Recombinant human erythropoietin promotes the acquisition of a malignant phenotype in head and neck squamous cell carcinoma cell lines in vitro

Abstract

BackgroundRecent studies indicate an increase in tumor progression and recurrence in head and neck squamous cell carcinomas (HNSCC) of cancer patients taking recombinant human erythropoietin (rhEpo) for anemia. This study was undertaken to investigate the potential role of rhEpo in invasion, proliferation, and cisplatin-induced cell death in HNSCC cell lines.MethodsThe following experiments were performed with two HNSCC cell lines, UMSCC-10B and UMSCC-22B. Presence of EpoR in both cell lines was determined by western blot and quantitative PCR. Colorimetric MTS assays and clonogenic assays were used to study the effect of rhEpo at pharmacologically relevant doses on cell proliferation. Matrigel invasion assays were performed in order to determine effects of exogenous rhEpo on invasive abilities. Clonogenic assays were also used to study potential cytoprotective effects of rhEpo against cisplatin. Immunoblotting was done to analyze the effect of rhEpo on Akt phosphorylation. Finally, MTS and TUNEL assays were performed to test our hypothesis that Akt activation by PI3K was involved in rhEpo-mediated cisplatin resistance.ResultsHNSCC cell lines were shown to express Epo receptor (EpoR). RhEpo increased invasion 1.8-fold in UMSCC-10B and 2.6-fold in UMSCC-22B compared to control. RhEpo at 10 U/ml increased cell proliferation by 41% and 53% in UMSCC-10B and UMSCC-22B, respectively, and colony formation by 1.5-fold and 1.8-fold. UMSCC-10B treated with cisplatin and exposed to rhEpo at 1 and 10 U/ml resulted in a 1.7-fold and 3.0-fold increase in colony number compared to control, respectively. UMSCC-22B treated with cisplatin and rhEpo at 1 or 10 U/ml resulted in ~2.5-fold increase in colony number. A TUNEL assay demonstrated a 30.5% and 76.5% increase in survival in UMSCC-10B and UMSCC-22B cells, respectively, in cisplatin and rhEpo-treated cells compared to cisplatin alone. MTS assay showed similar cytoprotective effects. Western blot revealed increased phosphorylation of Akt upon exposure of HNSCC cell lines to rhEpo. MTS assay and TUNEL analyses implicate Akt as a likely contributor to regulation of rhEpo-mediated cytoprotection.ConclusionsThe results demonstrate that, in HNSCC cells expressing functional EpoR, rhEpo promotes invasion, cell proliferation, and induces resistance to cisplatin, which may contribute to tumor progression.

Biomarkers Expression in Cervical Cancer and High Grade Squamous Intraepithelial Lesions

“…Moreover, among different biological markers of angiogenesis, only VEGFR2 expression was reported as predictor of response to radio-chemotherapy in cervical cancer [39,40]. It has been recently reported that EGFRc is an independent prognostic factor in cervix cancer FIGO stages IIb-IV [41]. Although we have not looked for EGFRc expression, is has been described a relation between EGF system and VEGF.…”

“…Epo and EpoR are downstream targets of HIF and can promote acquisition of malignant phenotype and exert antiapoptotic effects on certain tumor cell lines [41]. As such, treatment with rhEpo could have harmful consequences.…”

Functional significance of erythropoietin in renal cell carcinoma

“…This can be executed directly by HIF per se or through one of the many pro-inflammatory cytokines that are up-regulated in cancer patients, for example tumour necrosis factor-α [94-97]. To support this view, two recent studies have shown that hypoxia induced-EPO [98] and exogenous rhEPO [99] activate the PI3K/Akt/mTOR in retinal, and head and neck cancer cells respectively.…”

Association between FBP1 and hypoxia-related gene expression in clear cell renal cell carcinoma

“…Several studies observed that exogenous recombinant human EPO inhibits cancer progression, however, other studies indicated that it promotes cancer progression (20)(21)(22). EPO expression under a hypoxic environment is predominantly regulated by HIF2α (23).…”