State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China.
Cancer Immunoregulation and Immunotherapy Laboratory, Queensland Institute of Medical Research, Berghofer Medical Research Institute, Herston, Queensland, Australia.
Gastroenterology. 2019 May;156(6):1890-1904.e16. doi: 10.1053/j.gastro.2019.01.250. Epub 2019 Jan 31.
BACKGROUND & AIMS: Little is known about the composition and generation of plasma cell subsets in patients with hepatocellular carcinoma (HCC) and how these associate with outcomes. We investigated whether, or how, plasma cells differentiate and function in patients with HCC and mice with liver tumors.
We analyzed subset composition and distribution of plasma cells in HCC samples from 342 patients who underwent curative resection at the Cancer Center of Sun Yat-sen University in China; samples of non-tumor liver tissue were used as controls. We associated plasma cell profiles with patient outcomes. Tissue-derived leukocytes were analyzed by flow cytometry and real-time polymerase chain reaction. The ability of macrophages to regulate plasma cell differentiation was determined in ex vivo cultures of cells from human HCC tissues. C57BL/6 and BALB/c mice were given injections of Hepa1-6 cells, which formed hepatomas, or H22 cells, which formed ascitic hepatomas. Gene expression patterns were analyzed in human HCC, mouse hepatoma, and non-tumor tissues by real-time polymerase chain reaction. Mice with hepatomas were given injections of GSK126 (an inhibitor of histone H3 lysine 27 methyltransferase [EZH2]) and 5-AZA-dC (an inhibitor of DNA methyltransferases); tumor tissues were analyzed by immunofluorescence and immunohistochemistry for the presence of immune cells and cytokines.
B cells isolated from HCCs had somatic hypermutations and class-switch recombinations to the IgG phenotype that were not observed in non-tumor tissues. Increased level of plasma cells correlated with poor outcomes of patients. Activated CD4 T cells from HCCs stimulated C-X-C motif chemokine 10 (CXCL10) production by macrophages. CXCL10 bound CXC chemokine receptor 3 on B cells and signaled via extracellular signal-regulated kinase to cause them to become IgG-producing plasma cells. IgG activated Fc receptors on macrophages and induced them to produce interleukin 6, interleukin 10, and C-C motif chemokine ligand 20 (CCL20). In mice with hepatomas, depletion of B cells prevented generation of these macrophage, increased the anti-tumor T cell response, and reduced growth of hepatomas. However, these effects were lost after injection of CXC chemokine receptor 3-positive plasma cells. Human HCC and mouse hepatoma tissues had increased expression of DNA methyltransferase 1 and EZH2 compared with non-tumor tissues. Injection of mice with GSK126 and 5-AZA-dC induced expression of CXCL10 by tumor cells and caused plasma cell polarization, suppression of the anti-tumor T cell response, and hepatoma growth.
Human HCC tissues contain B cells with class-switch recombinations to the IgG phenotype. Activated CD4 T cells from HCCs stimulate CXCL10 production by macrophages; CXCL10 binds CXC chemokine receptor 3 on B cells and causes them to become IgG-producing plasma cells. IgG activates Fc receptor in macrophages to produce cytokines that reduce the anti-tumor immune response. In mice with hepatomas, depletion of B cells prevented generation of these macrophages, increased the anti-tumor T cell response, and reduced growth of hepatomas. This pathway involves increased expression of DNA methyltransferase 1 and EZH2 by HCC and hepatoma cells.
关于肝癌（HCC）患者浆细胞亚群的组成和生成以及这些亚群如何与预后相关，目前知之甚少。我们研究了浆细胞在 HCC 患者和肝癌小鼠中是否以及如何分化和发挥功能。
我们分析了中山大学肿瘤防治中心 342 例接受根治性切除术的 HCC 患者的 HCC 样本和非肿瘤肝组织样本中的浆细胞亚群组成和分布。我们将浆细胞谱与患者的预后相关联。通过流式细胞术和实时聚合酶链反应分析组织来源的白细胞。通过体外培养人 HCC 组织中的细胞来确定巨噬细胞调节浆细胞分化的能力。将 C57BL/6 和 BALB/c 小鼠注射 Hepa1-6 细胞（形成肝癌）或 H22 细胞（形成腹水肝癌）。通过实时聚合酶链反应分析人 HCC、小鼠肝癌和非肿瘤组织中的基因表达模式。给患有肝癌的小鼠注射 GSK126（组蛋白 H3 赖氨酸 27 甲基转移酶[EZH2]抑制剂）和 5-AZA-dC（DNA 甲基转移酶抑制剂）；通过免疫荧光和免疫组织化学分析肿瘤组织中免疫细胞和细胞因子的存在。
从 HCC 中分离出的 B 细胞发生体细胞高频突变和类别转换重组，而在非肿瘤组织中未观察到。浆细胞水平升高与患者预后不良相关。来自 HCC 的活化 CD4 T 细胞刺激巨噬细胞产生 C-X-C 基序趋化因子 10（CXCL10）。CXCL10 与 B 细胞上的 CXC 趋化因子受体 3 结合，并通过细胞外信号调节激酶信号使其成为产生 IgG 的浆细胞。IgG 激活巨噬细胞上的 Fc 受体，并诱导它们产生白细胞介素 6、白细胞介素 10 和 C-C 基序趋化因子配体 20（CCL20）。在患有肝癌的小鼠中，B 细胞耗竭可阻止这些巨噬细胞的生成，增加抗肿瘤 T 细胞反应，并减少肝癌的生长。然而，在注射 CXC 趋化因子受体 3 阳性浆细胞后，这些作用消失了。人 HCC 和小鼠肝癌组织中的 DNA 甲基转移酶 1 和 EZH2 的表达均高于非肿瘤组织。给小鼠注射 GSK126 和 5-AZA-dC 可诱导肿瘤细胞表达 CXCL10，并导致浆细胞极化、抑制抗肿瘤 T 细胞反应和肝癌生长。
人 HCC 组织中含有发生 IgG 表型类别转换的 B 细胞。来自 HCC 的活化 CD4 T 细胞刺激巨噬细胞产生 CXCL10；CXCL10 与 B 细胞上的 CXC 趋化因子受体 3 结合并使其成为产生 IgG 的浆细胞。IgG 激活巨噬细胞上的 Fc 受体以产生降低抗肿瘤免疫反应的细胞因子。在患有肝癌的小鼠中，B 细胞耗竭可阻止这些巨噬细胞的生成，增加抗肿瘤 T 细胞反应，并减少肝癌的生长。该途径涉及 HCC 和肝癌细胞中 DNA 甲基转移酶 1 和 EZH2 的表达增加。
