Estrogen receptor beta enhances chemotherapy response of GBM cells by down regulating DNA damage response pathways
Estrogen receptor beta enhances chemotherapy response of GBM cells by down regulating DNA damage response pathways
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DOI：
10.1038/s41598-019-42313-8
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发表时间：
2019-04-16
影响因子：
4.6
通讯作者：
Vadlamudi, Ratna K.
中科院分区：
文献类型：
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作者：
Zhou, Mei;Sareddy, Gangadhara R.;Vadlamudi, Ratna K.
胶质母细胞瘤（GBM）是最常见的脑肿瘤，死亡率高，化疗耐药是一个重要的临床问题。最近的研究表明，雌激素受体β (ER β)可能在GBM中起肿瘤抑制作用。然而，内质网β参与GBM抑制和化疗反应的机制尚不清楚。我们研究了ER β在GBM细胞DNA损伤反应中的作用，并测试了ER β是否使GBM细胞对化疗敏感。使用多个表位标记的表达已建立和原代GBM细胞的ER β进行细胞活力和存活试验表明，ER β使GBM细胞对包括替莫唑胺（TMZ）在内的DNA损伤剂敏感。利用ER β过表达模型进行的RNA-seq研究显示，参与DNA重组和修复、ATM信号传导和细胞周期检查点控制的基因数量下调。基因集富集分析（GSEA）表明，ER β调节基因与同源重组、错配修复和G2M检查点基因呈负相关。此外，RT-qPCR分析显示，化疗诱导的细胞周期阻滞和凋亡基因的激活在ER β KO细胞中减弱。此外，ER β过表达细胞在TMZ处理后具有更高数量的γ - H2AX灶。机制研究表明，ER β在同源重组（homologous recombination， HR）介导的修复中起重要作用，ER β降低了DNA损伤时ATM的表达和激活。更重要的是，在原位GBM模型中，与对照GBM细胞相比，表达ER β的GBM细胞的存活率更高。在TMZ敏感和TMZ耐药的GBM模型中，ER β过表达进一步提高了TMZ治疗小鼠的存活率。此外，免疫组化分析显示ER β肿瘤中γ - H2AX和cleaved caspase-3的表达增加。通过ER β -过表达和ER β - ko GBM模型细胞，我们已经提供了证据，证明ER β是最佳化疗诱导的GBM细胞DNA损伤反应和凋亡所必需的。
Glioblastoma (GBM) is the most commonly diagnosed brain tumor that exhibit high mortality rate and chemotherapy resistance is a major clinical problem. Recent studies suggest that estrogen receptor beta (ER beta), may function as a tumor suppressor in GBM. However, the mechanism(s) by which ER beta contributes to GBM suppression and chemotherapy response remains unknown. We examined the role of ER beta in the DNA damage response of GBM cells, and tested whether ER beta sensitizes GBM cells to chemotherapy. Cell viability and survival assays using multiple epitope tagged ER beta expressing established and primary GBM cells demonstrated that ER beta sensitizes GBM cells to DNA damaging agents including temozolomide (TMZ). RNA-seq studies using ER beta overexpression models revealed downregulation of number of genes involved in DNA recombination and repair, ATM signaling and cell cycle check point control. Gene set enrichment analysis (GSEA) suggested that ER beta-modulated genes were correlated negatively with homologous recombination, mismatch repair and G2M checkpoint genes. Further, RT-qPCR analysis revealed that chemotherapy induced activation of cell cycle arrest and apoptosis genes were attenuated in ER beta KO cells. Additionally, ER beta overexpressing cells had a higher number of gamma H2AX foci following TMZ treatment. Mechanistic studies showed that ER beta plays an important role in homologous recombination (HR) mediated repair and ER beta reduced expression and activation of ATM upon DNA damage. More importantly, GBM cells expressing ER beta had increased survival when compared to control GBM cells in orthotopic GBM models. ER beta overexpression further enhanced the survival of mice to TMZ therapy in both TMZ sensitive and TMZ resistant GBM models. Additionally, IHC analysis revealed that ER beta tumors had increased expression of gamma H2AX and cleaved caspase-3. Using ER beta-overexpression and ER beta-KO GBM model cells, we have provided the evidence that ER beta is required for optimal chemotherapy induced DNA damage response and apoptosis in GBM cells.