Table S4 from Disruption of TFIIH activities generates a stress gene expression response and reveals possible new targets against cancer

Disruption of the enzymatic activities of the transcription factor TFIIH by the small molecules Triptolide (TPL) or THZ1 could be used against cancer. Here, we used the MCF10A-ErSrc oncogenesis model to compare the effect of TFIIH inhibitors between transformed cells and their progenitors. We report that tumour cells exhibited highly increased sensitivity to TPL or THZ1 and that the combination of both had a synergic effect. TPL affects the interaction between XPB and p52, causing a reduction in the levels of XPB, p52 and p8, but not other TFIIH subunits. RNA-Seq and RNAPII-ChIP-Seq experiments showed that although the levels of many transcripts were reduced, the levels of a significant number were increased after TPL treatment, with maintained or increased RNAPII promoter occupancy. A significant number of these genes encode for factors that have been related to tumour growth and metastasis, suggesting that transformed cells might rapidly develop resistance to TPL/THZ inhibitors. Some of these genes were also overexpressed in response to THZ1, which depletion enhances the toxicity of TPL and are possible new targets against cancer.

小分子化合物雷公藤内酯（Triptolide, TPL）或THZ1可通过破坏转录因子TFIIH的酶活性发挥抗癌作用。本研究采用MCF10A-ErSrc致癌模型，对比TFIIH抑制剂在转化细胞与其祖细胞间的作用差异。研究发现，肿瘤细胞对TPL或THZ1的敏感性显著升高，且二者联合使用具有协同抗癌效应。TPL可干扰XPB与p52的相互作用，导致XPB、p52及p8的蛋白水平下调，但不影响其他TFIIH亚基的表达。RNA测序（RNA-Seq）与RNA聚合酶II染色质免疫沉淀测序（RNAPII-ChIP-Seq）实验结果显示，经TPL处理后，尽管多数转录本的丰度出现下调，但仍有大量转录本的丰度显著升高，且RNA聚合酶II在启动子区域的结合占有率保持稳定或有所提升。其中大量基因编码与肿瘤生长及转移相关的调控因子，这提示转化细胞可能快速对TPL/THZ抑制剂产生耐药性。部分此类基因在THZ1处理后同样出现过表达，敲低这些基因可增强TPL的细胞毒性，因此它们有望成为新型抗癌靶点。