TLR9 signaling through NF-κB/RELA and STAT3 promotes tumor-propagating potential of prostate cancer cells.
TLR9 signaling through NF-κB/RELA and STAT3 promotes tumor-propagating potential of prostate cancer cells.
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DOI：
10.18632/oncotarget.4029
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发表时间：
2015-07-10
期刊：
影响因子：
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通讯作者：
Kortylewski M
中科院分区：
文献类型：
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作者：
Moreira D;Zhang Q;Hossain DM;Nechaev S;Li H;Kowolik CM;D'Apuzzo M;Forman S;Jones J;Pal SK;Kortylewski M
前列腺癌的进展与促炎介质激活的致癌信号有关。然而，这些事件的病因仍然难以捉摸。在这里，我们证明了在雄激素非依赖性前列腺癌细胞中，先天免疫受体Toll样受体9(TLR9)的触发启动了导致肿瘤生长和进展加速的信号级联反应。通过有限稀释/系列移植实验，我们证明了TLR9对于前列腺癌细胞在体内的增殖和自我更新的潜力是必不可少的。此外，TLR9的低表达或沉默限制了LNCaP和PC3来源的前列腺癌细胞变异体的克隆形成潜力和间充质干细胞样特性。从异种移植的TLR9阳性和阴性肿瘤中分离出的前列腺癌细胞的全基因组转录分析显示了一个独特的基因表达特征，与炎症和干细胞相关的标记显著上调。TLR9信号调控NKX3.1、KLF-4、Bmi-1和COL1A1等干细胞相关关键基因在mRNA和蛋白水平的表达。我们进一步的分析发现，TLR9诱导的转录因子NKX3.1和κ3通过直接与这两个启动子结合而共同调节NKX3.1和KLF4基因的表达。最后，我们论证了使用TLR9靶向siRNA在体内阻断依赖RelA和STAT3的前列腺癌细胞自我更新的可行性。瘤内注射CpG-RELAsiRNA或CpG-STAT3siRNA，但没有对照结合物，可抑制已建立的前列腺癌的生长，并降低癌细胞的克隆形成能力。通过靶向抑制TLR9信号通路来克服癌细胞的自我更新和肿瘤生长潜能，可以为晚期前列腺癌患者提供治疗策略。
Prostate cancer progression was associated with tumorigenic signaling activated by proinflammatory mediators. However, the etiology of these events remains elusive. Here, we demonstrate that triggering of the innate immune receptor, Toll-like Receptor 9 (TLR9), in androgen-independent prostate cancer cells initiates signaling cascade leading to increased tumor growth and progression. Using limited dilution/serial transplantation experiments, we show that TLR9 is essential for prostate cancer cells' potential to propagate and self-renew in vivo. Furthermore, low expression or silencing of TLR9 limits the clonogenic potential and mesenchymal stem cell-like properties of LNCaP- and PC3-derived prostate cancer cell variants. Genome-wide transcriptional analysis of prostate cancer cells isolated from xenotransplanted TLR9-positive and -negative tumors revealed a unique gene expression signature, with prominent upregulation of inflammation- and stem cell-related markers. TLR9 signaling orchestrated expression of critical stem cell-related genes such as NKX3.1, KLF-4, BMI-1 and COL1A1, at both mRNA and protein levels. Our further analysis identified that TLR9-induced NF-κB/RELA and STAT3 transcription factors co-regulated NKX3.1 and KLF4 gene expression by directly binding to both promoters. Finally, we demonstrated the feasibility of using TLR9-targeted siRNA delivery to block RELA- and STAT3-dependent prostate cancer cell self-renewal in vivo. The intratumoral administration of CpG-RELAsiRNA or CpG-STAT3siRNA but not control conjugates inhibited growth of established prostate tumors and reduced clonogenic potential of cancer cells. Overcoming cancer cell self-renewal and tumor-propagating potential by targeted inhibition of TLR9 signaling can provide therapeutic strategy for late-stage prostate cancer patients.