藉由抑制第一型特異性蛋白及其下游路徑來克服膠質母細 胞瘤對於帝盟多藥物的阻抗性

Overcome temozolomide resistance in glioblastoma by inhibition of specific protein 1 and its’ downstream pathways

羅偉倫(Wei-Lun Lo)

指導教授 ： 莊健盈 ； 陳品元

共同指導教授 ： 葉修華(Shiu-Hwa Yeh)

臺北醫學大學/醫學科技學院/神經再生醫學博士學位學程/博士(2020年)

摘要

多形膠質母細胞瘤（GBM）是成人中最致命的原發性顱內惡性腫瘤。GBM
的主要治療挑戰是腫瘤細胞對化學療法和放射療法的抵抗性。在我們以前的研究中，我們知道特定蛋白1（Sp1）是促進GBM 細胞中產生替莫唑胺（TMZ）抗性的重要轉錄因子。為了研究Sp1 介導的治療耐藥性，我們發現細胞色素P450 17A1（CYP17A1）在TMZ 耐藥細胞和高侵襲性細胞中顯著上調，其增加是由Sp1介導的DNA 去甲基化引起的，其中Sp1 與DNA 甲基轉移酶3a 在這些細胞中的CYP17A1 啟動子有競爭性結合。此外，CYP17A1 能夠通過提高脫氫表雄酮（DHEA）的產生來減輕TMZ 誘導的DNA 損傷和細胞凋亡。此外，我們還使用樺木酸（BA）抑制Sp1，並發現BA 處理通過增加蛋白激酶RNA 樣內質網激酶（PERK)/C/EBP同源蛋白（CHOP）凋亡的激活來促進TMZ 的抗癌作用途徑。但是，Sp1 過表達逆轉了BA 誘導的細胞凋亡和PERK / CHOP 信號活化。總言之，我們發現Sp1 的活化誘導了CYP17A1-DHEA 促存活路徑的和抑制PERK/CHOP 促死亡信號，從而促進產生TMZ 耐藥性，並可能成為複發性GBM 的潛
在治療標的。

關鍵字

glioblastoma multiforme ； temozolomide resistance ； specificity protein 1 ； cytochrome P450 17A1 ； unfolded protein response ； betulinic acid

並列摘要

Glioblastoma multiforme (GBM) is the most fatal primary intracranial malignancy in adults. The major treatment challenge of GBM is the resistance of tumor cells to
chemotherapy and radiation therapy. In our previous studies, we determined that specificity protein 1 (Sp1) is a crucial transcription factor promoting temozolomide
(TMZ) resistance in GBM cells. Investigation of Sp1-mediated therapy resistance revealed that cytochrome P450 17A1 (CYP17A1) was greatly upregulated in TMZresistant
cells and highly invasive cells. This increase was caused by Sp1-mediated DNA demethylation, whereby Sp1 competed with DNA methyltransferase 3a to bind to the CYP17A1 promoter in these cells. In addition, CYP17A1 was able to attenuate TMZ-induced DNA damage and apoptosis by elevating dehydroepiandrosterone (DHEA) production. Furthermore, we also inhibited Sp1 using betulinic acid (BA), which facilitated the anti-cancer effect of TMZ via increased activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C/EBP homologous protein
(CHOP) apoptotic pathway. However, Sp1 overexpression reversed the observed cell apoptosis and the PERK/CHOP signaling activation induced by BA. In summary, we
discovered that the activation of Sp1 induces the CYP17A1–DHEA pro-survival axis and inhibits PERK/CHOP pro-death signaling, which promotes the development of TMZ resistance and may serve as potential therapeutic targets in recurrent GBM.

並列關鍵字

多形性膠質母細胞瘤 ； 替莫唑胺抗性 ； 特異性蛋白1 ； CYP17A1 ； 未折 疊蛋白反應 ； 樺木酸

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