Antitumor activity of satraplatin in cisplatin-resistant oral squamous cell carcinoma cells

Background. The aim of the current study was to identify the antitumor activity of satraplatin in paired cisplatin (CDDP)-resistant oral squamous cell carcinoma (OSCC) cell line and its parental cell line. Methods. CDDP-resistant (KB-R) cells and parental cells (KB) pair were used. Viability was assessed using the MTT and clonogenic assay. Real-time polymerase chain reaction (PCR), glutathione (GSH) assay, and flow cytometric analysis were used for further assessment. Results. KB-R cells did not show cross-resistance to satraplatin. The expression status of almost all transporters was upregulated in the KB-R cells. There was no difference in the GSH levels between the KB and KB-R cells. Flow cytometric analysis indicated that with satraplatin the G2/M phase was arrested in the KB-R cells. KB-R cells contain enriched side population cells. Conclusion. These data suggested that satraplatin has antitumor activity against the CDDP-resistant OSCC cells. The mechanism of cross-resistance to platinum agents seems to be multifactorial. © 2010 Wiley Periodicals, Inc. Head Neck 33: 309―317, 2011 cisplatin; cross-resistance; satraplatin; drug.