title: Tumors exposed to acute cyclic hypoxia show increased vessel density and delayed blood supply.
abstract: The purpose of this study was to investigate the effect of acute cyclic hypoxia on tumor vasculature. A-07 human melanoma xenografts growing in dorsal window chambers were used as tumor model. Acute cyclic hypoxia was induced by periodically exposing tumor-bearing mice to a low oxygen atmosphere. The hypoxia treatment consisted of 12 cycles of 10 min of low O(2) (8% O(2) in N(2)) followed by 10 min of air for a total of 4 hr. The treatment started the first day after tumor initiation, and was given daily for 9 days. Vascular morphology was assessed from high-resolution transillumination images, and tumor blood supply was assessed from first-pass imaging movies recorded after a bolus of 155 kDa tetramethylrhodamine isothiocyanate-labeled dextran had been administered intravenously. Hypoxia-treated tumors showed increased vessel density, decreased interstitial distance, and delayed blood supply compared to control tumors. The increase in vessel density was attributed to an increased number of small vessels. In conclusion, acute cyclic hypoxia induced angiogenesis in A-07 tumors resulting in increased density of small-diameter vessels and delayed tumor blood supply.
authors.affiliation: Group of Radiation Biology and Tumor Physiology, Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway. jon.vidar.gaustad@rr-research.no
authors.forename: Jon-Vidar
authors.initials: JV
authors.lastname: Gaustad
authors.forename: Trude Golimo
authors.initials: TG
authors.lastname: Simonsen
authors.forename: Ana Maria Acosta
authors.initials: AM
authors.lastname: Roa
authors.forename: Einar K
authors.initials: EK
authors.lastname: Rofstad
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000473:pathology; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D003911:Dextrans / Q000737:chemistry; D005260:Female; D006801:Humans; D000860:Hypoxia; D008545:Melanoma / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000098:blood supply* / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000473:pathology*; D010100:Oxygen / Q000378:metabolism; D012235:Rhodamines / Q000494:pharmacology; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D003911:Dextrans; D012235:Rhodamines; D042461:Vascular Endothelial Growth Factor A; C009434:tetramethylrhodamine isothiocyanate; D010100:Oxygen