Background: The aim was to establish and characterize adriamycin (ADM)-resistant cell lines.
Material/Methods: Two cell lines, named Saos-2/ADM1and Saos-2/ADM4, resistant to ADM, were established after 167 days.
Results: The resistance indices of methotrexate for the Saos-2/ADM1 and Saos-2/ADM4 cell lines to ADM were 49.8 and 74.6 times higher, respectively, than that of Saos-2. The two cells lines had resistance to MTX, IFO, EPI, THP, and PTX, while the cells were found to remain sensitive to cisplatin. Disordered and coenocytic structure were observed via microscopy.
Conclusions: This is the first report on ADM-resistant cells based on clinical peak doses in serum. MDR1 and MRP genes are involved in the resistance of cell lines to ADM, which are invaluable tools to study the resistance of anticancer drugs and to find the means to revert the resistance.

Keywords: Reverse Transcriptase Polymerase Chain Reaction, Osteosarcoma - metabolism, Methotrexate - pharmacology, Inhibitory Concentration 50, Flow Cytometry - methods, Drug Screening Assays, Antitumor, Doxorubicin - pharmacology, Cisplatin - pharmacology, Antineoplastic Agents - pharmacology, Tetrazolium Salts - pharmacology, Thiazoles - pharmacology