Purpose: Microvascular invasion (MVI) is a major unfavorable prognostic factor for intrahepatic metastasis and postoperative recurrence of hepatocellular carcinoma (HCC). However, the intervention and preoperative prediction for MVI remain clinical challenges due to the absent precise mechanism and molecular marker(s). Herein, we aimed to investigate the mechanisms underlying vascular invasion that can be applied to clinical intervention for MVI in HCC. Experimental Design: The histopathological characteristics of clinical MVI+/HCC specimens were analyzed using multiplex immunofluorescence staining. The liver orthotopic xenograft mouse model and mechanistic experiments on human patient-derived HCC cell lines, including co-culture modeling, RNA-sequencing, and proteomic analysis, were employed to investigate MVI‑related genes and mechanisms. Results: IQGAP3 overexpression was correlated significantly with MVI status and reduced survival in HCC. Upregulation of IQGAP3 promoted MVI+-HCC cells to adopt an infiltrative vessel co-optive growth pattern and accessed blood capillaries by inducing detachment of activated hepatic stellate cells (HSCs) from the endothelium. Mechanically, IQGAP3 overexpression contributed to HCC vascular invasion via a dual mechanism, in which IQGAP3 induced HSCs activation and disruption of the HSCs-endothelial interaction via upregulation of multiple cytokines and enhanced the trans-endothelial migration of MVI+-HCC cells by remodeling the cytoskeleton by sustaining GTPase Rac1 activity. Importantly, systemic delivery of IQGAP3-targeting small interfering RNA nanoparticles disrupted the infiltrative vessel co-optive growth pattern and reduced the MVI of HCC. Conclusions: Our results revealed a plausible mechanism underlying IQGAP3-mediated microvascular invasion in HCC, and provided a potential target to develop therapeutic strategies to treat HCC with MVI.

中文翻译：

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IQGAP3过表达诱导的浸润性血管共选择生长模式促进肝细胞癌微血管侵袭

目的：微血管侵犯（MVI）是肝细胞癌（HCC）肝内转移和术后复发的主要不良预后因素。然而，由于缺乏精确的机制和分子标记，MVI 的干预和术前预测仍然是临床挑战。在此，我们的目的是研究血管侵犯的潜在机制，并将其应用于 HCC MVI 的临床干预。实验设计：使用多重免疫荧光染色分析临床 MVI+/HCC 标本的组织病理学特征。采用肝脏原位异种移植小鼠模型和人类患者来源的 HCC 细胞系的机制实验（包括共培养建模、RNA 测序和蛋白质组分析）来研究 MVI 相关基因和机制。结果：IQGAP3 过度表达与 MVI 状态和 HCC 生存率降低显着相关。IQGAP3的上调促进MVI+-HCC细胞采取浸润性血管共选择生长模式，并通过诱导活化的肝星状细胞（HSC）与内皮分离来进入毛细血管。从机械角度来看，IQGAP3 过表达通过双重机制促进 HCC 血管侵袭，其中 IQGAP3 通过上调多种细胞因子诱导 HSC 激活并破坏 HSC-内皮相互作用，并通过重塑细胞骨架增强 MVI+-HCC 细胞的跨内皮迁移维持 GTPase Rac1 活性。重要的是，全身递送 IQGAP3 靶向小干扰 RNA 纳米颗粒破坏了浸润性血管共选择生长模式，并降低了 HCC 的 MVI。结论：我们的结果揭示了 IQGAP3 介导的 HCC 微血管侵袭的潜在机制，并为制定 MVI 治疗 HCC 的治疗策略提供了潜在的靶点。