title: Conditioned media from solid tumor cell lines treated with retinoic acids both decreases and increases proliferation of capillary endothelial cells.
abstract: These studies investigated the effects of retinoic acids on endothelial cell proliferation. Three human neoplastic cell lines, U-373 MG glioblastoma, DU-145 prostate carcinoma, and TCCSUP bladder transitional cell carcinoma, were treated with all-trans, 9-cis, or 13-cis retinoic acids at 0.0001 to 10 microM. Hypoxia was used to ensure the expression of the angiogenic phenotype. Conditioned media (CM) were prepared by hypoxic culturing of the tumor cells with retinoic acids for 24 hours. Then CM were transferred to bovine capillary endothelial cells for 48 hours of normoxic culturing, counted and compared to controls. CM from U-373 MG and DU-145 cells, but not TCCSUP cells, treated with all-trans or 9-cis retinoic acids at several concentrations below 1 microM, caused significant (P<0.05) increases in endothelial cell proliferation of between 13 to 18%. Both nonconditioned and conditioned media, for retinoic acid concentrations above 1 microM, inhibited endothelial cell proliferation. All CM for 13-cis retinoic acid decreased endothelial cell proliferation. These results show that the cytotoxicity of retinoic acids and the growth promoting/inhibiting ability of the conditioned media is retinoic acid isoform, time, concentration, and cell type dependent. Most importantly, the conditioned media from tumor cells treated with low concentrations of all-trans or 9-cis retinoic acids significantly increased endothelial cell proliferation.
authors.affiliation: Department of Natural Sciences, Dickinson State University, North Dakota 58601, USA. lynn_burgess@dsu.nodak.edu
authors.forename: L C
authors.initials: LC
authors.lastname: Burgess
authors.forename: J O
authors.initials: JO
authors.lastname: Hall
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002417:Cattle; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D015687:Cell Hypoxia; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D009369:Neoplasms; D009389:Neovascularization, Pathologic; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D017077:Culture Media, Conditioned; D014212:Tretinoin