Tumor Laboratory, Department of Oncology, The Affiliated Lianyungang Hospital of Xuzhou Medical University, No.182 North Tongguan Road, Lianyungang, 222002, China.
Department of Oncology, The Affiliated Lianyungang Hospital of Xuzhou Medical University, No.182 North Tongguan Road, Lianyungang, 222002, China.
J Cancer Res Clin Oncol. 2018 Jul;144(7):1329-1337. doi: 10.1007/s00432-018-2667-8. Epub 2018 May 17.
To determine if inhibiting neuropilin-1 (NRP-1) affects the radiosensitivity of NSCLC cells through a vascular endothelial growth factor receptor 2 (VEGFR2)-independent pathway, and to assess the underlying mechanisms.
The expression of VEGFR2, NRP-1, related signaling molecules, abelson murine leukemia viral oncogene homolog 1 (ABL-1), and RAD51 were determined by RT-PCR and Western blotting, respectively. Radiosensitivity was assessed using the colony-forming assay, and the cell apoptosis were analyzed by flow cytometry.
We selected two cell lines with high expression levels of VEGFR2, including Calu-1 cells that have high NRP-1 expression, and H358 cells that have low NRP-1 expression. Upon inhibition of p-VEGFR2 by apatinib in Calu-1 cells, the expression of NRP-1 protein and other related proteins in the pathway was still high. Upon NRP-1 siRNA treatment, the expression of both NRP-1 and RAD51 decreased (p < 0.01; p < 0.05). Upon ABL-1 siRNA treatment, the expression of NRP-1 was increased and the expression of RAD51 was unchanged. Calu-1 cells treated with NRP-1 siRNA exhibited significantly higher apoptosis and radiation sensitivity in radiation therapy compared to Calu-1 cells treated with apatinib alone (p < 0.01; p < 0.01). The apoptosis and radiation sensitivity in H358 cells with NRP-1 overexpression was similar to the control group regardless of VEGFR2 inhibition.
We demonstrated that when VEGFR2 was inhibited, NRP-1 appeared to regulate RAD51 expression through the VEGFR2-independent ABL-1 pathway, consequently regulating radiation sensitivity. In addition, the combined inhibition of VEGFR2 and NRP-1 appears to sensitize cancer cells to radiation.
通过非血管内皮生长因子受体 2（VEGFR2）相关途径，确定抑制神经纤毛蛋白 1（NRP-1）是否会影响非小细胞肺癌（NSCLC）细胞的放射敏感性，并评估其潜在机制。
采用 RT-PCR 和 Western blot 分别检测 VEGFR2、NRP-1、相关信号分子、abl 细胞白血病病毒癌基因同源物 1（ABL-1）和 RAD51 的表达。通过集落形成实验评估放射敏感性，通过流式细胞术分析细胞凋亡。
我们选择了两种 VEGFR2 高表达的细胞系，包括高 NRP-1 表达的 Calu-1 细胞和低 NRP-1 表达的 H358 细胞。在 Calu-1 细胞中，通过阿帕替尼抑制 p-VEGFR2 后，该通路中 NRP-1 蛋白和其他相关蛋白的表达仍然很高。用 NRP-1 siRNA 处理后，NRP-1 和 RAD51 的表达均降低（p<0.01;p<0.05）。用 ABL-1 siRNA 处理后，NRP-1 的表达增加，RAD51 的表达不变。与单独用阿帕替尼处理的 Calu-1 细胞相比，用 NRP-1 siRNA 处理的 Calu-1 细胞在放射治疗中表现出更高的凋亡和放射敏感性（p<0.01;p<0.01）。无论 VEGFR2 抑制如何，过表达 NRP-1 的 H358 细胞的凋亡和放射敏感性与对照组相似。
我们证明，当 VEGFR2 被抑制时，NRP-1 似乎通过 VEGFR2 非依赖性 ABL-1 途径调节 RAD51 的表达，从而调节放射敏感性。此外，联合抑制 VEGFR2 和 NRP-1 似乎可使癌细胞对放射敏感。
