Targeting epidermal growth factor receptor/human epidermal growth factor receptor 2 signalling pathway by a dual receptor tyrosine kinase inhibitor afatinib for radiosensitisation in murine bladder carcinoma
Journal
European Journal of Cancer
Journal Volume
49
Journal Issue
6
Pages
1458-1466
Date Issued
2013
Author(s)
Yeh C.-H.
KAI-YUAN TZEN
Ho P.-Y.
Tuan T.-F.
Abstract
Given the promising control of bladder cancer achieved by combined chemotherapy/radiotherapy with selective transurethral resection, obstacles remain to the treatment of unresectable bladder cancer. The aim of this study was to determine whether targeting epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) can radiosensitise a murine bladder tumour (MBT-2) cell line. Cell survival, expression of signal proteins and cell cycle changes in MBT-2 cells treated in vitro and in vivo with afatinib, an irreversible EGFR/HER2 inhibitor, plus radiotherapy were investigated by colony formation assay, Western blot assay and flow cytometry, respectively. Ectopic xenografts were established by subcutaneous injection of MBT-2 cells in C3H/HeN mice. Mice were randomised into 4 groups to receive afatinib (10 mg/kg/day on day 1-7) and/or radiotherapy (15 Gy on day 4). Positron emission tomography (PET) on day 8 was used to evaluate the early treatment response. Afatinib (200-1000 nM) increased cell killing by radiation (0-10 Gy). Pre-treatment of irradiated cells with afatinib inhibited radiation-activated HER2 and EGFR phosphorylation. As compared to either treatment alone, the combination increased the level of the cleavage form of poly (ADP-ribose) polymerase, the expression of phospho-γH2AX and the percentage of cells in subG1 phase (indicating enhanced induction of apoptosis), and decreased tumour metabolism and inhibited tumour growth by 64%. Afatinib has therapeutic value as a radiosensitiser of murine bladder cancer cells. The synergism between afatinib and radiation likely enhances DNA damage, leading to increased cell apoptosis. ? 2012 Elsevier Ltd. All rights reserved.
SDGs
Other Subjects
afatinib; epidermal growth factor receptor; epidermal growth factor receptor 2; histone H2AX; nicotinamide adenine dinucleotide adenosine diphosphate ribosyltransferase; animal cell; animal experiment; animal model; animal tissue; apoptosis; article; bladder cancer; cancer inhibition; cancer radiotherapy; cell survival; colony formation; controlled study; female; flow cytometry; G1 phase cell cycle checkpoint; in vitro study; in vivo study; metabolic inhibition; mouse; nonhuman; priority journal; protein cleavage; protein expression; protein phosphorylation; radiation dose; radiosensitization; treatment duration; treatment outcome; Western blotting; Animals; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Survival; Combined Modality Therapy; DNA Breaks; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; G1 Phase; Humans; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Phosphorylation; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-akt; Quinazolines; Radiation-Sensitizing Agents; Radiotherapy; Random Allocation; Receptor, Epidermal Growth Factor; Receptor, erbB-2; Signal Transduction; Urinary Bladder Neoplasms
Type
journal article