Hepatocellular carcinoma (HCC), the most prevalent primary liver cancer, is a leading cause of cancer-related death worldwide because of rising incidence and limited therapy. Although treatment with sorafenib or lenvatinib is the standard of care in patients with advanced-stage HCC, the survival benefit from sorafenib is limited due to low response rate and drug resistance. Ibrutinib, an irreversible tyrosine kinase inhibitor (TKI) of the TEC (e.g., BTK) and ErbB (e.g., EGFR) families, is an approved treatment for B-cell malignancies. Here, we demonstrate that ibrutinib inhibits proliferation, spheroid formation, and clonogenic survival of HCC cells, including sorafenib-resistant cells. Mechanistically, ibrutinib inactivated EGFR and its downstream Akt and ERK signaling in HCC cells, and downregulated a set of critical genes involved in cell proliferation, migration, survival, and stemness, and upregulated genes promoting differentiation. Moreover, ibrutinib showed synergy with sorafenib or regorafenib, a sorafenib congener, by inducing apoptosis of HCC cells. In vivo, this TKI combination significantly inhibited HCC growth and prolonged survival of immune-deficient mice bearing human HCCLM3 xenograft tumors and immune-competent mice bearing orthotopic mouse Hepa tumors at a dose that did not exhibit systemic toxicity. In immune-competent mice, the ibrutinib–sorafenib combination reduced the numbers of BTK+ immune cells in the tumor microenvironment. Importantly, we found that the BTK+ immune cells were also enriched in the tumor microenvironment in a subset of primary human HCCs. Collectively, our findings implicate BTK signaling in hepatocarcinogenesis and support clinical trials of the sorafenib–ibrutinib combination for this deadly disease.

中文翻译：

---

依鲁替尼通过靶向肿瘤细胞中的 EGFR 和基质中免疫细胞中的 BTK 增强索拉非尼的抗肝癌功效

肝细胞癌 (HCC) 是最常见的原发性肝癌，由于发病率上升和治疗有限，它是全球癌症相关死亡的主要原因。尽管索拉非尼或乐伐替尼治疗是晚期 HCC 患者的标准治疗，但由于反应率低和耐药性，索拉非尼的生存获益有限。依鲁替尼是 TEC（例如 BTK）和 ErbB（例如 EGFR）家族的不可逆酪氨酸激酶抑制剂 (TKI)，是一种已获批准的 B 细胞恶性肿瘤治疗方法。在这里，我们证明依鲁替尼抑制 HCC 细胞（包括索拉非尼耐药细胞）的增殖、球体形成和克隆存活。从机制上讲，依鲁替尼使 EGFR 及其下游的 Akt 和 ERK 信号在 HCC 细胞中失活，和下调一组涉及细胞增殖、迁移、存活和干性的关键基因，以及上调促进分化的基因。此外，依鲁替尼通过诱导 HCC 细胞凋亡显示出与索拉非尼或瑞戈非尼（索拉非尼同系物）的协同作用。在体内，这种 TKI 组合在不表现出全身毒性的剂量下显着抑制了 HCC 生长并延长了携带人 HCCLM3 异种移植肿瘤的免疫缺陷小鼠和携带原位小鼠 Hepa 肿瘤的免疫活性小鼠的存活。在有免疫能力的小鼠中，依鲁替尼-索拉非尼组合减少了肿瘤微环境中 BTK+ 免疫细胞的数量。重要的是，我们发现 BTK+ 免疫细胞也在一部分原发性人类 HCC 的肿瘤微环境中富集。总的来说，