Tutino Valeria, Defrancesco Marianna Loredana, Tolomeo Maria, DE Nunzio Valentina, Lorusso Dionigi, Paleni Didier, Caruso Maria Gabriella, Notarnicola Maria, Barile Maria
National Institute of Gastroenterology, S. de Bellis Research Hospital, Castellana Grotte, Bari, Italy.
Department of Bioscience, Biotechnology and Biopharmaceutics, A. Moro University of Bari, Bari, Italy.
Anticancer Res. 2018 May;38(5):2659-2667. doi: 10.21873/anticanres.12508.
BACKGROUND/AIM: Riboflavin transport in enterocytes is mediated by three translocators: RFVT3 located on the apical membrane, and RFVT1 and RFVT2 on the basolateral membrane. The aim of this study was to investigate whether the expression levels of RFVTs are altered in human colorectal cancer (CRC).
In human colon adenocarcinoma cell lines (CaCo2, DLD-1, HT-29) and in tissues of patients with CRC, gene and protein expression levels were evaluated by real time-polymerase chain reaction and western blotting. Intracellular flavin content was determined by high-performance liquid chromatography.
RFVT3 and RFVT2 gene and protein expression levels were higher in DLD-1 and HT-29 compared to Caco2 cells. In HT-29 cells, the RFVT1 protein level was drastically lower. These differences are presumably responsible for the higher total flavin content in DLD-1 and HT-29 cells. In tumor tissues of patients with CRC, RFVT1 content was reduced at both protein and mRNA levels compared to normal mucosa. RFVT3 and RFVT2 gene expression levels were increased, while protein expression was reduced, with a small reduction in riboflavin amount.
This study provides first evidence that transcription/translation of RFVTs are profoundly altered in CRC.
背景/目的：肠细胞中的核黄素转运由三种转运体介导：位于顶端膜的RFVT3，以及位于基底外侧膜的RFVT1和RFVT2。本研究的目的是调查核黄素转运体（RFVTs）的表达水平在人类结直肠癌（CRC）中是否发生改变。
在人结肠腺癌细胞系（CaCo2、DLD-1、HT-29）以及CRC患者的组织中，通过实时聚合酶链反应和蛋白质印迹法评估基因和蛋白质表达水平。通过高效液相色谱法测定细胞内黄素含量。
与CaCo2细胞相比，DLD-1和HT-29细胞中RFVT3和RFVT2的基因及蛋白质表达水平更高。在HT-29细胞中，RFVT1蛋白水平显著降低。这些差异可能是导致DLD-1和HT-29细胞中总黄素含量更高的原因。在CRC患者的肿瘤组织中，与正常黏膜相比，RFVT1的蛋白质和mRNA水平均降低。RFVT3和RFVT2的基因表达水平升高，而蛋白质表达降低，核黄素含量略有减少。
本研究首次证明CRC中RFVTs的转录/翻译发生了显著改变。
