No direct effects of erythropoietin beta on a head and neck squamous cell carcinoma cell line which is growth stimulated in vivo

Abstract

Introduction. Erythropoiesis-stimulating agents (ESAs) are used in cancer therapy to reverse anaemia. It has been suggested that ESAs might improve treatment outcome by reducing tumour hypoxia, but ESAs might also increase tumour growth. In this work, the effect of recombinant human erythropoietin (rHuEpo) β was investigated on a human head and neck squamous carcinoma cell (HNSCC) line in vitro. The cell line was previously growth stimulated in combination with surgery in a xenograft model and the investigation was initiated to see if rHuEpo directly affects the tumour cell line, alone or in combination with cell stress, or if the in vivo effect should be attributed to secondary effects. Material and methods. The cell line LU-HNSCC-7 was grown in vitro and treated with rHuEpo alone or in combination with radiation, cisplatin, hypoxia or tumour extracts. The expression of the Epo receptor (EpoR) was investigated by western blotting after one- and two-dimensional electrophoresis, RT-PCR and through analysis of the effect on EpoR signalling. Results. The cell line was shown not to express EpoR. Furthermore, it was only possible to detect a minor effect on cell growth (1.4 times over control, p < 0.001) under specific conditions and at supra-pharmacological concentrations of rHuEpo β. No effect was detected on cell migration. None of the cell stressing treatments could enhance the minor growth stimulatory effect of rHuEpo β. Discussion. The conclusion is that rHuEpo β does not stimulate tumour growth of the investigated cell line through a direct interaction with tumour cells. We hypothesise that interactions with stromal cells and the stimulation of wound healing responses might, at least partly, explain the negative effects of ESA administration during cancer treatment. We propose that EpoR expression in HNSCC tumour cells might not be a good marker for prediction of ESA induced worsening of outcomes after cancer treatment.