An alternative approach could be to selleck kinase inhibitor use licensed iron chelators such as deferoxamine (DFO) or deferasirox, which have a proven safety profile (Merlot et al., 2012). Both in vitro and in vivo data highlight their potential as possible anti-cancer agents (Richardson, 2002; Whitnall et al., 2006; Yu et al., 2006; Merlot et al., 2012). The iron chelator, DFO, has shown promise as an anti-tumour agent in human clinical trials involving neuroblastoma and leukaemia (Estrov et al., 1987; Donfrancesco et al., 1990; 1992; 1995). However, the utility of iron chelators in treating patients with oesophageal cancer has not yet been addressed. Therefore, the aims of this investigation were to assess whether DFO and deferasirox could inhibit iron-mediated tumour-promoting effects observed in oesophageal models and whether they possess anti-oesophageal cancer activity in vivo.

These studies could provide a sound rationale for evaluating the usefulness of these agents in human clinical trials as treatments for oesophageal cancer and also as potential chemo-sensitizers. The latter is particularly relevant in oesophageal cancer, as the majority of patients either receive neo-adjuvant or palliative chemotherapy. Methods Iron chelators and chemotherapeutic drugs DFO was purchased from Sigma-Aldrich (St. Louis, MO) and was used throughout this study at its IC50 value (10 ��M). Deferasirox (a kind gift from Novartis, Basel, Switzerland) was used at concentrations of 0�C40 ��M. The ligand, Dp44mT, was synthesized as previously described and used at 1 ��M, where it shows high anti-tumour activity (Yuan et al.

, 2004). Epirubicin (Mayne Pharma Plc, Warwickshire, UK), cisplatin (TEVA UK, Eastbourne, UK) and fluorouracil (5-FU; Mayne Pharma Plc) were used at concentrations between 0 and 32 ��M (IC50 values: 1, 8 and 8 ��M respectively). The IC50 values above were determined over a 48 h period using the OE33, OE19 and OE21 oesophageal cell lines. Cell culture The oesophageal adenocarcinoma lines, OE19 and OE33, and oesophageal squamous cell carcinoma lines OE21 and TE4, were routinely cultured in DMEM with 10% FCS (Invitrogen, Mulgrave, VIC, Australia) (Rockett et al., 1997; Takashima et al., 2011). In addition, the oesophageal squamous cell line, TE4 (kind gift from Prof W Dinjens, University of Rotterdam), previously reported to be cisplatin-resistant, was cultured with and without cisplatin (2 ��M) to maintain resistance (Takashima et al.

, 2011). Assessment of cellular iron uptake and efflux Inhibition of cellular 59Fe uptake by iron chelators Cells (1 �� 105 mL?1) were plated in triplicate to achieve 70% confluence Drug_discovery in culture dishes (35 �� 10 mm). Cell monolayers were then incubated for 3 h/37��C with media (1 mL) containing 59Fe-transferrin (59Fe-Tf; 60 ��g?mL?1) and the iron chelators (1�C20 ��M) (Richardson et al., 1995).