The synergistic cytotoxicity of cisplatin and taxol in killing oral squamous cell carcinoma.

Platinum, 5-fluorouracil (5-FU) and taxanes are commonly used in chemotherapeutic modalities of various carcinomas. However, taxanes are rarely used in patients suffering from head and neck squamous cell carcinoma (HNSCC) in Taiwan. The purpose of this study was to assess whether there is a synergistic effect produced by incorporating Taxol (paclitaxel) with cisplatin, carboplatin or 5-FU in the combined treatment of oral squamous cell carcinoma (OSCC). OSCC cells were surgically excised from a Taiwanese patient and cultured into a cell line, OECM-1. The viability of OECM-1 after drug treatment was determined by an XTT labeling reagent. The dose-dependent cytotoxicity of each drug was determined. The order of chemosensitivity of OECM-1 toward these drugs was Taxol, cisplatin, carboplatin and 5-FU, with 50% inhibitory concentrations (IC(50)s) of 10, 68, 332 and 3000 microM, respectively. In the combined drug treatment, low concentrations of platinum (10 microM) or 5-FU (500 microM) were included in the culture media with low cytotoxic concentrations of Taxol (0.025, 0.05 and 0.1 microM). When combined with 0.025 microM of Taxol, only cisplatin, rather than carboplatin and 5-FU, showed synergistic cytotoxicity with OECM-1. Cisplatin also acted synergistically with 0.05 and 0.1 microM of Taxol. On the other hand, carboplatin and 5-FU acted additively with low cytotoxic concentrations of Taxol (0.025, 0.05 and 0.1 microM). Our preliminary results suggest that there may be a beneficial outcome in incorporating Taxol into the chemotherapeutic modalities of HNSCC patients in Taiwan. Furthermore, at least some of the OSCC cells may be more sensitive to Taxol/cisplatin than to Taxol/carboplatin or Taxol/5-FU treatment.