Liu J, Chi N, Zhang J Y, Zhu W, Bian Y S, Chen H G
Department of Neurosurgery, Yantai Yuhuangding Hospital, Yantai, China.
Department of Neurosurgery, Yantai Yuhuangding Hospital, Yantai, China
Genet Mol Res. 2015 Apr 13;14(2):3355-61. doi: 10.4238/2015.April.13.15.
Brain cancer stem cells are a subset of tumor cells present in several types of brain tumor that evade treatment regimens and are responsible for tumor recurrence. Recent reports on several tumors have suggested that Hoechst 33342 dye exclusion is a powerful technique for isolating cancer stem cell-like side population (SP) cells. In the present study, we attempted to isolate the SP cells from medulloblastoma, a malignant brain tumor in children. The tumor samples obtained were subjected to fluorescence-activated cell sorting analysis for SP cell isolation. Further, the SP cells were characterized by a sphere-formation assay and analyzed for expression of stem cell genes by reverse transcription-polymerase chain reaction (RT-PCR). Using flow cytometry, we isolated 2.9% of cancer stem-like SP cells from malignant medulloblastoma, which was reduced to 0.4% in the presence of verapamil, an inhibitor of ABC transporter. These SP cells undergo rapid proliferation and have a high tendency to form tumor spheres when compared with non-SP cells. Further, RT-PCR analysis revealed that the isolated SP cells have increased expression of neural stem cell markers such as nestin, Notch1, and the ABC transporter protein ABCG2. Therefore, our findings suggest that SP cells of medulloblastoma share the characteristics of cancer stem cells. The increased expression of stem cell markers and ABCG2 protein may function collectively and be responsible for drug and apoptosis resistance, as well as tumor recurrence and invasion.
脑癌干细胞是存在于多种脑肿瘤中的一类肿瘤细胞，它们能逃避治疗方案并导致肿瘤复发。最近关于几种肿瘤的报道表明，Hoechst 33342染料排斥法是分离癌症干细胞样侧群（SP）细胞的有效技术。在本研究中，我们试图从髓母细胞瘤（一种儿童恶性脑肿瘤）中分离SP细胞。对获取的肿瘤样本进行荧光激活细胞分选分析以分离SP细胞。此外，通过成球试验对SP细胞进行鉴定，并通过逆转录-聚合酶链反应（RT-PCR）分析干细胞基因的表达。利用流式细胞术，我们从恶性髓母细胞瘤中分离出2.9%的癌症干细胞样SP细胞，在存在ABC转运蛋白抑制剂维拉帕米的情况下，这一比例降至0.4%。与非SP细胞相比，这些SP细胞增殖迅速，且具有较高的形成肿瘤球的倾向。此外，RT-PCR分析显示，分离出的SP细胞中神经干细胞标志物如巢蛋白、Notch1和ABC转运蛋白ABCG2的表达增加。因此，我们的研究结果表明，髓母细胞瘤的SP细胞具有癌症干细胞的特征。干细胞标志物和ABCG2蛋白表达的增加可能共同发挥作用，导致耐药性、抗凋亡能力以及肿瘤复发和侵袭。
