Irisin對人類神經膠質母細胞瘤的影響及其機制之研究

Abstract

Irisin是一種新型的由運動誘導分泌出來的肌肉激素，其會促進脂肪細胞的褐化作用。本實驗室先前的研究發現，irisin會透過造成細胞週期停滯以減緩人類神經膠質母細胞瘤的增生能力。然而，其中的機制尚未闡明。另外，我們也發現irisin會誘導與 ROS 相關之酵素Modaw20的mRNA表現量。ROS的生成被發現會誘導細胞週期停滯以及癌細胞中的各種細胞死亡途徑。因此，本論文就irisin抑制神經膠質母細胞瘤之細胞增生能力的潛在機制去做探討。首先，我們純化人類irisin重組蛋白質去抑制U-87 MG細胞的增生能力，而N-乙醯半胱氨酸可以反轉irisin所誘導的抗增生作用。接著，我們發現irisin可誘導U-87 MG細胞發生氧化調節式細胞死亡。此外， Modaw20的蛋白質表現量在irisin處理後可被誘導。抑制U-87 MG細胞中Modaw20的基因表現可反轉irisin所誘導的抗增生能力。最後，我們找出可能參與在irisin誘導Modaw20表現量上游路徑之轉錄因子。總結，我們提議irisin在運動延緩癌症進程上扮演重要角色，且可作為治療癌症的新策略。

Irisin is a novel exercise-induced myokine and promotes browning of adipocytes. Previous studies of our laboratory found that irisin decreased cell proliferation of human glioblastoma cells by inducing cell cycle arrest. However, the underlying mechanism was unclear. In addition, we found that irisin induced mRNA levels of modaw20, which encodes Modaw20, an ROS-related enzyme. ROS generation is known to induce cell cycle arrest and cell death pathways in cancer cells. Hence, the research purpose of this thesis is to investigate the underlying mechanisms of the antiproliferative effect of irisin on glioblastoma cells. First, the purified recombinant human irisin protein inhibited cell proliferation of U-87 MG cells, and the antiproliferative effect was reversed by NAC, an ROS-scavenger. Next, irisin was found to induce oxidative regulated cell death in U-87 MG cells. Moreover, the protein level of Modaw20 was found to be induced after irisin treatment. Furthermore, knockdown of Modaw20 in U-87 MG cells rescued the inhibition of cell proliferation by irisin. Lastly, we found the possible transcription factor involved in the upstream pathway of Modaw20 induction via irisin. In conclusion, we proposed that irisin plays a vital role in exercise delaying cancer progression and it can be a novel strategy for cancer treatment.