| 摘要: | 人類膠質瘤(Glioma)為中樞神經系統(CNS)最常見的惡性腦瘤並好發於成人中。人類膠質瘤之所以不易用外科手術根除，主因在於腫瘤細胞具有高度的移動性，使腫瘤細胞易轉移及侵襲週邊組織而造成治療上的限制。內皮素(ET-1)，為內皮素胜??(Endothelia)家族的成員，廣泛分佈於人體中。目前已知，內皮素參與調控多種癌症的發展過程，像是前列腺癌、卵巢癌、大腸癌、乳腺癌和腦癌…等癌症。除此之外，內皮素也被證實參與在調節細胞有絲分裂，細胞存活和細胞侵襲的過程中。先前的研究報導指出，內皮素在人類腦部微血管內皮細胞移行中，具有誘導的作用。但是，內皮素誘導人類膠質瘤細胞移行的相關機轉目前了解並不多，故找到內皮素誘導人類膠質瘤細胞移行的相關路徑，對腦瘤的治療發展上有很大的益處。在本研究中，我們使用人類膠質瘤細胞(U251)，觀察內皮素誘導人類膠質瘤細胞遷移的情形。實驗結果發現，細胞在經由內皮素的刺激之下，細胞的移行能力確實有增高的現象。此外，細胞受內皮素的刺激後，基質金屬蛋白??(MMPs)的蛋白質表現量與分泌量皆有增加的情形。接著，運用藥理方式事先給予細胞基質金屬蛋白?“簏s劑(GM6001)和中和性抗體後發現，內皮素所誘導的人類膠質瘤細胞移行能力及基質金屬蛋白??(MMPs)的表現均有被抑制的情況。然後，更進一步去探討有絲分裂原活化蛋白激??(mitogen-activated protein kinase, MAP kinase)和激活蛋白轉錄因子(activator protein, AP-1)是否參與內皮素誘導人類膠質瘤的細胞移行中。在我們的結果中發現，在給予內皮素的刺激後，MAP kinase會經由p38和JNK/c-Jun路徑進入細胞核內；AP-1與DNA結合之活性也有同樣的情況。這些結果表明，內皮素誘導人類膠質瘤細胞遷移能力可能是經由p38和JNK/c-Jun信號路徑的激活，活化細胞核內因子AP-1，並促進基質金屬蛋白??(MMPs)的基因活化、表現量增加，進而導致人類膠質瘤細胞移行。這些結果顯示了內皮素誘導人類膠質瘤細胞移行的分子機制，也提供人類在治療腦瘤的發展上有更深一層的了解。
Gliomas are the most common malignant brain tumors in central nervous system (CNS). It usually occurs in adults and seldom in children. Gliomas have highly mobility characteristical, they are easily migrating and invade into surrounding tissue, making complete surgical resection not successful. Endothelin-1 (ET-1), a member of endothelia peptide family and widely distributed in the body. Endothelin-1 participates in the growth and progression of a variety of tumor cells such as prostatic carcinoma, ovarian, colorectal, breast, and brain tumors. It can be in the process of regulated cell in mitogenesis, survival and invasiveness. Previous study has reported that ET-1 is a potent inducer of migration in human brain-derived microvascular endothelial cells. However, the mechanism of ET-1-induced glioma cell migration was poorly understood. In this study, we used the human U251 glioma cells observation the ET-1-induced glioma cell migration. We found that application of recombinant human ET-1 certainty enhances the glioma cells migration ability in a concentration-dependent manner. Furthermore, we also discovered the expression of matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-13 (MMP-13) protein, and secretion increase by the ET-1 stimulation. Treatment with general MMP inhibitor (GM6001), MMP-9 or MMP-13 neutralized-antibody reduced ET-1-induced glioma cell migration. We also found that MAPK and AP-1 pathways were activationed after treatment with ET-1. ET-1-induced MMP-9, MMP-13 and cell migration were attenuated by p38 and JNK inhibitors. Furthemore, treatment with p38 and JNK inhibitors also effectively reduced ET-1-induced AP-1 DNA binding activity situation. These results indicate that ET-1-induced glioma cell migration ability may activate p38 and JNK pathways, resulting in the MMP-9 and MMP-13 expression, then leads glioma cell migration. These findings reveal that molecular mechanisms promoting endothelin-1 enhances glioma cell migration, may lead to a better understanding of malignant progression of human gliomas. |
