Establishment and characterization of a cisplatin‑resistant human osteosarcoma cell line

: The aim of the present study was to establish a new cisplatin-resistant human osteosarcoma cell line and investigate its biological characteristics. The human osteosarcoma cell line SOSP-9607 was exposed to cisplatin by stepwisely increasing the concentrations in the medium to select for the drug-resistant subline, SOSP-9607/CDDP cells. The morphological features were observed using inverted microscopy. The growth curves of SOSP-9607 and SOSP-9607/CDDP cells were drawn to calculate the doubling time. FCM was also used to determine the distribution of the cell cycle. The MTT assay was performed to test the drug resistance of SOSP-9607 and SOSP-9607/CDDP cells. Transwell assay was used to examine the invasive capability of the SOSP-9607/CDDP and SOSP-9607 cells. RT-PCR was performed to determine the mRNA expression levels of drug resistance-related and apoptosis-related genes, MDR1, MRP1, MRP2, LRP, ABCG2, GST-π, Bcl-2 and Bax, in both cell lines. SOSP-9607/CDDP cells exhibited changes in morphology, proliferation rate, doubling time, cell cycle distribution and invasive capability as compared with the SOSP-9607 cells. SOSP-9607/CDDP cells were 6.24-fold resistant to cisplatin in comparison with the SOSP‑9607 cells and also exhibited cross-resistance to methotrexate and adriamycin. SOSP-9607/CDDP cells overexpressed MRP1, MRP2 and GST-π. In conclusion, SOSP-9607/CDDP cells are invaluable tools with which to study the resistance of anticancer drugs and to identify the methods to overcome resistance.