Du Four Stephanie, Maenhout Sarah K, De Pierre Kari, Renmans Dries, Niclou Simone P, Thielemans Kris, Neyns Bart, Aerts Joeri L
Laboratory of Molecular and Cellular Therapy; Department of Immunology-Physiology; Vrije Universiteit Brussel , Brussels, Belgium.
Department of Pathology ; UZ Brussel, Brussels, Belgium.
Oncoimmunology. 2015 Jan 22;4(4):e998107. doi: 10.1080/2162402X.2014.998107. eCollection 2015 Apr.
Melanoma patients are at a high risk of developing brain metastases, which are strongly vascularized and therefore have a significant risk of spontaneous bleeding. VEGF not only plays a role in neo-angiogenesis but also in the antitumor immune response. VEGFR-targeted therapy might not only have an impact on the tumor vascularization but also on tumor-infiltrating immune cells. In this study, we investigated the effect of axitinib, a small molecule TKI of VEGFR-1, -2, and -3, on tumor growth and on the composition of tumor-infiltrating immune cells in subcutaneous and intracranial mouse melanoma models. treatment with axitinib induced a strong inhibition of tumor growth and significantly improved survival in both tumor models. Characterization of the immune cells within the spleen and tumor of tumor-bearing mice respectively showed a significant increase in the number of CD3CD8 T cells and CD11b cells of axitinib-treated mice. More specifically, we observed a significant increase of intratumoral monocytic myeloid-derived suppressor cells (moMDSCs; CD11bLy6CLy6G). Interestingly, proliferation assays showed that moMDSCs isolated from spleen or tumor of axitinib-treated mice had a reduced suppressive capacity on a per cell basis as compared to those isolated from vehicle-treated mice. Moreover, MDSCs from axitinib-treated animals displayed the capacity to stimulate allogeneic T cells. Thus, treatment with axitinib induces differentiation of moMDSC toward an antigen-presenting phenotype. Based on these observations, we conclude that the impact of axitinib on tumor growth and survival is most likely not restricted to direct anti-angiogenic effects but also involves important effects on tumor immunity.
黑色素瘤患者发生脑转移的风险很高,脑转移瘤血管丰富,因此有显著的自发性出血风险。血管内皮生长因子(VEGF)不仅在新生血管形成中起作用,而且在抗肿瘤免疫反应中也起作用。靶向血管内皮生长因子受体(VEGFR)的治疗可能不仅会影响肿瘤血管生成,还会影响肿瘤浸润免疫细胞。在本研究中,我们研究了阿昔替尼(一种VEGFR-1、-2和-3的小分子酪氨酸激酶抑制剂)对皮下和颅内小鼠黑色素瘤模型中肿瘤生长及肿瘤浸润免疫细胞组成的影响。阿昔替尼治疗在两种肿瘤模型中均诱导了对肿瘤生长的强烈抑制并显著提高了生存率。对荷瘤小鼠脾脏和肿瘤内免疫细胞的表征分别显示,阿昔替尼治疗组小鼠的CD3CD8 T细胞和CD11b细胞数量显著增加。更具体地说,我们观察到肿瘤内单核细胞来源的髓系抑制细胞(moMDSCs;CD11bLy6CLy6G)显著增加。有趣的是,增殖试验表明,与从溶剂处理组小鼠分离的moMDSCs相比,从阿昔替尼治疗组小鼠脾脏或肿瘤中分离的moMDSCs单个细胞的抑制能力降低。此外,来自阿昔替尼治疗动物的MDSCs表现出刺激同种异体T细胞的能力。因此,阿昔替尼治疗诱导moMDSC向抗原呈递表型分化。基于这些观察结果,我们得出结论,阿昔替尼对肿瘤生长和生存的影响很可能不仅限于直接的抗血管生成作用,还涉及对肿瘤免疫的重要影响。