Establishment of a human urachal adenocarcinoma cell line (KO-BT-1) and its chemosensitivity

A new human urachal adenocarcinoma cell line (KO-BT-1) was established and characterized. It consisted of cuboidal, spindle, and polymorphic giant cells and continued to grow for more than 27 months without contact inhibition. Doubling time was about 15.5 h at the 70th passage. In nude mice the cells produced tumors, the histologies of which were similar to the original patient-derived tumor. Moreover, serum carcinoembryonic antigen level was elevated in the patient and the histological section of tumor formed in nude mice was stained with an antibody to carcinoembryonic antigen by peroxidase-antiperoxidase method. Electron microscopically, the cells covered with microvilli had cell-junction complexes. The chromosome number was aneuploid with a modal number of 60. At clinically achievable concentrations, doxorubicin, cis-platinum, mitomycin C, and 40487S which was an in vitro-active type of cyclophosphamide did not reduce colony formation to 30% or less of the control value; likewise in this patient chemotherapy had not been effective. In addition, among human recombinant tumor necrosis factor, alpha-interferon, and recombinant beta- and gamma-interferon, recombinant IFN-beta was most effective against this tumor. These results indicated that KO-BT-1 cells showed the similar chemosensitivity and properties to those of the original tumor, and might be useful in basic studies for the diagnosis, treatment, and etiology of urachal tumors.