title: Circulating endothelial cells as a novel marker of angiogenesis.
abstract: Measurement of tumor angiogenesis to predict and/or to assess the efficacy of antiangiogenic therapies is mainly based on the evaluation of microvessel density (MVD). We developed a novel flow cytometry procedure to measure circulating endothelial cells (CECs) and circulating endothelial cells progenitors (CECPs) in either preclinical and clinical studies. Preclinical studies were performed on an animal model of human lymphoma. A trend toward higher CECs values was observed on day 7 and 14 after transplant, and differences vs controls were highly significant on day 21 (p = 0.0061). A strong correlation was found between CECs and tumor volume (r = 0.942, p = 0.004) and between CECs and tumor-generated VEGF (r = 0.669, p = 0.02). In mice given cyclophosphamide, most of circulating apoptotic cells were hematopoietic and not endothelial. Conversely, in mice given endostatin, all of the increase in apoptotic cells was in the endothelial cell compartment. In a parallel study, we looked for CECs in the peripheral blood of 20 healthy controls and 76 newly diagnosed cancer patients by means of four-color flow cytometry. In breast cancer (n = 46) and lymphoma (n = 30) patients, both resting and activated CECs were increased by 5 fold (P < 0.0008 vs control). CECs significantly correlated with plasma levels of VCAM-1 and VEGF. Resting and activated CECs were similar to healthy controls in 7 lymphoma patients achieving complete remission after chemotherapy, and activated CECs were found to decrease in 13 breast cancer patients evaluated before and 24h after quadrantectomy. In conclusion, our findings indicate a close relation between CEC increase and tumor progression, and support CECs evaluation as a clinically relevant, non invasive angiogenesis marker. Furthermore, this assay offers insight into anti-angiogenic activity of different drugs.
authors.affiliation: Division of Hematology-Oncology, European Institute of Oncology, and IFOM-FIRC Institute of Molecular Oncology, Milan, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Mancuso
authors.forename: Angelica
authors.initials: A
authors.lastname: Calleri
authors.forename: Cristina
authors.initials: C
authors.lastname: Cassi
authors.forename: Alberto
authors.initials: A
authors.lastname: Gobbi
authors.forename: Manuela
authors.initials: M
authors.lastname: Capillo
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pruneri
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martinelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Bertolini
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003603:Cytotoxins / Q000494:pharmacology; D004195:Disease Models, Animal; D016228:Endothelial Growth Factors / Q000097:blood; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood; D008222:Lymphokines / Q000097:blood; D008223:Lymphoma / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008833:Microcirculation / Q000254:growth & development* / Q000473:pathology* / Q000503:physiopathology; D009369:Neoplasms / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D023041:Xenograft Model Antitumor Assays
chemical_list: D020533:Angiogenesis Inhibitors; D014408:Biomarkers, Tumor; D003603:Cytotoxins; D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors