title: [Radiosensitization of paclitaxel combined with radiation on nasopharygneal carcinoma cells (CNE-I) in vitro].
abstract: OBJECTIVE
  To evaluate the radiosensitization of paclitaxel combined with radiation on nasopharygneal carcinoma cells( CNE-I) in vitro.
  
  
  METHODS
  Human CNE-I cells were used for this study. Clonogenic assay was used to determine the drug dose of IC10, IC50 and IC90 for CNE-I Cells. The cells treated with different concentration of paclitaxel for 24 hours before or after radiation (dose ranged from 0 - 10 Gy ) were used to evaluate the radiosensitizing effect of paclitaxel combined with radiation. DNA flow cytometry was performed to define the cell cycle characteristics of cell populations treated for 0, 2, 6, 12, 18, 24 h with 0.1 nmol/L, 0.5 nmol/L, 1.0 nmol/L, 2.5 nmol/L paclitaxel, respectively.
  
  
  RESULTS
  The dose of IC10, IC50 and IC90 for paclitaxel in CNE-I cells was 0.05 nmol/L, 1.0 nmol/L and 2.5 nmol/L, respectively. Paclitaxel treatment at concentration of 0.05 nmol/L and 1.0 nmol/L for 24 hours combined with X-ray irradiation before or after radiation showed radiosensitivity-enhansing effects in CNE-I cells. G2/M block was present when the drug concentrations were 2.5 nmol/L and 10.0 nmol/L, and it peaked at 18 hours.
  
  
  CONCLUSIONS
  With an optimal paclitaxel/radiation combination, paclitaxel may exert a radiosensitizing effect on CNE-I cells. The effect might be related to the G2/M block caused by paclitaxel.
authors.affiliation: Department of Radiation Oncology, Cancer Institute (Hospital), Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Yuan
authors.forename: Wei-Zhi
authors.initials: WZ
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Jin
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Xin-Fan
authors.initials: XF
authors.lastname: Liu
authors.forename: Guo-Zhen
authors.initials: GZ
authors.lastname: Xu
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects* / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D017239:Paclitaxel / Q000008:administration & dosage / Q000494:pharmacology*; D010315:Particle Accelerators; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D011838:Radiation-Sensitizing Agents; D017239:Paclitaxel