title: Detection and characterization of a pancreatic tumor inhibitory factor.
abstract: Numerous growth factors which stimulate cellular proliferation have been identified and characterized. Little information is available on autocrine factors that inhibit growth. The objective of this study was to determine if an established human pancreatic cancer cell line, RWP-1, produced such a tumor growth inhibitory factor (TIF). RWP-1 serum-free conditioned media (CM) was concentrated and its effect on DNA synthesis was determined by measuring incorporation of [3H]thymidine. CM inhibited [3H]thymidine incorporation in a dose-dependent and nontoxic manner with all cell lines tested. TIF activity was stable at 56 degrees C, labile at 95 degrees C and partially inactivated by acid, reduction/alkylation, and enzymatic digestion. The TIF exhibited differential activity against the tested cell lines and was found to be active against a normal murine fibroblast line. The TIF appears to be a polypeptide with a molecular weight greater than 5000 Da. Attempts at isolation of TIF with affinity and ion-exchange chromatography have thus far been unsuccessful, implying that more than one factor may be involved. RWP-1 TIF is a potentially important factor because of its role in the regulation of cellular proliferation.
authors: Department of Surgical Oncology, Roswell Park Memorial Institute, Buffalo, New York 14263.
authors: D A
authors: DA
authors: Colacchio
authors: M H
authors: MH
authors: Goldrosen
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D003470:Culture Media; D009363:Neoplasm Proteins