Synergistic effect between erlotinib and MEK inhibitors in KRAS wild-type human pancreatic cancer cells.
Synergistic effect between erlotinib and MEK inhibitors in KRAS wild-type human pancreatic cancer cells.
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DOI：
10.1158/1078-0432.ccr-10-2214
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发表时间：
2011-05-01
期刊：
影响因子：
--
通讯作者：
Han H
中科院分区：
文献类型：
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作者：
Diep CH;Munoz RM;Choudhary A;Von Hoff DD;Han H
在晚期胰腺癌患者中，吉西他滨联合厄洛替尼与吉西他滨单药相比，显示出较小但在统计学上显著的生存优势。然而，使用厄洛替尼和吉西他滨联合治疗的总体存活率仍然很低。在这项研究中，我们试图确定基因靶点，当被抑制时，将增强胰腺癌细胞中EGFR靶向治疗的活性。进行高通量RNAi筛选以确定候选基因。选择的基因命中被进一步确认，并利用各种分析进一步研究其作用机制。来自siRNA筛选的6个基因命中被证实显著增加了BxPC-3胰腺癌细胞对厄洛替尼的敏感性。其中一种叫作MAPK1，被选作进一步的机制研究。在含有野生型KRAS的胰腺癌细胞株(BxPC-3和HS 700T)中，与含有突变KRAS的细胞株(MIA Paca-2和PANC-1)相比，erlotinib与两种MAPK抑制剂(RDEA119-erlotinib和AZD6244-erlotinib)的联合治疗显示出显著的协同作用。在BxPC-3和MIA Paca-2小鼠异种移植模型中进一步验证了联合治疗的增强抗肿瘤活性。Western blotting对MAPK信号通路的检测表明，联合用药能有效抑制KRAS野生型细胞中的EGFR信号转导，而对KRAS突变型细胞中的EGFR信号转导无抑制作用。总体而言，我们的结果表明，EGFR和MEK抑制剂的联合治疗可能会提高胰腺癌患者的疗效。
The combination of gemcitabine plus erlotinib has shown a small but statistically significant survival advantage when compared to gemcitabine alone in patients with advanced pancreatic cancer. However, the overall survival rate with the erlotinib and gemcitabine combination is still low. In this study we sought to identify gene targets that, when inhibited, would enhance the activity of EGFR-targeted therapies in pancreatic cancer cells. A high-throughput RNAi screen was carried out to identify candidate genes. Selected gene hits were further confirmed and mechanisms of action were further investigated using various assays. Six gene hits from siRNA screening were confirmed to significantly sensitize BxPC-3 pancreatic cancer cells to erlotinib. One of the hits, MAPK1, was selected for further mechanistic studies. Combination treatments of erlotinib plus two MAP kinase kinase (MEK) inhibitors, RDEA119 and AZD6244, showed significant synergistic effect for both combinations (RDEA119-erlotinib and AZD6244-erlotinib) compared to the corresponding single drug treatments in pancreatic cancer cell lines with wild-type KRAS (BxPC-3 and Hs 700T) but not in cell lines with mutant KRAS (MIA PaCa-2 and PANC-1). The enhanced antitumor activity of the combination treatment was further verified in the BxPC-3 and MIA PaCa-2 mouse xenograft model. Examination of the MAPK signaling pathway by Western blotting indicated effective inhibition of the EGFR signaling by the drug combination in KRAS wildtype cells but not in KRAS mutant cells. Overall, our results suggest that combination therapy of an EGFR and MEK inhibitors may have enhanced efficacy in patients with pancreatic cancer.