MKNK1 is a YB-1 target gene responsible for imparting trastuzumab resistance and can be blocked by RSK inhibition
MKNK1 is a YB-1 target gene responsible for imparting trastuzumab resistance and can be blocked by RSK inhibition
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DOI：
10.1038/onc.2011.617
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发表时间：
2012-10-01
期刊：
影响因子：
8
通讯作者：
Dunn, S. E.
中科院分区：
文献类型：
--
作者：
Astanehe, A.;Finkbeiner, M. R.;Dunn, S. E.
曲妥珠单抗(Herceptin)耐药是HER2阳性乳腺癌患者治疗的主要障碍。我们最近报道，转录因子Y-box结合蛋白-1(YB-1)通过依赖p90核糖体S6激酶(RSK)的磷酸化方式导致对曲妥珠单抗的抗性。为了探索YB-1是如何发生的，我们使用全基因组染色质免疫沉淀测序(芯片测序)比较了曲妥珠单抗敏感细胞(BT474)和获得性耐药细胞(HR5和HR6)之间的YB-1靶基因，在耐药细胞系中鉴定了1391个与YB-1唯一结合的基因。然后，我们使用KinexusKinex抗体微阵列检测了这些细胞系之间蛋白质表达和磷酸化的差异。交叉参考这两个数据集发现，丝裂原活化蛋白激酶相互作用激酶(MNK)家族可能与YB-1下游的获得性耐药性有关。随后发现MNK1和MNK2在耐药细胞系中过表达；然而，根据芯片-PCR和小干扰RNA(SiRNA)研究，只有前者是YB-1的靶标。重要的是，使用siRNA丢失MNK1的表达增强了对曲妥珠单抗的敏感性。此外，MNK1的过度表达足以使先前敏感的细胞对曲妥珠单抗产生耐药性。然后，我们建立了一个获得性耐药性的从头模型，将BT474细胞暴露于曲妥珠单抗60天(BT474LT)。与HR5/HR6细胞相似，BT474LT细胞MNK1水平升高，并依赖MNK1生存。此外，我们还证明了RSK使MNK1磷酸化，并且这种磷酸化是MNK1介导曲妥珠单抗耐药所必需的。此外，小分子BI-D1870对RSK的抑制抑制了MNK1介导的曲妥珠单抗耐药性。综上所述，这种无偏见的整合方法证实了MNK1是YB-1激活导致的曲妥珠单抗耐药的调节因子，并证明了RSK抑制是克服曲妥珠单抗耐药的一种手段。Oncogene(2012年)31,4434-4446；doi：10.1038/onc.2011.617；2012年1月16日在线发布
Trastuzumab (Herceptin) resistance is a major obstacle in the treatment of patients with HER2-positive breast cancers. We recently reported that the transcription factor Y-box binding protein-1 (YB-1) leads to acquisition of resistance to trastuzumab in a phosphorylation-dependent manner that relies on p90 ribosomal S6 kinase (RSK). To explore how this may occur we compared YB-1 target genes between trastuzumab-sensitive cells (BT474) and those with acquired resistance (HR5 and HR6) using genome-wide chromatin immunoprecipitation sequencing (ChIP-sequencing), which identified 1391 genes uniquely bound by YB-1 in the resistant cell lines. We then examined differences in protein expression and phosphorylation between these cell lines using the Kinexus Kinex antibody microarrays. Cross-referencing these two data sets identified the mitogen-activated protein kinase-interacting kinase (MNK) family as potentially being involved in acquired resistance downstream from YB-1. MNK1 and MNK2 were subsequently shown to be overexpressed in the resistant cell lines; however, only the former was a YB-1 target based on ChIP-PCR and small interfering RNA (siRNA) studies. Importantly, loss of MNK1 expression using siRNA enhanced sensitivity to trastuzumab. Further, MNK1 overexpression was sufficient to confer resistance to trastuzumab in cells that were previously sensitive. We then developed a de novo model of acquired resistance by exposing BT474 cells to trastuzumab for 60 days (BT474LT). Similar to the HR5/HR6 cells, the BT474LT cells had elevated MNK1 levels and were dependent on it for survival. In addition, we demonstrated that RSK phosphorylated MNK1, and that this phosphorylation was required for ability of MNK1 to mediate resistance to trastuzumab. Furthermore, inhibition of RSK with the small molecule BI-D1870 repressed the MNK1-mediated trastuzumab resistance. In conclusion, this unbiased integrated approach identified MNK1 as a player in mediating trastuzumab resistance as a consequence of YB-1 activation, and demonstrated RSK inhibition as a means to overcome recalcitrance to trastuzumab. Oncogene (2012) 31, 4434-4446; doi: 10.1038/onc.2011.617; published online 16 January 2012