Figure 2

Effect of Loratadine on Radiation or Cisplatin Dose Response. HT29 cells in log phase growth were treated with loratadine (75 μM) for 24 hrs prior to irradiation (A) or for 24 hrs after irradiation (B) to 0, 1.5, 3, 6 or 9 Gy or 12 Gy (controls only). A radiation DMF of 1.95 ± 0.07 was observed in cells pre-treated with loratadine. There was no significant radiation modification by loratadine treatment after irradiation. (C) HT29 cells in plateau phase growth pre-treated with loratadine (75 μM, 24 hrs) demonstrated a radiation DMF of 1.3 ± 0.16. Solid circles = loratadine + radiation, open circles = radiation alone. (D) HT29 cells in log phase growth were pre-treated with loratadine (75 μM, 24 hrs) prior to treatment with Cisplatin (7.5, 15, 30, or 45 μg/ml for 1 hr). A DMF of 2.6 ± 0.14 was observed. Open circles = loratadine + cisplatin, solid circles = cisplatin alone. Cell survival was assessed by clonogenic assay and corrected for the toxicity of loratadine alone. The figure represents the mean ± SD for 3 experiments.