Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, 53706, USA.
Department of Comparative Biosciences, University of Wisconsin, 2015 Linden Drive, Madison, WI, 53706, USA.
J Neurooncol. 2018 Mar;137(1):23-31. doi: 10.1007/s11060-017-2700-9. Epub 2017 Nov 30.
Gliomas are rich in extracellular nucleotides that modulate glioma cell production of multiple cytokines including interleukin (IL)-6, which strongly contributes to glioma cell proliferation. However, little is known about how nucleotide signaling modulates microglial/macrophage (MG/MP) cytokine production in the context of gliomas, nor how MG/MP purinergic P2 receptor expression changes in the tumor micro-environment. We hypothesized that: (1) expression of key P2Y receptors will be augmented in glioma-derived MG/MP, and (2) selective activation of these receptors in vitro will regulate microglial production of IL-6 and glioma cell proliferation. We tested these hypotheses using the murine GL261 glioma model. Compared to MG/MP isolated from the normal brain tissue, CD11b cells isolated from GL261 tumors expressed higher levels of several P2 receptors, including P2Y14 receptors. To evaluate microglial P2Y14 receptor function in the context of tumor cells, we first cultured N9 microglia in transwells with GL261 cells and found that microglial P2Y14 mRNA levels were similarly increased in transwell cultures. GL261 cells did not express detectable P2Y14 levels either when they were cultured alone or in transwell cultures with N9 cells. Selective P2Y14 receptor activation with UDP-glucose (UDPG) did not affect IL-6 levels in either cell type cultured alone, but in transwell cultures, UDPG decreased IL-6 protein levels in the medium. Application of conditioned medium from UDPG-treated microglia reduced GL261 cell proliferation. Together, these data suggest that P2Y14 receptors may be a key a receptor involved in glioma cell-MG/MP communication in the tumor environment.
神经胶质瘤富含细胞外核苷酸，可调节神经胶质瘤细胞产生多种细胞因子，包括白细胞介素 (IL)-6，这强烈促进神经胶质瘤细胞增殖。然而，关于核苷酸信号如何调节微胶质细胞/巨噬细胞 (MG/MP) 在神经胶质瘤中的细胞因子产生，以及 MG/MP 嘌呤能 P2 受体在肿瘤微环境中的表达如何变化，知之甚少。我们假设：(1) 神经胶质瘤衍生的 MG/MP 中关键 P2Y 受体的表达将增强，(2) 体外选择性激活这些受体将调节小胶质细胞产生 IL-6 和神经胶质瘤细胞增殖。我们使用小鼠 GL261 神经胶质瘤模型测试了这些假设。与从正常脑组织中分离的 MG/MP 相比，从 GL261 肿瘤中分离的 CD11b 细胞表达更高水平的几种 P2 受体，包括 P2Y14 受体。为了评估微胶质细胞 P2Y14 受体在肿瘤细胞背景下的功能，我们首先在与 GL261 细胞的 Transwell 中培养 N9 小胶质细胞，发现微胶质细胞 P2Y14 mRNA 水平在 Transwell 培养中也增加。GL261 细胞在单独培养或与 N9 细胞的 Transwell 培养中均未表达可检测到的 P2Y14 水平。用 UDP-葡萄糖 (UDPG) 选择性激活 P2Y14 受体不会影响单独培养的两种细胞类型的 IL-6 水平，但在 Transwell 培养中，UDPG 降低了培养基中 IL-6 蛋白水平。用 UDPG 处理的小胶质细胞的条件培养基的应用降低了 GL261 细胞的增殖。总之，这些数据表明 P2Y14 受体可能是肿瘤微环境中神经胶质瘤细胞-MG/MP 通讯的关键受体之一。
