Jackaman Connie, Yeoh Teong L, Acuil Manyual L, Gardner Joanne K, Nelson Delia J
Immunology and Cancer Group, School of Biomedical Sciences, Curtin University, Perth, Western Australia, WA, Australia; Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Perth, WA, Australia.
Oncoimmunology. 2016 Apr 22;5(6):e1173299. doi: 10.1080/2162402X.2016.1173299. eCollection 2016 Jun.
We used a murine model to monitor changes to myeloid cell subsets, i.e., myeloid-derived suppressor cells (MDSCs), M1 macrophages that secrete pro-inflammatory cytokines and express CD40 and CD80 and suppressive M2 macrophages that secrete anti-inflammatory cytokines and express CD206 and CX3CR1, during mesothelioma progression and during chemotherapy or immunotherapy-induced tumor regression. In vitro studies showed that mesothelioma-conditioned media generated CD206(-)CX3CR1(+)MCP-1(+)TGF-β(+) macrophages that induced T cell proliferation but prevented T cell IFNγ production. In vivo studies showed that co-inoculation of macrophages with mesothelioma cells led to faster tumor growth, and depleting macrophages using anti-F4/80 antibody induced tumor regression. Flow cytometry revealed increasing levels of different suppressive myeloid cells in lymphoid organs: MDSCs dominated bone marrow (BM) and spleens, M2 macrophages dominated tumor-draining lymph nodes (DLN) and a mixed IL-10(+)TNF-α(+)CD206(-)CX3CR1(+) M1/M2 (M3) macrophage subset dominated the mesothelioma microenvironment. Ki67 staining and cell cycle analysis showed that tumor-associated M1 and M3, but not M2, macrophages were proliferating in situ, with M1 cells arrested in the G1 phase while M3 cells progressed to mitosis. Immunohistochemistry showed that M1 and M3 cells were co-located supporting the hypothesis that M1 cells transition to M3 cells during proliferation. Gemcitabine reduced tumor-associated M3 and MDSCs, but not M2 macrophages, the latter likely contributing to the tumor outgrowth seen following treatment cessation. In contrast, IL-2/agonist anti-CD40 antibody therapy reduced M3 cells and polarized macrophages into M1 cells coinciding with tumor regression. These data show that myeloid cells, particularly M3 cells, represent a therapeutic target for the generation of antitumor immunity.
我们使用小鼠模型来监测间皮瘤进展过程中以及化疗或免疫治疗诱导肿瘤消退期间髓系细胞亚群的变化，即髓系来源的抑制性细胞（MDSCs）、分泌促炎细胞因子并表达CD40和CD80的M1巨噬细胞以及分泌抗炎细胞因子并表达CD206和CX3CR1的抑制性M2巨噬细胞。体外研究表明，间皮瘤条件培养基可产生CD206(-)CX3CR1(+)MCP-1(+)TGF-β(+)巨噬细胞，这些巨噬细胞可诱导T细胞增殖，但会阻止T细胞产生IFNγ。体内研究表明，巨噬细胞与间皮瘤细胞共同接种会导致肿瘤生长加快，而使用抗F4/80抗体清除巨噬细胞可诱导肿瘤消退。流式细胞术显示，淋巴器官中不同抑制性髓系细胞的水平在增加：MDSCs在骨髓（BM）和脾脏中占主导地位，M2巨噬细胞在肿瘤引流淋巴结（DLN）中占主导地位，而混合的IL-10(+)TNF-α(+)CD206(-)CX3CR1(+) M1/M2（M3）巨噬细胞亚群在间皮瘤微环境中占主导地位。Ki67染色和细胞周期分析表明，肿瘤相关的M1和M3巨噬细胞而非M2巨噬细胞在原位增殖，M1细胞停滞在G1期，而M3细胞进入有丝分裂期。免疫组织化学显示，M1和M3细胞共定位，支持了M1细胞在增殖过程中转变为M3细胞的假说。吉西他滨可减少肿瘤相关的M3和MDSCs，但不能减少M2巨噬细胞，后者可能是导致治疗停止后肿瘤复发的原因。相比之下，IL-2/激动剂抗CD40抗体疗法可减少M3细胞，并将巨噬细胞极化为M1细胞，这与肿瘤消退相一致。这些数据表明，髓系细胞，尤其是M3细胞，是产生抗肿瘤免疫的治疗靶点。
