Expression of liver X receptors in normal and refractory carcinoma tissues of the human lung and pancreas
Korehito Kashiwagi1,2, Mai Yanagida1, Daiki Matsui1, Mizuko Tanaka1, Kotaro Sugimoto1, Honglei Chen3, Naoki Ichikawa-Tomikawa1, Shigeru Marubashi4, Hiroyuki Suzuki5 and Hideki Chiba1
1Department of Basic Pathology, 4Department of Hepato-Biliary-Pancreatic and Transplant Surgery, 5Department of Chest Surgery, Fukushima Medical University School of Medicine, Fukushima, 2Department of Pathology, Dokkyo Medical University School of Medicine, Mibu, Japan and 3Department of Pathology, School of Basic Medical Science, Wuhan University, Wuhan, China
Offprint requests to: Hideki Chiba, Department of Basic Pathology, Fukushima Medical University School of Medicine, Hikarigaoka-1- Fukushima 960-125, Japan. e-mail: hidchiba@fmu.ac.jp
Summary. Liver X receptors (LXRs) participate not only in maintaining cholesterol homeostasis but also in controlling cellular growth in many types of normal and tumor cells. We previously reported that LXRα was aberrantly expressed in human oral squamous cell carcinoma (HOSCC) tissues and cell lines, and that LXR stimulation led to significant reduction of proliferation of HOSCC cells via accelerating cholesterol efflux. Since LXRs and downstream proteins involved in cholesterol metabolism could be also applied as therapeutic targets in small cell lung carcinoma (SCLC) and pancreatic ductal adenocarcinoma (PDAC), we herein analyzed the distribution of LXR proteins in these refractory cancers as well as in normal human lung and pancreatic tissues. LXRβ was observed in ciliated epithelial cells, bronchial gland epithelia, type II alveolar epithelia and alveolar macrophages of the lung, and was less expressed in bronchial basal cells and type I alveolar epithelia. In addition, LXRβ was detected in epithelium of the pancreatic duct and acinar cells of the pancreas, and was weakly expressed in pancreatic islet cells. By contrast, LXRα expression was restricted to alveolar macrophages, and was not evident in any types of epithelial cells in the lung and pancreas. We also demonstrated that LXRβ but not LXRα was abundantly expressed in nine cases of SCLC and twenty cases of PDAC tissues. These findings provide basic information for evaluating the efficacy of LXR-targeted treatment in SCLC and PDAC. Histol Histopathol 33, 497-505 (2018)
Key words: Liver X receptor, Nuclear receptor, Small cell lung carcinoma, Pancreatic ductal adenocarcioma, Epithelial cell
DOI: 10.14670/HH-11-949