Kishida Masato, Ishige Kazunori, Horibe Tomohisa, Tada Noriko, Koibuchi Nobutaka, Shoda Junichi, Kita Kiyoshi, Kawakami Koji
Department of Biomedical Chemistry, Graduate school of Medicine, The University of Tokyo, Tokyo 113-0033.
Oncol Lett. 2012 Mar;3(3):525-529. doi: 10.3892/ol.2011.528. Epub 2011 Dec 19.
Targeting tumor-specific receptors is a promising approach for cytotoxic agents. The orexin 2 receptor (OX2R) has reportedly been expressed in a few types of cancer, but not in normal, cells. This study aimed to explore and assess the expression levels of OX2R in a wide range of cancer cell lines and clinical samples to identify its localization. To analyze OX2R expression, we developed a polyclonal antibody specific to OX2R by immunizing two rabbits with a peptide cocktail. A total of 36 cancer cell lines were employed for reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, and 221 samples from various tissue arrays were used for the immunohistochemistry of OX2R expression. OX2R was identified in three cancerous cell lines, from the gallbladder, squamous cell carcinoma of the head and neck (SCCHN) and glioblastoma. With clinical samples of tissue arrays, 69/221 (31.2%) samples reacted positively with the OX2R antibody. We confirmed its presence on the cell membrane. In conclusion, OX2R was identified on several cancer cells as well as clinical samples. Further studies with larger numbers of clinical samples are required to confirm the statistical significance of the presence and relationships of OX2R with tumor histology. Results of the current study suggested that OX2R is a potent target for immunotoxin or antibody-drug conjugate (ADC) cancer therapy on OX2R-positive cancer cells.
靶向肿瘤特异性受体是细胞毒性药物的一种有前景的方法。据报道，食欲素2受体（OX2R）在几种癌症类型中表达，但在正常细胞中不表达。本研究旨在探索和评估OX2R在广泛的癌细胞系和临床样本中的表达水平，以确定其定位。为了分析OX2R的表达，我们用一种肽混合物免疫两只兔子，制备了一种针对OX2R的多克隆抗体。总共36个癌细胞系用于逆转录聚合酶链反应（RT-PCR）和蛋白质印迹分析，221个来自各种组织芯片的样本用于OX2R表达的免疫组织化学检测。在来自胆囊、头颈部鳞状细胞癌（SCCHN）和胶质母细胞瘤的三个癌细胞系中鉴定出OX2R。在组织芯片的临床样本中，69/221（31.2%）的样本与OX2R抗体呈阳性反应。我们证实其存在于细胞膜上。总之，在几种癌细胞以及临床样本中鉴定出了OX2R。需要用更多的临床样本进行进一步研究，以证实OX2R的存在及其与肿瘤组织学关系的统计学意义。本研究结果表明，OX2R是针对OX2R阳性癌细胞进行免疫毒素或抗体药物偶联物（ADC）癌症治疗的有效靶点。
