Esmaeili Seyed-Alireza, Nejatollahi Foroogh, Sahebkar Amirhossein
Recombinant Antibody Laboratory, Department of Immunology, Shiraz University of Medical Sciences, Shiraz, Iran.
Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.
Anticancer Agents Med Chem. 2018;18(12):1674-1679. doi: 10.2174/1871520618666171208092115.
Six-Transmembrane epithelial antigen of the prostate-1 (STEAP-1) is present at the intercellular junctions of the secretory epithelium of prostate and is overexpressed in all steps of prostate cancer. STEAP-1 acts as a transporter protein or a putative channel between cancer cells while it has limited expression in normal human tissues. This protein has been suggested as an attractive target for prostate cancer immunotherapy.
This study aimed at the development of a specific single chain fragment variable (scFv) antibody against STEAP-1 epitope and testing the inhibitory effect of the selected scFv antibody in blocking gap junctions between tumor cells.
In the current study, a phage library was used and a specific scFv antibody was isolated against STEAP-1 epitope using panning process.
PCR and DNA fingerprinting of the obtained clones demonstrated a dominant pattern of a specific clone. Binding of the selected scFv to the corresponding target on PC3 and LNCaP cell lines was tested using ELISA and flow cytometry techniques. The inhibitory effect of the selected scFv antibody in blocking gap junctions between the cells was tested using intercellular communication assay. The selected antibody reacted with the corresponding epitope in ELISA and bound to prostate cancer cells with an intensity of 44.6% (PC3 cells) and 73.4% (LNCap cells) as shown by FACS analysis. Intercellular communication assay indicated that dye transfer between the cells in PC3 and LNCaP cell lines treated with 1000 scFv/cell was significantly inhibited (80-90%).
Our results suggested that the selected specific anti-STEAP1 scFv highly inhibited intercellular communication between prostate cancer cells and has the potential to be used as a new effective agent in prostate cancer immunotherapy.
前列腺六跨膜上皮抗原-1（STEAP-1）存在于前列腺分泌上皮的细胞间连接处，在前列腺癌的各个阶段均过度表达。STEAP-1在癌细胞之间充当转运蛋白或假定通道，而在正常人体组织中表达有限。该蛋白已被认为是前列腺癌免疫治疗的一个有吸引力的靶点。
本研究旨在开发一种针对STEAP-1表位的特异性单链可变片段（scFv）抗体，并测试所选scFv抗体对肿瘤细胞间缝隙连接的抑制作用。
在本研究中，使用了噬菌体文库，并通过淘选过程分离出针对STEAP-1表位的特异性scFv抗体。
对获得的克隆进行PCR和DNA指纹分析，显示出一个特定克隆的主导模式。使用ELISA和流式细胞术技术测试所选scFv与PC3和LNCaP细胞系上相应靶点的结合。使用细胞间通讯分析测试所选scFv抗体对细胞间缝隙连接的抑制作用。所选抗体在ELISA中与相应表位反应，FACS分析显示其与前列腺癌细胞结合，强度分别为44.6%（PC3细胞）和73.4%（LNCap细胞）。细胞间通讯分析表明，用1000个scFv/细胞处理的PC3和LNCaP细胞系中细胞间的染料转移受到显著抑制（80-90%）。
我们的结果表明，所选的特异性抗STEAP1 scFv高度抑制前列腺癌细胞之间的细胞间通讯，有潜力作为前列腺癌免疫治疗的一种新型有效药物。
