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hsintzu13 asked in 科學生物學 · 1 decade ago

為何tumour promoter可誘發COX-2?

我們知道COX-2會被一些生長因子 內毒素等刺激而產生

包含了tumour promoter(腫瘤啟動子)

其中的途徑是經過Ras signaling pathway




1 Answer

  • 1 decade ago
    Favorite Answer

    tumour promoter(腫瘤啟動子) 這位同學你誤會了吧

    這裏講的Tumor promoter不是指promoter sequence 啦

    Tumor 要形成必須靠 initiator及promoter兩個階段! 你講的tumor promoter 應該是會誘發癌細胞生長的因子同時也會誘發出COX-2的表現吧

    如果問題是這樣的話:答案是Tumor promoter 有Transactive COX-2 promoter的功能

    We also find that loss of Rb leads to deregulated E2F activity, with increased expression of E2F target genes, and that exogenous expression of E2F1 results in elevated COX-2 mRNA and protein levels. COX-2 promoter studies reveal that E2F1 transcriptionally activates COX-2, which is dependent on the transactivation and DNA-binding domains of E2F1. Further analysis revealed that the E2F1 target gene, c-myb, is elevated in Rb–/–PrE cells and E2F1-overexpressing cells, whereas ectopic overexpression of c-myb activates the COX-2 promoter in prostate epithelial cells. Additionally, cotransfection with E2F1 and a dominant-negative c-myb inhibited E2F1 activation of the COX-2 promoter. Taken together, these results suggest activation of a transcriptional cascade by which E2F1 regulates COX-2 expression through the c-myb oncogene. This study reports a novel finding describing that deregulation of the Rb/E2F complex results in increased COX-2 expression and activity.

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