Abstract. The aim of the present study was to investigate dexamethasone (DEX)-induced secretion of cystatin C (Cys C) and the effect of cisplatin (CDDP) and 5-fluorouracil (5-FU) on Cys C secretion in human cancer cell lines. KYSE150, A549 and Caki-2 human cancer cell lines were cultured on plastic dishes and treated with DEX (100 nM) for 24, 48 and 72 h. KYSE150 cells were co-treated with DEX, CDDP (10 µM), and 5-FU (2 µM). The effects of DEX, CDDP and 5-FU on cell viability were evaluated. Results showed Cys C secretion levels in the culture medium of DEX-treated KYSE150 cells to be 1.8-to 2.3-fold higher compared to those in the culture medium of control cells. A similar tendency was observed in A549 cells at all the time points, whereas a significant increase in the Cys C secretion by Caki-2 cells was observed only 24 h after DEX treatment. Regarding KYSE150 cells, the secretion of Cys C was also enhanced by co-treatment of CDDP or 5-FU with DEX, although it was not affected by the co-administration of DEX and mifepristone, a glucocorticoid receptor antagonist. At concentrations that are typically used in esophageal cancer chemotherapy, CDDP and 5-FU demonstrated a moderate level of cytotoxicity in KYSE150 cells in contrast to DEX. These findings suggested that DEX has the potential to enhance the extracellular secretion of Cys C in esophageal cancer cells, possibly due to the transcriptional regulation mediated by glucocorticoid receptor activity.
IntroductionCystatin C (Cys C) is a non-glycosylated cationic 13.3-kDa protein belonging to the cystatin superfamily of cysteine protease inhibitors (1-3). Cys C is produced by nucleated cells and is secreted into the blood at a constant rate (1-3). It is freely filtered through the glomerular membrane, completely re-absorbed and then catabolized in the proximal tubular cells (1-3). Thus, similarly to creatinine, the biological fate of Cys C is a good endogenous marker of the glomerular filtration rate (GFR).In patients with esophageal cancer, cisplatin (CDDP) is used as a neoadjuvant or as a post-operative adjuvant chemotherapy in combination with continuous infusion of 5-fluorouracil (5-FU) (4,5). When CDDP-based chemotherapy is administered, antiemetic drugs, such as dexamethasone (DEX), 5-HT 3 serotonin receptor antagonists or aprepitant are administered to prevent treatment-associated nausea and vomiting (6). A transient elevation was previously reported in serum Cys C concentration during the perioperative chemotherapy period in patients with esophageal cancer. We suggested that renal function estimates determined on the basis of serum Cys C levels during this treatment period might be misleading (7).To understand the effect of DEX and other drugs in detail, it is crucial to investigate the renal effects associated with serum Cys C concentration. The aim of this study was to investigate the ability of DEX to induce Cys C secretion in human cancer cell lines, as well as the effect of CDDP, 5-FU and mifepristone (RU-486) on Cys C secretion.
Materials and metho...