Department of Biomedical Sciences, University of Guelph, Guelph, ON, United States of America.
Department of Pathobiology, University of Guelph, Guelph, ON, United States of America.
Gynecol Oncol. 2022 Jan;164(1):154-169. doi: 10.1016/j.ygyno.2021.11.006. Epub 2021 Nov 16.
Tumor vasculature is structurally abnormal, with anatomical deformities, reduced pericyte coverage and low tissue perfusion. As a result of this vascular dysfunction, tumors are often hypoxic, which is associated with an aggressive tumor phenotype, and reduced delivery of therapeutic compounds to the tumor. We have previously shown that a peptide containing the thrombospondin-1 type I repeats (3TSR) specifically targets tumor vessels and induces vascular normalization in a mouse model of epithelial ovarian cancer (EOC). However, due to its small size, 3TSR is rapidly cleared from circulation. We now introduce a novel construct with the 3TSR peptide fused to the C-terminus of each of the two heavy chains of the Fc region of human IgG1 (Fc3TSR). We hypothesize that Fc3TSR will have greater anti-tumor activity in vitro and in vivo compared to the native compound.
Fc3TSR was evaluated in vitro using proliferation and apoptosis assays to investigate differences in efficacy compared to native 3TSR. In light of the multivalency of Fc3TSR, we also investigate whether it induces greater clustering of its functional receptor, CD36. We also compare the compounds in vivo using an orthotopic, syngeneic mouse model of advanced stage EOC. The impact of the two compounds on changes to tumor vasculature morphology was also investigated.
Fc3TSR significantly decreased the viability and proliferative potential of EOC cells and endothelial cells in vitro compared to native 3TSR. High-resolution imaging followed by image correlation spectroscopy demonstrated enhanced clustering of the CD36 receptor in cells treated with Fc3TSR. This was associated with enhanced downstream signaling and greater in vitro and in vivo cellular responses. Fc3TSR induced greater vascular normalization and disease regression compared to native 3TSR in an orthotopic, syngeneic mouse model of advanced stage ovarian cancer.
The development of Fc3TSR which is greater in size, stable in circulation and enhances receptor activation compared to 3TSR, facilitates its translational potential as a therapy in the treatment of metastatic advanced stage ovarian cancer.
肿瘤血管在结构上是异常的，具有解剖畸形、周细胞覆盖减少和组织灌注降低。由于这种血管功能障碍，肿瘤通常处于缺氧状态，这与侵袭性肿瘤表型相关，并减少了治疗化合物向肿瘤的输送。我们之前已经表明，一种含有血小板反应蛋白-1 型重复序列（3TSR）的肽特异性靶向肿瘤血管，并在小鼠上皮性卵巢癌（EOC）模型中诱导血管正常化。然而，由于其体积小，3TSR 从循环中迅速清除。现在，我们引入了一种新型构建体，将 3TSR 肽融合到人 IgG1 的 Fc 区的两个重链的 C 末端（Fc3TSR）。我们假设 Fc3TSR 在体外和体内将比天然化合物具有更大的抗肿瘤活性。
使用增殖和凋亡测定法评估 Fc3TSR 在体外的作用，以研究与天然 3TSR 的疗效差异。鉴于 Fc3TSR 的多价性，我们还研究了它是否诱导其功能受体 CD36 更大程度的聚集。我们还在同源、同基因小鼠晚期 EOC 模型中比较了这两种化合物。还研究了两种化合物对肿瘤血管形态变化的影响。
与天然 3TSR 相比，Fc3TSR 显著降低了体外 EOC 细胞和内皮细胞的活力和增殖潜力。高分辨率成像后，通过图像相关光谱学证实，Fc3TSR 处理的细胞中 CD36 受体的聚类增强。这与增强的下游信号转导和更大的体外和体内细胞反应相关。与天然 3TSR 相比，Fc3TSR 在同源、同基因晚期卵巢癌小鼠模型中诱导了更大的血管正常化和疾病消退。
Fc3TSR 的开发，其尺寸更大，在循环中更稳定，并且与 3TSR 相比增强了受体激活，促进了其作为转移性晚期卵巢癌治疗的治疗潜力。
