Zhang Michael, Hutter Gregor, Kahn Suzana A, Azad Tej D, Gholamin Sharareh, Xu Chelsea Y, Liu Jie, Achrol Achal S, Richard Chase, Sommerkamp Pia, Schoen Matthew Kenneth, McCracken Melissa N, Majeti Ravi, Weissman Irving, Mitra Siddhartha S, Cheshier Samuel H
Division of Pediatric Neurosurgery, Department of Neurosurgery, Lucile Packard Children's Hospital, Stanford University School of Medicine, Stanford, California, United States of America.
Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California, United States of America.
PLoS One. 2016 Apr 19;11(4):e0153550. doi: 10.1371/journal.pone.0153550. eCollection 2016.
Tumor-associated macrophages (TAMs) represent an important cellular subset within the glioblastoma (WHO grade IV) microenvironment and are a potential therapeutic target. TAMs display a continuum of different polarization states between antitumorigenic M1 and protumorigenic M2 phenotypes, with a lower M1/M2 ratio correlating with worse prognosis. Here, we investigated the effect of macrophage polarization on anti-CD47 antibody-mediated phagocytosis of human glioblastoma cells in vitro, as well as the effect of anti-CD47 on the distribution of M1 versus M2 macrophages within human glioblastoma cells grown in mouse xenografts. Bone marrow-derived mouse macrophages and peripheral blood-derived human macrophages were polarized in vitro toward M1 or M2 phenotypes and verified by flow cytometry. Primary human glioblastoma cell lines were offered as targets to mouse and human M1 or M2 polarized macrophages in vitro. The addition of an anti-CD47 monoclonal antibody led to enhanced tumor-cell phagocytosis by mouse and human M1 and M2 macrophages. In both cases, the anti-CD47-induced phagocytosis by M1 was more prominent than that for M2. Dissected tumors from human glioblastoma xenografted within NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice and treated with anti-CD47 showed a significant increase of M1 macrophages within the tumor. These data show that anti-CD47 treatment leads to enhanced tumor cell phagocytosis by both M1 and M2 macrophage subtypes with a higher phagocytosis rate by M1 macrophages. Furthermore, these data demonstrate that anti-CD47 treatment alone can shift the phenotype of macrophages toward the M1 subtype in vivo.
肿瘤相关巨噬细胞（TAMs）是胶质母细胞瘤（世界卫生组织IV级）微环境中的一个重要细胞亚群，也是一个潜在的治疗靶点。TAMs在抗肿瘤的M1和促肿瘤的M2表型之间呈现出连续的不同极化状态，M1/M2比值较低与预后较差相关。在这里，我们研究了巨噬细胞极化对体外抗CD47抗体介导的人胶质母细胞瘤细胞吞噬作用的影响，以及抗CD47对在小鼠异种移植瘤中生长的人胶质母细胞瘤细胞内M1与M2巨噬细胞分布的影响。体外将骨髓来源的小鼠巨噬细胞和外周血来源的人巨噬细胞极化为M1或M2表型，并通过流式细胞术进行验证。将原代人胶质母细胞瘤细胞系作为体外小鼠和人M1或M2极化巨噬细胞的靶标。添加抗CD47单克隆抗体可增强小鼠和人M1及M2巨噬细胞对肿瘤细胞的吞噬作用。在这两种情况下，M1巨噬细胞由抗CD47诱导的吞噬作用比M2更显著。对在NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ小鼠体内异种移植的人胶质母细胞瘤进行解剖，并给予抗CD47治疗，结果显示肿瘤内M1巨噬细胞显著增加。这些数据表明，抗CD47治疗可增强M1和M2巨噬细胞亚型对肿瘤细胞的吞噬作用，且M1巨噬细胞的吞噬率更高。此外，这些数据还证明单独使用抗CD47治疗可在体内使巨噬细胞表型向M1亚型转变。
