RNAi screening identifies TAK1 as a potential target for the enhanced efficacy of topoisomerase inhibitors.
RNAi screening identifies TAK1 as a potential target for the enhanced efficacy of topoisomerase inhibitors.
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DOI：
10.2174/156800911797264734
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发表时间：
2011-10
影响因子：
3
通讯作者：
Caplen NJ
中科院分区：
文献类型：
--
作者：
Martin SE;Wu ZH;Gehlhaus K;Jones TL;Zhang YW;Guha R;Miyamoto S;Pommier Y;Caplen NJ
为了开发提高现有抗癌药物疗效的策略，我们进行了基于siRNA的RNAi筛选，以鉴定当被siRNA靶向时提高拓扑异构酶I（Top1）毒性喜树碱（CPT）活性的基因。使用一组对应于MDA-MB-231乳腺癌细胞中超过400个乳腺癌相关基因的siRNA进行筛选。在这些研究的过程中，我们鉴定了MAP 3 K7的沉默作为CPT活性的显著增强剂。对caspase活性和caspase依赖的组蛋白H2 AX磷酸化的后续分析表明，MAP 3 K7的沉默增强了CPT相关的凋亡。沉默MAP 3 K7也使细胞对其他化合物敏感，包括CPT临床类似物。这种活性不限于MDA-MB-231细胞，因为MAP 3 K7的沉默也使乳腺癌细胞系MDA-MB-468和HCT-116结肠癌细胞敏化。然而，MAP 3 K7沉默不影响相对正常的乳腺上皮细胞系MCF 10A以及一些其他致瘤细胞系中的化合物活性。MAP 3 K7编码TAK 1激酶，TAK 1激酶是一种对调节与癌细胞生长相关的许多过程（例如NF-κB、JNK和p38信号传导）至关重要的酶。TAK 1信号通路成员的分析显示，TAB 2的沉默也使MDA-MB-231和HCT-116细胞对CPT敏感。这些发现可能为降低癌细胞中Top1抑制剂的有效剂量提供了途径，并在此过程中扩大了其应用范围。
In an effort to develop strategies that improve the efficacy of existing anticancer agents, we have conducted a siRNA-based RNAi screen to identify genes that, when targeted by siRNA, improve the activity of the topoisomerase I (Top1) poison camptothecin (CPT). Screening was conducted using a set of siRNAs corresponding to over 400 apoptosis-related genes in MDA-MB-231 breast cancer cells. During the course of these studies, we identified the silencing of MAP3K7 as a significant enhancer of CPT activity. Follow-up analysis of caspase activity and caspase-dependent phosphorylation of histone H2AX demonstrated that the silencing of MAP3K7 enhanced CPT-associated apoptosis. Silencing MAP3K7 also sensitized cells to additional compounds, including CPT clinical analogs. This activity was not restricted to MDA-MB-231 cells, as the silencing of MAP3K7 also sensitized the breast cancer cell line MDA-MB-468 and HCT-116 colon cancer cells. However, MAP3K7 silencing did not affect compound activity in the comparatively normal mammary epithelial cell line MCF10A, as well as some additional tumorigenic lines. MAP3K7 encodes the TAK1 kinase, an enzyme that is central to the regulation of many processes associated with the growth of cancer cells (e.g. NF-κB, JNK, and p38 signaling). An analysis of TAK1 signaling pathway members revealed that the silencing of TAB2 also sensitizes MDA-MB-231 and HCT-116 cells towards CPT. These findings may offer avenues towards lowering the effective doses of Top1 inhibitors in cancer cells and, in doing so, broaden their application.