Department of Experimental Biology - Laboratory of Tumor Biology, School of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic.
Department of Experimental Biology - Laboratory of Tumor Biology, School of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic ; Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic.
Cancer Cell Int. 2014 Jun 13;14:51. doi: 10.1186/1475-2867-14-51. eCollection 2014.
A detailed analysis of the expression of 440 cancer-related genes was performed after the combined treatment of medulloblastoma cells with all-trans retinoic acid (ATRA) and inhibitors of lipoxygenases (LOX) and cyclooxygenases (COX). The combinations of retinoids and celecoxib as a COX-2 inhibitor were reported to be effective in some regimens of metronomic therapy of relapsed solid tumors with poor prognosis. Our previous findings on neuroblastoma cells using expression profiling showed that LOX/COX inhibitors have the capability of enhancing the differentiating action of ATRA. Presented study focused on the continuation of our previous work to confirm the possibility of enhancing ATRA-induced cell differentiation in these cell lines via the application of LOX/COX inhibitors. This study provides more detailed information concerning the mechanisms of the enhancement of the ATRA-induced differentiation of medulloblastoma cells.
The Daoy and D283 Med medulloblastoma cell lines were chosen for this study. Caffeic acid (an inhibitor of 5-LOX) and celecoxib (an inhibitor on COX-2) were used in combined treatment with ATRA. The expression profiling was performed using Human Cancer Oligo GEArray membranes, and the most promising results were verified using RT-PCR.
The expression profiling of the selected cancer-related genes clearly confirmed that the differentiating effects of ATRA should be enhanced via its combined administration with caffeic acid or celecoxib. This effect was detected in both cell lines. An increased expression of the genes that encoded the proteins participating in induced differentiation and cytoskeleton remodeling was detected in both cell lines in a concentration-dependent manner. This effect was also observed for the CDKN1A gene encoding the p21 protein, which is an important regulator of the cell cycle, and for the genes encoding proteins that are associated with proteasome activity. Furthermore, our results showed that D283 Med cells are significantly more sensitive to treatment with ATRA alone than Daoy cells.
The obtained results on medulloblastoma cell lines are in accordance with our previous findings on neuroblastoma cells and confirm our hypothesis concerning the common mechanism of the enhancement of ATRA-induced cell differentiation in various types of pediatric solid tumors.
对全反式维甲酸（ATRA）和脂氧合酶（LOX）和环氧化酶（COX）抑制剂联合处理髓母细胞瘤细胞后，对 440 种癌症相关基因的表达进行了详细分析。报道称，视黄酸和塞来昔布作为 COX-2 抑制剂的组合在一些预后不良的复发性实体瘤的常规治疗方案中是有效的。我们之前使用表达谱对神经母细胞瘤细胞的研究结果表明，LOX/COX 抑制剂具有增强 ATRA 分化作用的能力。本研究旨在继续我们之前的工作，通过应用 LOX/COX 抑制剂来证实这些细胞系中增强 ATRA 诱导的细胞分化的可能性。本研究提供了有关增强髓母细胞瘤细胞 ATRA 诱导分化的机制的更详细信息。
选择 Daoy 和 D283 Med 髓母细胞瘤细胞系进行本研究。咖啡酸（5-LOX 抑制剂）和塞来昔布（COX-2 抑制剂）用于与 ATRA 联合治疗。使用人类癌症寡核苷酸 GEArray 膜进行表达谱分析，并使用 RT-PCR 验证最有前途的结果。
所选癌症相关基因的表达谱分析清楚地证实，通过与咖啡酸或塞来昔布联合给药，ATRA 的分化作用应得到增强。在两种细胞系中均检测到这种作用。在两种细胞系中，以浓度依赖的方式检测到参与诱导分化和细胞骨架重塑的蛋白质编码基因的表达增加。这种作用也观察到了编码 p21 蛋白的 CDKN1A 基因，p21 蛋白是细胞周期的重要调节剂，以及与蛋白酶体活性相关的蛋白质编码基因。此外，我们的结果表明，D283 Med 细胞对 ATRA 单独处理的敏感性明显高于 Daoy 细胞。
在髓母细胞瘤细胞系上获得的结果与我们之前对神经母细胞瘤细胞的研究结果一致，并证实了我们关于在各种儿科实体肿瘤中增强 ATRA 诱导的细胞分化的共同机制的假设。
