TLR5/NF-κB信号通路介导的CXCL8+ γδT细胞促进神经母细胞瘤EMT的机制研究

Neuroblastoma (NB) is one of the most prevalent extracranial solid tumors in children. Metastasis of tumor cells after epithelial-to-mesenchymal transition (EMT) presents the biggest obstacle for the NB remedy. Our preliminary data revealed a pathological augment of γδT cells in NB patients. On top of that, there are more CXCL8 releasing γδT cells in NB patients with a positive correlation to the level of tumor cell EMT transition. Transcriptome and quantitative PCR analysis showed that NF-κB and CXCL8 expression were upregulated in PAM-induced expanding γδT cells. PTDC, a NF-κB signaling inhibitor, abolished the CXCL8 synthesis and release from γδT cells. Coculture experiment indicated that CXCL8+γδT cells promote the migration of NB cell lines. Based on our findings, we hypothesize that CXCL8 releasing γδT cells promote tumor cell EMT transition via TLR5/NF-κB signaling pathway, following which a tumor metastasis establishes. The present study will be implemented to understand the underlined mechanism with regards to the role of TLR5/NF-κB signaling in directing CXCL8 expression in γδT cells as well as the effect on the tumor EMT transition. This study will provide useful information for containing progressive NB resulting from tumor cell metastasis.

神经母细胞瘤（Neuroblastoma, NB）是儿童最常见的颅外实体肿瘤。肿瘤细胞发生EMT后远端转移，是NB治疗的难点。前期研究证明NB患儿γδT细胞呈现病理性升高。进一步研究表明NB患儿CXCL8+ γδT细胞显著升高，并和肿瘤转移呈正相关。表达谱芯片及qPCR证实CXCL8以及TLR5的表达在NB患儿γδT细胞中特异性上调。加入NF-kB抑制剂PTDC能够抑制γδT细胞中CXCL8合成及分泌。共培养实验表明CXCL8+ γδT细胞促进NB肿瘤细胞系的迁移。基于前期基础，我们猜测γδT细胞可能通过TLR5/NF-κB信号通路增强γδT细胞的CXCL8基因表达及分泌，促进NB细胞发生EMT，成为肿瘤远端转移的先决条件。本课题拟深入研究TLR5/NF-κB信号通路调控γδT细胞分泌CXCL8的分子机制，并进一步验证CXCL8在NB肿瘤EMT中的作用，为遏制NB肿瘤细胞转移提供理论基础。

神经母细胞瘤（Neuroblastoma, NB）是儿童最常见的颅外实体肿瘤。肿瘤细胞发生EMT后远端转移，是NB治疗的难点。在前期的研究中我们发现NB患儿CXCL8+ γδT细胞显著升高，并和肿瘤转移呈正相关。目前，γδT细胞分泌CXCL8的分子机制尚不清楚，其对EMT介导神经母细胞瘤发生转移也未见报道。为了深入地探讨上述假说，本课题在文献报道以及前期工作的基础之上，提出γδT细胞促进NB肿瘤转移的机制假说：神经母细胞瘤γδT细胞通过TLR5/NF-κB信号通路，促进CXCL8的分泌，进而促进NB肿瘤细胞发生EMT。我们通过RNA-seq、qPCR、流式细胞术等均证实CXCL8以及TLR5/pNF-κB的表达在NB患儿γδT细胞中特异性上调。我们进一步的研究结果表明，敲减TLR5或加入NF-kB抑制剂PTDC能够抑制γδT细胞中CXCL8合成及分泌。共培养实验表明，γδT细胞通过TLR5/pNF-κB信号通路调控CXCL8的分泌，进而促进NB肿瘤细胞系的迁移。上述研究结果表明γδT细胞通过TLR5/NF-κB信号通路增强γδT细胞的CXCL8基因表达及分泌，促进NB细胞发生EMT，成为肿瘤远端转移的先决条件。本课题的成果将为遏制NB肿瘤细胞转移提供理论基础。