iNOS/NO在 glioma與microglia交互活化所扮演的角色

腦部的巨噬細胞-microglia的活化在調控大腦發炎反應上扮演重要的角色，並被發現與腦癌的發展有關，可以做為腦瘤惡性程度的指標。然而，微膠細胞是如何促進腦瘤的發展目前還是不清楚的。在本研究中我們收取培養過三株神經膠質瘤細胞 (U87、GBM8401、C6) 的培養液來探討微膠細胞BV-2的活化情形，並釐清活化的微膠細胞與神經膠質瘤之間的關係。實驗結果顯示神經膠質瘤細胞的培養液可以有效誘導微膠細胞產生發炎反應，包括大量nitric oxide (NO) 和自由基的產生，以及在蛋白質層級中inducible nitric oxide synthase (iNOS) 的大量表現。在微膠細胞受到神經膠質瘤培養液的刺激前先行處理抗氧化劑 (NAC, Vitamin C) ，則發現自由基會參與產生iNOS/NO的發炎反應。此外，微膠細胞在受到神經膠質瘤培養液的刺激後會引起MAP kinases (ERK, JNK) 的活化，以及iNOS的上游轉錄因子AP-1和NF-κB的活化。同時，利用穿透式細胞移行實驗可以發現當微膠細胞與神經膠質瘤共同培養時，神經膠質瘤移動的情形會增加，而在加入NOS 抑制劑L-Nitroarginine Methyl Ester (L-NAME) 之後，神經膠質瘤移動的情形會被抑制；另外，在實驗中也發現神經膠質瘤可能透過釋放細胞激素Tumor necrosis factor- α (TNF-α 和 monocyte chemotactic protein -1 (MCP-1) 到培養液中而造成微膠細胞的活化。因此，本研究結果發現神經膠質瘤細胞可能透過釋放TNF-α 和 MCP-1刺激微膠細胞產生大量ROS並活化下游 ERKs, JNKs 的訊息傳遞路徑而導致iNOS/NO的產生，進而回饋神經膠質瘤細胞並促進其侵犯能力。

關鍵字

發炎；微膠細胞

並列摘要

Activation and infiltration of microglia cells have been described as malignant markers of brain tumors. However, how microglia contributes to glioma malignancy is still unclear. Here, conditioned medium (CM) derived from three glioma cell lines including U87, GBM, and C6 were applied to examine their effects on the activation of microglia cells BV-2. It indicated that CM from indicated glioma cells significantly induced iNOS/NO production in BV-2 cells in according with increased intracellular reactive oxygen species (ROS) production. Antioxidants NAC and Vit C addition effectively reduced iNOS/NO production elicited by glioma-CM. Co-culture of glioma cells with BV-2 using in vitro transwell system showed BV-2 at the lower chamber stimulated the migration/invasion of glioma cells, and the stimulatory effects were abolished by adding NOS inhibitor L-NAME through reducing NO production. Activation of ERK and JNK by glioma-CM was observed in BV-2 cells, and that was inhibited by addition of antioxidants NAC and Vitamin C. And, application of ERK and JNK inhibitors, U0126 and SP600125 significantly attenuates CM-induced iNOS/NO expression in BV-2 cells. Furthermore, Tumor necrosis factor- α (TNF-α and monocyte chemotactic protein -1 (MCP-1), but not Colony-stimulating factor -1 (CSF-1) and transforming growth factor-β (TGF-β) showed inductive effects on iNOS/NO production in BV-2 cells, and neutralization of TNF-α and MCP-1 in CM significantly decreased CM-induced iNOS/NO production in BV-2 cells. These data provide evidence to support the role of iNOS/NO production from glioma-activated microglia in the migration/invasion of glioma cells via a ROS-dependent of ERK and JNK activation.

並列關鍵字

inflammatory ； microglia

參考文獻

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國際替代計量

iNOS/NO在 glioma與microglia交互活化所扮演的角色

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