Background: Emerging evidences have highlighted the roles of neutrophils, as the major host microenvironment component, in the development of hepatocellular carcinoma (HCC). Neutrophils extracellular traps (NETs) produced in the infection can strengthen the behavior of cancer metastasis. Here, we investigated the roles of NETs in HCC metastasis and further explore the underlying mechanism of how NETs interact with cancer.
Methods: The neutrophils were isolated from whole blood of HCC patients and used to evaluate the formation of NETs. NET markers were detected in tissue samples, plasma and cell climbing slice. Mouse models were used to evaluate the roles of NETs in HCC metastasis in vivo, and the corresponding mechanisms were explored using in vivo and in vitro assays.
Results: An increase in the release of NETs in patients with HCC, particularly those with portal vein tumor thrombosis (PVTT). The presence of NETs in HCC tumor tissues closely correlated with a poor prognosis. Functionally, the invasion ability of HCC cells was enhanced by co-culture with HCC neutrophils, through NETs formation, while the neutrophils from a healthy donor (HD) exhibited the inhibition of the invasion ability. Furthermore, we observed an enhanced ability of forming NETs in neutrophils from HCC patients in vitro, especially patients with PVTT or extra-hepatic metastasis. An in-vivo animal study demonstrated that neutrophils of HCC facilitated the metastatic behavior towards the lung. The further mechanistic investigation unveiled that HCC cells-derived cytokine IL-8 triggered NETs formation in an NADPH oxidase-dependent manner, and NETs-associated cathepsin G (cG) promoted HCC metastasis in vitro as well as vivo. Clinically, the expression of the cG protein in tumor tissues displayed a close correlation with the disease prognosis of HCC patients.
Conclusion: Our findings implicated that the induction of NETs by HCC cells is a critical metastasis-supporting cancer–host interaction and that NETs may serve as an immune-based potential therapeutic target against HCC progression.



中文翻译：

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癌细胞和中性粒细胞之间的串扰通过中性粒细胞胞外陷阱相关的组织蛋白酶 G 成分增强肝细胞癌转移：一个潜在的治疗靶点

背景：新出现的证据强调了中性粒细胞作为主要宿主微环境成分在肝细胞癌 (HCC) 发展中的作用。感染中产生的中性粒细胞胞外陷阱（NETs）可以加强癌症转移的行为。在这里，我们研究了 NETs 在 HCC 转移中的作用，并进一步探索了 NETs 如何与癌症相互作用的潜在机制。
方法：从 HCC 患者的全血中分离出中性粒细胞，用于评估 NETs 的形成。在组织样本、血浆和细胞爬片中检测到 NET 标志物。小鼠模型用于评估 NETs 在体内 HCC 转移中的作用，并使用体内和体外测定探索相应的机制。
结果：HCC 患者，尤其是门静脉肿瘤血栓形成 (PVTT) 患者的 NET 释放增加。HCC 肿瘤组织中 NETs 的存在与不良预后密切相关。在功能上，通过与 HCC 中性粒细胞共培养，通过 NETs 形成增强了 HCC 细胞的侵袭能力，而来自健康供体 (HD) 的中性粒细胞表现出对侵袭能力的抑制。此外，我们观察到体外 HCC 患者的中性粒细胞形成 NET 的能力增强，尤其是 PVTT 或肝外转移的患者。一项体内动物研究表明，HCC 的中性粒细胞促进了向肺的转移行为。进一步的机制研究揭示了 HCC 细胞衍生的细胞因子 IL-8 以 NADPH 氧化酶依赖性方式触发 NETs 形成，和 NETs 相关的组织蛋白酶 G (cG) 在体外和体内促进 HCC 转移。临床上，肿瘤组织中cG蛋白的表达与HCC患者的疾病预后密切相关。
结论：我们的研究结果表明，HCC 细胞对 NETs 的诱导是一种关键的转移支持癌症 - 宿主相互作用，并且 NETs 可以作为基于免疫的潜在治疗靶点来对抗 HCC 进展。