Effects of docetaxel in combination with radiation on human head and neck cancer cells (ZMK-1) and cervical squamous cell carcinoma cells (CaSki )

Int J Cancer. 2001 Mar 15;91(6):840-5. doi: 10.1002/1097-0215(200002)9999:9999<::aid-ijc1142>3.0.co;2-u.

Abstract

The purpose of this study was to determine, as we did for paclitaxel, the cytotoxic and radiosensitizing potential of docetaxel in human head and neck cancer cells (ZMK-1), and in cervical squamous cell carcinoma cells (CaSki). ZMK-1 cells were incubated with docetaxel for 3, 9 or 24 hr before irradiation and 24 hr after irradiation. CaSki cells were incubated with docetaxel 24 hr before and after irradiation. For ZMK-1 cells, the docetaxel concentrations (0.7, 0.7 and 0.35 nM) were determined to obtain approximately equivalent cell survival at the different incubation times (3, 9 and 24 hr, respectively). For CaSki cells, the necessary concentration of docetaxel was 0.07 nM. Radiation doses were given from 0 to 7 Gy. Cell survival was measured by a standard clonogenic assay after a 9-day incubation. Flow cytometry was used to measure the capacity of docetaxel to accumulate cells in the G2/M phase of the cell cycle. We observed a weak accumulation of cells in the G2/M phase for the ZMK-1 cells and a pronounced accumulation for CaSki cells. For docetaxel incubation before irradiation, the isoeffect enhancement ratios for ZMK-1 cells determined at the 37% survival level were 1.18, 2.01, and 2.40 for pre-incubation at 3, 9 and 24 hr, respectively; for CaSki cells the ratio was 1.44. For a docetaxel incubation of 24 hr after irradiation, the isoeffect enhancement ratios determined at the 37% survival level were 1.54 and 1.17 for the ZMK-1, and CaSki cells, respectively. A radiosensitizing effect of docetaxel could be demonstrated unambiguously in the two cell lines used. In contrast to our previously published results with paclitaxel, docetaxel seems to be a better radiosensitizer than paclitaxel.

Publication types

  • Comparative Study

MeSH terms

  • Carcinoma, Squamous Cell / therapy*
  • Cell Cycle / drug effects
  • Cell Cycle / radiation effects
  • Cell Survival / drug effects
  • Cell Survival / radiation effects
  • Combined Modality Therapy
  • Docetaxel
  • Dose-Response Relationship, Drug
  • Female
  • Flow Cytometry
  • Head and Neck Neoplasms / therapy*
  • Humans
  • Paclitaxel / analogs & derivatives*
  • Paclitaxel / therapeutic use*
  • Radiation Tolerance
  • Radiation-Sensitizing Agents / therapeutic use*
  • Radiotherapy
  • Taxoids*
  • Time Factors
  • Tumor Cells, Cultured
  • Uterine Cervical Neoplasms / therapy*

Substances

  • Radiation-Sensitizing Agents
  • Taxoids
  • Docetaxel
  • Paclitaxel