TRAIL誘發HL60白血病細胞株分化為單核球之訊息傳遞路徑研究

Investigating signaling pathway of TRAIL induced-monocytic differentiation in HL60 leukemic cells

王茂華(Mao-Hua Wang)

指導教授 ： 胡忠怡

國立臺灣大學/醫學院/醫學檢驗暨生物技術學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.10284

摘要

Tumor necrosis factor (TNF) -related apoptosis-inducing ligand (TRAIL) 是新近被發現的腫瘤壞死因子家族的成員，與Fas ligand具有很高的相似度。因為TRAIL可以殺死許多種類的腫瘤細胞，但在細胞培養和實驗動物中不會傷害正常細胞，現在被認為有希望將TRAIL發展成為強有力的癌症治療藥物。在許多正常的組織中TRAIL和TRAIL receptors廣泛的表現，可以推測TRAIL在生理中扮演的角色較引起癌症細胞進行細胞凋亡更加複雜。關於這方面，其他的研究顯示TRAIL參與在血液生成作用中，在正常和疾病引起的情況下TRAIL減少紅血球生成，並在HL60細胞株與正常CD34衍生骨髓性白血球細胞中促進單核球分化成熟。某些研究表示受到維他命D3或phorbol esters刺激的白血病細胞株與正常單核球前驅細胞，在單核球分化時會增強mitogen-activated protein (MAP) kinase活化。並且受MAP kinase調控的轉錄因子像是 CCAAT enhancer binding proteins β (C/EBP β) and activating protein-1 (AP-1) 皆參與在單核球分化中。在本篇論文中，我們利用TRAIL處理HL60人類白血病細胞株來調查發生單核球分化中相關的訊息傳遞路徑。
　　TRAIL處理HL60細胞後會造成迅速的細胞毒性伴隨著存活細胞朝向單核球系成熟。在TRAIL處理的細胞藉由細胞表面CD14表現顯著的增加，並獲得與典型的成熟單核球細胞形態特徵，證實朝向單核球系分化。在細胞內訊息路徑的調查中，TRAIL明顯的刺激 extracellular signal-regulated kinase 1/2 (ERK1/2)及p38磷酸化增加，但對 c-Jun N-terminal kinase (JNK) 路徑沒有影響。利用ERK路徑的藥物抑制劑U0126使得TRAIL在HL60細胞表面引起的CD14表現量降低，一致的證實ERK1/2在調控TRAIL誘發的單核球分化扮演關鍵的角色。此外，在TRAIL處理後p90Rsk的活化增加，在抑制劑U0126作用下TRAIL引起分化的能力被抑制，ERK1/2與p90Rsk的磷酸化也明顯減少。根據結果顯示ERK1/2-p90Rsk路徑在TRAIL誘發的單核球分化中扮演相當重要的角色。未來TRAIL將有機會應用在白血病的引導治療 (induction therapy) 上。

關鍵字

白血病 ； 單核球分化

並列摘要

Tumor necrosis factor (TNF) -related apoptosis-inducing ligand (TRAIL), a recently disclosed TNF family member, shares high digree of similarity with Fas ligand. Currently, TRAIL is under development as a potential cancer therapeutic agent because it kills many types of tumor cells but spares normal cells in cell culture and experiment animals. The wide expression of TRAIL and TRAIL receptors in many normal tissus suggests that physiologic role of TRAIL is more complex than induction of apoptosis in cancer cells. In this respect, other studies shown that TRAIL involves in modulation of hematopoiesis. TRAIL was reported to impair erythropoiesis in normal and pathological conditions, and to promote monocytic maturation in the HL60 leukemic cell line as well as primary CD34-derived myeloid cells. Some studies have described increased mitogen-activated protein (MAP) kinase activity during monocytic differentiation of leukemic cell lines and normal monocytic precursors in response to vitamin D3 or phorbol esters. Moreover, the transcription factors modulated by MAP kinase, such as CCAAT enhancer binding proteins β (C/EBP β) and activating protein-1 (AP-1) complex, involves in monocytic differentiation. In this study, the signaling pathway involved in TRAIL-induced monocytic differentiation in HL60 leukimic cell line was investigated.
　　Treatment of the HL60 cells with TRAIL resulted in rapid cytotoxicity and accompanied with progressive maturation of the surviving cells along the monocytic lineage. The occurrence of monocytic differentiation was demonstrated by a significant increase of CD14 surface expression, and the acquisition of typically morphologic features of mature monocytes in TRAIL-treated culture. Among the intracellular pathways investigated, TRAIL significantly stimulated the extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 but not the c-Jun N-terminal kinase (JNK) pathway. Consistently with a key role of ERK1/2 in mediating the positive effect of TRAIL-induced monocytic differentiation, U0126, a pharmacologic inhibitor of the ERK pathway, decreased the surface expression of CD14 of TRAIL on HL60 cells. Furthermore, activation of p90Rsk was increased by treatment of TRAIL. The potentiation of differentiation by TRAIL was inhibited by inhibitor U0126, and ERK1/2 and p90Rsk phosphorylation was significantly decreased. The results indicate that ERK1/2-p90Rsk pathway has an important role in TRAIL-induced monocytic differentiation. TRAIL should be further evaluated for use in induction therapy of acute myeloid leukimia.

並列關鍵字

TRAIL ； acute myeloid leukemia (AML) ； mitogen-activated protein (MAP) kinase ； monocytic differentiation

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