Clinical Cancer Research, 2016.

VEGF potentiates GD3-mediated immune suppression by human ovarian cancer cells

Irina V Tiper, Sarah M Temkin, Sarah Spiegel, et al

Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland

Natural killer T (NKT) cells are important mediators of antitumor immune responses. We have previously shown that ovarian cancers shed the ganglioside GD3, which inhibits NKT-cell activation. Ovarian cancers also secrete high levels of VEGF. In this study, we sought to test the hypothesis that VEGF production by ovarian cancers suppresses NKT-cell-mediated antitumor responses.

EXPERIMENTAL DESIGN:

To investigate the effects of VEGF on CD1d-mediated NKT-cell activation, a conditioned media model was established, wherein the supernatants from ovarian cancer cell lines (OV-CAR-3 and SK-OV-3) were used to treat CD1d-expressing antigen-presenting cells (APC) and cocultured with NKT hybridomas. Ovarian cancer-associated VEGF was inhibited by treatment with bevacizumab and genistein; conditioned medium was collected, and CD1d-mediated NKT-cell responses were assayed by ELISA.

RESULTS:

Ovarian cancer tissue and ascites contain lymphocytic infiltrates, suggesting that immune cells traffic to tumors, but are then inhibited by immunosuppressive molecules within the tumor microenvironment. OV-CAR-3 and SK-OV-3 cell lines produce high levels of VEGF and GD3. Pretreatment of APCs with ascites or conditioned medium from OV-CAR-3 and SK-OV-3 blocked CD1d-mediated NKT-cell activation. Inhibition of VEGF resulted in a concomitant reduction in GD3 levels and restoration of NKT-cell responses.

CONCLUSIONS:

We found that VEGF inhibition restores NKT-cell function in an in vitro ovarian cancer model. These studies suggest that the combination of immune modulation with antiangiogenic treatment has therapeutic potential in ovarian cancer.

美国《临床肿瘤研究》, 2016.

VEGF增强人卵巢癌细胞的GD3介导的免疫抑制

Irina V Tiper, Sarah M Temkin, Sarah Spiegel, et al

马里兰州的巴尔的摩，马里兰大学医学院免疫学和微生物学系

自然杀伤T（NKT）细胞是抗肿瘤免疫反应的重要介质。我们曾表明卵巢癌脱落神经节苷脂GD3，抑制NKT细胞活化。卵巢癌也分泌高水平的VEGF。在这项研究中，我们试图检验由卵巢癌的VEGF生成抑制NKT细胞介导的抗肿瘤反应的假说。

实验设计：

为了研究VEGF对CD1d介导的NKT细胞活化的影响，建立条件培养基模型，其中来自卵巢癌细胞系（OV-CAR-3和SK-OV-3）的上清液用于治疗CD1d-表达抗原呈递细胞（APC）并与NKT杂交瘤共培养。卵巢癌相关VEGF受到贝伐单抗和染料木素的治疗抑制; 收集条件培养基，通过ELISA测定CD1d介导的NKT细胞反应。

结果：

卵巢癌组织和腹水含有淋巴细胞浸润，表明免疫细胞运输到肿瘤，但是然后被肿瘤微环境内的免疫抑制分子抑制。OV-CAR-3和SK-OV-3细胞系产生高水平的VEGF和GD3。 用OV-CAR-3和SK-OV-3的腹水或条件培养基预处理APC，阻断CD1d介导的NKT细胞活化。VEGF的抑制导致GD3水平降低和NKT细胞反应也相应减少。

结论：

我们发现VEGF抑制恢复体外卵巢癌模型中的NKT细胞功能。这些研究表明免疫调节与抗血管生成治疗的组合在卵巢癌中具有治疗潜力。