title: Recombinant human erythropoietin alpha targets intratumoral blood vessels, improving chemotherapy in human xenograft models.
abstract: Recombinant human erythropoietin (rHuEPO) is widely used for correction of hemoglobin level in cancer patients. However, apart from hematopoiesis, rHuEPO reportedly has an effect on endothelial cells. We describe here how rHuEPOalpha can modulate tumor vasculature in human squamous cell (A431) and colorectal carcinoma (HT25) xenograft models. In vivo rHuEPO treatment of xenografts at human-equivalent dose significantly increased the proliferation index of the tumor-associated endothelial cells and the size of CD31-positive intratumoral blood vessels, whereas the pericyte coverage became fragmented. Moreover, rHuEPO administration resulted in decreased expression of vascular endothelial growth factor both by cancer cells and tumor stroma, measured by quantitative PCR. Due to the morphologic alterations in tumoral microvessels, DNA-binding agents (Hoechst and Doxorubicin) labeled significantly larger areas in the tumor mass. Furthermore, rHuEPO treatment led to a significantly improved efficacy of 5-fluorouracil (5-FU) chemotherapy in the case of both tumor xenografts. Meanwhile, rHuEPO had no effect on the in vitro proliferation of erythropoietin receptor-positive tumor cells, and did not interfere with the effects of 5-FU either. These data reveal a new effect of rHuEPO administration: remodeling tumoral microvessels, suppressing vascular endothelial growth factor expression, thereby augmenting antitumor effects of a cancer drug, 5-FU, even in erythropoietin receptor-positive human cancer xenografts.
authors.affiliation: Department of Tumor Progression and Central Laboratory, National Institute of Oncology, Budapest, Hungary.
authors.forename: József
authors.initials: J
authors.lastname: Tóvári
authors.forename: Réka
authors.initials: R
authors.lastname: Gilly
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Rásó
authors.forename: Sándor
authors.initials: S
authors.lastname: Paku
authors.forename: Bíborka
authors.initials: B
authors.lastname: Bereczky
authors.forename: Norbert
authors.initials: N
authors.lastname: Varga
authors.forename: Agnes
authors.initials: A
authors.lastname: Vágó
authors.forename: József
authors.initials: J
authors.lastname: Tímár
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000098:blood supply* / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000188:drug therapy* / Q000378:metabolism; D004357:Drug Synergism; D004921:Erythropoietin / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D020286:Pericytes / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D017467:Receptors, Erythropoietin / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins; D023041:Xenograft Model Antitumor Assays
chemical_list: D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin; D005472:Fluorouracil