In vitro radiosensitization by oxaliplatin and 5-fluorouracil in a human colon cancer cell line.
The current study was designed to compare the radiosensitizing effects of oxaliplatin and 5-fluorouracil (5FU) in a human colon cancer cell line. A human colon cancer cell line (S1) was treated with various doses of oxaliplatin, 5FU, radiation, and combinations thereof. Various clinically used schedules were mimicked. 5FU was either incubated during 1 h ("bolus") or 24 h ("continuous infusion"). When combining oxaliplatin and 5FU, an isobologram analysis revealed synergistic effects, regardless of 5FU schedule. The IC(10) and IC(50)-doses for the drugs where then combined with radiotherapy. With equitoxic drug doses (IC(50)), radiosensitization was observed in the following order: oxaliplatin > 5FU 24 h > 5FU 1 h exposure. The degree of potentiation corresponded to approximately 0.8 Gy, 0.7 Gy, and 0.2 Gy, respectively. In this experimental setting, oxaliplatin seemed to be a better radiosensitizer than 5FU, and longer incubation time with 5FU was better than short exposure.
Kjellström
Johan
J
Department of Oncology, University hospital, Lund, Sweden. johan.kjellstrom@onk.lu.se
Kjellén
Elisabeth
E
Johnsson
Anders
A
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D009944:Organoplatinum Compounds / Q000627:therapeutic use*; D000077150:Oxaliplatin; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects
D000970:Antineoplastic Agents; D009944:Organoplatinum Compounds; D011838:Radiation-Sensitizing Agents; D000077150:Oxaliplatin; D005472:Fluorouracil