title: A combretastatin-mediated decrease in neutrophil concentration in peripheral blood and the impact on the anti-tumor activity of this drug in two different murine tumor models.
abstract: The vascular disrupting agent combretastatin A-4 disodium phosphate (CA4P) induces fluctuations in peripheral blood neutrophil concentration. Because neutrophils have the potential to induce both vascular damage and angiogenesis we analyzed neutrophil involvement in the anti-tumoral effects of CA4P in C3H mammary carcinomas in CDF1 mice and in SCCVII squamous cell carcinomas in C3H/HeN mice. Flow cytometry analyses of peripheral blood before and up to 144 h after CA4P administration (25 and 250 mg/kg) revealed a decrease 1 h after treatment, followed by an early (3-6 h) and a late (>72 h) increase in the granulocyte concentration. We suggest that the early increase (3-6 h) in granulocyte concentration was caused by the initial decrease at 1 h and found that the late increase was associated with tumor size, and hence independent of CA4P. No alterations in neutrophil infiltration into the C3H tumor after CA4P treatment (25 and 250 mg/kg) were found. Correspondingly, neutrophil depletion in vivo, using an anti-neutrophil antibody, followed by CA4P treatment (25 mg/kg) did not increase the necrotic fraction in C3H tumors significantly. However, by increasing the CA4P dose to 250 mg/kg we found a significant increase of 359% in necrotic fraction when compared to neutrophil-depleted mice; in mice with no neutrophil depletion CA4P induced an 89% change indicating that the presence of neutrophils reduced the effect of CA4P. In contrast, neither CA4P nor 1A8 affected the necrotic fraction in the SCCVII tumors significantly. Hence, we suggest that the initial decrease in granulocyte concentration was caused by non-tumor-specific recruitment of neutrophils and that neutrophils may attenuate CA4P-mediated anti-tumor effect in some tumor models.
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Anja Bille
authors.initials: AB
authors.lastname: Bohn
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wittenborn
authors.affiliation: Department of Pathology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Anne Sofie
authors.initials: AS
authors.lastname: Brems-Eskildsen
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Tinne
authors.initials: T
authors.lastname: Laurberg
authors.affiliation: The MR-Research Centre, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lotte Bonde
authors.initials: LB
authors.lastname: Bertelsen
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nielsen
authors.affiliation: The MR-Research Centre, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Hans
authors.initials: H
authors.lastname: Stødkilde-Jørgensen
authors.affiliation: Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Bjarne Kuno
authors.initials: BK
authors.lastname: Møller
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Horsman
mesh_terms: D000818:Animals; D001632:Bibenzyls / Q000008:administration & dosage; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000473:pathology; D006801:Humans; D015674:Mammary Neoplasms, Animal / Q000097:blood* / Q000188:drug therapy; D051379:Mice; D009336:Necrosis / Q000097:blood / Q000188:drug therapy / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D009504:Neutrophils / Q000187:drug effects* / Q000473:pathology
chemical_list: D001632:Bibenzyls; C040105:combretastatin