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Abstract：
BACKGROUND: During mitosis the cell depends on proper attachment and segregation of replicated chromosomes to generate two identical progeny. In cancers defined by overexpression or dysregulation of the MYC oncogene this process becomes impaired, leading to genomic instability and tumor evolution. Recently it was discovered that the chromatin regulator WDR5-a critical MYC cofactor-regulates expression of genes needed in mitosis through a direct interaction with the master kinase PDPK1. However, whether PDPK1 and WDR5 contribute to similar mitotic gene regulation in MYC-overexpressing cancers remains unclear. Therefore, to characterize the influence of WDR5 and PDPK1 on mitotic gene expression in cells with high MYC levels, we performed a comparative transcriptomic analysis in neuroblastoma cell lines defined by MYCN-amplification, which results in high cellular levels of the N-MYC protein.
RESULTS: Using RNA-seq analysis, we identify the genes regulated by N-MYC and PDPK1 in multiple engineered CHP-134 neuroblastoma cell lines and compare them to previously published gene expression data collected in CHP-134 cells following inhibition of WDR5. We find that as expected N-MYC regulates a multitude of genes, including those related to mitosis, but that PDPK1 regulates specific sets of genes involved in development, signaling, and mitosis. Analysis of N-MYC- and PDPK1-regulated genes reveals a small group of commonly controlled genes associated with spindle pole formation and chromosome segregation, which overlap with genes that are also regulated by WDR5. We also find that N-MYC physically interacts with PDPK1 through the WDR5-PDPK1 interaction suggesting regulation of mitotic gene expression may be achieved through a N-MYC-WDR5-PDPK1 nexus.
CONCLUSIONS: Overall, we identify a small group of genes highly enriched within functional gene categories related to mitotic processes that are commonly regulated by N-MYC, WDR5, and PDPK1 and suggest that a tripartite interaction between the three regulators may be responsible for setting the level of mitotic gene regulation in N-MYC amplified cell lines. This study provides a foundation for future studies to determine the exact mechanism by which N-MYC, WDR5, and PDPK1 converge on cell cycle related processes.
RESULTS: Using RNA-seq analysis, we identify the genes regulated by N-MYC and PDPK1 in multiple engineered CHP-134 neuroblastoma cell lines and compare them to previously published gene expression data collected in CHP-134 cells following inhibition of WDR5. We find that as expected N-MYC regulates a multitude of genes, including those related to mitosis, but that PDPK1 regulates specific sets of genes involved in development, signaling, and mitosis. Analysis of N-MYC- and PDPK1-regulated genes reveals a small group of commonly controlled genes associated with spindle pole formation and chromosome segregation, which overlap with genes that are also regulated by WDR5. We also find that N-MYC physically interacts with PDPK1 through the WDR5-PDPK1 interaction suggesting regulation of mitotic gene expression may be achieved through a N-MYC-WDR5-PDPK1 nexus.
CONCLUSIONS: Overall, we identify a small group of genes highly enriched within functional gene categories related to mitotic processes that are commonly regulated by N-MYC, WDR5, and PDPK1 and suggest that a tripartite interaction between the three regulators may be responsible for setting the level of mitotic gene regulation in N-MYC amplified cell lines. This study provides a foundation for future studies to determine the exact mechanism by which N-MYC, WDR5, and PDPK1 converge on cell cycle related processes.
摘要：
背景：在有丝分裂期间，细胞依赖于复制染色体的适当附着和分离来产生两个相同的后代。在由MYC癌基因的过度表达或失调定义的癌症中，该过程变得受损，导致基因组不稳定和肿瘤进化。最近发现染色质调节剂WDR5-一种关键的MYC辅因子-通过与主激酶PDPK1的直接相互作用来调节有丝分裂中所需基因的表达。然而,PDPK1和WDR5在过表达MYC的癌症中是否有助于类似的有丝分裂基因调控仍不清楚.因此,表征WDR5和PDPK1对MYC水平高的细胞中有丝分裂基因表达的影响，我们在MYCN扩增定义的神经母细胞瘤细胞系中进行了比较转录组学分析，这导致高细胞水平的N-MYC蛋白。
结果：使用RNA-seq分析，我们在多种工程化CHP-134神经母细胞瘤细胞系中鉴定了N-MYC和PDPK1调控的基因,并将它们与之前发表的在抑制WDR5后CHP-134细胞中收集的基因表达数据进行了比较.我们发现，正如预期的那样，N-MYC调节多种基因，包括与有丝分裂有关的，但是PDPK1调节参与发育的特定基因集，信令,和有丝分裂。对N-MYC-和PDPK1调节基因的分析揭示了一小组与纺锤体极形成和染色体分离相关的共同控制基因。与也受WDR5调控的基因重叠。我们还发现N-MYC通过WDR5-PDPK1相互作用与PDPK1物理相互作用，表明有丝分裂基因表达的调节可以通过N-MYC-WDR5-PDPK1连接来实现。
结论：总体而言，我们确定了一小群基因高度富集在与通常由N-MYC调控的有丝分裂过程相关的功能基因类别中，WDR5和PDPK1，并表明三个调节因子之间的三方相互作用可能负责设定N-MYC扩增细胞系中有丝分裂基因调节的水平。本研究为今后研究确定N-MYC,WDR5和PDPK1收敛于细胞周期相关过程。
结果：使用RNA-seq分析，我们在多种工程化CHP-134神经母细胞瘤细胞系中鉴定了N-MYC和PDPK1调控的基因,并将它们与之前发表的在抑制WDR5后CHP-134细胞中收集的基因表达数据进行了比较.我们发现，正如预期的那样，N-MYC调节多种基因，包括与有丝分裂有关的，但是PDPK1调节参与发育的特定基因集，信令,和有丝分裂。对N-MYC-和PDPK1调节基因的分析揭示了一小组与纺锤体极形成和染色体分离相关的共同控制基因。与也受WDR5调控的基因重叠。我们还发现N-MYC通过WDR5-PDPK1相互作用与PDPK1物理相互作用，表明有丝分裂基因表达的调节可以通过N-MYC-WDR5-PDPK1连接来实现。
结论：总体而言，我们确定了一小群基因高度富集在与通常由N-MYC调控的有丝分裂过程相关的功能基因类别中，WDR5和PDPK1，并表明三个调节因子之间的三方相互作用可能负责设定N-MYC扩增细胞系中有丝分裂基因调节的水平。本研究为今后研究确定N-MYC,WDR5和PDPK1收敛于细胞周期相关过程。
