来昔布和/或电离辐射(IR)处理。采用克隆形成实验、细胞辐射、细胞周期分析、Western印迹和异种移植等方法，观察塞来昔布对CD133(+)和CD133(-)胶质母细胞瘤细胞的作用。用310只严重联合免疫缺陷(SCID)小鼠进行了三种不同的异种移植实验：1)最初的致瘤性评估，将来自7种不同肿瘤的3种不同数量的未经处理的CD133(-)细胞或未经处理或预处理的CD133(+)细胞(5种治疗条件)注射到2只小鼠(总共210只)的纹状体内；2)肿瘤生长研究(50只小鼠)；以及3)生存研究(50只小鼠)。在后两项研究中，使用了与成瘤性相同的5类细胞(未经处理的CD133(-)细胞、未经处理或经预处理的CD133(+)细胞，预处理包括单独的塞来昔布、单独的IR或IR和塞来昔布)，但只使用了一个细胞来源(例2)和数量(5×104个细胞)。在CD133(+)的胶质母细胞瘤细胞中检测到高水平的COX-2蛋白，而在CD133(-)的胶质母细胞瘤细胞中未检测到COX-2蛋白。作者进一步证明，30mU的塞来昔布能有效地增强在塞来昔布处理的CD133(+)胶质母细胞瘤细胞中抑制集落形成和增加IR介导的凋亡的IR效应。此外，辐射抗性的降低与G2/M期停滞的诱导有关，这部分是通过磷酸化cdc2水平的增加来调节的。体内异种移植分析进一步证实，塞来昔布治疗显著抑制了CD133(+)相关的致瘤性。重要的是，CD133(+)胶质母细胞瘤细胞在注射到SCID小鼠纹状体内之前，用塞来昔布和IR联合处理后，肿瘤生长显著减少，小鼠的平均存活率显著提高。塞来昔布联合放射治疗在抑制CD133(+)胶质母细胞瘤干细胞样细胞生长中起关键作用。因此，塞来昔布是一种可用于治疗胶质母细胞瘤的放射增敏药物。(DOI：10.3171/2009.11.JNS091396)
Object. Glioblastoma, the most common primary brain tumor, has a poor prognosis, even with aggressive resection and chemoradiotherapy. Recent studies indicate that CD133(+) cells play a key role in raclioresistance and recurrence of glioblastoma. Cyclooxygenase-2 (COX-2), which converts arachidonic acid to prostaglandins, is over-expressed in a variety of tumors, including CD133(+) glioblastomas. The COX-2 derived prostaglandins promote neovascularization during tumor development, and conventional radiotherapy increases the proportion of CD133(+) cells rather than eradicating them. The aim of the present study was to investigate the role of celecoxib, a selective COX-2 inhibitor, in enhancing the therapeutic effects of radiation on CD133(+) glioblastomas.Methods. Cells positive for CD133 were isolated from glioblastoma specimens and characterized by flow cytometry, then treated with celecoxib and/or ionizing radiation (IR). Clonogenic assay, cell irradiation, cell cycle analysis, Western blot, and xenotransplantation were used to assess the effects of celecoxib alone, IR alone, and IR with celecoxib on CD133(+) and CD133(-) glioblastoma cells. Three separate xenotransplantation experiments were carried out using 310 severe combined immunodeficient (SCID) mice: 1) an initial tumorigenicity evaluation in which 3 different quantities of untreated CD133(-) cells or untreated or pretreated CD133(+) cells (5 treatment conditions) from 7 different tumors were injected into the striatum of 2 mice (210 mice total); 2) a tumor growth study (50 mice); and 3) a survival study (50 mice). For these last 2 studies the same 5 categories of cells were used as in the tumorigenicity (untreated CD133(-) cells, untreated or pretreated CD133(+) cells, with pretreatment consisting of celecoxib alone, IR alone, or IR and celecoxib), but only 1 cell source (Case 2) and quantity (5 x 104 cells) were used.Results. High levels of COX-2 protein were detected in the CD133(+) but not the CD133(-) glioblastoma cells. The authors further demonstrated that 30 mu M celecoxib was able to effectively enhance the IR effect in inhibiting colony formation and increasing IR-mediated apoptosis in celecoxib-treated CD133(+) glioblastoma cells. Furthermore, reduction in radioresistance was correlated with the induction of G2/M arrest, which was partially mediated through the increase in the level of phosphorylated-cdc2. In vivo xenotransplant analysis further confirmed that CD133(+)-associated tumorigenicity was significantly suppressed by celecoxib treatment. Importantly, pretreatment of CD133(+) glioblastoma cells with a combination of celecoxib and IR before injection into the striatum of SCID mice resulted in a statistically significant reduction in tumor growth and a statistically significant increase in the mean survival rate of the mice.Conclusions. Celecoxib combined with radiation plays a critical role in the suppression of growth of CD133(+) glioblastoma stemlike cells. Celecoxib is therefore a radiosensitizing drug for clinical application in glioblastoma. (DOI:10.3171/2009.11.JNS091396)